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ENGINEERING PROPERTIES AND APPLICATIONS OF LEAD ALLOYS

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ENGINEERING PROPERTIES AND APPLICATIONS OF LEAD ALLOYS Sivaraman Guruswamy University of Utah Salt Lake City, Utah

Prepared for the International Lead Zinc Research Organization, Inc. Research Triangle Park, North Carolina

M A R C E L

MARCEL DEKKER, INC. D E K K E R

-

N E WYORK BASEL

ISBN: 0-8247-8247-X

This book is printed on acid-free paper. Headquarters

Marcel Dekker, Inc. 270 Madison Avenue, New York, NY 10016 tel: 2 12-696-9000; fax: 2 12-685-4540 Eastern Hemisphere Distribution

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http://www.dekker.com The publisher offers discounts on this book when ordered in bulk quantities. For more information, write to Special Sales/Professional Marketing at the headquarters address above. Copyright 0 2000 by Marcel Dekker, Inc. All Rights Reserved.

Neither this book nor any part may be reproduced or transmitted in any form or by anymeans,electronic or mechanical,includingphotocopying,microfilming,and recording, or by any information storage and retrieval system, without permission in writing from the publisher. Current printing (last digit): I O 9 8 7 6 5 4 3 2 1 PRINTED IN THE UNITED STATES OF AMERICA

To vdsantha, Kavitha, and our parents


Foreword

This book represents the first new compilation on lead technology in a half century. Prior to this publication, the definitive source on lead was Wilhelm Hoffman's Leacl and Leacl Alloys-P1.c)pc.r-ties und Technology, the tirst edition of which was published in German i n 1941, based on the research work Hoffman and his colleagues conducted at the Lead Research Center in Berlin. Following World War 11, there was a major expansion in the technical and scientific literature on lead and several years' work was required before the second edition of the book was published in 1962. That book contained virtually all the relevant technical data on lead, its alloys, and its uses, along with processing methodologies. An English translation by Hoffman was pubthe lished in 1970. It is noteworthy that in the forewordHoffmannotes initiative of the then relatively young International Lead Zinc Research Organization (ILZRO) to carry out an active international program of research on lead. ILZRO is pleased to have sponsored the work of Sivaraman Guruswamy and trusts that his efforts will ensure that modern technical knowledge of the properties of this ancient metal will be readily available to technologists in the new century. Special acknowledgment must be paid to Jeffrey Zelms, president of the Doe RunCompany,and to CharlesYanke,president of VulcanLead Resources,both of whomrecognized the need for thisbook and urged ILZRO to undertake this project. . l e u m e F . Cols President International Lead Zinc Research Organization,

Inc. V


Preface

Lead is a rare element in the earth’s crust, but since it is found in concentrated deposits it can be produced atlow cost, and ranks fifthin tonnage consumed after iron, copper, aluminum, and zinc. Some of the many applications of lead are: automobile batteries, uninterruptible power sources for computers that store and process vital national security and business information, solders used in printed circuit boards, radiation shields in nuclear facilities, radiation shields in CAT scanners and other medical X-ray apparatus, keels in yachts, balancing weights in computer hard disk drives, lead and lead-lined vessels in chemical plants, vacuumseals in lightbulbs, the explosive detonation cords in the Space Shuttle, acousticbarrier panels, crystal glasses, fiber-optic cables, and infrared detectors in pollution monitoring. These applications underscore the importance of lead to modern life. The most comprehensive text on this topic is Lead and Lead Alloys by Hoffmann,published by Springer Verlag in 1941andrevised in 1962 of the Interand 1970. In response to a recognized need, Frank Goodwin, national LeadZincResearchOrganization, initiated andorganizedaconon lead. sortium of sponsorsforanup-to-dateandcomprehensivebook When Dr. Goodwinapproachedmetowrite this book, I wasexcitedand honored to be trusted with this enormous task. The book is intended as an introductory resource on lead and lead alloys, providing information on engineering properties, processing of various lead forms, and engineering applications that takeadvantage of the unique properties of lead and lead alloys. The book will also be a resource for professionals involved in the production and application of lead alloy products. Itis hoped that the text will stimulateimprovements in existing applicationsanddevelopment of new applications to take advantage of the unique properties of lead and lead vii

viii

Preface

alloys. The book focuses on the use of lead in pure or alloy form for engineering applications. In setting boundaries for the scope of the book, we decided not to address the use of lead in the form of chemicals. The book has five chapters. The introductory chapter provides information on worldwide sources of lead, production of refined lead from Pb ores, and key information on pure lead. This is followed, in Chapter 2 , by the presentation of an exhaustive set of data on the physical, mechanical, corrosion, acoustic, damping, and nuclear properties of lead and lead alloys. Adequate background information is given so that the reader can appreciate the importance and limitations of the data. Chapter 3 deals with the processing of lead products and gives the user a general appreciation and background of the processing of commercially available lead product forms. The topics covered include casting, rolling, extrusion, machining, welding, and mechanical joining techniques. New developments in continuous casting of strips for battery grids, continuous casting of rods, friction-stir welding, and water-jet machining of lead products are included in this section. Chapter 4 introduces the reader to a wide spectrum of modern and historic applications in which lead and its alloys have been used and provides a rationalization for the choice of lead in these applications. Most applications involve the use of lead in a form that is recycled. Chapter 5 provides information on health and safety issues, and the recommended guidelines for the safe and appropriate handling of lead products. It is our hope that the book will meet the many needs of experienced and nascent users of lead and lead alloys. Publications by the International LeadZincResearchOrganization (ILZRO), Lead Industries Association (LIA), Lead Development Association (LDA), and Lead Sheet Association (LSA), and the groundbreaking work of Hoffman have been heavily relied on in preparing this book. Many individuals and companies were also helpful.I am grateful for their generosity in providing the information and permission to use it extensively. Special thanks are due to SpringerVerlag for generously allowing use of the material from Dr. Hoffmann’s classic book. I would like to thank the following for responding generously to my requests for information. David Wilson, Lead Development Association, London Jerome F. Smith, Lead Industries Association, N Y Michael King, V. Ramachandran, and Alan Kafka, ASARCO, NY Eugene Valeriote and Jennifer Coe, Cominco, Canada Peter Bryant and Paul Frost, Britannia Refined Metals, United Kingdom Stan Hall, Lead Sheet Association, Kent, United Kingdom E. G. Russell, Aberfoyle Limited, Australia

Preface

ix

Masao Hirano and F. Sakurai, Mitsubishi Materials, Japan Tatsuya Yamamoto, Mitsui Mining and Smelting, Japan John Manders, PASMINCO, Australia Takao Mori, Japan Lead Zinc Development Association Chuck yanke and Scott Hutcheson, Vulcan Lead, W1 Toshiharu Kanai, Sumitomo Metal Mining, Japan Kazuyoshi Inoue, Toho Zinc Co., Japan Goran Villner, Boliden Market Research, Sweden Francois Wilmotte, Centre d’lnformation du Plomb, France David Prengaman, RSR Corporation, Dallas, TX Akiro Hosoi, Dowa Mining, Japan Albano Piccinin, Union Miniere, Belgium P. R.JanischandRichardD.Beck,BlackMountainMineralDevelopment, South Africa Shuya Fujie, Nippon Mining, Japan

I would like to express my great appreciation to Pat Mosley and Robert Putnam of ILZRO, Paul Frost of Britannia Metals, Eugene M. Valeriote and his colleagues at Cominco, and Dr.Venkoba Ramachandran of ASARCO of the manuscript and valuable comments. I also for their critical review would like to thank Janice Atkinson at ILZRO for all her help. I would also like to acknowledge the kindness of all my teachers, in particular John Hirth, who generously shared their knowledge and wisdom. The invaluable, timely, and enthusiastic help of my student Nakorn Srisukhumbowomchai in the preparation of this book is gratefully acknowledged. 1 would also like to thank my other students and colleagues in the Department of Metallurgical Engineering at the University of Utah who have been very supportive and provided a conducive environment during this period. Finally, I would like to take this opportunity to express my deep sense of gratitude to Frank Goodwin, ILZRO, for his confidence in me, providing materials from ILZRO as I needed them, reviewing the manuscript, giving permission to use extensively many of his publications, helping promptly whenever I needed it, and for his friendship. Most of all, I am very lucky to have the unqualified love, encouragement, and support of my wife, Vasantha, and daughter, Kavitha.


Contents

Foreword Preface 1.

1’

Jerome F. Cole

1’11

Introduction I. WorldwideSources of Lead 11. Refined LeadProductionandConsumption 111. Production of LeadMetal IV. HealthandSafety Issues V. Properties of PureLead

Patterns

1 2 6 15 18 19

2.

Properties of Leadand Its Alloys I. PhysicalProperties of Leadand Its Alloys 11. Mechanical Properties of Lead and Lead Alloys 111. Creep Behavior IV. Fatigue Strength V. CorrosionProperties VI. AcousticProperties of LeadandLeadComposites VII. NuclearProperties

27 27 57 123 168 192 232 276

3.

Processing of LeadProducts I. MeltingandCasting 11. Metal Forming 111. Joining of Lead

309 310 342

4.

Applications of Lead I. Lead-Acid Batteries

of LeadAlloys

377 429 430 xi

Contents

xii

11. 111. IV. V. VI. VII. VIII. IX. X. XI. XII. XIII.

XIV.

x v.

XVI. XVII. XVIII. XIX.

Use of Lead in Earthquake Protection Use of Lead in Brick Wall Infills Lead-Tin Alloys in Organ Pipes Use of Lead Sheets in Architecture Lead in Radiation Shielding and Waste Management Use of' Lead Alloys for Printing Types Bearing Metals Packaging and Sealing Fusible Alloys Lead Heat-Treating Baths Use of Lead in Inertial Applications Solders Ammunition Lead Cable Sheathing Insoluble Lead Anodes Use of Lead in Bi-Based Oxide High-T, Superconductors Lead in Glass Lead Chalcogenide Semiconductors

S. Lead in the Environment I . Toxic Properties of Lead 11. Occupational Exposures

4s 8 476 479 483 499 530 534 539 542 546 547 550 5 69 570 585 587 589

S9 1 593

596 599 60.5

Index

62 I

ENGINEERING PROPERTIES AND APPLICATIONS OF LEAD ALLOYS


Introduction

In a world of rapidly changing technologies, lead and other classical metals and alloys havecontinued to maintain their importance.Lead (chemical symbol Pb), is an essential commodity in the modern industrial world, ranking fifthin tonnageconsumed after iron,copper,aluminum, and zinc. In 1996, the UnitedStates,China, the UnitedKingdom,Germany,Canada, Japan, South Korea, Italy, France, Mexico, Spain, Taiwan, India, and Brazil accounted for 77% of the 6,045,000 metric tons of refined lead consumed in the world [l]. Slightly over half of the lead produced in the world now comes from recycled sources. Lead,copper, silver, andgoldwere the metals first used by ancient humans[2,3].Leadhasbeenmined and smeltedfor at least 8000 years. Lead beads found in Turkey have been dated to around 6500 B.C. The Egyptians used lead as early as 5000 B.C. A leadmine in RioTinto in Spain B.C. operated in 2300 BC. and the Chineseused lead coinsaround2000 Simplicity of reduction from ores, low melting point, and ease of fabrication presumably led to its use. Leadwasalsowidelyused by the Greeks and in 3-m lengths and in 15 different standard diRomans. Lead water pipes ameters have been found in the ruins of Rome and Pompeii, confirming the use of lead during that period. Some pipes still in excellent condition have been found in modern-day Rome and Britain [4]. The toxicity of lead was identified by Marcus Vitruvius Pollio, a first-century Roman architect and engineer, from the poor color of the lead workers of those times [3]. Despite their known toxicity, lead and its alloys can be handled safely and continue to be critical in many areas for the modem society. This continued dependence on lead arises from several of its unique properties. The low melting point, ease of casting, high density, softness and high mallea1

2

Chapter 1

bility at room temperature, low strength, ease of fabrication, excellent resistance to corrosion in acidic environments, attractive electrochemical behavior in manychemicalenvironments,chemical stability in air, water, and earth, the highatomicnumber, and stable nuclearstructurehavemadea unique place for lead in our life. Lead affords us the protection from dangerous x-ray, gamma ray, neutron, and other ior.izing radiation. I t serves as one of the most efficient acoustic insulation materials. It also acts as a sealthat hasservedwell in seismic ant. It hasuniquedampingcharacteristics protection of buildings and other structures. It acts as a space-efficient counterweight. Its chemical and electrochemical characteristics make it useful as the most economically viable material in batteries that serve as a primary electrical powersource in automobiles and asaback up powersupply for computers that store andprocess vital national security andbusiness information. As with many elements used in high technology, health hazards posed by lead is a concern. Lead and its compounds are cumulative poisons and should be handled with recommended precautions. These materials should not be used in contact with food and other substances that may be ingested. A proper understanding and appropriate use of lead and its alloys in existing applications and in applications yet to be conceived require an up-to-date sourcebook on the properties of lead and its alloys, its processing techniques, and their engineering applications. The intent of this book is to serve suchpurpose. In preparing this book, International LeadZincResearch Organization (ILZRO) publications, Lead Industries Association (LIA) publications, LeadDevelopmentAssociation(LDA) publications, Lead SheetAssociation (LSA) publications, help of many in the industry and academia, and the classic work of Professor Hoffman [2] have been relied upon heavily.

I.

WORLDWIDE SOURCES OF LEAD

Lead constitutes only about 12.5 ppm by weight of the Earth’s crust, and it ranks 34th among elements in relative abundance [S,6]. It ranks well below (0.57%), aluminum (8.23%), iron (5.63%), magnesium(2.33%),titanium zirconium (165 ppm), chromium (100 ppm), nickel (75 pp”), zinc (70 ppm), and copper (SS ppm). However, the occurrence of concentrated and easily accessible lead ore deposits is unexpectedly high, and these are widely distributed throughout the world. This makes lead easily mined and produced at low cost. The most important ore mineral is galena, PbS (87% Pb), followed by (77.5% Pb). The latter two anglesite, PbSO, (68% Pb), and cerussite, PbCO,%

Introduction

3

minerals result from the natural weathering of some galena. Lead and zinc Ores are frequently found together because of their similar affinity for both oxygen (lithophile) and sulfur (chalcopile) and their transport to the same degree by carbonate solutions [6]. Galena ores may be associated with sphalerite (ZnS), pyrite (Fe$), marcasite (Fe$, a low-temperature polymorph of pyrite), chalcopyrite (CuFeS,), tetrahedrite [ ( C U F ~ ) , ~ S ~ , S cerussite ,,], (PbCO,), anglesite (PbSO,), dolomite [CaMg(CO,),], calcite (CaCO,), quartz (SiO,), and barite (BaSO,), as well as the valuable metals gold, silver, bismuth, and antimony [2,4,7,8]. The formation of lead ore deposits likely occurred by the concentration of metal sulfides in the liquid remaining after the crystallization of silicates from molten magma and the penetration of this liquid under pressure into available channels such asfault fissures. Aqueous solution of these minerals, including PbS, in hydrothermal fluids leads to their transport and the preon cipitation of PbS as the temperature and pressure decreases. Depending the temperature and pressure at which they are formed, the ore deposits are classified into five categories (listed in the decreasing order of temperature and pressure): telethermal, leptothermal,mesothermal,pyrometasomatic, and hypothermal [2,7]. The types of deposits with lead as a major constituent include strata-bound deposits, volcanic-sedimentary deposits, replacement deposits, veins, and contact metamorphic deposits [8]. Strata-bound deposits are bedded layered deposits formed at the same time as the host rock. Volcanic-sedimentary deposits contain massive sulfide bodies commonly interlayered with volcanic or sedimentary rocks. The ore is commonly a finegrained mixture of pyrite or pyrrhotite, sphalerite, galena, and chalcopyrite, withminoramounts of nonmetallicandcarbonateminerals.Replacement deposits of lead and zinc are commonly irregular hydrothermal deposits in carbonate rocks, but some also occur in quartzites or metamorphic rocks. The vein deposits are commonly situated in faults, joints,orformational contacts. The veins are generally arranged in pod-shaped deposits or shoots 3-30 ft long horizontally anddippinghundreds of feet vertically. Many highlyproductivevein-typedeposits are in Europe,CentralAmerica,and South America. Contact metamorphic deposits are found near igneous intrusions, which have either provided the solutions or emanations creating the deposits, or have altered and rearranged a mineral deposit already present prior to the intrusion. Depositsrange in sizefromsmall vein systems to massive pods hundreds of feet long (81. The estimated economic reserves of lead in the world are 71 million tons and are scattered around the world [4,8-10]. Australia(19.4million tons), the United States (8 million tons), Canada (4 million tons), Mexico (3 milliontons), the formerSovietUnion (9 milliontons),andChina (7 million tons) account for over two-thirds of these reserves. The total world

4

Chapter 1

reserve base (which includes marginal deposits) is estimated at 124 million tons. If lead scrap, now a major source of lead, and less economic lead ore deposits are considered, the entire reserve base for the world is estimated at 140 million tons [4]. The concentration of lead in ore bodies of commercial interest generally ranges from 2% to 6%, with an average of 2.5%. Improvements in ore-dressingtechniqueshavemadepossible the exploitation of deposits having lead contents even less than 2%. Australia, the United States, Canada, Peru, Mexico, China, the former USSR,Sweden,andSouthAfrica are the leadingcountries in leadmine production [l]. Thecombinedproduction in the RussianFederation,Kazakhstan,andUzbekistanhaveprecipitouslydroppedfrom the levels at 1993. In contrast, the production in Chinese mines have doubled between 1993 and 1996. Table 1 presents the levels of lead mined in different countries during 1993- 1996. The total world lead mine production in 1997 and 1998 were 3.03 and 3.1 1 million tons respectively. Most (88%) of the lead mined in the United States comes from 8 mines in Missouri and the rest comes from 11 mines in Colorado, Idaho, Montana, Alaska, Washington, and Nevada. Most of the known U.S. reserves for lead are located in federally owned land in Missouri; future mine development depends on the outcome of the U.S. government’s intent to reform the Mining Law of 1872. The bulk of the Canadian lead mine output comes from Trail MineB.C.;FaroMine, Yukon Territories; No.12Mine at Bathurst, N.B.; andFIin FlonandSnowLake,Manitoba.The principal lead mines in SouthAmerica are CerrodePasco,Milpo,Huanzala,Atacocha,and Colquijirco mines in Peru, Naica, Real de Angeles, Sta Barbara, San Fran del Oro, and El Monte mines in Mexico, Aguilar Mine in Argentina, and Quiomo Mine in Bolivia. About 56% of lead mined in Latin America came from 12 mines and the rest came from over 60 small mines producing lead as a by-product of Zn and/or Ag extraction. Mexico and Peru produce more than 90% of lead mined in Latin America [9- 1 l]. When the newBHPMine at Cannington,Australiareaches its full capacity of 175,000 tons/year, it will be the largest lead mine in the world. This together with the other two largest mines in Australia at Broken Hill (South) (N.S.W.) and Mount Isa (Queensland) will account for the bulk of lead mined in Australia. The other major mines are McArthur River Mine (NT), Hellyer Mine (TAS), Rosebery Mine (TAS), Thalanga Mine (N.S.W), Woodlawn Mine (N.S.W.), and Woodcutters Mine (NT). The lead output of Sweden, the majorproducer in westernEurope, comes from mines at Garpensburg, Laisvall, Langdal, Petiknas, Renstrom, and Ammeberg. In the former USSR, the larger lead mines are in the Leninogarsk region, the Kentau region, and the Karatau region in Kazakhstan, Uchkulachskoye deposits in Uzbekistan, and the Maritime region in the Rus-

5

Introduction Table 1 Total Mine Production in Thousands of Tons [ 11 Annual totals

Europe Austria Bulgaria Czech Republic'' Finland Greece Ireland Italy Macedonia Norway Poland Romania Russian Federation Slovenia Spain Sweden United Kingdom Yugoslavia F.R.

1993

1994

1995

39 1 2 34 2

398 32 0

383 33 -

-

-

-

26 45 7 33 2 49 17 34 1

25 104 1

9

Africa Algeria Morocco Namibia South Africa Tunisia Zambiah

206 I 79 18

Oceania Australia

52 1 521

Americas Argentina Bolivia Brazil Canada Honduras Mexico Peru United States

950 12 23 0 183 4 141 225 362

100

0 8

20 54 14 29 3 53 21 25 0 23 113 2 9 192 1 70 21 96 3

21 46 15

25 1 55 20 23 -

30 100

2 12

1996 363 -

28 -

3 8 45 12 27 2 54 19 18 24 99 2 22

-

189 1 74 20 89 5 -

487 487

424 424

475 475

979

1047 10 20 7 210 3 164 238 394

I IS5 11 16 8 257 5 172 249 436

1

10

20 1 171 3 170 233 370

186 1

68 22 88 7

Chapter 1

6 Table 1 Continued

Annual totals 1996

1995 Asia China India

1994 6.54 462 30

Iran 10 Japan Kazakhstan38 Korea, D.P.R. Korea, Rep. 2 2 (Burma) Myanmar Thailand Turkey Uzbekistan19 Other CIS World total Monthly average 226 Western world 2004 Monthly average

1993 632 338 30 15 17 104 70 7 2 S

819 643 35 16

14

18

8 28 S5 21

7

11

10

30 3

1

27 2700 225 2019 I68

10

250 2159 167

Note: Lead content by analysis of lead ores and concentrates ores and concentrates known to be intended for lead recovery. "Prior to 1993, data refer to Czechoslovakia. hContent of ore hoisted.

7 520 34 16 10 40 S0

40

4

4

S 12

2

10 12 1

IO IO

300 2754 230

1

2000 167

2

l80

plus the lead content of other

sian Federation. The principal lead mines in China are the Fdnkau Mine in Guangdong, Mengru Lead/Zinc Mine in Yunan, Changba LeadIZinc Mine in Gansu, Lijiagou Mine in Gansu, QiandongshanMine in Shaanxi,and Hunan Mine in Hengyang. The major lead mine in Thailand is located in Song Toh, 250 km northwest of Bangkok. The major lead mines in India are Rajpura-Dariba Mine and the Zawar Minegroup in Rajasthan. The major lead mines in Japan are at Kamioka in Gifu Perfecture and Toyoha in Akita Perfecture. In Africa, the major mines are located in Bou Jaber (Fedj Hassen Mine) and Bougrine (Tunisia), Black Mountain (South Africa), and Tuissit, Zeida, and Marrakech (Morocco).

II. REFINED LEAD PRODUCTION AND CONSUMPTION PATTERNS

Summaries of the world production ofrefinedlead and lead consumption patterns around the world are presented in Tables 2 and 3. The United States,

Introduction Table 2

7

RefinedLead:MetalProductioninThousands

of Tons [ I ]

Annual totals 1993

1994

I995

I996

I806 21 112 60 23 2.59 334 10 198 22 23 65 8 18 45 12 62 82 6 20 416 6

1839 16 I23 62 25 260 332

1826 23 122 72 22 297 3 l4

I830 24 121 74 22

Africa Algeria Kenya Morocco Namibia Nigeria South Africa Zimbabwe

1 54

135 6 2 64 24 4 32 3

141 7 2 62 27 8 32 3

131

Americas Argentina Brazil Canada Colombia Mexico United States Venezuela

1870 28 67 217 3 256 1196 14

1915

2059 28 50 28 I 4 230 1358 16

2 142 28 39 309

Europe Austria Belgium Bulgaria Czech Republic France Germany Ireland Italy Macedonia Netherlands Poland Portugal Romania Russian Federation Slovenia Spain Sweden Switzerland Ukraine United Kingdom Yugoslavia ER.

7 2 72 31 5

32 3

10

I1

223 21 24 63 13 21 34

189 22 21 70 8 23 30 14 82 83 7 14 387

15

75 83 6 9

416 4

25 64 252 3 214 I249 16

II

30 l

238 12 210 24 22 70 6 19 30 13

91

84 7 21 406 30 8

2 62 19

5

32 3

10

222 141I 25

Chapter 1

8

Table 2 Continued Annual totals

Asia

China India Indonesia

Iran Israel Japan Kazakhstan Korea, D.P.R. Korea, Rep. Malaysia Pakistan

Philippines Saudi Arabia Taiwan, China Thailand Turkey U.A.E.

Oceania Australia New Zealand World total

I993

I994

I995

1996

1401 412 51 35 35 7 309 245 65 128 29 3 23 31 17 4 4

1341 468 70 30 31 8 292 I45 50 130 33 3

1475 608 66 30 30 8 288 93 45

IS28 706 67 30 30 8 287 69 40 141 36 3

17 36 17 4 4

18

6 36 19 4 4

41 18 12 4

24 I 236 5

242 236 6

243 237 6

234 228 6

5472

5472

5744

5865

181

33 3

18 15

Note: Excludes secondary lead recovery by remelting alone

China, Canada, the United Kingdom, France, Japan, Germany, Australia, Mexico, Belgium, South Korea, Spain, and Sweden account for 73% of world production of refined lead. The United States alone accounts for 25% of the world production. The world refined lead production levels in 1997 and I99X were 6.0 and 5.96 million tons respectively. The Doe Run Co. accounts for nearly 100% of primary lead production in the United States. Both companies employ sintering/blast furnace operations at their smelters and pyronietallurgical methods in their refineries. Domestic mine production in 1992 accounted for over 90% of the U S . primary lead production; the balance originated from the smelting of imported ores and concentrates. Secondary lead production made up about 77% of the lead produced in the United States in 1996 versus 54% in 1980 (Table 4). The amount of sec-

6

Introduction

9

Table 3 RefinedLead:MetalConsumptioninThousands

of Tons [ l ]

Annual totals 1995

1994

Europe Austria Belgium Bulgaria Czech Republic" Denmark Finland France Germany Greece Hungary Ireland Italy Netherlands Poland Portugal Romania Russian Fed. Slovenia Spain Sweden Switzerland United Kingdom Yugoslavia ER.

1993 1813 62 74 25 23 2 4 226 352 6 8 23 238 48 59 26 20 92 11

102 24 4 353 5

1878 64 65 20 18 4 5 237 354 7 8 28 25 1 58 55

34 16 103 13 112 31 8 355

1970 65 69 19 27 4 3 263 360 8 12 25 27 1 62 55 34 19 93 14

1979 58 53 17 32 7 4 255 342 8 12 27 268 57 62 34 22 95

131

137 41

36

15

IO

IO

355

5

8

368 12

Africa Algeria Egypt Morocco Nigeria South Africa Tunisia

108

1IO

112

1 l9

18 7 6

18

19

6

6 9 5 60 5

20 9 7 5 63

Americas Argentina Brazil Canada Colombia Mexico Peru United States Venezuela

1760 33 75 70

7

5

5

59

59 5

3

II

I57 13 1367 27

1925 33 85 73 8

1976 30

5

2087 31 105 63 10 141

161

92 71 9 134

13 1513 28

IO

IO

1592 28

1687 30

Chapter 1

10

Table 3 Continued

Annual totals 1996

Asia

China India

Indonesia Iran Japan

Kazakhstan Korea D.P.R. Korea, Rep. Malaysia Pakistan Philippines Singapore Taiwan, China Thailand Turkcy Oceania 82 Australia 78 New Zealand World total

1995 I993

1994

147 I 300 70 75 60 370 30 40 20 1 51 X 32

1 507 290 90 91 60 345 20 36 233 53 X 25

8

IO

117 48 37

121 62 35

1726 445 96 90 67 334 15 35 272 66 X 27 12 I32 63 34

4

81 77 4

67 62 5

71 67 4

6045 52195865

1789 470 1 04 x7 70 330 12 32 290 75 9 26 13 I24 x0 35

5 502

N o f c : The consumption of retined lead. including the Iced content of nntlrnonial lead regardless 1.e.. whether ores, concenlrrrles, lead bullion, alloys. of source material from which produccd, resdues, slag. or scrap. Pig lead and Icnd alloys wlthout undergoing further treatment before reuse are excluded. "Prior to 1993, data refer to Czechoslovakia.

ondary lead produced was 698 X 10' tons in 1988, 888 X I O3 tons in 1990, and 1085 X 10' tons in 1996. The leading secondary lead producers include GNB Battery Technologies (Atlanta, GA), Exide Corporation (Reading, PA), and RSR Corporation (Dallas, TX). In Canada, the leading refined lead producers are Cominco, Hudson Bay Mining and Smelting Co. Ltd. (Minorco), Brunswick Mining and Smelting Co. Ltd. (Noranda), and Anvil Range Mining Co. Secondary lead accounts for about 37% of refined lead production in Canada. In South America, major lead producers include CENTROMIN in Peru and PenBIes and Empresas Frisco in Mexico. In the United Kingdom, the major lead producers are Brittania Refined Metals Co., MIM Holdings,

Table 4

Recovery of Secondary Lead in Thousands of Tons

[l]

Annual totals retined lead and lead alloys" I995

1994

1993

Europe Austria Belgium France Germany" Greece Ireland Italy Macedonia Netherlands Portugal Slovenia Spain Sweden Switzerland United Kingdom

808 14 25 146 160 4 10 93 3 23

885

8

13 1.5

12 62 38 6 204

Africa Morocco South Africa Other

51 3

Americas Argentina Brazil Canada Mexico United States Venezuela Other

IO64 16 39 69 60

Asia India Japan Korea, Rep. Taiwan, China Other

315

Oceania Australia New Zealand

32 16

86 1

14 5

939 24

4

925 23 30 168 I64 4

IO

11

128 3 24

126

12 144 4 22 6

16 26 155 1S6

75 43 6 21 I

5

21 8

14 82 41 7 22 1

49 3 32 14

S4 3 32

1137

1236 26 40 104 60 984 16

18

40 99 60 898 16 6

19

6

31

163 I 50 S

13 91

42 7 225 S3

4 32 17 1362 25 39 I 15

60 1085

25 13 404 25 I47 52 16 164

97 43

332 24 1 10 43

15

17

16

142

138

147

27 22

30

5

31 25 6

26 4

28 24 4

Total

2265

2434

2625

2786

Totalrecovery

2654

2829

3026

3185

18

380 26 140 51

"Retined lend and lend alloys (lead content) produced from secondary materials (scraps. wastes and residues). "Dataprior to 1991 include the former Federal Rcpublic only. 'Recovery of secondary mnteriul by renlelting wilhout undergomg further treatment.

11

12

Chapter 1

and Biliton (U.K.). About 55% of lead produced in the UnitedKingdom comes from secondary lead. Major lead producers in Europe include MetaleuropWeser Blei GmbH,Berzelius Metallhiitten GmbH, and Norddeutsche Affinerie in Germany, Societe Miniere et Metallurgique de Penin Italy, Boliden naroyyaS.A. in France,governmentownedEnirisorse Mineral AB in Sweden, and Metallurgie-Hoboken-Overpelt SA (Union Minere) in Belgium. In Italy, 68% of lead production comes from secondary lead, whereas in France and Germany, secondary lead accounts for about 54% and 6370, respectively. Mitsui Mining and Smelting Co., Mitsubhishi Mining and Smelting Co., Sumitomo Metal Mining Co., and Hosakura Mining Co. are the major lead producers in Japan and secondary lead makes up 5 1% of lead produced in Japan. Other major producersin Asia include Korea Zinc Co. in South Korea and the government-owned Hindustan Zinc Ltd. in India. In Australia, the major lead producers are MIM Holdings, GSM, Pasminco, Aberfoyle, and Biliton. Table 4 provides a summary of the secondary lead component of refined lead in different countries. The data show that the secondaryleadcomponent inlead productionhasbeen steadily increasingworldwide and currently slightly over half (53%) of the lead produced in the world comes from secondary sources. World consumption of lead grew steadily through the mid-1980s at a rate of 3-4% until 1989. The consumptiondecreasedbetween1989and 1993 and was followed by steady growth at 5 % per annum to a level of about 6 million tons. Consumption in the United States followed a similar trend. With the opening of the Communist Bloc production to Western markets in 1989, there was a change in the lead supply situation. The Communist Bloc exported 180,000 tons to the West in 1993, as opposed to a net import of 140,000 tons of lead in 1980. This dramatic change in the market/supply situation impacted on the price of lead. During 1987-1997, the price range for lead ranged from 20 to 40@/lband typically about 25@/lb [ 121. Longterm trends in the price of lead are dependent on the overall world economy as well as on the investments in industrial infrastructure in the former Communist Bloc and Asian economies. The primary market for lead at this time is in energy storage batteries followed by the chemical and cable sheathing applications. In Table 5, consumption patterns of major lead users are provided. The future use of lead may be decided by the resolution of environmental concerns. Some markets for lead are declining or being phased out due to environmental concerns, whereas other segments are growing and newer marketsare being developed. In 1990, the state of California (United States) required that 2% of new cars by 2003. meetzero-emissionstandards in 1998, 5% by 2001,and10% in New York, Massachusetts, and Similar laws were subsequently enacted seven other eastern U.S. states [ 13,141. In 1996, the California Air Resources

13

Introduction

Table 5 Production and Consumption Patterns and Consumers [ I ]

I996

I995

1994

of Major Producers

1993

France Refined lead Production Primary Secondary Consumption Principal uses Batteries Cable sheathing Sheet/strip Ammunition Alloys Gas. additives Oxides Miscellaneous

259 1 l3 146 226 244 156 16 19 8 4 5 24 12

260 138 105 163 155 255 237 254 170 14 17 8

Germany Refined lead Production Primary Secondary Consumption Principal uses Batteries Cable sheathing Pipe/sheet/shot Chemicals Gas. additives Alloys Miscellaneous Italy Refined lead Production Primary Secondary Consumption Principal uses Batteries Cable sheathing Pipe/sheet Ammunition

24

30 297 129 168 263 279 192 14 18 7 5 6 27

11

IO

334 174 160 352 362 204 9 50 80 2 8 9

332 176 156 150 354 342 378 333 216 194 8 8 49 57 66 77 3 3 9 8 8

3 l4

198 105 93 238 236 107 34 12 24

223 210 66 95 128 25 1 234

5 5

115

27 12 22

1

150

238 88

164 360 360 207 8 54 73 3 8 7

5

189 63 126 27 1 247 125 27 11

24

144

268

14

Chapter 1

Table 5 Continued ~

1996

1995 Alloys Gas. additives Oxides Miscellaneous

Japan Refined lead Production Primary Secondary Consumption Principal uses Batteries Cable sheathing Pipe/sheet Chemicals Alloys Miscellaneous United Kingdom Refined lead Production Primary Secondary Consumption Principal uses Batteries Cable sheathing Pipe/sheet Shot Tetraethyl Chemicals Alloys Miscellaneous United States Refined lead Production Primary Secondary Consumption

1994

1993 3 4 42

40

4 4 42

10

10

10

309 212 97 370 37 1 256 7

292 182

288 148 I40 334 334 232 4

287 140 147 330 330 233

11

12 41

10

3 5

I 10

345 346 239 5 10 51

59 14 25

13 28

416 212 204 353 299 103 9 84

416 205 21 1 355 303 100 9 94

46 12 29

387 166

22 1 355 328 109 10

102 6

6

I1

27

406 181 225 368 316 107 9 94

3

5

39 18 21 22

32 18 22 23

35

19 23 24

38 18 20 25

I l96 335 86 1 1367

1249 3s 1 898 1513

1358 374 984 I592

141I 326 1085 1687

5

introduction

15

Table 5 Continued

1996

I995

Principal uses Batteries Cable sheathing Pipe/sheet Chemicals Ammunition Alloys Gas. additives Miscellaneous

1994

1993 1599 1356 6 30 62 71 47

l68 1 1412

17 27 64 65 44

1450 I223 16 25 63 62 43

18

18

27

31

1286 105 1

7

37 67 58

69

Boarddecided not to mandate the introduction of zero-emissionvehicles and let the auto companies voluntarily sell zero-emission vehicles from 1998 to 2002. The auto industry committed to reach a goal of 10% of the vehicles sold to be zero-emission vehicles in 2003. Zero-emission vehicles are generallyaccepted to mean electric (i.e., battery-poweredcars) and there is considerable research efforttobringsuitableelectricvehicles to market. Although many battery systems are being investigated for powering electric vehicles, the lead-acid battery is by far the most mature and accepted. If lead-acid battery technology is adopted, the demand for lead is expected to increase strongly. The established world resources of 7 1 X 10' tonscan meet the demand for electric vehicles for a long time. In addition, seismic protection and damping applications are also likely to increase.

111.

PRODUCTION OF LEAD METAL

Lead is processedfromore to refined metal in fourstages:oredressing, smelting, drossing, and refining [2-41. The ore-dressing step involves crushing (jaw or gyratory crushers), grinding (rod mill or ball mill or autogenous), and concentration (gravity or froth flotation). Crushing and grinding are done so as to physically liberate galena and other minerals from the interlocking unwanted waste rock or gangue. The mineral ground to smaller than 0.2 the gangueusing gravity mm is separated in the concentrationstepfrom concentrators or froth flotation. Froth flotation is generally used for sulfide ores. The fine slurry is mixed with frothing agents and collector agents and air is pumped through the solution. The collector agent adsorbs to the surface of the mineral, making the particle hydrophobic, and causes the particle to attach to the air bubble and raise to the froth. Frothing agents such as pine

16

Chapter 1

oil, cresylic acid, polyglycols, and long chain alcohols which stabilize the froth are used along with collectors such as xanthates. The concentrate is obtained by skimming the froth from the cell, dewatering by settling, and vacuum filtering to a moisture content of 15%. The lead concentrate would typically have, by wt.%, 45-75 Pb, 0-15 Zn, 10-30 S, 1-8 Fe, 0.1-2 Sb, 0-3 CaO, 0-3 Cu, 0.5-4 insolubles, and small amounts of Au, Ag, As, and Bi. The concentrate is then smelted using a sinter-blast furnace or Imperial smelt process. In sintering and smelting steps, Pb and other metal sulfides are reduced in a series of steps. Before being fed in to the blast furnace, the concentrate is roasted to remove most of the sulfur and to agglomerate further the fine products so that they will not be blown out of the blast furnace. In this step, the concentrate is mixed with coke and fluxing agents such as limestone or iron oxide, and spread on a moving grate. Airis blown through the grate at a temperature of 1400°C. Sulfur along with coke that has been addedservesasfuel, and the sulfurdioxideformed is recovered for the production of sulfuric acid. The roasting results in a sintered brittle product containing oxides of lead, zinc, iron, and silicon along with lime, metallic lead, and the remaining sulfur. The sinter is broken into lumps as it comes off the moving grate. The prefluxed sinter lumps are loaded on top of the blast furnace along with coke fuel. The blast of air admitted to the bottom of the blast furnace aids the combustion of coke, generating a temperature of 12OO"C, and the carbonmonoxideproducedreduces the metaloxides, producing molten metal and carbon dioxide. Nonmetallic wastes form a slag with the fluxing materials. Typical composition of the slag is, by wt.%, 2533 FeO, IO- 17 CaO, 20-22 SiO,, 1-2 Pb, and 13- 17 Zn. Some lead is trapped in the slag also and this is kept to a minimum. The molten metal is tapped into drossing kettles or molds. The liquid metal containing 95-99% lead and dissolved metallic and nonmetallic impurities is referred to as the base bullion. In addition to noble metals, base bullion contains the impurities Sb, As, Sn, Cu, and Bi. Copper sulfide has a lower solubility in lead and, therefore, some of it is removed as matte (molten sulfide layer). If Sb or As is present, Fe and Cu could react with them to form arsenate or antimonides and removed as a speiss layer (consisting of antimonides and arsenates and having a density of -6). Several new commercialsmeltertechnologieshavebeendeveloped, including KIVCET, Isasmelt, and QSL processes but the sinter-blast furnace and Imperialsmeltfurnace are still widely used [3,4,15]. These new processes are direct smelting processes carried out in relatively small, intensive reactors. These processes require neither the sintering of feed materials nor the use of metallurgical coke. They also produce lower volumes of gas and dust that would require treatmentwith pollution-control equipment.The

Introduction

17

KIVCET and QSL processes consist of a single furnace, and unifyin a single structure all phases of desulfurization and reduction of lead oxide into lead bullion. KIVCET is a Russian acronym for “flash-cyclone-oxygen-electricsmelting.” It employs the autogenous (i.e., fuelless) flash smelting of raw materials, with the heat-producing oxidation of the concentrated sulfide ore raising the temperatureto 130O-140O0C, which is enough to reduce the oxidized materials to metal. The process involves the proportioning, drying, and mixing of the lead-bearing materials and fluxes, followed by their injection into the reaction shaft. The injected materials are ignited by a heated blast of commercially pure oxygen. The smeltedlead bullion and slag collect in the hearth while zinc vapor undergoes combustion with carbon monoxide in the electric furnace to produce zinc oxide. Hot sulfurous gases generated by the smelting process are used to produce steam and sulfuric acid as byproducts. TheKIVCETprocessappears to produce significantly less flue dustthanother direct processes,and its furnacebrickworkhasalonger service life. The QSL (Queneau-Schuhmann-Lurgi) process can handle all grades of lead concentrates, including chemically complex secondary minerals. A pelletized mixture of concentrates, fluxes, recirculated flue dust, and a small amount of coal is dropped into the melt consisting mainly of primary slag in a refractory-lined reactor. Oxygen is blown through tuyeres at the bottom to oxidize the unroasted charge in the molten bath at a temperature of 1000- 1 100°C to produce metallic lead, primary slag with as much as 30% lead oxide, and sulfurous off-gas. The primary slag is reduced via coal injected into the second section of the furnace through submerged tuyeres. In the Isasmelt process, an air lance is brought in through the top of a furnace and its tip is submerged in the melt containing the sulfide concentrate. A blast from the lance produces a turbulent bath in which the concentrates are oxidized to produce a high-lead slag. This slag is tapped continuously and it is reduced with coal. Crude lead transferred to a second furnace, where and slag are tapped continuously from the second furnace and separated for further refining. The final stage is the refining of lead when the impurities are removed to meet the standards for commercial sale and to recover valuable by-products. The impure bullion is cooled so that most of the copper segregates in the kettle due its low solubility in lead at temperatures just above the melting point. The dross that contains Cu is skimmed off along with the remaining CO, Ni, and Zn. The rest of the Cu is removed by treating it with S (10 kg/ ton) (at Cu levels of 0.6TM.The strain rate i n this region is given by an empirical relationship [ 1181

Here D,, is the lattice diffusion co-efficient and A is an empirical constant. The value of observed IZ varies from 3 to about 10. These equations should be treated as empirical because of uncertainties in the relationship

Table 14 Lead-BasedBearingMetals12x1.(Courtesy Association, New York.)

of LeadIndustries

Nominal or preferred composition (wt.%)

onyTin

No.

UNS ~~

13

L54727 L53560 L53620 L53320

-

25 5 I 5

15

15

9

59

x0 0.15 I .4

0.5

-

-

0.6

x2 86

aUTI

Table 15 Lead-Tin Solder Alloys [28]. (Courtesy of Lead Industries Association, New York.) Composition (wt.7c) UNS No.

L542 10 L54320 L54520 L54560 L547 10

Tin

2 5 10

15 20

?! $ v)

Temperature ("C)

Lead

Solidus

Liquidus

Pasty range

98 95 90 85 80

316 305 267 226 182

32 1 312 302 288 277

5 7 35 62 95

L54720 L.54820 L54850 L549 15

25 30 35 40

75 70 6.5 60

182 182 182 182

266 255 247 237

84 73 65 55

L549.50

45

55

182

227

45

L55030

50

50

182

216

34

L 13600

60

40

182

190

8

L13630

63

37

182

182

0

Uses Side seams for can manufacturing For automobile radiators For coating and joining metals

For coating and joining metals; for filling dents or seams in automobile bodies For machine and torch soldering General purpose and wiping solder Wiping solder for joining lead pipes and cable sheaths; for automobile radiator cores and heating units For automobile radiator core and roofing seams For general purpose use; use most popular of all Primarily used in electronic soldering applications where low soldering temperatures are required Lowest melting (eutectic) solder for electronic applications

0, r (D m m

3 P

-

D

2 b

5

86

Chapter 2

Table 16

Most CommonSilver-ContainingSolders [28]. (Courtesy of Lead Industries Association, New York.) Composition (wt.%)

Temperature ("C)

Solidus Liquidus Lead Silver TinNo. UNS ~ _ _

L50131 L55 133 L50151

1

I .5

62

2.0 2.5

-

97.5 36.0 97.5

~~~~

309 179 304

309 189 304

between applied stress and dislocation densities, and theoretical models of flow. The region where creep is limited by core-diffusion-controlled climb is referred to as the "low-temperature-creep" region. Here, the lattice diffusion coefficient is replaced by D,,,,, which varies as (a,Jp)' and, therefore, In some materials, at very low stress levels, the creep rate varies as (a,,/p)'i'2. the strain rate varies linearly with u,,/p,suggesting that the dislocation density under these conditions remains constant. This region, referred to as the Harper-Dorncreep [ 1 19, 1201 regime, is observed in verylarge-grained material, when diffusional creep fields are suppressed. There is a region at In this high stress levels (>lo-.' p) where the powerlawbreaksdown. region, the controlling mechanism transitions from climb-plus-glide to glide alone. At low stress levels (stress < 5 X lo-" p), linear viscous creep occurs at rates higher than that from diffusional creep. The dislocation creep mechanism that results in this linear viscous creep is referred to as Harper-Dom creep and occurs under conditionsthat maintain constant dislocation density. At very high temperatures (>0.6TM)and stress levels, power-law creep may be accompanied by repeated recrystallization. Following each recrystallization step, the dislocation density drops allowing for a period of pri-

Table 17 Typical Solder Alloys with Their Melting Points 1281. (Courtesy of Lead Industries Association, New York.) point ("C)

Composition Melting (wt.%)

UNS No. ~

47 21

~~~

Tin

Bismuth Indium Cadmium

Lead

Solidus Liquidus

~~~~~

22.6L50620 5.3 49.9 12.0 L50640 L50645 50.0 L50665 L56680

8.3 19.1

44.7

9.3 15.5 -

52.5 55.5

.o

-

-34.5 - 95 -

6.2 -95 124 -124

18.0

32.0 44.5

58 70

58

78

U

a '0

Table 18 Electrical Properties of Lead Alloys [28]. (Courtesy of Lead Industries Association, New York.) Alloy composition" Pb >99.94 Pb-( 1.3- 1.7)Ag Pb-1.5 Ag-5 Sn Pb-(2.3-2.7)Ag Pb-(2.3-2.7)Ag Pb-2.5 Ag-2 Sn Pb-5 Ag Pb-5 Ag-5 Sn Pb-5 Ag-5 In Pb-(5-6)Ag Pb-0.15 As-0.1 Sn-0.1 Bi Pb-42 Bi-11 Sn-9 Cd Pb-42.9 Bi-5. I Cd-7.9 Sn-4 Hg- 18.3 In Pb-44.7 Bi-5.3 Cd-8.3 Sn-19.1 In Pb-48 Bi-14.5 Sn-9 Sb Pb-49 Bi-21 In-I2 Sn Pb-50 Bi-10 Cd-13.3 Sn Pb-5 1.7 Bi-8.1 Cd Pb-52.5 Bi-15.5 Sn Pb-55.5 Bi Pb-0.065 Ca-0.7 Sn Pb-0.065 Ca-1.3 Sn

4 g

Conductivity (%IACS)

Resistivity

L50OOI -L50042 L50132 L50 134 L50 150 L50151 L50152 L50 170 L19171 L10172 L50 180 L503 10

8.3%

206.43

5

L50605 L506 10

4%

Fusible Alloy

L50620

4.5%

Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Battery Grid Alloy Battery Grid Alloy

L50630 L50640 L50650 L50660 L50665 L50680 L50740 L50750

3% 3% 4 Yo

219 220

03

UNS No.

Common name Corroding Lead Solder Alloy-Grade Ag Solder Alloy-Grade 5s Solder Alloy-Grade Ag Solder Alloy-Grade Ag Solder Alloy Solder Alloy Solder Alloy Solder Alloy Solder Alloy-Grade Ag Arsenical Lead Cable Sheathing Alloy Fusible Alloy Fusible Alloy

1.5 2.5 2.5

5.5

(nn-m)

u)

3% 4

a3 a3

Table 18 Continued Alloy composition Pb-0.07 Ca Pb-0.1 Ca-0.3 Sn Pb-0.1 Ca-0.5 Sn Pb-0.1 Ca-1 Sn Pb-17 Cd

Pb-4.76 In-2.38 Ag Pb-5 In Pb-5 In-2.5 Ag Pb- 19 In Pb-20 In Pb-25 In Pb-40 In Pb-40 In-40 Sn Pb-50 In Pb-60 In Pb-70 In Pb-80 In-5 Ag Pb-I S b Pb-1.2 Sb-0.8 Ga Pb-2 Sb

Common name Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Lead-Cadmium AlloyEutectic Copperized Lead Lead-Indium-Silver Solder Alloy Lead-Indium Solder Alloy Lead-Indium-SiIver Solder Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy 1% Antimonial Lead Lead-Antimony-Gallium Alloy 2% Antimonial Lead

UNS No.

Conductivity (YoIACS)

Resistivity (nR-m)

L50760 L50775 L50780 L50790 L50940

218 219 219 212

L51110-L51123 and L5 1125 L51510

206 5.5%

L51511 L51512

5.5%

L51.530 L5 1532 L51535 L5 1540 L5 1545 L5 15.50 L5 1560 L5 1570 L5 1585 L.52605 LS26 18 L52705

5.1%

4.5% 4.6% 5.2%

7.0% 8.8% 13%

Pb-2.5 Sb-2.5 Sn Pb-3 Sb-3 Sn Pb-4 Sb Pb-6 Sb Pb-8 Sb Pb-9 Sb Pb-(9.5- 10.5)Sb-(5.56.5)Sn Pb-ll Sb-3 Sn Pb-l 1 Sb-5 Sn Pb-12 Sb-4 Sn Pb-13 Sb-6.5 Sn Pb-14 Sb-6 Sn Pb-( 14- 16)Sb-(4.5-5.5)Sn Pb-15 Sb-7 Sn Pb-15 Sb-8 Sn Pb-15 Sb-10 Sn Pb-( 14-16)Sb-(9.3- 10.7)Sn Pb-( 14.5-1 7.5)Sb-(0.81.2)Sn Pb-17 Sb-8 Sn Pb-19 Sb-9 Sn Pb-24 Sb-12 Sn Pb-( 1.5-2.5)Sn Pb-3 Sn-5.1 Sb

Electrotype-General Electrotype-General 4% Antimonial Lead 6% Antimonial Lead 8% Antimonial Lead 9% Antimonial Lead Lead-base Bearing Alloy

L52730 L52830 L52901 L53105 L53230 L53305 L53346

Linotype Alloy Linotype-Special Alloy Linotype B (Eutectic) Alloy Stereotype-General Alloy Stereotype-Flat Alloy Lead-base White Metal Bearing Alloy Monotype-Ordinary Alloy Stereotype-Curved Alloy Rules Monotype Alloy Lead-base White Metal Bearing Alloy Lead-base Bearing Alloy

L53420 L53425 L53455 L53510 L53530 L53565

6.1%

282

L.53570 L.53575 L53580 L5358.5

6.0% 6.070

286

Display Monotype Alloy Lanston Standard Case Type Monotype Alloy Monotype Case Type Alloy 2% Tin Solder Solder Alloy

L.53650 L53685

L53620

L53750 LS42 10 L54280

7.7% 7.6% 7.5% 7.4% 6.0%

2.53 26.5 27 1 287

=i v)

2 -

0 Y v)

Table 18 Continued ~

Alloy composition Pb-4 Sn-3 Sb

Pb-(4.5-5.5)Sn-(O.2-O.S)Sb Pb-5 Sn-4 Sb-0.5 As Pb-8 Sn-0.3 Sb Pb-10 Sn-(0.2-0.5)Sb Pb-(9- 1 1)Sn-( 1.7-2.4)Ag99.94 Pb-( 1.3-1.7)Ag Pb-1.5 Ag-5 Sn Pb-(2.3-2.7)Ag Pb-(2.3-2.7)Ag Pb-2.5 Ag-2 Sn Pb-5 Ag Pb-5 Ag-5 Sn Pb-5 Ag-5 In Pb-(5-6)Ag Pb-0.15 As-0.1 Sn-0.1 Bi Pb-42 Bi-I 1 Sn-9 Cd Pb-42.9 Bi-5.1 Cd-7.9 Sn-4 Hg-18.3 In Pb-44.7 Bi-5.3 Cd-8.3 Sn-19.1 In Pb-48 Bi-14.5 Sn-9 Sb Pb-49 Bi-21 In-I2 Sn Pb-50 Bi-10 Cd-13.3 Sn Pb-51.7 Bi-8.1 Cd Pb-52.5 Bi-15.5 Sn Pb-55.5 Bi Pb-0.065 Ca-0.7 Sn Pb-0.065 Ca- 1.3 Sn

Density, (g/cm')

Volume change on freezingh

Common name

UNS No.

Corroding Lead Solder Alloy-Grade Ag 1.5 Solder Alloy-Grade 5s Solder Alloy-Grade Ag 2.5 Solder Alloy-Grade Ag 2.5 Solder Alloy Solder Alloy Solder Alloy Solder Alloy Solder Alloy-Grade Ag 5.5 Arsenical Lead Cable Sheathing Alloy Fusible Alloy Fusible Alloy

L50001 -L50O42 L50132 L50 134 L50150 L50151 L50152 L50 170 L19171 L10172 L50 180 L503 10 L50605 L506 10

9.45 9.28

-2%

Fusible Alloy

L50620

8.85

- 1.4%

Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Fusible Alloy Battery Grid Alloy Battery Grid Alloy

L50630 L50640 L50650 L50660 L50665 L50680 L50740 L50750

9.50 8.60 9.40 10.25 9.7 1 10.30 11.34 11.34

- 1.5% - 1.5% - 1.7%

4=. (P v)

11.34

11.33 11.28 11.30 11.00 1 1 .oo 11.33

- 1.5% (0

w

Table 20

(0

Continued

P

~

Alloy composition" Pb-0.07 Ca Pb-0.1 Ca-0.3 Sn Pb-0.1 Ca-0.5 Sn Pb-0.1 Ca-1 Sn Pb-17 Cd

Pb-5 In Pb-5 In-2.5 Ag Pb-19 In Pb-20 In Pb-25 In Pb-40 In Pb-40 In-40 Sn Pb-50 In Pb-60 In Pb-70 In Pb-80 In-5 Ag Pb-1 Sb Pb- I .2 Sb-0.8 Ga Pb-2 Sb Pb-2.5 Sb-2.5 Sn

Common name Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Lead-Cadmium AlloyEutectic Copperized Lead Lead-Indium Solder Alloy Lead-Indium-Silver-Solder Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy Lead-Indium Alloy 1% Antimonial Lead Lead- Antimony -Gallium Alloy 2% Antimonial Lead Electrot ype-General

UNS No.

Density, (g/cm')

L50760 L50775 L50780 L50790 L50940

11.34 11.34 11.34 11.34

L5 1 1 IO-L51123. L51125 L51511 L51512

11.34 11.06 1 1.02

L5 1530 L51532 L5 1535 L5 1540 L5 1545 L5 1550 L5 1560 L5 1570 L51585 L52605 L526 18

10.27 10.16 9.97 9.29 7.86 8.86 8.52 8.19 7.85 11.27 11.20

L52705 L52730

11.19

Volume change on freezingh

Pb-3 Pb-4 Pb-6 Pb-8 Pb-9

Sb-3 Sn Sb Sb Sb Sb

Pb-(9.5-10.5)Sb-(S.5-6.5)Sn Pb-11 Sb-3 Sn Pb-1 1 Sb-5 Sn Pb-12 Sb-4 Sn Pb-13 Sb-6.5 Sn Pb-14 Sb-6 Sn Pb-( 14- 16)Sb-(4.5-5.5)Sn Pb-15 Sb-7 Sn Pb-15 Sb-8 Sn Pb-15 Sb-10 Sn Pb-( 14- 16)Sb-(9.3- 10.7)Sn Pb-( 14.5- 17.5)Sb-(0.81.2)Sn Pb-17 Sb-8 Sn Pb-19 Sb-9 Sn Pb-24 Sb-12 Sn Pb-( 1S-2.5)Sn Pb-3 Sn-5.1 Sb Pb-4 Sn-3 Sb

Electrot ype-General 4% Antimonial Lead 6% Antimonial Lead 8% Antimonial Lead 9 9 Antimonial Lead Lead-base Bearing Alloy Linotype Alloy Linotype-Special Alloy Linotype B (Eutectic) Alloy Stereotype-General Alloy Stereotype-Flat Alloy Lead-base White Metal Bearing Alloy Monotype-Ordinary Alloy Stereotype-Curved Alloy Rules Monotype Alloy Lead-base White Metal Bearing Alloy Lead-base Bearing Alloy Display Monotype Alloy Lanston Standard Case Type Monotype Alloy Monotype Case Type Alloy 2% Tin Solder Solder Alloy Electrotype Curved Plate Alloy 5% Tin Antimonial Solder

L52830 L5290 1 L53105 L53230 L53305 L53346 L53420 L53425 L53455 L535 10 L53530 L53565

11.02 10.88 10.74 10.60 10.50

am'21 3.1 1% 2.88% 2.76% 2%

c

z

v)

0,

r (D (u

P (u

2%

3

a =i v)

9.96

2

270

b U u)

LS3570 L53575 L53580 L53585

9.70

2.3%

L53620

10.10

2.5%

1 1 .OO

3.6%

L53650 L53685 L53750 L542 10 L54280 L543 10 L.54320

(0

VI

Table 20

Continued

Alloy composition" Pb-5 Sn-4 Sb-0.5 As Pb-8 Sn-0.3 Sb Pb- 10 Sn-(0.2-0.5)Sb Pb-(9- I 1)Sn-( 1.7-2.4)Ag2% Sb, inhibited recrystallization. Fora50%reduction at roomtemperature, the worked structure was visible after 2 h, recrystallization began after a day, and complete recrystallization was observed after 12 days. A very high-purity (99.9999%) lead recrystallizes at -59°C [144]. The addition of Ag and Te and, to a smaller extent, Sn slowsthe recrystallization process. The addition of Bi has no effect. With Ca addition, the alloy age hardens after working at -73°C. In alloysdeformed in the age-hardened condition, a pronounced delay in recrystallization occurs. Dynamic recrystallization that takes place during rolling leads to softening and the softening is more pronounced with the increase of deformation (Figure 34). Pb-Sb

115

Properties of Lead andIts Alloys

.4

I

I

I

I

350

321

3%

250

I 200

I 175.

1

Temperature (“C)

Figure 33 Grain growth rate versus l/T for Pb, Pb-0.005 Ag, and Pb-0.005 12,1421. (Courtesy of Springer Verlag, New York.)

Reduction in thickness (%)

Figure 34

Hardnessversus rollingreduction (Courtesy of Springer Verlag, New York.)

in age-hardened Pb-Ca alloys 121.

116

Chapter 2

and Pb-Ca alloys given a 99.9% reduction are stable with regard to recrystallization on storage for days and months, respectively. The behavior of Pb-Te, Pb-Li, and Pb-Na are similar but not as pronounced [84,145,146]. If supersaturation was avoided by slow cooling to room temperature, recrystallization sets in immediately upon rolling the alloy. In supersaturated alloys, precipitate formation could lead to a reduction in strength. The data on grain growth and the limiting grain size at different annealing temperatures and for different deformation strains could be presented in the form of recrystallization diagrams. Such diagrams have been prepared for purest lead, technical lead with Cu, Fe, Sb, As, Zn, and Ag (1471, electrolytic lead, Parkes lead, and Pattinson lead [ 1401. Figure 35 shows that for Pattinson lead (containing about 0.06% Cu), no grain growth occurred until an annealing temperature of 200°C and that the differences between three types of lead disappear at 310°C. The grain-refining action of Cu additions of 0.04-0.05% i n refined lead and Bi-containing lead is also well demonstrated [6X]. Limiting grain sizes in lead and lead alloys after 50% and 60% deformation and after annealing at 160-200°C has been examined by a number of investigators [57,140,141,148]. Cast grains are generally coarse for moderate alloying additions. In rolled and room-temperature recrystallized alloys of Pb-Ca and Pb-Li, grain sizes are below 0.1-0.2 mm, and in Pb-Au alloys, the grain sizes exceed 0.2 mni. On heat treatment at 160-200"C, greater differences are observed. A grain diameter much larger than 1 mm is obtained in purest lead, and in many technical leads, it could be around 1 mm. Bi, few multiples of 0.1% Sb, small amounts of Sn, TI, and Cd affected the grain size only slightly. At high concentrations of these elements, some grain refinement occurs.

Figure 35 Recrystallization diagrams for Pb: (a) Electrolytic lead, (b) Parkes lead, and (c) Pattinson lead [2,1401. (Courtesy of Springer Verlag, New York.)

117

Propertiesof Lead and Its Alloys

V

Figure 36 Grain diameter versus tensile strain after recrystallization [2,149]. (Courtesy of Springer Verlag, New York.)

When inclusions or precipitates are present, the average grain size is limited by the size and number density of inclusions. With elements that have limited solubility, the limiting grain size is well below 1 mm. With a few hundredths of 1% of Cu, Ca, Te, and Ni, strong grain refinement is observed (Figure 36) [l49]. Sb and Sn also have a grain-refining effect at larger concentrations.

C. Short-Term MechanicalTest Data on Lead and Lead Alloys

1 . Tensile Tests Because of creep, a permanent plastic deformation occurs in lead and lead alloys at stress levels well below the yield point at room temperature. Thus, the measured yield points of lead and lead alloys depends on the duration of the test or strain rate. Therefore, the interpretation and use of these yieldpoint data needs some caution. Faust and Tammann [lSO] determined the compressive yield strength by determining the stress level at which surface steps were formed on an initially well-polished surface by slip on crystal

Chapter 2

118

planes. The yield point thus determinedwas2.45MPa -+ 8%.Chalmers [38] determined the limit of proportionality in lead usingan interference method at 0.882 MPa and this value is similar in magnitude to the creep strength of pure lead. The tensile strengths of lead and lead alloys fall with a decreasing rate of strain, and with longer durationtests, the tensile strength approaches the creep strengthkreep limit. Tensile strengths of lead and PbSb and Pb-Sn alloys as a function of strain rate are shown in Figure 37 [151]. The tensile strength as a function of T is given in Figure 38 for Pb and Pb-Sb alloys [ 1521. The variation of tensile strength of lead with grain size is shown in Figure 39 [29]. The data for tensile strength and elongation at room temperature and 265°C is given in Table 22. Data from various investigations on elongation at failure is unsatisfactory, because of variations in specimengeometryand variations in grain size, strain rates, and impurities. Data on commercial lead show values from 2 1% to 73%, with corresponding tensile strengths from 1 l to 21.8 MPa. In commercial lead, the reduction of area is taken as 100%. The necking occurs to a point even at - 1OO"C, indicating the high workability of lead [ 1531. No marked dependence on temperature is observed in the elongation and reduction in area in the temperature range - 100°C to 150°C. However, lead alloys show a marked drop below 0°C. In general, an increase in concentration of solutes increases the strength and decreases the elongation 1291. Figure 40 [ 153al shows a relationship between breaking strain (elongation) and UTS for refined Pb and Pb-Te and Pb-Sb-As alloys. The Pb-Sb-As alloy with high elongation at fracture was extruded at 240°C and quenched immediately in water, and the alloy withlowerelongation at fracturewas homogenized at 250°C(leadingto grain coarsening)andquenched.The

I

0

l

P

I

I

I

8 72 1 Rate of extension (x0.1 I min.)

I

zu

Figure 37 Tensile strengths of lead and Pb-Sb andPb-Sn alloys as a function strain rate [2,151]. (Courtesy of Springer Verlag, New York.)

Of

Properties of Lead and Its Alloys

I

- 1w

l -50

119

l

I

-20

0

Temperature ("C)

Figure 38 Tensile strength of Pb and Pb-Sb alloys as a function of temperature [2,152]. (Courtesy of Springer Verlag, New York.)

Figure 39 The variation of tensile strength of lead with grain tesy of Springer Verlag, New York.)

size [2,29]. (Cour-

Chapter 2

120

Table 22 Variation of Tensile Strength and Elongation of Lead with Temperature 1021 ~

Temperature (“C) Tensile strength (MPa) Elongation (6) (%)

20 13.2 31

82 7.8 24

1 so

4.9 33

19.5 3.9

20

265 2 20

breaking strain in Figure 40 includes both the uniform elongation (that which occurs before necking) and the elongation that arises from the necking.

2. Hardness Tests The hardness of lead on Moh’s scale is about 1.5 [23,154]. However, the Brinell hardness and Rockwell “ R ” hardness scales are more widely used for lead. Hardness is an excellent probe of the strength of a material. The yield strength of a rigid-plastic materials is expected to be one-third the hardness value. Such a relationship is observed in the case of lead, where the plot of hardness of a number of uncorrelated lead alloys were plotted versus their UTS, and the H,{ was found to be three times the UTS 121. In Brinell tests, it is recommended that a 10-mm ball be used and the diameter of the impression to the diameter of the ball be kept between 0.2 and 0.7 by choosing the loads depending on the hardness expected. Loads of 15.6, 31.2, 62.5, 125, and 250 kg are used. Loads to be used in different hardness ranges are given in Table 23.

Figure 40 A relationship between breaking swain (elongation) and UTS for retined Pb and Pb-Te and Pb-Sb-As alloy [2.153a]. (Courtesy of Springer Verlag, New York.)

Properties Its andof Lead

Alloys

121

Table 23 Recommended Loads for DifferentBrinell Hardness Ranges [2] Test Load (kg) Hardness range (H,,), kg/mm'

62.5 1.5-19.5

31.2

15.6 0.38-4.9

0.75-9.75

125

250

3-39

5.6-78.8

The hardness values in lead and lead alloys are sensitive to the duration all tests is recommended and a 30-S of loading. A standarddurationfor duration is commonly used. The hardness values are accompanied by information on the ball diameter (mm), load or load/diameter squared (kg or kg/ mm2), and time. The dependence of hardness on theduration of testing depends on the operative creep mechanism, the nature of the alloy, and the grain size. In general, there is a greater dependence for fine-grained material than coarse-grained material (Figure 41) [ 1551. The Brinell hardness (H10/100/30) of high-purity (Cominco) lead of 99.9999% is 27 2 0.4 MPa at 20°C for a grain size of 0.2 mm'. The grain sizes are given here in terms of cross-sectional area of the grains [ 1561. For a 99.99% purity lead, the Brinell hardness is determined to be 35 2 0.5 MPa at 20°C for a grain size of 0.5 mm'. The hardness of commercial lead is typically in the range 2.5-3H,, at room temperature and is corrected by

1

o fine groin, extruded

22 0

zoo

af 80 C

400

I

2 600

Time (sec.)

Figure 41 Dependence of hardnessonduration Springer Verlag, New York.)

of testing [2,155]. (Courtesy of

Chapter 2

122

0.5% for everydegreechange [84]. Thehardness of polycrystalline lead falls by 0.027 for every 1°C rise from 0 to 60°C [ 1571. H . has been measured from -253°C to 125°C [lS8,159]. At -183"C, the H,, value was 2.1 times the value at 20°C. With a decrease in duration of testing, H" increases, and at a duration of < l ms, a maximum value of 78 MPa is obtained. A similar value is obtained in liquid air independent of the duration of test [ 1601. Thedynamichardness of lead,annealed at 270"C,overarangeof temperatures for different metals was determined by Sauerwald and Knehans [ 1611. These hardness tests may be used for a comparative evaluation of materials. A linear decrease with temperature was observed with the dynamic hardness value decreasing from 7.44 X 10' m kg/m3 at 25°C to 4.24 X 10' m kg/m' at 267°C [ 1621. 3.

Compression Tests in Static and Dynamic Conditions

Deformation of 20-mm-diameterand17.7-mm-high lead pieces by static compression and by dynamic blow has been examined by Heyn and Bauer [ 1631. Compressive stress or the average specific work of impactversus percentage compression in these tests is shown in Figure 42. Specific work of impact/blow amounted to 37.4 cm kg/cm3. The influence of the amount of alloying element on specific work of impact was examined using 16-mmdiameter X 16-mm-high specimens at room temperature [ 1641. Comparison at 50% reduction is shown in Figure 43. It can be seen that Ag and Te have large strengthening effects. Bailey and Singer [ 1651 developed a constant-

l

Figure 42 Compressive stress or theaverage specific work of impact for lead versus percentage of compression [2,163]. (Courtesy of Springer Verlag, New York.)

123


Figure 43 Resistance to impactversuspercentage (Courtesy of Springer Verlag, New York.)

of alloyingelement

[2,164].

strain-rate plane strain plastometer which can apply very high compression rates (0.4-31 l S" strain rates) and, thus, simulate practical working processes.Between 22°C and300°C,theyobserved that stress-strain data obeyed the relationship U = (T,,E"'. The strain-rate sensitivity, m, varied from 0.04 (E = 0.1 at 22°C) to 0.26 (E = 0.5 at 300°C). Notched-bar impact tests oncoarse-and fine-grained specimens, 15 X 15 X 180 mm3 andnotched to a depth of as much as 10 mm, resulted in brittle fracture [29] which is in contrast with ductile fracture generally observed in lead. Coarse-grained specimens had a lower value. The impact resistances of commercial lead at >3.7, and >4.4 m kglcm', respec20"C, - 183"C, and -253°C were >2.3, tively [ 1661. Ductile fracture was observed in these tests at all temperatures of this test. Tables 24-29 present the yield strength, ultimate strength, elongation, shear strength, hardness, impact, fatigue or endurance strength, and creep strength data for different lead and lead alloys [ 167-1761.

Ill. CREEP BEHAVIOR Creep refers to the time-dependent progressive deformation (flow) of a metallic or nonmetallic material under load. It gains significance as the tem-

A

g

Table 24

Mechanical Properties of Lead Alloys 1281. (Courtesy of Lead Industries Association, New York.) Ultimate tensile strength

Nominal alloy composition

Common name

(MPa)

Pure lead Pb >99.94

Corroding Lead

12-13

Pb-Ag alloys Pb-( 1.3- I .7)Ag

Pb- 1 .5 Ag-5 Sn

Pb-5 Ag-5 In Pb-(S-6) Ag Pb-As alloys Pb-0. I5 As-0. I Sn-0.1 Bi

Pb-Bi alloys Pb--42 Bi-l I Sn-9 Cd Pb-44.7 Bi-5.3 Cd-8.3 Sn 19.1

Solder AlloyGrade Ag 1.5

Solder AlloyGrade 5s

Solder Alloy Solder AlloyGrade Ag 5.5 Arsenical Lead Cable Sheathing Alloy

Elongation

30

Yield strength (MPa)

Shear strength (MPa)

Hardness Brinell/ Rockwell R

Impact energy

53

12.5

3 2-4.5

14.1 Charpy V

35 1.8 @ 100°C 30

28

19 @

25

100°C 40 32

16-30

Fusible Alloy

38

Fusible Alloy

37

13

(J)

Creep strength

19.5 MPa (1000 h) 7.5 MPa (1000 h )

Fatigue strength

UNS No.

3.2 MPa@ 10’ cycles

50042

50132

50134

20

50172 SO I80

28

0. I3Wyr @ 2.1 MPd

50310

25-40

5-10

220

9

50605

12

50620

Pb-48 Bi-14.5 Sn-9 Sb Pb-49 Bi-21 In-I2 Sn Pb-50 Bi-I0 Cd-13.3 Sn Pb-55.5 Bi Pb-Ca alloys Pb-0.065 Ca0.5 Sn Pb-0.065 Ca0.7 Sn Pb-0.065 Ca1.3 Sn Pb-0.07 Ca Pb-0.07 12-0.7 Sn Pb-0.1 Ca Pb-0. I Ca-0.3 Sn Pb-0. I Ca-0.5 Sn Pb-0.1 Ca-1 Sn Pb-1 Ca Pb-Cu alloys Pb-(0.01-0.08) 4

N

ul

cu

Fusible Alloy

90

I

50630

Fusible Alloy

43

50

50640

Fusible Alloy

41

140-200

50650

Fusible alloy

44

61

50680

Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Battery Grid Alloy Lead-Calcium Alloy

45 48 62

15 15 10

55

50737 50738 50740

70

10

66

36-39

35-40

45

25

50765

38

30-45

50770

4 1-45

20-35

90-95"

50775

44.8-5 1.7 48.3 52-55

25-35 20-30 20-35

85-90"

50780 50785 50790

Lead-Copper Alloy

38

30-45

16-19

30-60

21 MPa (500 h) 28 MPa (500 h)

50750

70-80"

50760

90-95'

50840

6-8

4-6

11-16 Charpy V

3% per year @ 2.07 MPa

4.3 MPa for 10' cycles

51 I10 5 I 120 51 121

4

g

Table24 Continued

Nominal alloy composition Pb-(0.04-0.08) C~-(0.0350.055) Te

Ultimate tensile strength Common name Grade D per QQ-C-40

(MPa) 21

Elongation (o/.)

40

Yield strength (MPa)

Shear strength (MPa)

Hardness Brinell/ Rockwell R

1-5

Impact energy (J)

Creep strength

Fatigue strength

UNS NO.

6.9 MPa for 10’ cycles

51 123 5 I 124 51125 51 126 51127

Same as 5111051 121

above

Ph In alloys Pb-4.76 In2.38 Ag Pb-5 In-2.5 Ag

Ph-25 In Pb-40 In

Pb-60 In Pb-70 In Pb-Sb alloys Pb-0.2 Sb-0.4 Sn

Lead-lndiumSilver Solder Alloy Lead-IndiumSilver Solder Alloy Lead-Indium Alloy Lead-Indium AlIoy Lead-Indium Alloy Lead-Indium Alloy Cable Sheathing Alloy

32

51510

31.4

$1512

37.6

5 I535

34.5

5 I540

28.6

51560

23.8

51570

6.3 MPa @ 10’ cycles

52520

Pb-0.5 Sb-0.25 Cd Pb-0.85 Sb 10' cycles.Under these conditions, the strains are predominantly elastic. In the low cycle fatigue, N < lo4 cycles, the stresses are higher and the fraction of total strain that is due to plastic strain becomes appreciable. Low cycle fatigue tests are usually carried out under strain cycle control. at The S-N curves for steel and few other metals become horizontal a limiting stress. Below this limiting stress, they endure infinite cycles without failure. This limiting stress is known as endurance limit or fatigue limit. In many nonferrous metals, including lead and lead alloys, S - N curves show amonotonicdecreasewithincreasing stress cycles. In thesecases, it is common practice todefinefatiguestrengthas the stress at whichfailure occurs after an arbitrary number of cycles,usually 1 X IO8 or 5 X lo8. Even at the highest number of cycles (100 million), a horizontal asymptote

173

Properties of Lead and ItsAlloys

Creep rate (l 0-4% I h) 0'04'0 0 0.055% CU

0.05% Cu

o.l

m 0.014% Cu Cu 0.042% Cu

} (According t.o MOORE amongothers [l841). ] (According t o GREENWOODand WORNER[21

l ] ).

(According to GREENWOODand COLE 12221).

B 0.037% 0

A 0.059% Cu A 0.1% Cu

(According to DOLLINS [223] ). (According to HOPRIN and THWAITES [200] ).

Figure 67 Creeprates of copper-alloyed lead [2,184,200,211,222,223]. (Courtesy of Springer Verlag, New York.)

Figure 68 Effect of extrusion temperature on creep strain of commercial lead and of copper-alloyed lead, at a tensile stress of 1.5 MPa [ 2 ] . (Courtesy of Springer Verlag, New York.)

Chapter 2

174

3

a005

..

Creep rate

0.018% Ag -1- 0.004% Cu 0.005% Cu

I h)

j

+ } (According to MCKEOIVN andHOPKIN 12241 ). # 1%Ag 0.0024%Ag + 0.06% CU (According to DOLLINS [223]). A 0.005% Ag + 0.064% Cu A 0.0054% rig + 0.061% C,) (According to GOIIh- among others (at 30°C) [208]). 0 0.005% Ag

0.01% Ag [211] ). (According t o GREENWOODand U'ORNEK

0.05% Ag

Figure 69 Creep rates of silver-alloyed lead and of copper-alloyed lead [2,208,209,211,223,224].(Courtesy of Springer Verlag, New York.)

Figure 70 Comparison of creepstrainsin some lead alloys (cable sheathings) at various temperatures after 10,000 h under 1.37 MPa tensile stress; extrapolated from tests of 2000 h duration 12,2261. (Courtesy of Springer Verlag, New York.)

175


d

b

C

e

f

h

Figure 71 Temperaturedependence of creeprate of lead and leadalloys: (a) 0.03% Ca + 0.04% Cu; (b) 0.03% Ca + 0.05% Cu; (c) 1.0% Sb; (d) 2.0% Sn; (e) ASTM Grade I11 with 0.07% Bi; (f) Grade I1 with 0.06% Cu + 0.04% Bi; (g) Grade I11 with 0.09% Bi; (h) Grade I1 with 0.04% Cu + 0.03% Bi; (i) U-Lead (Port Pirie) with a total of 0.009% impurities. (a) to (i): [2,184,216,227]. (Courtesy of Springer Verlag, New York.)

176

Chapter 2

-9.5 -10

-0.2

0

0.2

0.4

0.6

08

1

1.2

Log (Stress, MPa)

Figure 72 Thestressdependence of thesecondarycreepratefor 99.99% pure lead at various temperatures [ 2 2 8 ] .(Courtesy of ILZRO, Dr. M. K. Sohoto and Prof. J. R. Riddington, Univ. of Sussex, Brighton, UK.)

-5.5 6

"6 . 5 v)

@I

-7

2

.-c -1.5

g

2 "

E? -8.5

J

-Q -9.5 -10 -0.2

0

0.2

0.4

0.6

0.8

1

l.2

Log (Stress, MPa)

Figure 73 Thestress dependenceof thesecondarycreeprate

for Pb-0.06 Cu-

0.04 Te alloy at various temperatures [228]. (Courtesy of ILZRO, Dr. M. K. Sohoto

and Prof. J. R. Riddington, Univ. of Sussex, Brighton, UK.)

177


0.2

0

0.2

0.8 0.4

1

0.0

1.2

Log (Stress,MPa)

Figure 74 The stress dependence of thesecondarycreeprate for Pb- 1.2% Sb alloy at varioustemperatures [ 2 2 8 ] . (Courtesy of ILZRO, Dr. M. K. Sohoto and Prof. J. R. Riddington, Univ. of Sussex, Brighton, UK.)

-IO J -0.2

0

0.2

0.4

0.6

0.8

1

1.2

Log (Stress, MPa)

Figure 75 The stress dependence of thesecondarycreeprate for Pb-0.06% Cu alloy atvarioustemperatures [228]. (Courtesy of ILZRO, Dr. M. K. Sohoto and Prof. J. R. Riddington, Univ. of Sussex, Brighton, UK.)

Chapter 2

178

Table 34 Summary of Tests Carried out on 99.99% Lead at Various Stresses and Temperatures 12281. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) 5°C Stress (MPa) 1.0 2.5 5.0 7.5 10.0 12.5

40°C

20°C &>

(s

.I)

6.02E-10 1.30E-09 2.27E-09 4.48E-09 1.838-08

Stress (MPa) 1 .o

2.5 5.0 7.5 10.0 12.5

b, (s-')

2.628-09 3.53E-08 6.34E-08 9.23E-08 1.43E-07

60°C

Stress (MPa)

6, (s-I)

Stress (MPa)

1.0 2.5 5.0 7.5 10.0 12.5

7.77E-10 3.14E-09 7.91E-08 1.328-07 5.60E-07 8.65E-07

2.5 5.0 7.5 10.0 12.5

e.> (s-')

1 .o

-

Table 35 Summary of Tests Carried out on Pb-0.06% Cu-0.04% Te Alloy at Various Stresses and Temperatures 12281. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) 5°C Stress (MPa) 1 .o 2.5 4.0 5 .o 6.5 7.5

10.0 12.5

20°C

6, (s-I)

-

7.02E-10 -

3 . I9E-09 7.ME-09 1.16E-08 2.33E-08

Stress (MPa) 1 .o

2.5 4.0 5 .O 6.5 7.5 10.0 12.5

40°C 8, (s

I)

7.55E-10 2.568-09 3.7 1 E-09 5.43E-09 1.81 E-08 3.53E-08 7.32E-08 I .37E-07

Stress (MPa)

60°C E\ (s I )

1 .o

-

2.5 4.0 5.0 6.5 7.5 10.0 12.5

2.82E-09

-

1.43E-08 -

4.53E-08 8.80E-08 1.688-07

Stress (MPa) 1 .o

2.5 4.0 5.0 6.5 7.5 10.0 12.5

e, (s

I)

4.34E-09 7.9 1E-09 I . 12E-08 6.34E-08 8.85E-08 1.62E-07 1.76E-07


179

Table 36 Summary of Tests Carried out on Pb-1.2% Sb Alloy at Various Stresses and Temperatures 12281. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) 20°C

5°C Stress (MPa)

6, (s-I)

I .o 2.5 4.0

2.898-09

5.0 7.5 10.0

8.688-09 8.218-08 -

-

-

Stress (MPa) 1.0 2.5 4.0 5.0 7.5 10.0

40°C

t, (s

I)

1.368-09 1.868-08 4.908-08 8.51E-08 3.838-07 -

60°C

t,

Stress (MPa)

(s-l)

3.858-08

1.0 2.5 4.0 5.0 7.5 10.0

-

1.19E-07 2.698-07 3.078-07

e,

Stress (MPa)

(s-')

I .o 2.5 4.0 5.0 7.5 10.0

1.148-07 3.96E-07 9.OIE-07 -

-

Table 37 Summary of Tests Carried out 011 Pb-0.06% Cu Alloy at Various Stresses and Temperatures [228]. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) 5°C

e,

Stress (MPa) 1.o 2.5 4.0 5.0 7.5 10.0

20°C (s-')

2.85E-09 1.038-08

2.288-08 5.938-08

Stress (MPa) 1.0

2.5 4.0 5.0 7.5 10.0

40°C

t, (s

I)

7.858-10 2.748-09 7.07E-09 1.768-08 6.758-08 I .60E-07

Stress (MPa) 1.0 2.5 4.0 5.0 7.5 10.0

60°C 6,

(s

I)

2.778-09 6.988-09 -

1.54E-08 1.048-07 -

Stress (MPa) 1.0 2.5 4.0 5.0 7.5 10.0

E,

(s-l)

2.50E-09 8.748-09 -

2.568-08 1.1 IE-07 -

Table 38 Summary of Norton's Values for Pure Lead and Three Lead Alloys [228]. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) Materials

5°C

20°C

40°C

60°C

99.99% lead Pb- 1.2% Sb Pb-0.06% CU Pb-0.06% Cu-0.04% Te

1.26 2.89 2.12 2.12

2.4 1 2.70 2.34 2.10

2.93 1.57 I .63 1.57

1.87 1.78 1.87

Chapter 2

180

Table 39 Summary of Activation Energies Q, (kJ/mol) Values for Pure Lead and Three Lead Alloys [228]. (Courtesy of ILZRO, Dr. M. K. Sohoto, and Prof. J. R. Riddington, University of Sussex at Brighton, UK.) 1.0 MPa 2.5 MPa

Materials

5.0 MPa ~

99.99% lead 72.1 1.2% PbSb 44.8 Pb-0.06% 21.4 CU 10.6 331.441.330.335.5Pb-0.06% Cu-0.04% Te

17.9

5.3 27.9 -48.5 18.1 24.0

7.5MPa 10.0 MPa ~

~~~~

68.6 48.5

68.7 -

to S-N curve of lead is not reached [23l]. In determining the fatigue strength of lead, the number of cycles is set high and is stated in the results. In the case of low cycle fatigue, the plastic strain range, AE,,, during a fatigue cycle is plotted against N, and usually a straight line is obtained (Figure 78) [232].Such behavior, known as the Coffin-Manson relationship, is described by [233]

where A E , , / ~is the plastic strain amplitude, E;.- is the fatigue ductility coefficient and is equal to the strain intercept at 2N = 1, 2N is the number of strain reversals to failure, andc is the fatigue ductility exponent which varies from -0.5 to -0.7. Under varying conditions of fatigue loading, one can estimate the linear cumulative damage and the remaining part life using Miner's rule. If n,, n2, . . . , n, represent the number of cycles of operation at a specific stress level and N , , N 2 , . . . , N k represent the life in cycles at these stress levels, then failure will occur when

This rule is empirical in nature and does not have a is, however, widely used [234].

B.

firm physical basis. It

Structural Features of Fatigue

Two structural features that are observed to develop on the surface of the component during fatigue deformationare the ridges and grooves called slip-

181


+

+ I

+ In

In

E

G I

Cycles-

V

Figure 76 Thegeneraltypes of fluctuatingstress [179]. (Reprintedwithpermission from McGraw Hill Companies, New York.)

Number of cycles to failure, N Figure 77 Typical S-N curves inmetals [1791. (Reprintedwithpermissionfrom McGraw Hill Companies, New York.)

Chapter 2

0

" L

-400.0 0.1

1

IO0

10

1,000

10,000

Cycles to Failure Figure 78 Plot of plasticstrainrange,

AE,,, versus N for Type 1020 steel [232].

(Courtesy of TMS, AIME, Warrendale, PA.)

band extrusions and slip-bandintrusions. The fatigue cracks has been shown to initiate at intrusions and extrusions. A mechanism for producing slip-band extrusions and intrusions has been suggested by Wood 1235,2361. Based on microscopic observations of slip produced by fatigue, it was suggested that the slip bands are the result of a systematic buildup of fine slip movements, corresponding to movements of the order of 1 nm. Slip produced by static deformation would produce a contour at the metal surface similar to that In contrast, the back-and-forth fine-slip shown in Figure79a[235,236]. movements of fatigue could build up notches (Figure 79b) or ridges (Figure 79c) at the surface[235,236].Thenotchwouldbea stress raiser witha notch root of atomic dimensions. Such a situation might well be the start of

Figure 79 Development of intrusions and extrusions by fatigue loading (a) surface steps, (b) intrusions, and (c) extrusions.

Properties andof Lead

Its Alloys

183

a fatigue crack. This mechanism for the initiation of a fatigue crack agreement with experimental observations.

C.

is in

Fatigue Strength of Lead and Lead Alloys

An S-N curve for lead in air and in vacuum is shown in Figure 80 [2,231]. The data were obtained using a Haigh direct stressing machine in vacuum. in this case.The The S-N curve is a straight line withanegativeslope fatigue strength (at IO' cycles) is higher in vacuum than in air. Tests in oil and even acetic acid also show higher fatigue strength than that in air [237]. The difference in strength increases with the duration of the test. Table 40 presents data on fatigue strength of lead and lead alloys in different enviin air tendsto be intergranular, whereas that in ronments[238].Fracture vacuum exhibit 45% shear fracture. [ 184). The The fatigue strength of lead has a frequency dependence stress fluctuations in cablesheathingand outdool. installations frequently arise fromtemperaturechanges that occurover the day, andfrequencies commonlyencountered[239] will have - 1 cycles/dayas the lowestfrequency. Another source of themla1 stress is the variations in current in the case of high-voltage power transmission cables. Fatigue behavior of Pb and 1650 per the Pb-l wt.% Sb alloy at frequencies of 0.25perminuteand minute are compared in Figure 81 [239]. At an alternating strain of +-0.2%, 80

1

'b

5 Figure80 S-N curves for lead in air and in vacuum [2,231 1. (Courtesy of Springer Verlag, New York.)

Chapter 2

184

Table 40 Effect of Surrounding Media and Protective Coatings on the Fatigue Resistance of Lead and Lead Alloys [2,238). (Courtesy of Springer Verlag, New York.)

Materials Pb

+ 1.5% Sn + 0.25% Cd Pb + 0.5% S b

Pb

+ 0.25%

Cd

Surrounding medium or protective coating

Semirange of stress ( 2 MPa)

Air Normal acetic acid Rape oil Vaselin Air Petroleam bitumen Air Rape oil Vaselin

0.54 0.54 0.54

0.62 1.o

1.2 1.2

1.4 1.4

Endurance cycles ( 10")

1.3 8.5 u 7.9 9.8 U 1.6 9.3 u 1.3 9.6 6.4

"U = unbroken.

708 Cycles to failure Figure 81 Effect of frequency on number of cycles to failure [2,239]. (Courtesy of Springer Verlag, New York.)


185

pure lead withstands10,000and20,000cycles respectively (lives of 700 and 2 h). In lead with 1 wt.% Sb, the corresponding number of cycles are 130,000and2million(lives of 8670 and 20 h). If the duration of the vibration cycle exceeds 4-6 min, then fatigue strength does not seem to depend on frequency [240]. It seems that with harder alloys, the dependence of fatigue strength onfrequency is less marked. On the contrary, the life expressed in units of time decreases in all known cases at constant amplitude withincreasingfrequency of vibration (Table 41) [2,238]. The frequency dependence arises from the creep-fatigue interaction and environmental effects. Figure 82 presents the fatigue life of lead in units of time as a function of frequency at two different alternating strain levels [2,241]. The data from McKeller [2,238] on pure Pb and Pb-Sb-Sn and Pb-Sb alloys are shown in Table 42. The yield strength increases with decrease in grain size and a similar trend is expected for high cycle fatigue strength. Effect of grain size on the fatigue strength of lead was examined by Hopkins and Thwaites [200] on an alloy with 0.85% Sb which did not recrystallize during the tests. The SN curves were obtained using a rotating bending fatigue specimens at 3000 stress cycles per minute. In this study, the endurance limit was designated as a stress that causes failure in 20 million cycles. A superiority offinegrained material can be seen from these data presented in Table 43 [2,200]. The curves obtained with Pb-Sn alloys show the effect of alloy concentration and grain size simultaneously (Figure 83) [2,200]. The stability of microstructure during fatigue is important in the assessment of fatigue strength. Recrystallization and grain growth during testing leads to a reduction of fatigue strength. In fine-grained Pb and Pb-Sn alloys with less than 1 wt.% Sn, recrystallization is observed at a stress level just above fatigue strength. Tests with a single cycle per day are of significance for evaluating the effect of daily temperature fluctuations on the durability of lead-sheathed

Table 41 Effect of Cyclic Speed on Endurance of Lead Alloy Under Conditions of Rotating Flexure [2,238]. (Courtesy of Springer Verlag, New York.) Cyclestofailure Strain

at

3000 1.35 cycles/min cycles/min cycles/min cycles/min

Material

(%)

Pure lead Pb-0.2% Sn Pb-0.2% Sn-0.85% Sb

0.1 0.09 X IO6 0.1 0.2 X 10* 0.1 1.0 X IO*

4,700 16,600 100.000

Timetofailure

(h) at

3000

1.35

0.5 1.1

58 205 1,230

S .S

186

Chapter 2

I

100

1000

ro

9

Number of cycles per day

Figure 82 Relation between fatigue life in units of time and the frequency at two different alternating strain levels [2,241]. (Courtesy of Springer Verlag, New York.)

telephonecables, lead pipes, and so forth.The nightly coolingcausesa contraction,followed by the expansion of lead duringwarming. In highvoltage cables, longitudinal movements result from fluctuations in current day. However, both are much load. It is more frequent than one cycle per smaller than the frequency of fatigue testing machines. A frequency of 15 cycles/h has been used for cable sheaths [239]. For comparison of the fatigue strength of different alloys, the use of simple test pieces in the form of

Table 42 Fatigue Resistance of Extruded Lead and Lead Alloys in Direct-Stress Tests 12,2381. (Courtesy of Springer Verlag, New York.) Endurance limit at IO7 cycles, ?MPa Material

Pure lead Lead + 0.06% Te Lead + 1.5% Sn + 0.25% Cd Lead + 0.5% Sn + 0.25% Cd

At room temperature 2.8 7.6 8.8 11.5

At 100°C 1.2 5.1 4.3 6.2

187

Properties of Lead and Its Alloys Table 43 Effect of Grain-Size on the Fatigue-Resistance of the Lead-0.85% Antimony Alloy 12,2001. (Courtesy of Springer Verlag, New York.) Extrusion temp. ("C) 160 200 250 300

Average grain area (mm')

Endurance limit ( 2MPa)

0.0039 0.012 0.043 0. I9

9.7

8.6 8.1 7.1

extruded flat bars are recommended. However, in predictions of actu' 1 service performance, test piece geometry and testing conditions should be simulated as closely as possible. Pfender and Schulz [97] consider alternative bending strain as more significant than bending stress for cable sheath applications. They compared the fatigue behavior of soft lead containing 0.025% Sb, 0.046% Sn, 0.001% As, 0.002% Zn, 0.006% Cu, 0.001% Ag, 0.02% Si, and traces of Cd with a series of lead and lead alloys. Figure 84 presents data for soft lead and Pb containing 0.1% Sb, 0.1% Sn, and 0.08% As [2,97]. The data were

Average grain size (mm2) Figure 83 Effect of grain size on fatigue strength of Pb-Sn alloys. The grain size is expressed in terms of average projected grain area 12,2001. (Courtesy of Springer Verlag, New York.)

188

Chapter 2

Figure 84 S-N curves of commerciallead (Pb-0.025% Sb-0.046%Sn-0.001% As-0.002% Zn-0.006% Cu-0.001% Ag-0.02% Si-traces of Cd) and Pb-0.1% Sb0.1% Sn-0.08% As [2,97]. (Courtesy of Springer Verlag, New York.)

obtained using flat test pieces in a plane-bending fatigue machine. Figure 85 presents the data for all alloys [2,97]. The 5.5% Sb alloy shows good fatigue resistance when plotted in terms of either alternating stress or strain. However, when plotted in terms of stress, it is more marked. The decrease of stress with cycles suggests the beginning of damage to the material. With the use of alternating strain behavior as the criterion, the differences between unalloyed and alloyed lead becomes progressively smaller with increasing amount of strain. The curves for various alloys intersect at a strain of 0.1% and a number of cycles of 5 X 10' (Figure 85). This is the transition from a high cycle fatigue regime to the low cycle fatigue regime.In the low cycle fatigue regime, the ductility of lead alloy is important, whereas in the high cycle regime, the strength and hardness of the material is important. This is confirmed by the observations of Gohnand Ellis [239] (Figure86),who suggest a leveling of the different types of lead with respect to alternating strain behavior at -1% and a number of cycles at 2 X lo4. At alternating strains below 0.4% (high cycle fatigue regime) such as that in cable sheaths, the fatigue life of the cable can be increasedby alloying. The fatigue behavior of alloys with (1) 1% Sb, 0.15% As, 0.1% Sn, and 0.1% Bi and (2) that with 0.65% Sb and 0.25% Zn can be regarded as very similar (Figure 84). Then, behavior of very impure lead is similar to that of Pb with 0.64% Sb.


189

Cycles to failure Figure 85 S-N curves for leadalloys: (A) commerciallead; (B) Pb-0.08% As; (C) 0.8% Zn; (D) 1.5% Zn; (E) 0.6470Sb; (F) 0.47% Sb + 0.18% Cd; (G) 5.5% Sb [2,97]. (Courtesy of Springer Verlag, New York.)

The temperature dependence of fatigue strength is important because of the increasing impact of creep-fatigue interaction. A decrease of fatigue strength with temperature is expected in all cases, as can be seen from Table 42. Comparisons are usuallymadeon the basis of alternatingstress. According to Hopkins and Thwaites [200], antimony in lead increases the fathe Sb tigue strength as long as the alloys are single phase. However, as increases from 0.5 to 0.85 into the two-phase region, the fatigue strength

190

Chapter 2

0.010

+H t ";--

0.008

At m0 c y k perminute

Q)

K 0

g 0.006

& l

--

"

F v)

m

1

0 k

0.004

0.002

0

' 2 Cycles to failure

Figure 86 S-N curves of some cable sheathing alloys [2,239]. (Courtesy of Springer Verlag, New York.)

increase is not very significant (from 6.89 to 7.74 MPa). Additions of Sn 0.001% As,afurther showa similar effect. In alloyswith0.9%Sband increase in fatigue strength is obtained.Thefatigue strength increase in direct-tension compression tests in lead was obtained with small additions of c u 12421. Alloying of lead with Cd, Sb, or Sn alone or combined considerably increased the fatiguestrength,asdoesalloyingwith Te, Li, Ca, andCu. exMany alloys with high fatigue strength also exhibit high hardness, as pected. Pb-0.5 Sb-0.01 Te, Pb-0.5 Sb-0.15 As, and Pb-As-0.1 Sn-0.1 Bi show good fatigue strength among the 19 alloys examined by Hanffstengel and Hanemann [243]. In particular, the alloy with Te had a finer grain size and showed higher fatigue strength. Figures 87a and 87b illustrate the intergranular fracture of commercial lead and of arsenical Pb-antimony alloys in fatigue [2,243]. Pb-Ca alloys, however, show intragranular fracture (Figure 87c) [2,243].


Its Alloys

191

Figure 87 The intergranularfracture of (a)commerciallead,(b) arsenical Pbantimony alloys, and (c) Pb-Ca alloys in fatigue [2,243]. (Courtesy of Springer Verlag, New York.)

192

Chapter 2

A summary of fatigue strength of alloys with different thermomechanical history under different loading conditions are summarized in Tables 4446 [2,169,244].

V.

CORROSION PROPERTIES

Lead has an excellent record of service in the four major types of environments: chemical, atmosphere, water, and underground [2,61]. Resistance of lead to corrosion in contactwith sulfuric acidhasbeen critical in many chemical industries, including paper, petroleum, plastics, and photographic materials. Of particular importance in recent years has been the use of lead in the protection of devices for the removal of sulfur from industrial waste gases. Several industrial processes, such as ore roasting or burning of fossil fuels for power generation and industrial heating, produce large volumes of waste gases from which sulfur-containing species must be removed. Because of its excellent corrosion resistance in different water environments, lead has shown a long and reliable service in lead pipes for transporting water and in applications such as a water barrier in pools and showers, waterproofing, and flashings. Although current environmental regulations do not permit its use in the drinking-water supply system, lead or lead-lined components continue to be used in the handling of alum used in industrial-water-treatment systems. Thousands of kilometers of lead water service pipes and lead-sheathed cables have shown reliable long-term performance worldwide because of the extraordinary corrosion resistance of lead alloys to a variety of soil types. Using lead-covered copper for grounding systems, as for power plants, reprotection. The use of lead in duces or eliminates the needforcathodic nuclear-waste burial arises from its excellent resistance to corrosion in soil in addition to radiation shielding characteristics. Lead roofs, whether sheet lead, lead-coated copper, or perhaps terne-coated steel, have provided a superior performance in a variety of atmospheres in different partsof the world. The excellent corrosion performance of lead and its alloys is attributable to the formation of a strong, adherent, and impermeable protective film that is stable orinsoluble in the solution withwhich it is in contact. An appreciation for the ability for and the limits of corrosion protection afforded by lead can be gained by a brief examination of the film formation process and its stability. In the next sections, the nature of lead corrosion in aqueous solutions, the experimental corrosion rate data in several industrial chemical solutions of interest, and corrosion behavior under atmospheric exposure, soil exposure, and exposure to natural and industrial waters are presented.

9

0

Table 44

P

Fatigue Strength of Lead

Grade 99.99% Lead

Treatment Extruded Extruded, 100 h, 250°C Cold rolled Cold rolled 1 h,

T

Machine Haigh Push Pull Haigh Push Pull Haigh Push Pull Haigh Push Pull

No. of cycles

Frequency (min-')

Fatigue strength (MPa)

1o7 1o7

2000 2000

22.7 2.7

1o7 1o7

2 v)

5 Ref.

6 m

2 2

m 3 P

P

2000 2000

2.6 3 .O

2 2

2200 2200 700 700 2500

2.5 5.7 1.5 4.8 4.5

2 2 2 2 2

2000 3000 740 800 800

2.1-2.9

250°C

Broken Hill (99.99%) Commercial lead Commercial lead with 0.09% Bi Commercial lead 99.99% Lead

Commercial lead ~

"Extrapolated value.

Extruded Extruded Extruded Extruded Extruded -

Extruded Extruded Extruded Extruded Extruded

-

P

2 9 v)

Haigh Push Pull in air Haigh Push Pull in vacuum Rotating Illinois Plane Bending Illinois Plane Bending

3 x lo7 3 x 107 5 x lo7

Haigh Push Pull Haigh Push Pull DVL Plane Bending Rotating Rotating Rotating

1o7 3.6 x lo7 lo7" 3.6 x lo7 3.6 x lo7 2 x 10'

1 o7 1o7

2.8

3.1 1.3 2.2 2.0

Table 45

Fatigue Strength of Lead Alloys

Addition

Wt. %

Ca

0.026 0.038 0.04

0.03 0.028-0.039 0.06 0.07 0.04

0.06

Treatment

Solid solution + aging precipitation aging Solid solution + precipitation Extruded Extruded Solid solution + aging + precipitation

+

Machine

1o7

+

-

Extruded Solid solution + aging + precipitation Extruded and age hardened Extruded and stored 2 weeks Extruded and stored 6 months Extruded and stored 6 months

No. of cycles

Frequency (min-.')

I o7 lo7 10'

2500 700 2000

-

10'

s

s

x 10' x lo7

244 -

2 2 2 244

10.0

-

4.6-5.8 7.7

18.7-23.8

2 2 244

10.7 10.3 11.0-1 1.4

5.6- 10.3 2000 700

Ref.

244

4.7-5.7

5 x 107 Haigh Push Pull Rotating

UTS (MPa)

7.1

s x 107 Haigh Push Pull


-

I o7

740

9.8

Rotating

5 x lo7

800

5.9

23.9

2

Rotating

sx

lo7

800

7.2

28.6

2

Rotating

s

x lo7

800

7.9

30. I

2

DVL Plane Bending

2

0.04

Extruded Extruded

Cd

0.3 0.3 0.5

cu

0.06

Sb

0.25 0.50 0.75

I .o

Rolled 1 h, 250°C Rolled 1 h, 250°C Extruded Precipitation Extruded in laboratory Extruded in laboratory Extruded in laboratory Extruded Extruded Extruded Rolled 1 h, 250°C Extruded and stored 6 months Extruded Extruded in laboratory Aging

Illinois Plane Bending Illinois Plane Bending

-

Haigh Push Pull Haigh Push Pull Haigh Push Pull Haigh Push Pull

-

Rotating Illinois Plane Bending Haigh Push Pull

1700

10.3

31.0

2

lo7"

1700

8.3

26.3

2

6.3 x lo7" 1o7 1o7

-

Haigh Push Pull

lo7"

s

I o7 I o7 I o7 I o7 I o7 x lo7 -

2200 2200 2200 2500 700 2000 700 -

7.0 6.3 9.7 8.8 4.3 6.9 5.8 7.6 9.1 9.0 8.3 8.1 2.1-3.1 9.7 9.3 3.6

5 x lo7

800

I o7

1700

6.9

I o7 5 x lo7

2200

9.6 2-7

-

20.7

2 2 2 2 2 244 2 2 2 2 2 2 2 2 2 2

22.1

2

-

-

-

-

-

19.0-27.6 -

-

2 244

Table 45

Continued ~~~~

Addition Sn

~

Wt. % 1.o

2.0

Treatment Extruded in laboratory Extruded in laboratory Extruded Extruded -

3.0

Te

0.05

Cd with Sn Cd with Sb Sn with Cd + Sb Sb with As

0.25 1.5

0.25 0.5 1.2 0.2 0.1 1.o 0.05

"Extrapolated value.

Aging Rolled 1 h, 250°C Extruded in laboratory Extruded

Machine Haigh Haigh Haigh Haigh Haigh

Push Push Push Push Push

-

Pull Pull Pull Pull Pull

Haigh Push Pull Haigh Push Pull Haigh Push Pull Haigh Push Pull Rotating -

Extruded 1 h, 250°C Extruded 1 h, 250°C Extruded

DVL Plane Bending

Extruded

DVL Plane Bending

No. of cycles I o7 1 o7

I o7 10'

I o7

Frequency (rnin-') 2200 2200 2500 700 2000

5 x lo7


UTS (MPa)

Ref.

5.1 6.8 6.6

4.8 6.1 5.5 8.1

1o7 2 x 107

2200

740

7.2 7.4 7.7 5.9 8.5 7.6 11.1 10.6 6.9

740

12.3

2 x lo7

-

1074

-

2

Properties andof Lead Table 46

Its Alloys

Fatigue Properties of Russian Cable Sheathing Alloys [ 1691

N

IO-'" (unannealed)

compositions Alloy Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb

197

+ 0.05% Cu

+ 0.3% Sb + 0.5% Sb + 0.7% Sb + 1.0%Sb

+ 0.03% Te

+ 0.05% Te + 0.1% Te + 0.3% Sb + 0.03% Te + 0.5% Sb + 0.03% Te + 0.5% Sb + 0.05% Te + 0.5 Sb + 0.1 Te + 0.5 Sb + 0.1 Se + 0.5 Sb + 0.08 Cu + 0.3 Sb + 0.03% Te + 0.05% c u Pb + 0.5 Sb + 0.03% Te

+ 0.05% c u

X

0.8

5.9 1.7 1.2

2.4 2.1 5.7

7.9 12.8 12.0 14.5 15.7 6.6 4.2 1.6 2.5 15.5

N ,X IO-'" (after annealing at 100°C)

N z X IO-'" (after annealing at 250°C)

1.2 1.8 3.6 6.7 7.5 9.5 6.6 9.0 14.8

9.9 10.3 14.6 16.7 6.9 7.4 10.8

12.5

9.9

"Cycles to failure in alternating bend tests at an amplitude of t0.5 mm and a frequency of 7 Hz.

In presenting this information, the LeadIndustryAssociationmanual corrosion behavior of lead and its alloys has been consulted.

A.

on

The Nature of Lead Corrosion in Chemical Solutions

The corrosion of lead in aqueous electrolytes is an electrochemical process. In the case of lead, the Pb is oxidized to Pb'+ at the anode. The Pb'+ ions either enters the solution at the anodic sites as metallic cations or form solid insoluble compound films. The reaction at the anode could be represented by Pb

+ Pb2' + 2e-

(24)

This oxidation reaction that takes place at the anodic sites is accompanied by a reduction of some constituent in the electrolyte at the cathodic sites. In neutral salt solutions, the cathodic reaction is the reduction of dissolved oxygen:

Chapter 2

198

In acid solutions free of oxygen, the corresponding cathodic reaction is

2H'

+ 2e + H2

During the corrosion of a material such as lead, local anodes and cathodes the surface of lead that may havea may be set up on adjacentsiteson different chemical activity because of differences in composition, crystalline orientation or structure, stress variations, and temperature. Structural inhomogeneities of importance include inclusions and grain boundaries. In the case in which two metals are coupled, one of the metals takes on a net anodic behavior and corrodes in preference to the more noble metal that has become a net cathode as a result of the coupling of the two metals. In most environments, lead is cathodic to steel, aluminum, zinc, cadmium, and magnesiumand, thus, will accelerate corrosion of these metals. In contactwith titanium and passivated stainless steels, lead will serve as the anode of the cell and will sufferacceleratedcorrosion. The corrosion rate in both the casesdepends on the difference in potential between the twometals, the ratio of their areas, and their polarization characteristics. As the net charge transferred at the anode should be the same as that at the cathode, the corrosion rate could be controlled by retarding either the anodic or the cathodic reaction. In the case of lead and its alloys, the solubility and physical characteristics of the corrosion product film formed at the anode is the rate-determining factor; thus, the corrosion rate of lead is usuallyunderanodic control. Thecorrosionproduct films formedon the surface of lead in many corrosion environments are relatively insoluble and impervious salt films that tend to retard further attack. The formation of such protective films is responsible for the high resistance of lead to corrosion by sulfuric, chromic, and phosphoric acids. Leadformsadherent protective films overabroadrange ofpHin aqueous solutions except at very high and very low pH levels. The exceptions at the low pH level include sulfuric and phosphoric acids. Soft water will cause some corrosion of lead, but in water containing mineral salts such as carbonates and sulfates, aprotective lead-salt film forms, limiting further attack. The solubility of the protective film depends on factors such as concentration and temperature. Table47 presents solubility data for various lead compounds in water (pH = 7) [61]. Table 48 shows the variation of the solubility of PbSO, film in sulfuric acid with concentration and temperature 1611. It is seen that lead sulfate is less soluble in sulfuric acid solution than in water. At intermediate concentrations, it is negligible. With an increase

C)


Its Alloys

199

Table 47 Solubility of Lead Compounds 1611. (Courtesy of Lead Industries Association, New York.)

Lead Formulacompound

water

cm' of

~~~

Acetate Bromide Carbonate Basic carbonate Chlorate Chloride Chromate Fluoride Hydroxide Iodide Nitrate Oxalate Oxide Orthophosphate Sulfate Sulfide Sulfite

Pb(C2HIOZ)2 PbBr, PbCO, 2PbCO,, Pb(OH), Pb(CIO,), . HZO PbClz PbCrO, PbF, Pb(OH), Pb12 Pb(N0,)2 PbC20, PbO PbdPO,), PbSO, PbS PbS03

20 20 20

44.3 0.844 1

-

Insoluble 151.3

0.000 1 1

18 20 25 18 18 18 18 18 18 18 25

0.99

0.0000058 0.064 0.0 I55 0.063 56.8 0.00016 0.00 17 0.000014 0.00425 0.0 1244 Insoluble

18

Table 48 Solubility of Lead Sulfate in Sulfuric Acid at Various Concentrations and Temperatures [61]. (Courtesy of Lead Industries Association, New York.)

Sulfuric acid concentration (wt %) 25°C 0

Lead sulfate dissolvcd mg in 1 L of' solution at 0°C 33

0.005

X

0.0 1

7 4.6 1.8 1.2 0.5 0.4 0.4 1.2 2.8 6.5

0.1 1 10

20 30 60

70 75

80

44.5 10

8 5.2 2.2 1.6 -

1.2 1.2 1.8 3 11.5

57.7 24.0 21 .o 13.0 11.3 9.6

8 4.6 2.8 3 6.6 42

Chapter 2

200

in temperature, the solubilities increase and the corrosion rate will be expected to increase. In the case of lead in nitric acid, the lead nitrate film is soluble in dilute and intermediate strengths but not at high concentrations, and lead is quite resistant to attack in concentrated nitric acid (Figure 88). The dissolved oxygen in the solution and the velocity of corrosive medium across the metalfacealsoimpact the corrosion rates. In addition to the solubility of the surface film, other factors that influence the corrosion rate include the extent of mechanically disruptive influences such as the agitation of solution or the creep of lead that damage the film and expose a fresh surface to the corrosive medium. Depending on the corrosion environment, one usually deals with different forms of corrosion. Uniform corrosion of the material is experienced when lead is exposed to atmosphere. Pitting corrosion, which is very localized to the pit region, will be experienced when conditions of partial passivity or cavitation exists. Intergranular corrosion is experienced when the grain-boundary region has a higher relative chemical activity. Accelerated corrosion can occur when erosion, fatigue, and fretting are synergistically coupled with corrosion.

HNOB concentration (YO) Figure 88 Solubility of leadnitrateinnitricacid tries Association, New York.)

[61]. (Courtesy of LeadIndus-

Its Alloys


201

B. Corrosion Rates of Lead in Acids Lead has high corrosion resistance to chromic, sulfurous, sulfuric, and phosphoricacidsand is widelyused in their manufactureandhandling.Lead satisfactorily resists all but the most dilute strengths of sulfuric acid (Figure to 95% at ambient tem89) [61]. It performs well with concentrations up peratures, up to 85% at 220°C and up to 93% at 150°C. Below a concentration of 5%, the corrosion rate increases, but it is still relatively low. In the lower range of concentration, antimonial lead is recommended. Similar corrosion behavior is observed with higher concentrations of chromic, sulfurous, and phosphoric acids at elevatedtemperatures.Lead finds awide application in the manufacture of phosphoric acid from phosphate rock when sulfuric acid is used in the process. Corrosion rates of lead are low for 49) [61]. However,when in purephosconcentrationsupto85%(Table phoric acid manufactured from elemental phosphorus, lead shows a higher corrosion rate due to the absence of sulfates. Lead has a fair corrosion resistance to dilute hydrochloric acid up to 15% at 24°C. The corrosion rate increases at higher concentrations and at

e l-

500

-

400

-

200

-

(U

175

-

125

-

0-5 mpv

Less than 5 mpv below 50% conc

50

60

70

80

90

Sulfuric acid (wt.%) Figure89 Corrosion rate of lead in sulfuric acid [61]. (Courtesy of Lead Industries Association, New York.)

Chapter 2

202

Table 49 Corrosion of ChemicalLeadin Phosphoric Acid at 21°C [61]. (Courtesy of Lead Industries Association, New York.)

Corrosion rate Solution

(mpy).' 3.4 4.9 5.7 6.4

20% H,PO, (commercial) 30% H,PO, (commercial) 40% H,PO., (commercial) 50% H,PO, (commercial) 85% H,PO, (commercial) 85% H,POJ (pure)

1.6

12.8

"Mils per year (= mdd X 0.127). mdd = milligrams/declmeter/day, I mil = 25.4 km.

higher temperatures (Table 50) [61]. The presence of 5% ferric chloride also accelerates the corrosion rate (Table 51) [61]. Most concentrations of nitric, acetic, and formic acids corrode lead at a rate high enough to preclude its use. However, although dilute nitric acid rapidly attacks lead, at strengths of 52% to 70% it has little effect (Table 52) [61]. This pattern of action is also true of hydrofluoric acid, acetic acid, and acid sodium sulfate. The resistance of lead to attack by hydrofluoric acid is fair. However, the corrosion rate in this acid if it is free of air is less than 20 mpy for a wide range of temperatures and concentrations (Figure 90) [61 I. In general,

Table 50 Corrosion of Lead in HydrochloricAcidat24°C Lead Industries Association. New York.)

Solution

Chemical lead (mPY)

1611. (Courtesy of

6% Antimonial lead (mpy)" 33

1% HCI 5% HCI 10% HCI

24 16 22

IS% HCI 20% HCI 25%HCI 35% HClh

31

I S0

72 170 350

160 200 540

"Mils per year (= mdd X 0.127). "Concentrated HCI commercially available.

20 43


Its Alloys

203

Table 51 Corrosion of LeadinHCI-FerricChlorideMixturesat24°C[61]. (Courtesy of Lead Industries Association, New York.)

Antimonial Chemical 6% lead lead Solution 76

5% HCI 10% HCI 15% HCI 20% HCI

+ 5% FeCI, + 5% FeCI, + 5% FeCI, + 5% FeCI,

“Mils per year (= mdd

X

37

28

41 160 190

88 150

0.127).

lead is used with hydrofluoric acid because it is the only material in its price range that has any significant corrosion resistance. In mixed acids. the presence of sulfuric acid tends to retard corrosion rates, as illustrated in Figure 91 and by the data of Tables 53-56 [61].

C.

Corrosion Rates of Lead and Lead Alloys in Chemical Solutions

The many different chemicals and thermodynamic conditions normally encountered in the chemical environment make it difficult to present a complete set of corrosion rates for any material of construction. The corrosion data for lead under a variety of environments are presented in Tables 5759 [61]. The grade or alloy of lead to which some data apply is not specified. or copper-bearing lead. The Most tests, however,correspondtochemical data for nuclear repository applications are presented in Chapter 4.

Table 52 Corrosion of Lead in Nitric Acid [61]. (Courtesy of Lead Industries Association, New York.)

Corrosion rate (mpy)“ Solution 1% HNO,

3490

5% HNO, 10% HNO, “Mils per year (= mdd X 0.127).

140 1650 3400

600 1850

204

Chapter 2

Figure 90 Corrosion resistance of lead in air-free hydrofluoric acid[611. (Courtesy of Lead Industries Association, New York.)

D. Corrosion of Lead in Atmosphere Lead in most of its forms exhibits excellent corrosion resistance in different types of atmospheric exposure, including industrial, rural, and marine. The primary causes of corrosion in the three atmospheric environments are different. In rural areas, which are relatively free of pollutants, the only important environmental factors influencing corrosion rate are humidity, rainfall, and airflow. However, near or on the sea, chlorides entrained in marine air often exert a strong effect on corrosion. In industrial environments, sulfur oxide gases and the minerals in solid emissions considerably change patterns of corrosion behavior. Pure lead does not tarnish in dry air. In moist air, a dull oxide film forms on its surface. The studies of the mechanism of lead oxidation indicates that the film formed on the lead is extremely thin and impervious and,

205

Properties of Lead andIts Alloys 100% HNO,

Figure 91 Corrosionresistance oflead Industries Association. New York.)

tomixedacids

1611. (Courtesy of Lead

thus, protective. The character of the film and its rate of formation are determined by the adsorption of oxygen and water vapor on the lead. Althoughfactorssuchas industrial andmarinepollution,humidity, temperature, and rainfall profoundly affect the aggressiveness of the atmosphere, the protective films formed on lead are so effective that corrosion is insignificant in most natural atmospheres. The extent of this protection is demonstrated by the survival of lead roofingand auxiliary products after hundreds of years of atmospheric exposure. Table 60 shows very low corrosion rates that do not vary significantly among different locations [61].

Table 53 Effect of Nitric Acid-Sulfuric Acid

Mixture on the Corrosion of Lead at 118°C 1611. (Courtesy of Lead Industries Association, New York.) Solution ~~

~

54% H,SO, 54% H,SO, 54% H,SO,

~~

Chemical lead WPY)

6% Antimonial lead (mPY)

7.4 5.9 8.4

14 22 114

~~

+ 0% HNOz + 1% HNO, + 5% HNOz

Chapter 2

206

Table 54 Corrosion of Chemical Lead in Sulfuric Acid-Nitric Acid Mixtures [61]. (Courtesy of Lead Industries Association, New York.)

Corrosion rate (mpy) ~

Solution HISO,

50°C

HNO, + 78% 78%HZSO, + 78% H2S0, + 78% 35 H,SO, +

~~~

~~

24°C

0% 1%HNO, 3.5% HNO, 7.5%HNO,

2 12 18

l

3 3.6 4

Antimonial lead exhibits approximately the same corrosion rate in atits greater hardness, mosphericenvironments as chemicallead.However, it moredesirable for usein strength,and resistance tocreepoftenmake roofs and reflecting pools. The ability of some antimonial leads to retain this greater mechanical strength in atmospheric environments has been demonstrated in exposure tests. Lead sheets containing 4% antimony and smaller

Table 55 Corrosion of Lead in Hydrochloric Acid-Sulfuric Acid Mixtures (Courtesy of Lead Industries Association, New York.)

Antimonial 6% Chemical lead lead (mpyY’ 66°C Solution 24°C 1 % HCI

3% HCI 5% HCI

7%HCI 9% HCI 5% HCI 10%HCI 15% HCI 20%HC1 25%HCI 5% HCI 10%HCI 15% HCI 20%HCI 25%HCI

66°C

+ 9% H2S0, + 7% H2S0, + 5% H,SO, + 3% HISO,

+ 1% H$O, + 25% H2S0, + 20%HZSO, + 15% HZSO, + 10% H,SO, + 5% H2S0, + 45% H2SOJ + 40% H2S0, + 35% H2S0, + 30%H$O,

+ 25%H$OJ

“Mils per year (= mdd

X

0.127).

[61].

(mpy)“

24°C 5

9

5

14 14

32 42 45 47 22 42 74 120 I60

21 21 22

16 18 10 17

41 86 I40 62 65

30

22 80 90 I 10 150

53 x4

66

I20

x4 I20

130 210

12 41 65 74 84 34 58 180

180 210


Alloys

207

Table 56

Effect of Sulfuric Acid on the Corrosion of Lead in Fluosilicic Acid at 45°C (611. (Courtesy of Lead Industries Association, New York.)

(mPY)Solution

9

5% H,SiF, 5% H,SiF, + 5% H2S0, 10% H2SiF, 10% H,SiF, + 1% H,SO, 1% H,SiF, + 10% H,SO,

Chemical lead (mPY)

6% Antimonial lead

53

77 14 1 l5 76

9 64 88 4

amounts of arsenic and tin wereplaced in semirestricted positions for 3 years. They showed less of a tendency to buckle than chemical lead indicating that their greater resistance tocreepwas retained. In the case of electrodeposited lead coatings, the porosity and pinholes present in the coating make the corrosion data suspect and misleading.

Corrosion of Lead in Various Chemical Solutions 16 1 1. (Courtesy of Lead Industries Association, New York.)

Table 57

rateCorrosion Temperature ("C)

Solution 33% Sulfuric acid sodium chloride

+ 6.7%

Sulfurous acid (3% SO,) Sodium sulfate (saturated) Sodium sulfide (10%) Triethanolamine Phthalic anhydride Calcium acid sulfite Sodium chloride (0.25-6%) Potassium nitrate (0.5- 10%) Calcium carbonate Calcium bicarbonate Sodium carbonate Magnesium sulfate "Mils per year (= mdd X 0.127).

24 60 80 24 24 24 60 88 24 8 8 X

8 8 8

(mpy 6 12 36 1 1

1 18 17 I 0.2- 1.2

0.9-3.0 0.3 0.2 0.6 0.3

N

Table 58 Corrosion of Lead in Chemical Processes [61]. (Courtesy of Lead Industries Association, New York.) Process Sulfation of oils with 25% sulfuric acid (66" Be)-14O0F (60°C) Castor Tallow Olive Cod liver Neatsfoot Fish Vegetable Peanut Sulfonation with 93% sulfuric acid (66" Be) Naphthalene Phenol Washing and neutralization of sulfated and sulfonated compounds Sulfated vegetable oil + water wash-neutralized with sodium hydroxide Naphthalene sulfonic acid + water wash-neutralized with caustic soda pH 3 Washing tallow with 2% by weight 60" Be sulfuric acid Storage of liquid alkyl detergent Storage of 50% chlorosulfonic acid-50% sulfur trioxide Mixing tank and crystallizer-saturated ammonium sulfate-5% sulfuric acid solution Splitting Olive oil and 0.5% sulfuric acid (66" Be) Storage of split fatty acids Storage of split fatty acids Extraction of aluminum sulfate from alumina Bauxite + sulfuric acid-boiling Bauxite + sulfuric acid-boiling

Temp ("C)

0 03

Corrosion rate (mpy)"

3 12 3 6 11 11

23 18 166 120

45 3

60 70 121

9 39 5 0.3 0.6 1-5

47

88

11

Liquid 0.8 Liquid level 12 Liquid 16 Vapor 5

3 p)

-2

2

h)

Alum evaporator Tank for dissolving alum paper mill Storage of 24% alum solution Dorr setting tank 19.5 Sulfuric acid, 20% ferrous sulfate, 10% titanium oxide as TiSO, Evaporator Nickel sulfate solution Zinc sulfate solution Ammonium sulfate production Solution-saturated ammonium sulfate + 5% sulfuric acid Solution-saturated ammonium sulfate + 5% sulfuric acid Acid washing Lube oil-treatment with 25% sulfuric acid Sludge oil + 15% sulfuric acid-stream treatment Benzol (crude)-treatment with 3% sulfuric acid washed with water, neutralized with lime Tar oil-treatment with 25% sulfuric acid, washed with water, neutralized with sodium hydroxide Wet acid gases from regeneration of sulfuric acid Polymerization Polymerization of butenes with 72% sulfuric acid Polymerization of butenes with 72% sulfuric acid Viscose rayon spinning bath Evaporator-6% sulfuric acid, 17% sodium sulfate, 30% other inorganic sulfates Evaporator-concentrated bath of 20% sulfuric acid, 30% sodium sulfate Vapors from spin bath evaporator Spinning bath drippings Storage-reclaimed spinning bath liquor Pickling solution Brass and copper-sulfuric acid + 5% cupric sulfate "Mils per year (= mdd

X

0.127).

116 49

3 16 0.6

70

10

100 107

6

47 47

Mixing tank 1 Crystallizer 5

104

25 20

60 77 121 80 80

6

6

24 6

0.5 14 pits

40 55 49 46

4 5

71

5

5

8 2

Chapter 2

210

Table 59 Classifying Corrosion Behavior of Lead in Different Environments 1611 (See Footnote). (Courtesy of Lead Industries Association, New York.)

Chemical Abietic acid Acetaldehyde Acetaldehyde Acetanilide Acetic acid Acetic acid Acetic anhydride Acetoacetic acid Acetone Acetone cyanohydrin Acetophenetidine Acetophenone Acetotoluidide Acetyl acetone Acetyl chloride Acetyl thiophene Acetylene, dry Acetylene tetrachloride Acridine Acrolein Acrylonitrile Adipic acid Alcohol, ethyl Alcohol, methyl Alkanesulfonic acid Alkyl aryl sulfonates Alkyl naphthalene sulfonic acid Allyl alcohol Allyl chloride Allyl sulfide Aluminum acetate Aluminum chlorate Aluminum chloride Aluminum ethylate Aluminum fluoride Aluminum fluorosulfate Aluminum fluosilicate Aluminum formate Aluminum formate Aluminum hydroxide Aluminum nitrate Aluminum potassium sulfate

Temp. ("C) 24 24 24- 100 24 24 24 24 24 24- IO0 24- 100 24 24- 100 24 24- 100 24 24- 100 24 21 24-52 24-52 24- 100 24- 100 24- 100 24- 100 24 24- 100

93 24 24 24 24- 100 24- 100 24 24- 100 24- 100 24 24- 100 24 100 24- 100 24 24- I00

Concentration Corrosion (%o)

class

D A B A B C A B A B B B B B A B A B B B A A A A D B C B C D A B B B B A B B D B B A

Properties and of Lead

Its Alloys

21 1

Table 59 Continued Concentration Temp. Corrosion ("C) (%)

Chemical Aluminum potassium sulfate Aluminum sodium sulfate Aluminum sulfate Aminoazobenzene Aminobenzene sulfonic acid Aminobenzoic acid Aminophenol Amniosalicyclic acid Ammonia Ammonium acetate Ammonium azide Ammonium bicarbonate Ammonium bifluoride Ammonium bisulfite Ammonium carbamate Ammonium carbonate Ammonium chloride Ammonium citrate Ammonium diphosphate Ammonium fluoride Ammonium fluosilicate Ammonium formate Ammonium hydroxide Ammonium hydroxylamine Ammonium metaphosphate Ammonium nitrate Ammonium oxalate Ammonium persulfate Ammonium phosphate Ammonium picrate Ammonium polysulfide Ammonium sulfamate Ammonium sulfate Ammonium sulfide Ammonium sulfite Ammonium thiocyanate NH,OH Ammonium tungstate Amyl acetate Amyl chloride Amyl laurate Amyl phenol Amyl propionate

+

24- 100 24- 100 24-1 18 24 24- I00 24-93 24- 100 100- 149 24- I00 25 24 24- 100 24 24-52 24- 149 24- 100 24 I00

24- 100 24 24-52

20- 100 10 -

__ -

10-30 3.85 -

10 10 10 0- 10 10

0-20 20

100

10

27 20- 100 24 20-52 24 24- 100

3.5-40 34

66

24- 100 24- 100 24- 100 24 24- 100 24- 100 24 24 24 24 24- 100 200 24- 100

10 10-30 10-30 10-30 -

10 10 10 -

10

10-40 -

IO 80- 100 -

class

B B A C B B B C B B B B B A A B B D B B B C A B B D D B A B B B B C B A D B D B D B

Chapter 2

212

Table 59 Continued Chemical Aniline Aniline hydrochloride Aniline sulfate Aniline sulfite Anthracene Anthraquinone Anthraquinone sulfonic acid Antimony chloride Antimony pentachloride Antimony sulfate Antimony trifluoride Arabic acid Arachidic acid Arsenic acid Arsenic trichloride Arsenic trioxide Ascorbic acid Azobenzene Barium carbonate Barium chlorate Barium chloride Barium cyanide Barium hydroxide Barium nitrate Barium peroxide Barium polysulfide Barium sulfate Barium sulfide Benzaldehyde Benzaldehyde sulfonic acid Benzamide Benzanthrone Benzene Benzene hexachloride Benzene sulfonic acid Benzene sulfonic acid Benzidine Benzidine disulfonic acid 2.2 Benzidine 3 sulfonic acid Benzilic acid Benzobenzoic acid Benzocathecol

Concentration Temp. Corrosion ("C) (%l

20 24 24- 100 24- 100 24- 100 24- 100 24- 100 24 24- 100 100

24- 100 24- 100 24 24 100-149 24- I O 0

24 24- 100 24 24- 100 24- 100 24 24 24- 100 24 100

24- 100 24 24 24- 100 24- 100 24- 100 24 24 24 100

100

24- 100 24-100 24- 100 24- 100 24- 100

class A D B B B B B C B C A B B B B B

D B D B B D D B D D B B D B B B B B B D B B B B B B


213

Table 59 Continued Chemical Benzoic acid Benzol Benzonitrile Benzophenone Benzotrichloride Benzotrifluoride Benzoyl chloride Benzoyl peroxide Benzyl acetate Benzyl alcohol Benzylbutyl phithalate Benzyl cellulose Benzyl chloride Benzyl ethyl aniline Benzylphenol Benzylphenol salicylate Benzylsulfonilic acid Beryllium chloride Beryllium fluoride Beryllium sulfate Boric acid Bornyl acetate Bornyl chloride Bomyl formate Boron trichloride Boron trifluoride Bromic acid Bromine Bromobenzene Bromoform Butane Butanediols Butyl acetate Butyl benzoate Butyl butyrate Butyl glycolate Butyl mercaptan Butyl oxalate Butyl phenols Butyl phthalates Butyl stearate Butyl urethane

Concentration Temp.Corrosion W) ("C)

24 24 24- 100 24- 100 24- 100 24- 100 100

24242424242424242424-

l00 100 100 100 100 100 100

I00 100 100 100 24- 100 24- I00

24- 149 24- 100 24- 100 24- 100 24- 100 24-204 24- 100 24 24- 100 24- 100 24 24 24 24- 100 24- 100 24- 100 24 24 24 24- 100 24- 100 24- 100

class

D A A A B B C B B B B B B B B B B D B B B B B B B A B B B B A B B B B B C B C B B B

Chapter 2

214

Table 59 Continued Concentration Temp.Corrosion ("C) (%)

Chemical Butyric acid Butyric aldehydes Butyrolactone Cadmium cyanide Cadmium sulfate Calcium acetate Calcium acid phosphate Calcium benzoate Calcium bicarbonate Calcium bisulfite Calcium bromide Calcium carbonate Calcium chlorate Calcium chloride Calcium chromate Calcium dihydrogen sulfite Calcium disulfide Calcium fluoride Calcium gluconate Calcium hydroxide Calcium lactate Calcium nitrate Calcium oxalate Calcium phosphate Calcium pyridine sulfonate Calcium stearate Calcium sulfaminate Calcium sulfate Calcium sulfide Calcium sulfite Camphene Camphor Camphor sulfonic acid Capric acid Caprolactone Capronaldehyde Capronaldehyde Cabozole Carbitol Carbon disulfide Carbon fluoride Carbon tetrabromide

+ SOz

24 24- I O 0 24- 100 24 24- 100 24 24 24- 100 24 24 24- 100 24 24 24 24- 100 24 24 24- 100 24- 100 24 IO0

24 24- 100

+ H?SOJ

IO-l00 10-30

10-30

20

A

10-30 -

-

30

20

IO S IO 10 IO IO 10

24 24- 100 24- 100 24- 100

20

100

100

24 24- 100 24- 100 24 52- 100 24- 100 24- 100 24- 100 24- 100 100

D B B D A B B B C B B D B

20

100

24- 100 24- IO 0

class

IO IO IO 20- 100

-

-

-

B A

B B B

D B D B B A B A B C B B A C B B A B B B A

B C

Properties and of Lead

Its Alloys

215

Table 59 Continued Chemical Carbon tetrachloride (dry) Carbonic acid Carnallite Carotene Cellosolves Cellulose acetate Cellulose acetobutyrate Cellulose nitrate Cellulose tripropionate Cerium fluoride Cesium sulfate Cesium chloride Cesium hydroxide Cetyl alcohol Cetyl alcohol Chloroacetic acid Chloral Chloramine Chloranil Chloranthraquinone Chlordane Chlorethane sulfonic acid Chloric acid Chlorine Chlorine dioxide Chloroacetaldehyde Chloroacetone Chloroacetyl chloride Chlo-alkyl ethers Chloroanlinobenzoic acid Chloroaniline Chlorobenzene + SO, Chlorobenzotrifluoride Chlorobenzoyl chloride Chlorobromomethane Chlorobromopropane Chlorobutane Chloroethylbenzene Chloroform Chlorohydrine Chloromethonic ester Chloronaphthalenc

Concentration Temp.Corrosion ("C) (%) BP 24 24- 100 24- I00 24- I00 24 24- 100 24- 100 24- I00 24- 100 100

24- 100 24 24 100 24 24- 100 24 24- 100 24- 100 24- 100

class A

D A A A A B B B B C B D

24 38 6 24 24- 100 24 24- 100 24- I00 24- 100

B C B B B B B B C D B B B B B B B B

18

A

24- 100 24- IO0 24 24- 100 24 24- 100 24-BP 24- 100 24- 100 24- 100

B B B B

100

B

B B B B B

Chapter 2

216

Table 59 Continued Temp. ("C)

Chemical Chloronitrobenzene Chlorophenohydroxy acetic acid Chlorophenol Chloroquinine Chlorosilanes Chlorosulfonic acid Chlorosulfonic acid + 50% SO, Chlorotoluene Chlorotoluene sulfonic acid Chlorotoluidine Chlorotrifluro ethylene Chloroxylenols Chloroxylols Cholesterol Chromic acid Chromic chloride Chromic fluoride Chromic hydroxide Chromic phosphate Chromic sulfate Chromium potassium sulfate Chromium sulfate (basic) Chromyl chlorides Citric acid Citric acid Cobalt sulfate Copper chloride Copper sulfate M-cresol + 10%water M-cresol 10% water 0-cresol + 10%water 0-cresol + 10%water Cresote Cresylic acid Cresylic acid Crotonaldehyde Crotonic acid Cumaldehyde Cumene Cumene hydroperoxide Cyanamide Cyanoacetic acid

+

24- 100 24- 100 24 24 24- 100 24 19

24- 100 24 24- 100 24- 100 24 24- I O 0 24- 100 24 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24-79 24 24 24 24- 100 25

Concentration Corrosion W)

class

-

B B C C B C C B C B B C B B B B B B B B B B B B D B D B B D B D D D B B D B B D B D

-

-

40 -

-

IO 10

20-50 -

10-30 50- l00 10-30

10-40 10-70 Liquid

BP

Vapor

25

Liquid Vapor 90 90

BP

24 24 24 24- 100 24 24- 100 24- 100 24 24- 100 24

100 -

__

-

217


Table 59 Continued Chemical Cyanogen gas Cyclohexane Cyclohexanol Cyclohexanol esters Cyclohexanone Cyclohexene Cyclohexy lamine Cyclopentane DDT Dialkyl sulfates Dibenzyl Dibutyl phthalate Dibutyl thioglycolate Dibutyl thiourea Dichlorobenzene Dichlorodifluro-methane (Freon- 12) Dichlorodiphenyldichloroethane (DDD) Dichloroethy lene Diethanolamine Diethyl ether Diethylamine Diethy laniline Diethylene glycol Difluoroethane Diglycolic acid

Dihydroxydiphenylsulfone Diisobutyl Dimethyl ether Dioxane Diphenyl Diphenyl chloride Dipheny lamine Diphenylene oxide Dipheny lpropane Epichlorohy drin Ethane Ether Ethyl acetate Ethyl benzene Ethyl butyrate Ethyl cellulose Ethyl chloride

Temp. ("C)

24 24 24 24- 100 24 24- 100 24 24- 100 24 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24 24 24 24- 100 24-52 24- 100 24 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24- 100 24 24-100 24 24-19 24- 100 24- 100 24- 100 24- 100

Concentration (700)

Corrosion class

D B B B B B D B B B B

B B B B A B A B B D B

I? B D

B B B B

B B A B B A A

B B B B B B

Chapter 2

218 Table 59

Continued

Chemical Ethyl ether Ethyl formate Ethyl lactate Ethyl mercaptan Ethyl stearate Ethyl sulfonic acid Ethyl sulfonic acid Ethylene Ethylene bromide Ethylene chlorohydrin Ethylene chlorohydrin Ethylene cyanohydrin Ethylene cyanohydrin Ethylene dibromide Ethylene dichloride Ethylene glycol Ethylene oxide 2-Ethylhexoic acid Ferric ammonium sulfate Ferric chloride Ferric ferrocyanide Ferric sulfate Ferrous ammonium sulfate Ferrous chloride Ferrous sulfate Fluoboric acid Fluocarboxylic acid Fluorine Fluosilicic acid Formaldehyde Formamime Formic acid Furfural Gluconic acid Glutamic acid Glycerol Glycerophosphoric acid Glycol monoether Glycolic acid Glycolic acid Heptachlorobutene Heptane

Concentration Temp.Corrosion (TOO) (“C)

24- 100

-

100 24- I O 0 100 24- 100

-

24

-

100 24- 100 100

-

24 52- 100 24 52- l00 24 24- 100 -

24 71 24- 100 24 66-93 24-79 24 24 24- I O 0 24 24 24- I O 0 45 24-52 24- 100 24- 100 24- 100 24 24 24 24 24- 100 24 100

24 24- 100

-

-

-

90 100 100

90

class

B C B D B B C A B A

B A B D

-

B B B C A D A A B C B C D A D B B D B B D B B B B D B

-

A

-

50 -

96 10-20 20-30 -

10-20 10 10-30 IO 30 -

10 20- 100 -

IO-l00 -

10-100 -

10-100 10

219

Properties of Lead and Its Alloys Table 59 Continued Chemical Hexachlorobutadiene Hexachlorobutene Hexachloroethane Hexamethylene tetramine Hydrazine Hydriodic acid Hydrobromic acid Hydrochloric acid (see Table IO) Hydrofluoric acid Hydrogen bromide (Anh HBr) Hydrogen chloride (Anh HCI) Hydrogen peroxide Hydrogen sulfide Hydroquinine Hydroxyacetic acid Hypochlorous acid Iodine Iodoform Isobutyl chloride Isobutyl phosphate Isopropanol Lactic acid Lead acetate Lead arsenate Lead azide Lead chloride Lead chromate Lead dioxide Lead nitrate Lead oxide Lead peroxide Lead sulfate Lithium chloride Lithium hydroxide Lithium hypochlorite Lithopone Magnesium carbonate Magnesium chloride Magnesium chloride Magnesium hydroxide Magnesium sulfate Magnesium anhydride

Concentration Temp. Corrosion ("C) (%)

24- 100 24 24- 100 24- 100 24 24 24 24 24 100

24 24 24 24- IO0 24 24 24 24- I O 0 24 24 24 24 24 24- 100 24- 100 24- 100 24- I00 24- IO0 24- 100 24- IO0 24- I00 24- IO0 24- I O 0 24 24-79 24 24 24 24 24 24- 100 27

-

10-40 20- 100 10-50

10-70 0- 10

2-10 -

100 10-30 90- 100 10 -

-

IO -

-

IO-l00 10-30 -

-

10 -

10 -

IO 0- 10

IO-IO0 10-30 10-60 IO

class A B B B D D D C B D A D B B A

D D B B B A D D B B B B B B B B B B

D A A D C D D B C

Chapter 2

220

Table 59 Continued Chemical Malic acid Mercuric chloride Mercuric sulfate Mercurous nitrate Mercury Methanol Methyl ethyl ketone Methyl isobutyl ketone Methylene chloride Monochloroacetic acid Monochlorobenzene Monoethanolamine Naphthalene Naphthalene sulfonic acid + HZSO, Nickel ammonium sulfate Nickel nitrate Nickel sulfate Nitric acid (see Table 5 ) Nitrobenzene Nitrocellulose Nitrochlorobenzene Nitroglycerine Nitrophenol Nitrosyl chloride Nitrosylsulfuric acid Nitrotoluene Nitrous acid Oleic acid Oxalic acid Oxalicacid + 1.5-3% H2S0, Pentachloroethane Perchloroethylene Persulfuric acid Phenol Phenolsulfonic acid Phenyl isocyanate Phosgene Phosphoric acid Phosphorous acid Phosphorous chloride Phosphorous oxychloride Phosphorous pentachloride

Concentration Temp.Corrosion ("C) (%) 100

24 24- 100 24 24 30 24- 100 24- 100 24- 100 24 24 171

24 88

24- 100 24- 100 24- 100 24-52 24 24 24 24 24 24-79 24 24 24 24 S2 79 24 100

24 24- 100 24 24- 100 24-93 27 24- 149 24 24

class

B C B D D B B B B D D C B B B B B B A

D C D B B B D D D A

B B C B B B B B A

B B A

Properties Its and of Lead

Alloys

22 1

Table 59 Continued ~~

Chemical Phosphorous pentachloride Phosphorous tribromine Phosphorous trichlorine (dry) Phthalic anhydride Picric acid Potassium aluminum sulfate Potassium bicarbonate Potassium bifluoride Potassium bisulfate Potassium bisulfite Potassium bromide Potassium carbonate Potassium chlorate Potassium chlorate Potassium chloride Potassium chromate Potassium cyanide Potassium dicromate Potassium ferricyanide Potassium fluoride Potassium hydroxide Potassium hypochlorite Potassium iodate Potassium iodide Potassium metabisulfite Potassium nitrate Potassium permanganate Potassium peroxide Potassium persulfate Potassium sulfate Potassium sulfite Propionic acid Pyridine Pyridine sulfate Pyridine sulfonic acid Pyrogallic acid Quinine Quinine bisulfate Quinine tartrate Quinizarin Quinoline Quinone

Temp. ("C)

Concentration Corrosion class -

52- l49 24 24 82 20 26 24 24-79 24- 100 24- 100 24- 100 24 24

10 10

B B

10-20 10-50 10-50

C

100

10

8 24- 100 24 24- 100 24- 100 24-79 24-60 24 24-BP 24 79 8

24 24 24 24- 100 24 24 24- 100 24 24 24 24- 100 24- l00 24- 100 24- 100 24- 100 24- 100

B A

5.25 25

B B C

-

A

10-30

D

10

10

0.25-8.0 10-40 10-30

10-60 10-60 20 0-50 10 2- I O 30 10-30

0.5- 10 10-40 IO 10

10-20

B C B D B B D B

B B B B B D

B B C D D B

10

B

10-70 IO IO

D

20

A

-

IO -

IO

B B B B B B

B B B

222

Chapter 2

Table 59 Continued Chemical Saccharin solutions Salicylic acid Selenious acid + H,SO, + HNO, Silver nitrate Sodium acetate Sodium acid fluoride Sodium aluminate Sodium bicarbonate Sodium bifluoride Sodium bisulfate Sodium bisulfite Sodium carbonate Sodium carbonate Sodium chloride Sodium chlorite Sodium chromate Sodium cyanide Sodium hydrogen fluoride Sodium hydrosulfite Sodium hydroxide Sodium hypochlorite Sodium hyposulfite Sodium nitrate Sodium nitrite Sodium perborate Sodium percarbonate Sodium peroxide Sodium persulfate Sodium phosphate Sodium phosphate (tri-basic) Sodium silicate Sodium sulfate Sodium sulfide Sodium sulfite Sodium tartarate Stannic chloride Stannic tetrachloride (dry) Stannous bisulfate Stannous chloride Succinic acid Sulfamic acid Sulfur dioxide

Concentration Temp. Corrosion (%) ("C)

24- 100 24- 100 93 24 25 24 24 24 24 24- 100 24- 100 24 52 25 24 24- 100 24 71

24 26 24 24 24 24- I00

24 24 24 24 24- 100 24 24 24 24- 100 24- 100 24 24 24 24- 100 24 24- 100 22 24-204

class

-

B B

-

A

10-60 4 10

IO IO -

10-30 10 10

20 0.5-24 IO 10 IO 8

10-20

D B B D B B B B B D A

B B B B A

-

B C B D B D D D B B D B

2-20 10-30

A A

10-30

B D D B B D B B B

0-30 1 10 10 10-60 IO -

IO IO 10-100

10-20

-

20 100 10 10-50

10-50

3-20 90


223

Table 59 Continued Concentration Temp. Corrosion ("C) (%)

Chemical Sulfur trioxide Sulfuric acid (see Figure 4) Sulfurous acid Sulfuryl chloride Tanning mixtures Tannic acid Tartaric acid Tetraphosphoric acid Thionyl chloride Thiophosphoryl chloride Tetrachloroethane Titanium sulfate Titanium tetrachloride Toluene Toluene-sulfochloride Thrichloroethylene Thrichloronitromethane Triethanolamine Triphenyl phosphite Turpentine Vinyl chloride Zinc carbonate Zinc fluosilicate Zinc hydrosullite Zinc sulfate Zinc chloride

24

90

60 24 21 24 100 2024 30-70 24 10-100 24- 149 24 63 24- I00 10-30 24 24- 100 24 27 24 60 0.4 27 24 24 10 24 21 30-36 24

35

79

-

25

class

B A

B B D B D B B A

B B A A

B C B A B D B D B B B

Notc,: Data mostly correspond t o chemical lead. The corrosion rates of different grades of lead In contact with the same chemical a l l normnlly fall within the same category. Thereforc, no mention is made of any variatlon ~n the corrosion rate for other grades of lead. The four corrosmn pcrfonnnncc categorles are a s follows:

A < 2 mils/year; negligible corrosion; lead recommended for use. B < 2O/mpy; practically resistant; lead recommended for use. C is 20-SO mpy. Lend may be used where this effect on service lifc can he tolerated. D > SO mpy. Corrosion rate too hlgh t o merlt any consideration of lead. The absence

01 concentrat~on

data IS indicated by a dash.

224

Chapter 2

Table 60 Corrosion of Lead in Various Natural Outdoor Atmospheres [61]. (Courtesy of Lead Industries Association, New York.)

Location Altoona, Pennsylvania New York Sandy Hook, New Jersey Key West, Florida La Jolla, California State College, Pennsylvania Phoenix, Arizona Kure Beach, North Carolina, 80 ft. side Newark, New Jersey Point Reyes, California State College, Pennsylvania Birmingham, England Wakefield, England Southport, England Bourneville, England Cardington, England Cristobal, C Z Miraflores, C Z

Type of atmosphere

Material

Industrial Industrial Industrial Industrial Seacoast Seacoast Seacoast Seacoast Seacoast Seacoast Rural Rural Semiarid Semiarid East coast, marine East coast, marine Industrial Industrial West coast, marine West coast, marine Rural Rural Urban Urban Industrial Marine Suburban Rural Tropical, marine Tropical, marine

Chem Pb 1% Sb-Pb Chem Pb 1% Sb-Pb Chem Pb 1% Sb-Pb Chem Pb 1% Sb-Pb Chem Pb 1% Sb-Pb Chem Pb I % Sb-Pb Chem Pb 1% Sb-Pb Chem Pb 6% Sb-Pb Chem Pb 6% Sb-Pb Chem Pb 6% Sb-Pb Chem Pb 6% Sb-Pb 99.96% Pb 1.6% Sb-Pb 99.995% Pb 99.995% Pb 99.995% Pb 99.995% Pb Chem Pb Chem Pb

"mdd = milligrams/square decimeters/day. hmpy = mils per year.

Duration (years) 10

10 20 20 20 20 10 10

20 20 20 20 20 20 2 2 2 2 2 2 2 2 7 7 1 I 1 1

8 8

Corrosion Rate mdd

mpyb

0.23 0.18 0.12 0.10 0.17 0.16 0.18 0.17 0.16 0.18 0.10 0.11 0.03 0.09 0.4 1 0.32 0.46 0.33 0.28 0.20 0.43 0.3 1 0.29 0.03 0.58 0.55 0.61 0.44 0.42 0.24

0.029 0.023 0.0 15 0.013 0.02 1 0.020 0.023 0.022 0.02 1 0.023 0.013 0.014 0.004 0.012 0.052 0.041 0.058 0.042 0.036 0.026 0.055 0.039 0.037 0.004 0.074 0.070 0.077 0.056 0.053 0.030


225

E. Corrosion of Lead in Water Distilled water free of oxygen and carbon dioxide does notattack lead. Pure water containing carbon dioxide butnot oxygen also has little effect on lead. However, when lead comes into contact with pure water through which air free of carbon dioxide is being bubbled, it quickly oxidizes to form a film of white lead hydroxide. This film is nonadherent and allows the attack on the lead to continue. Because the lead hydroxide is low in solubility, it settles out. This is one case in which even though the corrosion product is insoluble, its nonadherent characteristic fails to prevent lead corrosion. A yellow crystalline lead oxide forms on the lead surface at or near the waterline. In pure or distilled water containing both oxygen and carbon dioxide, a basic lead carbonate film forms at ahigherratio of carbondioxide to dissolved oxygen, protecting the lead from further attack. However, once a certain ratio of CO, to 0, is reached, further increases in the carbon dioxide level cause the insoluble lead carbonate film to convert to soluble lead biattack carbonate.When this occurs, the film dissolvesandcorrosive commences. Thus, the corrosion behavior of lead in water containing carbon dioxide and oxygendependson the concentration of the former gas. This dependency, which causes many reactions to take place in a narrow range of concentration, explains the contradictory nature of much of the corrosion data reported in the literature. The influence of carbondioxidealsoshowswhy lead steam coils which handle pure water condensate are not severely corroded. In the case where all the condensate is returned to the boiler and negligible makeup is used, there is an absence of oxygen and often of carbon dioxide. Sometimes, there is some carbon dioxide present. This is from the breakdown of carbonates and bicarbonates in the boiler water. In either case, lead will not significantly corrode. If a substantial amount of condensate is discarded and fresh water is continually fed to the boiler, corrosion of lead can occur. This is usuallyprevented by keeping the oxygen level low by addingoxygen scavengers, such as sodium sulfite or hydrazine, to the makeup water. In the case of dimineralized water, corrosion rates are very low for chemical lead and Pb-6% Sb and Pb-2% Sn alloys (Table 61) [61]. Most natural waters contain silicates, sulfates, and carbonates which can form lead-salt surface films stifling further attack. In general, the corrosion rate will dependon the hardness of the water. Naturalwaters of moderate hardness (i.e., greater than 125 ppm as calcium carbonate) form adequate protective films on the lead; thus, attack is negligible. The presence of salts, such as silicates, increases the hardness and the protective nature of the film. In contrast, nitrates interfere with the formation of the protective film, causing increased corrosion.

Chapter 2

226

Table 61 Corrosion of Lead in DemineralizedWater 1611. (Courtesy of Lead Industries Association, New York.)

Lead Chemical (ASTM) 6% Antimonial lead 2% tin-lead

mpy"

mdd"

2.3 0.2 0.6

18 I .6

4.8

"Mils per year. "Milligrams/square decimeter/day.

In soft aerated waters, the corrosion rate depends both on the hardness level of the waterand its oxygen content. The corrosivity of soft waters with a hardness level of less than 125 ppm depends on the same factors that govern the action of distilled water. This often eliminates lead as a material that can be used in piping or containers for handling potable waters, in which no more than 0.10 ppm (see Chapter 5 ) of lead is permissible. This issue of contamination also affects the use of lead even in situations where, from a service point of view, the corrosion rate is negligible. Other waters corrosive to lead include those containing enough carbonic acid to convert calcium carbonate deposits into soluble calcium bicarbonate. The presence of organic acids whose lead salts are soluble also promotes corrosion. Conversely, film-forming lime or sodiumsilicate can be added to the water to lower the corrosion rate. The corrosion rates of lead in some industrial and domestic waters are shown in Table 62 [61]. It shouldbenoted that in all cases, even where hardness was below 125 ppm, the corrosion rate is relatively low. A corrosion rate forfreshwater is alsoincludedamong the data for seawater in Table 63 [61]. The maincomponentdissolved in seawater is sodiumchloride,but there are also several other major constituents and at least a trace of almost all of the elements. The proportions of the major constituents in ocean water are quite uniform, and their total concentration influences many properties of the water. This total concentration, called the salinity, is defined as the to total amount of solid materialwhen all carbonatehasbeenconverted oxide, the bromine and iodine replaced by chlorine, and organic matter completely oxidized. The salinity of natural seawaters varies between 33 and 37 parts per thousand, with the average being approximately 35. This is equivalent to a salt content of about 3.4%. Coastal waters and tide-swept harbors may have lower salinity. In enclosed seas, the level depends on the relative rates of evaporation and land drainage.


Its Alloys

227

Table 62 Corrosion Rates of Lead in Some Industrial and Domestic Waters 1611. (Courtesy of Lead Industries Association, New York.)

Type of water Condensed stream, traces of acid Mine water, pH 8.3, 110 ppm hardness Mine water, 160 ppm hardness Mine water, 1 I O ppm hardness Cooling tower, oxygenated Lake Erie water Los Angeles aqueduct water, treated by chlorination and copper sulfate Spray cooling water, chromate treated 16

Corrosion rate"

Temp. ("C)

Aeration Agitation mdd

21-38 20

None Yes

Slow Slow

6.75 0.26 2.08

0.85

19 22 16-29

Yes Yes Complete

Slow Slow None

2.2 1.98 41.7

0.28 0.25 5.3

Ambient

-

0.5 ft/s

0.38 2.95

Yes

mpy

-

2.9

0.37

"Total immersion.

Table 63 Corrosion Rate of Lead in Natural Waters 1611. (Courtesy of Lead Industries Association, New York.) Corrosion rate Location type and

of water

Type of Agitation test mdd

mpy

about Immersion Bristol seawater Channel, Southampton, seawater docks,

CZ, Lake, Gatun tropicalImmersion water fresh Fort Amador, CZ, tropical Pacific Ocean San Francisco Harbor, seawater Port Hueneme Harbor, California, seawater Beach, Kure seawater "150 mm/s. "60 mm/s.

3.9 93% of time 0.1At0.86 half tide level Immersion Mean tide level Mean tide level Immersion

0.50 1

Still 0.5 ft/s flow" 0.5 ft/s flow" Flowing 0.2 ft/s flowh

0.66 2.7 1.6 3.31 1.7

0.08 0.36 0.20 0.42 0.22

228

Chapter 2

The corrosion of lead in seawater is relatively slight and may be retarded by incrustations of lead salts. Data that represent the performance of lead in seawater at several locations are given in Table 63 [61]. This table shows that at the same tropical location, lead corrodes in freshwater at about one-fourth the rate it does in ocean water. The factors that can affect the corrosiveness of ocean harbor waters are salt content, pollution, rate of flow, wave action, sand or silt content, temperature, and marine growth.

F. Corrosion of Lead in Soil Lead is used extensively in the form of sheathing for power and communications cables because of its impermeability to water, ease of forming, and its excellent resistance to corrosion in a wide variety of soil conditions. The incidence of corrosion failure of lead-sheathed cables is low in relation to the total mileage of cables in undergroundservice.Lead is also usedin nuclear-waste burial in underground repositories. Serious corrosion of lead in the underground is an exception rather than the rule. Cables are either installed in ducts or buried directly in the ground. IntheUnited States, the preferred method is to put the cable in ducts or conduits made of materials such as cement, vitrified clay, wood, and so forth. Theenvironmental factors generallyhavea greater effect onunderground corrosionthan differences in leadcomposition,and there is a significant difference in the environments of lead buried in ducts and directly in soils. The environment within ducts is often quite complex. It can include combinationsofhighlyhumidmanholeandsoilatmospheres,freelime leached from concrete, and alkalis formed by the electrolysis of salts in the water which seeps into ducts. The galvanic coupling, differential aeration, alkalinity, and stray currents are major factors that influence the corrosion of lead sheaths in ducts. When the surface of the lead is scratched, exposing bright, activemetal, the freshmetalsurface will be the anodeand will corrode. The amount of air able to penetrate the silt and reach the crevice where the cable sheath and duct meet is less than the amount available at the upper surface of thecable sheath. Such differential aerationconditionsleadto corrosion of the lead sheath. Cable sheaths installed in continuous concrete or asbestos cement ducts in concrete tunnels under waterways could sometimesbe exposed to alkaline water (pH 10.9-12.2) containing mainly calcium hydroxide and sometimes sodium hydroxide. The source of the calcium hydroxide is traced to incompletely cured concrete. Electrolysis of solutions of deicingsalts that had seeped into the tunnels could be a source of sodium hydroxide. The buildup in concentration can occur if seepage water is not drained.


Alloys

229

Stray currents can cause serious corrosion of lead pipe or lead cable sheathing.Sources of stray currentsincludeelectricrailwaysystems, grounded electric direct current power, electric welders, cathodic protection systems and electroplating plants. Alternating currents are much less damaging than direct currents. Corrosion is at a minimum when the sheath potential is cathodic to the ground. Other factors that can initiate corrosion of lead sheaths include contact with acetic acid in wood ducts, microorganisms, and corroded steel tapearmor. Bacterial corrosionusuallyoccursunder poorly aerated conditions in the presence of mud, water, and organic matter. Bacteria capable of reducing sulfate to sulfides are the principal cause of the attack on lead. Microbial decomposition of the hydrocarbons present in cable coatings may also produce organic acids corrosive to lead. Corrosion of lead by corroded steel tape armor can occur when the oxide-coated steel formed is cathodic to lead. When the lead is buried directly in soil, the extent of corrosion varies widely as the physical and chemical characteristics of the soils differ over a wide range. The physical properties of soils which are of most interest in corrosion are those that influence the permeability of the soil to air and water. This is because good drainage tends to minimize corrosion. Soils with a coarse texture such as sands and gravels permit free circulation of air. The corrosion in such soils is approximately the same as that occurring in the atmosphere. Clay and silt soils are generally characterized by a fine texture and high water-holding capacity, which results in poor aeration and drainage. Numerous chemical compounds are present in soils, but the ones that play an important role in corrosion are those soluble in water. The presence of base-forming elements, such as sodium, potassium, calcium, and magnesium, and the acid-forming groups, such as carbonate, bicarbonate, chloride, nitrate, and sulfate,caninfluence the progress of corrosion, as was discussed earlier. Another factor which directly affects the corrosion of leadsheathed cable is the differences among the soils through which the cable passes. Corrosion can be caused by soils which differ in ionic content, moisture level, and degree of aeration. These differences can set up anodic and cathodic areas separated by large distances. Tables 64 and 65 present the corrosion data of lead and lead alloys in a variety of soil conditions [61]. The forms of lead used for their corrosionresistant properties are castings, extrusions, androlled products. The castings used for corrosion resistance include filter grids, anodes, valves, pipe fittings and flanges, pumps, and a few types of vessels like evaporators. Some of the lead and lead-alloy extrusions used in applications requiring corrosion resistance are battery anodes, seamless pipe, heating and cooling coils and tubes, cable sheathing and sleeves, and burning bars. The rolled lead sheets may be used as Supported Lead, Bonded Lead, and Brick Lead.

230

Chapter 2

Table 64 Corrosion Data of Lead Alloys in Various Soils after I 1 Years [61]. (Courtesy of Lead Industries Association, New York.) Chemical le a d Type of soil Cecil clay loam Hagerstown loam Lake Charles clay Muck Carlisle muck Rifle peat Sharkey clay Susquehanna clay Tidal marsh Docas clay Chino silt loam Mohave tine gravelly clay Clinders Merced silt loam

Corrosion rate (mPY)

Max pit depth (mils)

4.0

15.9 19.0 22.2 31.8

4.4 6.7 8.5

0,

Mm. contacting overlap, Lb (mm)

12.7 14.3

r

8 P

7 in. 8 C

17.5

19.0

?tvo equal thicknesses of each gauge. Commercial coating weights up to 137 dm'. Material must be free from dirt. grease, paint, and so forth. Qimensional variables are as shown in sketches (a), (b) and (c):

(a) Electrode Diameter and Shape

(b)Weld Nugget Diameter

(c) MinimumContactingOverlap

Blectrode Material Croup A, Class 2. Water cooling with 7.5 L/min. P 0 tJl

406

Chapter 3

5. Automotive Fuel Tank Production The corrosion protection trend among domestic North American automakers is toward widespread application of two-side coated steel [349]. The current and near-future corrosion protection specifications of coated sheet products emphasize manufacturability (i.e., forming,joining, and painting criteria). The coated-sheet products used by the domestic North American manufacturers include both hot-dip and electroplated pure zinc and zinc-iron coatings to 100 g/m*/side) and terneplate. The current and future higher usage of coated steel and the heavier coatings being specified by North American manufacturers are reflections of the philosophy that use of such materials is both a technical improvement and a cost-effective way of providing durability in a highly corrosive environment. The use of terneplate (usually long terne) for automotive fuel tanks is standard practice, as it is corrosion resistant and can be soldered or welded readily using the resistance seam-welding process (RSEW) to produce an economical, leakproof unit. A recently developed material variant is the top coating of a long terne sheet with organic coatings. Azinc-rich organic coating is used for additional protection on the outside of the fuel tank, and an aluminum-rich organic coating is used for additional protection on the inside of the fuel tank. The aluminum augments the long terne’s resistance to the newer auto fuels [e.g., those containing low concentrations (about 10%) of methanol, ethanol, or both]. Through the years, refinement in welding terneplated steel for use in automotive fuel tanks has resulted in welding speeds of 300 in./min (127 mm/s) for 20-22-gauge (0.93-0.78 mm) material. Welding normally is accomplished with seam welders either facing each other or in tandem. Welding is performed in a straight line across one side or end of the fuel tank, with automatic equipment handling the tanks. Welding at the indicated travel speed requires heavy-duty equipment, using a one-cycle-on/one-cycle-off timing schedule (or similar) for AC machines, or a continuous schedule for DC machines to obtain consistently sound welds. Tack welding is required and care must be exercised when crossing prior welds at the corners in order to prevent leaks or blowholes. To give consistent production quality, careful attention must be paid to the knurl drive wheel design.The knurl drive wheel can control the buildup of tin and lead on the wheel electrodes by breaking up the buildup. Also, the knurl drive wheels may function to control the shape of the contact face of the wheel electrodes. This can be accomplished by using knurlers designed with a radius in the wheel contact area or by using a flat knurler design equipped with side cutters that constantly trim the wheel contact face

Processing Products of Lead

407

to a specific width. Both electrodes should be knurl driven, ideally, to deliver a more positive drive, lessen the possibility of skidding, and provide constant maintenance of both electrode contact faces.

H. Mechanical Fastening of Supported Lead In supported lead, the lead sheets are reinforced by mechanically fastening to the supportive steel, wood, or concrete structure. The major types of such equipment are loose-lined and cage-supported vessels, flues, ducts, launders, towers, reactors, floors, floor linings, expanded lead-lined pipe, cable sheathing. rooting, and anodes [611. 1.

Loose-Lined Equipment

Loose-lined construction involves hanging or fastening lead sheet linings to the walls and bottoms of steel, wood, or concrete vessels. This is one of the least expensive and most easily repaired types of vessel. Its use is limited to moderate-temperature ranges and when abrasive conditions, vacuum service, or very large tanks are not involved. Theoutersupporting shell of loose-lined vessels such as tanks, stills, and evaporators may be steel, wood, or concrete. Digestors, evaporators, mixing tanks, and stills are usually made with steel. Woodis generally used only for moderate-sized storage tanks, plating tanks, or vats. Concrete tank shells are often used in making electrolytic cells. A bituminous or asphaltic coating is applied cold to the concrete shell before lining it with lead to prevent incompletely curedor “green” concrete from corroding the lead. Chemical lead is usually chosen for loose-lining small tanks under mild conditionssuchas negligible abrasion,agitation, and flow.Useof 6-8% antimonial lead is recommended when abrasion from mechanical abuse, agitation, or flow is involved, when the tank is very large, or when the operating temperatures exceed 65°C. The thickness of the lead lining may be 8-, 12-, or 16-lb-lead, depending on the expected corrosion rate, mechanical loads, and thermal cycling. The joints or seams should be located where they will be subjected to the minimum stress during operation. Loose lead linings are fastened to the outer shell using lead-covered bolts, lead buttons, and lead-covered steel strapping, or by spot bonding. If the lining exceeds 3.3 m (10 ft) in height, lead-covered, half-oval steel straps should be used. Metallurgically bonding small areas of loose linings (spot bonding) helps support them and distributes the weight load more evenly. Figures 70 and 71 illustrate the different methods of fastening lead sheet to the walls of steel vessels [61]. Figure 72 shows the fastening of lead sheet to wood orconcrete walls [344]. Figure 73 shows the different types of joints used in a lead-lined steel vessel [61].

408

Chapter 3 Burned

Figure 70 Fastening of steel straps in loose-lined vessels 1611. (Courtesy of Lead Industries Association, New York.)

2.

Cage Supported Equipment

Cage or basket construction is a framework of steel pipes, fiats, and angles welded together to support a vessel formed by welding lead sheet together. This type of vessel can be prefabricated and assembled in the field. The main features of cage construction are low cost, rapid heat dissipation, early

Carria e bolt

Stove bolt

Lead strap

Roundhead bolt

Figure 71 Bolt support of loose-leadlinings 1611. (Courtesy of LeadIndustries Association, New York.)

Processingof Lead Products

409

a. Simple, visible fixlng ROWd-heeded

m e w and washer. May be coated with high lead-content

c Lead button or dome

Stamlesss t e e l screw

d. Soldered dot

ReamedWbrass m e w and washer Wiped, soldered or

leadburned dot finished flush

Figure 72 Some of the methods for fastening lead sheet on wood and concrete walls [344a]. (Courtesy of Lead Development Association, UK.)

Chapter 3

410 D d l of l a p . u m

D a i l of top

b.1.d of band iron oupport of load lining

Detail of lapping and burningat bottom of flat tank

Altmato mothad uoing a wood fillw

Shell lmng

Tank bottom1 lining

Lapping and burningat con.

Figure 73 Loose-lined leadtank [61]. (Courtesy of Lead Industries Association, New York.)

leak detection,andeasy repais. Figure 74 showsanexample of this cage (or basket) type of construction [611. Many hazardous fluids may be safely contained in this type vessel, because it has a high percentage of visually exposed surface area which speeds up the detection and repair of leaks.

41 1

Processing of Lead Products

abd le of tank

Figure74 Cage-constructed lead vessel [61]. (Courtesy of Lead Industries Association, New York.)

412

3.

Chapter 3

Floors and Floor Linings

Lead sheet has been used as a corrosion-resistant membrane under the floors of metal-plating and acid plants. In other cases, such as in nitroglycerine plants, the lead sheet is made the top layer of the floor. This takes advantage of the fact that lead is nonsparking and is easier to clean than wood. As lead is resistant to corrosion by most natural waters, it is also used as a waterproof membrane under reflecting pools, shower pans, and planters and as flashing on buildings.

4.

Expanded Lead-Lined Pipe

Expanded lead-lined pipe is often used when operating pressures are too high to be safely handled by lead or hard lead pipe. This supported lead pipe is made by inserting lead pipe into steel pipe and expanding the lead pipe tightly against the inside steel wall. Thesize of lead pipe to use in making expanded pipe is the one which will have the minimum clearance between it and the steel pipe. Expanded lead-lined pipe is available in a wide range of diameters in standard lengths of 20 ft (6.6 m) with lead linings of from 1/8 in. to 3/8 in. (3.2-9.5 mm) in thickness. Typical sizes and weights are shown in Table 15 [61].

1.

Bonded Lead

Bonded lead is metallurgically joined laminates of lead and another metal, usually steel (Figure 75) [61]. This type of composite material has the corrosion resistance of lead combined with the stronger mechanical properties of steel. It will resist delamination so strongly that only by melting the lead or the solder bonding layer or chipping it off with a pneumatic hammer can it be separated from the steel. These excellent performance characteristics allow bonded-lead-type equipment to meet such demanding operating conditions as rapidly fluctuating temperatures, vibration, and changes in pressure from positive levels to vacuums. In addition,as lateral movement of the lining is severely restricted, the only response to thermal cycling is an occasional increase in lining thickness. The thermal and electrical conductivities of bonded-lead vessel walls are high, due to the gapless nature of the metallurgical bond. The cost of bonded-lead vessels is higher than supported-lead vessels with strapped-on linings because of the cost of the metallurgical bonding process. Other metals have been joined metallurgically with lead to make bonded-lead equipment, such as lead-clad copper steam coils. The essential difference between bonded lead and the metallurgically bonded lead coatings is that the former has a much thicker layer of lead,

Table 15 Expanded and Homogeneously Bonded Lead-Lined Pipe 161I. (Courtesy of Lead Industries Association, New York.) I.D.

L. Th. mm

in.

mm

12.5 19 25.4

1/2 314

31.8

1-114

38. I

1-112

50.8

2

63.5

2- I12

76.2

3

101.6

4

127

5

152.4

6

in.

3.18 3.18 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25 3.18 4.76 6.25

1

L. wt.

I.D. mm

kE

in. ~~

203

8

254

10

254

10

305

12

~

Wt.

kg/m

Ib/ft

2.98 3.43 3.72 5.5 1 7.00 6.85 8.04 9.23 8.19 9.68 11.17 10.43 12.8I 14.90 14.90 17.87 20.85 19.81 22.94 26.36 27.70 32.02 36.94 37.39 42.0 48.4 I 45.88 52.88 60.62

2.0 2.3 2.5 3.7 4.7 4.6 5.4 6.2 5.5 6.5 7.5 7.0 8.6 10.0 10.0 12.0 14.0 13.3 15.4 17.7 18.6 21.5 24.8 25.1 28.2 32.5 30.8 35.5 40.7

L. Th. lb

mm

~

Wt.

in.

kg/m

Iblft

70 80 75.8 85.8 88.2 100.4 92.8 104.9 102.2 1 14.2 114.1 132.1 122.6 140.6

47.0 53.7 50.9 57.6 59.2 67.4 62.3 70.4 68.6 76.7 76.6 88.7 82.3 94.4

~

11.4 11.4 13.2 13.2 14.5 14.5 15.9 15.9 18.6 18.6 20.4 20.4 23.2 23.2

25 25 29 29 32 32 35 35 41 41 45 45 51 51

4.76 6.25 4.76 6.25 4.76 6.25 4.76 6.25 4.76 6.25 4.76 6.25 4.76 6.25

3/16 I 14 3/16 114 3/16 114 3/16 1/4 3/16 1 14 3/16 114 3/16 I 14

Nore: I.D. = inside diameter: L. Th. = lining thickness: L. Wt. = weight classilicntion of lining: Wt. = Weight in kg/m2 and Ib/l't (approx).

414

Chapter 3 Bonded Lead

X:Lead or lead alloy Y:Steel, wood or concrete Z:Metallurgical bond

Figure 75 York.)

Bondedlead

[61]. (Courtesy of Lead IndustriesAssociation,

New

which allows it to provide long service life even in severely corrosive chemical environments. The three steps necessary to make bonded-lead materials are careful surface preparation, precoating with a lead alloy, and metallurgically bonding the lead to the precoat. Surface preparation involves cleaning and degreasing the steel or other underlying metal. The lead alloys generally used as precoats contain either tin or antimony. Bonding the lead to the precoat is accomplished using pressure, temperature,or a combination of both. When all of the potentially joinable surface areas of a lead sheath is metallurgically bonded to steel, the resulting composite is said to be homogeneously bonded. If only a few small areas are joined, the process is “spot bonding.” There are three ways to homogeneously bond lead to steel: welding, casting, and cold rolling.

1.

Cold Rolling

One of the important innovations in lead corrosion resistance technology is a new, low-cost method of homogeneously bonding lead sheet to steel. Instead of using the laborious welding or casting procedures, lead-clad steel can be made by coldrolling lead sheet ontoprecoatedsteel plates. The rolling mill used in this new method is a conventional mill which has been modified. In the cold-rolling process, the steel is degreased, pickled if covered with oxides, and then fluxed with a mixture of zinc and ammonium chlorides


415

and hydrochloric acid. Next, a precoat is applied by hot-dipping the steel in a molten bath of a lead-tin or lead-nickel alloy. Finally, the lead sheet, degreased and wire brushed to remove the oxide film, is roll bonded to the steel. This last step is done in a rolling mill in one pass to avoid buildup of lead. If both sides of the steel are to be lined with lead, it is done in two separate passes to avoid deforming the steel. Cold-roll-bonded, lead-clad steel, as it is called by its originators, the British Non-Ferrous Metals Research Association, is available with lead linings of approximately 1/64-1/16 in. thick on 14-26-gauge steel in plates 2.5 m X l m (7.5 ft X 3.5 ft) in size. To maintain overall rigidity of the thinner cold-roll-bonded plates, the thickness of the steel should be at least equal to that of the lead lining. 2.

Welding and Casting

All the methods used to bond lead sheet to steel have four distinct steps: surface preparation, precoating, lead coating, and finishing. Surface preparation generally involves mechanical cleaning using grit blasting with shot or sand, or grinding. Chemical cleaning such as by pickling is also used. Copper is usually chemically cleaned before lead bonding. The precoat may be a SO% lead solder or 6% antimonial lead. A tin chlorideor zinc chloride flux is applied.The precoat is added either by dipping the cleaned steel (or copper) into a molten bath or by using a torch to melt and apply the precoating material. While the precoat is still hot, the molten excess should be wiped off. After solidification, flux residues should be removed with a cloth that has been dipped in hot water. The lead lining is applied either by pouring molten lead on to the base metal surface or by melting filler metal with a torch and applying it. If molten lead is used, twice the desired thickness is cast on and insoluble impurities such as dross are allowed to float to the top. After cooling, the excess lining is scraped or machined off, and the surface is smoothed over by flame-washing. To apply the lining with a torch, the precoat and then the filler material are alternately melted and then joined. The required lining thickness is built up in several passes. Usually three passes are required for each 1/4 in. (6.4 mm) of thickness. When the lining exceeds the required thickness, the excess should be machined or scraped off and flame-washed to provide a uniform and smooth lead lining.

3. Spot Bonding When lead linings are subjected to extensive thermal expansion and contraction, a buildup of stresses can occur at fixed points in the linings.

Chapter 3

416

One way to prevent this buildup of local stress concentrations is to metallurgically bond to the outer supporting shell those spots of the lead lining which are in low-stress areas. This procedure, called spot bonding, can also be profitablyusedonoccasion as a substitute for mechanical fastening.

BricWlead

J.

In certain corrosive environments, the abrasion resistance of even the hardest lead alloy is not sufficient. In many other situations, the operating temperature is above the melting point of lead. It is under these circumstances that a lead-lined piece of equipment requires either the abrasion protection or insulation of a layer of chemical-resistant masonry set with a suitable cement. This combination of an outer supporting structure of steel or concrete, a lead membrane, and an inner layer of acid-brick or tile or borosilicate glass is called brickbead (Figure 76a) [61]. The lead layer in bricuead may be chemical, acid-copper, or antimonial or other alloy. It may be bondedmetallurgically to a steel shell, mechanically fastened to a shell or framework of steel or a concrete shell, or simply hung between the brickwork and a shell. Thus bricuead is actually supported lead or bonded lead with a layer of chemically resistant Bricknead Y A

z B

X X: Lead or lead alloy Y: Steel or concrete 2:Metallurgical or mechanlcal bond A: Chemical-reustant masonry bnck B: Cushloning material (optional)

(a)

(b)

Figure 76 (a) Details of the interfaces in brick/lead and (b) a section of a brick/ lead vessel [61]. (Courtesy of Lead Industries Association, New York.)


41 7

masonry added to it. A section of a brick/lead vessel is shown in Figure 76b 16 1 I. The mechanical and thermal protection provided by the masonry allows lead to indirectly handle process temperatures as high as 982°C and above and abrasivesolutions.Good performance has been obtained with vacuums as low as 0.25 in. of mercury at 127°C. The use of masonry greatly increases the types of corrosive environments that can be handled by brick/ lead vessels. The supporting shell of a brick/lead vessel is similar to those used with loose linings. However, it should be designed to withstand the additional stress imposed by the thermal expansion of the masonry. If operating temperatures are 260°C or higher, the vessels should be supported in such a way to permit outside air cooling. This will reduce heat buildup on the bottom of the vessel and prevent damage to the brickwork. Brick/ lead cage vessels are sometimes used. However, for high-pressure operation, a shell must be used, and the bottom of the vessel should be dished and welded joints placed at orabove the bottom edge.The masonry used is usually 3-4% porous brick, which is resistant to the spalling caused by thermal shock, sustained high temperatures, and absorption of solutions that crystallize on cooling. The total thickness of the brickwork should be high enough to keep the temperature at the brick-lead interface at 74°C or below. The upper limit is 52°C if the lead layer is homogeneously bonded to a steel shell with a precoat containing a substantial amount of tin. The temperature gradient through the brickwork of a brick/lead vessel with a steel shell is about 3.3"C per centimeter of thickness for fire clay or shale-type brick and 2.2"C per centimeter for carbon brick. These figures are valid for process temperatures up to 204°C. The temperature gradient through the brickwork of a concrete brick/lead vessel is somewhat less. This is due to the insulating effect of the concrete shell. Another factor to be considered when setting the thickness of the brick layer in a steel brick/lead vessel is thermal expansion. The brickwork must elongate more than the steel shell expansion. This ensures that the lead lining receives continued support. Two or three layers of asbestos paper are often put between the brickwork and the lead. This is done to protect the lead from mechanical abuse when the brickwork is being laid and from the abrasive compression caused by thermal expansion of the brickwork. The use of asbestos may help create pockets of acidity. Therefore, it is not used if operating temperatures are high enough to enable leaking chemicals to significantly corrode lead. Instead, a 1/8 in. coating of either certain resin cements or a plastic coat of silicate cement is applied. Glass cloth can be used in addition to the coatings, if further abrasion resistance is necessary. Another important situation in which brickbead should be used is where a process fluid contains components which are corrosive to lead but

Chapter 3

41 8

cannot seep through chemical-resistant masonry. The lead membrane is necessary t o contain any other components able t o penetrate the masonry or eat through thc cement used t o set the masonry. An example of this type of brick/lead usage is i n vessels used to contain both polar and nonpolar organic compounds. The polar organics. many of which attack lead, cannot penetrate the brickwork. and penetratingnonpolarsareeffectivelycontained by the lead membrnnc. The cost of brick/lead is comparable to that of other material combinations that can handle the same high temperatures and mechanical abrasion. However, thc use of lead makes the overall corrosion resistance of brick/ lead equipmentsuperior to that o f equipment that use chemical-resistarlt masonry with other membranes. Applications handled by brick/lead equipment include vacuum concentrators and storage tanks handling mixtures of sulfuric acid and organic chemicals. such as petroleum distillates and vessels used to alternately bandle acids and alkalis. Autoclaves and the high-temperature portions of the ducts, scrubbers, acid-mist precipitators, and towers used t o handle acid and sulfur dioxide-laden gases are olten of brick/lead construction.

K.

Machining of Lead

The machining process used in thc case of lead alloys principally involve diecuttingor water jetcuttingforhigh-performance ancl high-precision parts. Draw Knives, hand or electric saws, or hand shears also could be used i n parts for less demanding applications.

1.

Die Cuting and Stamping

Die cutting and stamping arc two processes valuable for creating intricate parts from pure chemical lead and antimonial and calcium lead [WO].Each process has proven advantageous in specific applications. Dic cutting i n volves low to moderate tooling cost, meets moderate tolerance requirements. is excellent for low to medium volumes, and involves short tooling delivery time. The typical maximum size that can be die cut is 0.6 m X 1.8 m (24 i n X 72 in.). Tolerances achievable in die cutting are t 0 . 0 1 0 to 2 0.020 in. Stamping involves moderate to high tooling cost, meets high tolerance requirements, is excellent for medium to high volumes. and involves modcrate tooling delivery time of about a month. Stamping can be done using inserts in a master die LIP to a 2.5 i n . cross section or by using dedicated die sets. Typical tolerances achievable i n stamping is t 0.005 i n . and tighter tolcrances are also possible.


419

Figure 77 Die cut and stamped shapes made from lead and lead alloys [300]. (Courtesy of Vulcan Lead, Milwaukee, W.)

There are many options in die cutting and stamping. Lead parts can be provided with paper backing, adhesive backing, or no backing in thicknesses from 0.001 to 0.375 in., making this ideal for x-ray or nuclear use. Adhesive backing is available for applications such as computer disk pack balance weights or for x-ray and nuclear use. When stamping, interchangeable inserts can be used in a master die to minimize tooling costs.Die cutting, in turn, is perfect for prototyping because the tooling is inexpensive and can be changed rapidly with ease. Vulcan lead uses die cutting and stamping to produce lead parts for a extensive variety of applications. The applications include (1) gasketsin chemical industries, (2) shielding, both for x-ray and nuclear situations, (3) balance weights, with or without adhesive backing, (4) sealing washers, (5) vibration and sound-dampening components and (6) acid-resistant applications. Figure 77 shows a number of die-cut and stamped shapes made from lead and lead alloys [300].

2. Water-Jet Cutting Abrasive water-jet cutting technology is now a widely used by Vulcan Lead and other lead metal fabricators to cut lead sheets and foils with high precision [300]. In the Vulcan’s abrasive water-jet cutting, an intensifier pump pressurizes water to 370 MPa (55,000psi) and forces it through a nozzle as small as 0.1 mm (0.004 in.)indiameter. This generates a high-velocity, coherent stream of water traveling at speeds up to 912 m/s (3000 ft/s). This stream of water will cut lead and other soft materials like rubber, foam, and plastic. For hard materials like stainless steel, titanium, or aluminum, an

420

Chapter 3

optional abrasive (typically 80-120-grit garnet) is entrained into the water stream. Part of the water's momentum is transferred to the abrasive particles which do most of the cutting. Controlled by CNC equipment, the cutting head precisely cuts almost any material into any shape. Figure 78 shows the water-jet-cutting unit used in the fabrication of lead parts [300]. Figure 79 shows water-jet-cut lead parts [300]. Reduced material waste, decreased cutting costs, exceptionally precise shaping and customized, programmable cutting capabilities makes this very attractive in cutting lead and lead alloys. Contour cutting of intricate artistic shapes and cutting delicate material such as lead makes it attractive in cutting lead parts or sheets. The abrasive jet eliminates heat damage and frayed

Figure 78 Vulcan Lead waterjet cutting unit used in the fabrication of lead parts [300].(Courtesy of Vulcan Lead, Milwaukee, W.)


421

Figure 79 Water-jet-cutleadparts [300]. (Courtesy of Vulcan Lead, Milwaukee, WI.)

edges, creating a smooth finish. The abrasive jet’s precision cutting allows elaborate contouring to create a special product. The abrasive water jet’s flexibility allows both prototypes and multiple pieces to be cut. The abrasive water jet eliminates the expense of diamond wheels and diamond-tipped cutting tools.

L.

Lead Coatings

Instead of lead lining the equipment with lead sheet thicknesses of 1/16 in. or more, a thin coating of lead can be applied to equipment surfaces to provide corrosion protection in an economical manner. The amount of lead alloy per unit area of coating is of the order of g/m2 (oz/ft2) instead of the kg/m2 (lb/ft2)used for sheet lead. The three major methods of applying lead and lead alloy coatings are spraying, hot dipping, and electrodeposition. The corrosion resistance and mechanical performance of equipment protected with lead coatings depend on the strength of the interfacial bond between the coating and substrate bondandtheamountof microscopic porosity. Coatings that are metallurgically well bonded to their substrates will maintain their integrity even when forced to undergo bending, forming, drawing, or other changes of shape. Microscopic pores are introduced in the coating during the deposition of coating. This could lead to a direct contact between the corrosive medium and the substrate metal through these pores. Controlling the coating process to minimize or eliminate this porosity is important. An increase in coating thickness to a value much larger than the pore sizes could also minimize the potential for such direct contact. Microscopic pores in lead or lead alloy coatings are sealed by peening, painting, or an organic sealant. Overall corrosion resistance can be increased by choosing as a substrate a metal which

Chapter 3

422

is either cathodic (e.g., stainless steel) to the lead coating or which f o r m a tight corrosion product (e.g.. copper-bearing steel).

l.

Sprayed Coatings

Thermalspraying of lead coating is an economical wayof applying lead coatings. However. the containment of tine particulates that are generated during thermal spray is of concern because of the toxicity associated with lead. Thermal spray deposition process involves melting of the lead wire or powder feed to the spray gun, the formation of tine droplets by an impinging gas jet, and acceleration and spraying of the tine droplets onto the substrate by the gasstream.Thedroplet may be either i n complete liquid form or semisolid form as it impacts the substrate ancl flows into a lamellar form and solidities completely. The metal-spraying gun or device requires either a fuel gas-air mixture or an electrical arc source to melt the lead i n wire orpowderform.When the combustiblemixture is used 21s a heat source. the process will be referred to a s a flame spray process (Figure 80) [3501. When an electric arc is used as heat source with the wire feed acting as ;I consumableelectrode, the process is rcfcrretl to as an electric arc spray process (Figure X I ) 13501. The plasma spray process is similar to the spray process but uses a non-consumable tungsten electrode, with the feed material melted by the electrically induced plasma (Figure 82) (3501. The lead metal to be sprayed. usually i n the form of a 2-mm-diametcr wire, is fed through a driving mechanism into the llarne (or arc). The compressedair jet atomizes the metal melted in the Harne or arc and hurls it onto the surface, which has previously been cleaned and toughened by sandblasting. The velocity of the particles in the .jet, depending on the operating condi-

Sprayed materla1

Air cap

Ceramlc or wire

/ Burnmg G ,ases

6 Spray stream

Air channel

Figure80 Flame spray deposition o f International. Materials Park. Ohio.)

Prepared substrate

;I

Icad nlloy coatmg [ 3 5 0 ] (Co~~rtcsy . of ASM

423

Processingof Lead Products Substrare

Reflector

Figure 81 Arcspray deposition of a lead alloy coating [3501.(Courtesy of ASM International, Materials Park, Ohio.)

tions, is between 150 and 500 m/s. On impingement, the metal particles, some of which are already solidified to a pasty consistency are pressed flat and matted together. The entrapment of atomizing gas molecules in the liquid is possible and that leads to the formation of microscopic porosity in the coating. Prior to deposition of lead coating, the substratesurface is cleaned and roughened by abrasion. Roughening helps to increase the mechanical bonding of the coating to the substrate. The relatively low strength

Cu Anode

Powder

Coatlng

Figure 82 Flame spray deposition with a powder feed [350].(Courtesy of ASM International. Materials Park, Ohio)

424

Chapter 3

of the mechanical bond limits the use of this type of coating in applications involving any bending or forming that can cause delamination. The low melting point of lead and the ease of the spray process make this process flexible and economical enough to be used in both construction and on-site repair work. Relatively thin coatings (several micrometers) to thick coatings (several millimeters) can be applied by this process. In general, lead coatings should be sprayed on whenever the low cost and flexibility of this method outweigh the thinness, porosity, and low resistance to flexure failure of the resultant coating.This is the caseeven in severely corrosive chemical environments. The application of sprayed lead coatings for protection against corrosion include (1) copper evaporating coils with 1.5-mm-thick lead coating, destined for hot aluminum sulfate, (2) precipitating baths of rayon spinning machines (0.3-l-mm lead coating), and (3) electrofilters in sulfuric acid plants with a 0.3-l-mm-thick lead coating.

2. Hot-Dipped Coatings Hot dipping is another approach to applying a lead coating to a component. Here, the part is dipped in a molten lead alloy bath and taken out; the liquid metal layer attached to the part is allowed to solidify. The surfaces to be coated are chemically cleaned, pickled, and fluxed before dipping. Unalloyed lead will not metallurgically bond to steel, copper, or other metals. Therefore, the coating material is usually a tin or antimony alloy of lead. In addition to tin and antimony, other alloying elements in lead alloys that help the bonding of the lead to steel are silver, nickel, mercury, or cadmium. Porosity formation from trapped gas molecules is less likely in this process and the lead coatings applied by hot dipping contain fewer microscopic pores than sprayed-on coatings. The coatings are also metallurgically bound to the substrate metal. Theequipment coated by hot dipping can, therefore, be used in applications involving bending and drawing without the risk of delamination. The most important hot-dipped coating alloys used in applications requiring high corrosion resistance are (1) lead-tin alloys, including lead alloys containing less than 5 % tin to which small amounts of antimony, silver, and/or zinc are often added to improve fluidity and (2) terne alloys, which can have from 5% to 50% tin in them, but usually contain less than 20% tin. Antimony is sometimes added to both types of alloys to improve abrasion resistance. Astin and antimony are both more costly than lead,the higher their concentration, the more expensive the coating will be. However, for low-tin alloys, increasing the tin content will produce a more abrasionresistant coating. Therefore, 12-20% tin is the concentration used whenever


425

the equipment to be coated will be subject to mechanical abuse. Antimony is also added to increase the hardness of a coating. The alloys with less than 5% tin are generally used to coat small parts. The parts are centrifuged after hot dipping to remove excess metal, leaving a coating usually 5 pm thick. Some larger parts are hot dipped in this type of alloy but are not centrifuged. The coating thickness on these parts will depend on the temperature of the alloy bath and the mass of the unit being coated. However, the maximum thickness is generally kept below 15 pm. Terne alloys are used to coat steel and form what are called short terne and long terne. Short terne is primarily used as a roofing material and to make cans which hold paints and lacquers. The short terne used in roofing contains 20% tin. This roofing material has been called by many other names, including valley tin, roofer’s tin, terne-coated steel, terneplate, and, at times, just terne. The metals most frequently coated with terne are mild, rim, special killed, and copper-bearing steels, copper, and, recently, passivated stainless steel. Copper-bearing steel coated with terne has especially high resistance to corrosion, as the steel surface exposed at pores forms a tight corrosion product which prevents further attack. Terne-coated stainless steel is the material with the hot-dipped fonn of lead coating which has the highest resistance to corrosion. This is because passivated stainless steel is cathodic to the lead coating which means that even at pores, the corrosive attack will be entirely focused on the lead coating. Roofing terne is often specified in units of pounds per double base box. The surface area of a single base box is equal to one side of 1 12 plates of 14 in. X 20 in. size or 31,360 in.’ (20.23 m’). A double base box has I 12 plates of 20 in. X 28 in. or a total one-side surface area of 62,720 in.’ (40.46 m’). Therefore, an 8-lb double base box of roofing terne has a 3.81 pm-thick coating on each side of such a surface. Roofing terne is generally available in 26-, 28-, and 30-gauge sheets in 100 ft lengths wound on coils having widths of 12, 14, and 40 in. Other sizes are available as required. including plates with base box dimensions (20 in. X 28 in. and 14 in. X 20 in.). Long terne is available in long lengths on coils o r in cut form with a maximum length of 144 in. Widths are available in sizes up to 54 in. and total thicknesses range from 0.01 13 to 0.0635 in. (0.287 to I .613 mm). These thicknesses carry coatings of a total weight on both sides of 0.25, 0.35, 0.45, and 0.55 oz/ft’ (76, 107, 122, and 168 g/m’) and higher. Tests to check weight and composition of long terne are in ASTM Specification B309. Other specifications include ASTM B308 and Federal Specification QQ-T19 I . Long terne is used in automobile brake lines, radiators, air and gas filters, and gasoline tanks, and in television and radio chassis, air cleaning and conditioning equipment, metal furniture parts, and as a roofing material.

Chapter 3

426

Lead coatings with I2-20% t i n have been used to provide protection against atmosphericattack. The use o f terne as a roofing material is also due to the fact that it is very receptive to forming and painting.The last feature is especially important when high light reHectance is desired. Terne coatings. pcriodicnlly repainted. have lasted S O or more years. A coating thickness on eachside of 9.65 p m (20-lbdouble base box) is often used with terne-coated copper-bearing steel to provide protection against atmospheric attack. This protection is normally adequate if thc terne is painted periodically. ASTM Specitication B 1 0 1 contains recommendations on how thick lead coatings on copper (hot dipped or electrodeposited) should be to meet different environmental conditions.

3.

Electrodeposited Coatings

Lead can be deposited at high rates onto steel or copper by electroplating. Anodes of the same composition a s the desired coating are used to replace the material being continuously plated out of the solution. Two plating solutions commonly used to electrodeposit lead alloys arc lead fluosilicate and lead sulfamute. A third solution, lead Huoborate, can be used to electrodeposit both lead alloys and pure lead.Thestructure and density of the coatings are controlled by small amounts of additives in a l l three electroplating baths. The use of Huosilicate bath is preferred because of its lowest cost in large-scale production. However, this type of bath has limited stability. The chemicals used in sulfamate baths are initially i n a noncorrosive solid form, making handing procedures easier. In both solutions, a Hash coating must be applied prior to the electrodeposition of lead coating. The electroplating with fluoborate solution is the most expensive, but a tluoboratc bath is the most stable and gives the finest grain size i n the deposit. In addition, this

Table 16 Recommended Thicknesses lor Lead Coatings (Courtesy ot' Lead Industries Association. New York.)

on Copper [ h 1 1.

Weight of lead coating

(kg/m')

Class 1: Light

Class 2: Standard (for general Class 3: Heavy

use)

Minimum

Maximum

O.SX6

0.733

0.977

1.466

1.95s

2.443

Processing of Lead Products

427

solution has been used i n high-speedstrip-platingoperations with current densities of from 200 to 1000 A/ft.' (2153 to 10.764 A/m'). The fine-grained coatings produced provide good surface coverage. Pure lead coatings which are resistant to peeling. chipping, or delaminationcan be deposited from fluoborate solutions onto steel or copper without having to first put down a flash coat. One important advantage of electrodepositingcoatings, instead of spraying them on or using the hot-dipmethod. is being able to produce coatings free of microscopic porosities. Lead coatings without pores provide the best possiblecorrosionprotection for underlyingmetals. Another important advantage of electrodeposition is that pure lead coatings can be metallurgically bonded to other metals without requiring a precoat. The thickness of electrodeposited lead coatings on ferrous met'd I: \ required to provide adequate corrosion protection for different environments are discussed in ASTM Specification B200. These thicknesses range from below 12.7 p m where a paint aftercoat is used and the environment is mild to more than 38.1 pm when there is exposure to corrosive chemicals such a s sulfuric acid. When a highly corrosive environment is involved or therc is a good possibility of mechanical damage, coatings are made as thick as 127-254 pm. The second appendix of ASTM Specification B200 contains electrodepositionprocedures which helpproducecoatings of acceptable quality. Copper flash coats are deposited from cyanide and alkaline solutions. These range i n thickness from a minimum of 0.38 p m to a maximum of 2.54 pm. Many copper products are protected by lead coatings applied by both electrodeposition and hot dipping. ASTM Specification B 10 I lists desirablecoatingthicknessesfor this type of coating in differentsituations. However, for optimum corrosion protection, the Lead Industries Association, Inc. recommends the coating weights shown in Table 16 [61].


Applications of Lead

The attractive properties of lead andits alloys, as described in detail in Chapter 2 and the ease with which it can be processed as illustrated in Chapter 3, makes them invaluable in a wide range of modern applications. Contrary to the image in the general public that lead is a poisonous material that a society may be better off without, it is an invaluable material that one cannot do without in many areas of modern life. One cannot imagine a transportation industry today without lead acid batteries, a nuclear industry without lead shielding, electronic circuit boards without lead-based solders, or medical and industrial x-ray equipment without lead alloy collimators and shields. Like many other metals that are vital to high-technology industry, lead certainly poses environmental hazards, and this awareness has led to the minimization of the pathways of lead to humans and other biological species. Thishas led to the elimination of applications in which leadis dispersed in such a way that its recovery and recycling is difficult or human contact cannot be avoided. Such applications include use in paint, gasoline, water pipeline joints, and bearings. Whereas lead in gasoline is being eliminated, the gasoline tank itself is made of a terne-coated steel sheet,as illustrated i n Chapter 3. Newer and modem applications of lead are continuously emerging and all these applications involve the use of lead in such a form that lead is almost completely recovered and recycled. In this chapter, we provide a brief discussion of a wide range of applications in which lead alloys are used. For more detailed treatments, readers are referred to sources listed in the References and the publications of various lead industry associations worldwide. Some of these applications such as its use as an acoustic barrier, handling of corrosive chemicals, nuclear radiation protection, and acoustic damping have been described tosome extent in Chapter 2. By 429

Chapter 4

430

design, the chapter includes mostly those applications in which lead is used in ii metallic alloy form and has avoided applications in which lead is used primarily as a chemical. This has been done mainly to limit the scope of the book. The following sections describe applications that include use of lead in energy storage batteries, earthquake dampers, intill-walls, soldcrs, packaging, nuclear waste storage, other radiation shielding (aspects not covered in Chapter 2), organ pipes, solders, inertial applications. waterproofing and architectural applications, optical glass. infrared semiconductor devices, sitperconductors. fusible alloys in heat-transfer and prototyping applications, liigli-volta,oe-cable sheathing, ~indother miscellaneous applications. Applications in which the use of lead has diminished or eliminated such a s type metals and bearings are also briefly described because of their historic iniportance. It is hopcd that the reader comes away with a bettcr appreciation for the importance of lead and its alloys to modern lifc.

1.

LEAD-ACID BATTERIES

Lend-acid batteries are the most widely used secondary battery at present time. The total capacity of electrical energy storage in lead-acid batteries far exceeds that of any other competing energy storage devices that include zi nc/air. ti ic ke I/cad in i 11m , s o d i iim/me t al ch lo ride, nic ke I tne t al hy dride , I i thiuni ion. zinc/bromine. and sodiuni/sulfur batteries. The relatively low cost a i d availability of the raw materials, room-temper~itureoperation, ease of manufacture. long cycle life. versatility, and the excellent reversibility of the electrochemical system make lead-acid batteries very attractive compared to competing systems. Although these new systems have higher specific energy atid specific power, they are unlikely to replace lead-acid batteries in its traditional markets. Lead-acid cells have extensive use both a s portable power sources for autoniobile service and traction and in stationary applications ranging from small emergency supplies to load-leveling systems. Based on the application, there are three main types of batteries. natnely SLI (starting, lighting, and ignition) batteries, industrial batteries (traction and stationary), and small sealed portable batteries. Over 300 million batteries are in use. with capacities ranging from 2 W h cells in portable applications to 100 W h in SLI battery units t o 40 MW h in load-leveling battery modules 135 1,3521.

A.

Basic Electrochemistryof Lead-Acid Battery

Gaston PlantC. a French physicist, constructed the lirst practical rechargeable cell in 1859. The intent was to tind a replacernent for primary batteries used


431

i n telegraphy [ 35 1 l. Although there have been continued improvemcnts i n battery design. the basic clectrochemistry of the lead-acid battery system has not changed since they were developed nearly 150 years ago [ 2.35 1 3541. The lead-acid cell consists o f a negativeelectrodc of porous lead (lead sponge) and ;I positive electrode of lead dioxide, Pb02, both immcrsed i n an aqueous solution o f sulfuric acid:

Pb(s)/PbSO,(s)/H,SO,(aq)/PbSO.,(s)/PbO,(s)/Pb(s)

(1)

the concentration range used in the batteries, thc sulfuric acid dissociates . The sum of the clcctrochemical reaction steps at the positive electrode is describcd ;IS 111

as H ' nnd HSO,

The sum of the reaction steps at the negative electrode is given a s

The overall electrochemical processes is represented by the equation

+ 2H,O(I) The free-energy changc o f the reaction is -372.6 kJ/mol and the standard equilibrium (Nernst) potential is I .93 1 V [ 353,3541. More often. the reaction is written as follows:

Pb(s)

+ PbO,(s) + 2H,SO,(aq)

SO0 W/L. specific energy o f SO W h/kg. energy density of 100 W h/L, cycle life of 500. ancl recharge rates of 50% in S min. 80% i n 1 S min, and 100% in 4 h. These are more ambitious than othcr udv~unced battery systems [360.3611. The goals of fast charging and higher charging efficiency has already been accomplished in the new VRLA batteries, Some or the current efforts include development of optimized tubular and flat gricls with improved surface area and active material utilization. The llat tubular design for itnproved active material utilization is shown in Fig. 9 [360].The

Chapter 4

444

problem of premature capacity loss due to expansion/contraction of the active mass during cycling is being addressed through the development of high-compression valve-regulated designs. Other efforts include the development of improved materials for grid, AGM mat, and expander.

1.

Battery-Grid Alloys

Alloying additions are made to improve mechanical and electrochemical properties of lead-acid battery grids and spines. The Pb-Sb-based ternary alloys with As, Sn, Ag, Se, Cu, S, and Cd and Pb-Ca-based ternary alloys with Sn, Ag, and AI have been considered in grid alloysfor batteries [ 1 1 1,362,3631. In the early battery grids, Sb was the main alloying element used and up to 1 1% Sb was used. By 1950, the phenomenon of Sb poisoning ofthe negative plate was recognized and the Sb content was decreasing, with 6-9% Sb alloys becoming common. However, the low-Sb alloys had inferior castability, mechanical strength, and corrosion resistance under battery operating conditions. Arsenic addition increased the rate of age hardening and reduced the time of grid storage required after casting. Arsenic also increased creep resistance, which was very beneficial in deep cycling conditions. The Electric Storage Battery Co. of USA used a 0.5% As addition to a 6% Sb alloy for positive grids, even in automotive applications. The Sn addition increased fluidity and thus castability. It increased cycle life of batteries containing thin plates. Chloride Electric Storage Battery Co. added 2.5 wt.% Sn in Pb-9 Sb positive grids for a special military battery for cycling service. Ag additions increased both the corrosion and creep resistance in Pb-Sb-alloy grids. The disadvantage was the high cost of Ag. Continuous pressure to reduce Sb to below 6% led to the development of Pb-Sb alloys with less than 3% Sb.Se,Cu, and S were used as the addition to Pb-3 Sb to refine grain size, and among these, Se was the most effective and widely used. Sn additions were used to act synergistically with As and Sb to improve fluidity and castability. Ag improved corrosion resistance. CO also is thought to improve corrosion resistance. Cd additions improved castability oflow Sb alloys, as it decreased the two-phase solidification range. Corrosion resistance was also improved. Pb-( 1.5-2.5)Sb(1.5-2.5)Cd alloys had good properties, but Cd use was inhibited by environmental considerations. Cast Pb-Sb-based alloys are typically used in grid alloys as the PbSb-based wrought alloys have lower yield strength, tensile strength, and creep strength compared to cast alloys. Corrosion behavior of wrought alloys are inferior because of the nature of the distribution of the Pb-Sb eutectic phase and lower creep resistance. Corrosion of cast Pb-Sb alloy occurs by the attack of the Pb-Sb eutectic phase. It solubilizes some Sb and stresses


445

of corrosion product are accommodated. In rolled alloys, the eutectic phase is isolated, which leads to stresses in the grid. As mentioned earlier, Sb migration from Pb-Sb-based positive grid :llloys to negative electrode results in the reduction of hydrogen overvoltage and consequent decrease in cell voltage. This led to increased degassing and water loss. The move to purer systems with no poisoning of negative plates led to the use of Pb-Ca alloys. The cast and wrought Pb-Ca binary alloys are significantly inferior to cast Pb-Sb alloys in hardness, creep resistance, and corrosion resistance. Thecycle life of lead-acid batteries is mainly limited by the performance of the positive plate, the capacity of which decreases on cycling, especially under deepdischarge.The common degradation mechanisms [ 3571 include ( 1 ) loss of interparticle contact, (2) shedding of active material due to morphological changes and grid corrosion, ( 3 ) grid deterioration and growth, and (4) irreversible plate sulfation due to acid stratification effects. The growth of positive plates due to corrosion in service reduced the cycle life in batteries with Ca grids and low-Sb alloy grids. This is attributed to ( 1 ) the formation of high-resistance a-PbO on the grid, (2) the increased tendency for cracking and delamination of corrosion layers, and (3) the structural changes in active material that is aggravated by the absence of Sb in the grid alloy. This effect together with other plate mechanisms that reduce battery life to fall well short of design life is known as the antimony-free effect or premature capacity loss (PCL). The antimonyfree effect underlined an urgent need for additions to Pb-Ca. The mechanical properties in Pb-Ca binary alloys peak at 0.07% Ca. Above 0.06% Ca, cellular precipitation of Pb,Ca leads to the fine-grain size. In VRLA batteries, using thin grids of high Ca have been used to aid processing (faster aging rate), but they produce fine grains. Increasing Ca contents above the 0.07% level accelerates corrosion and this is believed to be due to fine grains and primary Pb,Ca. Sn additives increase mechanical properties by changing the mode of precipitation as the precipitate phase is changed from Pb,Ca to more stable Pb(Sn,Ca),. Sn addition aids electrochemical properties by preventing passivation of the grid and permitting recharge of batteries from the deeply discharged condition. Pb-Ca-Sn alloys have become established in traditional automotive batteries and in VRLA batteries. Pb-Ca-Sn alloys are inferior to Pb-Sb-As alloys in terms of mechanical properties, but the properties are adequate. Additions of Ag to Pb-Ca and Pb-Ca-Sn alloys increases creep and corrosion resistance and the durability of batteries. Pb(0.025-0.06)Ca-(0.3-0.7)Sn-(0.015-0.04S)Agpositive grid alloys show improved creep and corrosion resistance. Increased Ag additions are being considered for severe deep cycling conditions. The addition of AI tends to stabilize drossing loss of Ca. Pb-Sr alloys are better than corresponding

Chapter 4

446

Table 1 Typical Composition Range of Battery-Grid Alloys Alloy

Coinposi t ion

Conventional high-Sb alloy-cast LOWSb tilloys-cast Cnst/wrought Pb-Ca-Sn

Ph-(9- I2)Sb-(0.3S-O.S)As Pb-2.SSb with other minor additions Pb-(0.025-0.06)Ca-(0.3-0.7)Sn-(O.O1 S 0.04S)Ag with minor Al addition

Pb-Ca alloys, but the high cost of Sr is an inhibiting factor as long as PbCa-based alloys are behaving adequately. Other grid alloys that have been used include ASTAG alloys (Pb with small amounts of As, Te, and Ag) and ASTATIN alloys (Pb with small amounts of As. Te, Ag, and Sn). Composite grids involving lightweight metals as well as polymers are being explored. Purity levels are strictly controlled in grid alloys, active materials, and electrolyte to minimize elements that promote degassing, corrosion, and passivation of electrode. These elements include As, Co, Cr, Cd, Cu, Fe, Ni, Sb, Te, and Se. Bi has been claimed to have beneficial effect of reducing degassing, but conflicting opinions on the influence of Bi are expressed in the literature. Fe is also detrimental from drossing considerations. The future efforts are expected to be directed toward development of higher-tin-content Pb-Ca alloys, Ag addition to Pb-Ca alloys, Pb-Sr alloys, Pb-Li alloys, and very low-Sb alloys. The development of newer alloy systems and the continued use of existing grid alloys is being reevaluated from the point of recycling of Pb in the battery alloys. These issues are discussed later. Grid alloys for battery applications and their mechanical properties have been already covered i n Chapter 2. Table 1 provides the composition ranges of typical battery-grid alloys.

E.

Bipolar Batteries

One of the factors that limit the specific power (W/kg) is the voltage drop in the cell due to internal resistance of materials used as current collectors and of the electrolyte. A significant reduction of resistance is achieved by a design of bipolar electrode storage batteries. The geometrical configuration of a bipolar battery is shown in Fig. 10 13.561. Here, one side of the lead sheet acts a s a cathode and the other side acts as the anode of the adjacent cell. Between the plates is a microglass tiber separator that absorbs and retains the electrolyte. The cells are connected in series and provide a higher output voltage. Bipolar batteries provide a better performance than traditional systems when high currents are required. Figure 1 1 shows a typical


447

Figure 10 Configuration of a bipolarbattery [356]. (Courtesy of Lead Development Association. London.)

current-discharge curve for a battery [356].

bipolar battery compared with a traditional

F. Types of Lead-Acid Battery and Their Applications As mentioned earlier, there are three main types of battery: SLI (starting, lighting, and ignition) batteries, industrial batteries (traction and stationary), and small sealed portable batteries [351-3531. 1. Starting,Lighting,andIgnitionBatteries Starting, lighting, and ignition batteries are used for cranking automobile internal combustion engines and for powering devices when the engine is

Chapter 4

448

-

15 14

-

Tradilionalsealed battery DIPOLAR battery

0.1

1

13

12 11

10

9

10

20

Discharge time (hours)

Figure 11 Typical current-discharge curve for a bipolarbatterycompared with a traditional battery [356].(Courtesy of Lead Development Association, London.)

not running. Nearly 80% of all lead-acid battery production goes to supply the automotive market. SLI batteries should be capable of supplying short but intense discharge currents at rates of greater than 5 C over a wide temperature range. They are generally constructed of thin pasted plates, with thin composite separator/retainer layers and short connector buses to minimize the internal resistance. In this unit, the positive plates are usually inserted into pocket-shaped separators to increase their resistance to shock and prevent the shedding of material onto the cell floor. The through-partition connections reduce the internal resistance and weight of the battery. In recent years, maintenance-free batteries using advanced alloy grids (and catalytic recombiners) and valve-regulated batteries have become more common for SLI applications. SLI batteries generally have nominal voltages of 12 V and 30-100 A h capacities for cars, and 24 V and up to 600 A h for trucks and construction and military vehicles [352]. Typical specific energies of SLI batteries are 30-40 W h/kg (75 kW h/n13) may be obtained. Service lifetimes of 4-6 years are nonnal. For vehicles used in rugged terrain, batteries with tubular positive plates are required. 2.

Motive Power Batteries

Motive power lead-acid batteries are designed for use in electrically powered industrial trucks, aircraft service vehicles, electric service vehicles used


449

in industry and hospitalcomplexes,robots,andguidedvehicles. The key requirements of motivepower batteries areconstant output voltage, high volumetric capacity at relatively low unit cost, good resistance to vibration, and a long service life. The electric motors using the motive power require high currents for longperiods, so the traction batteries must be able to sustain prolonged and deep discharges followed by recharges at 1-5 h rates. Cycle life could vary from 1000 to IS00 cycles. This is based on discharges to 80% of the 5-h capacity when charged according to the manufacturers recommendations. Operation at lower depths of discharge extends the cycle life substantially. Two-volt cells in 24-96-V assemblies are common. The voltages of traction battery assemblies vary over a wide range from 24 to 240 V, with capacities from 100 to IS00 A h. The specitic energy of these units is typically 20-30 W h/kg 13521. Both flat-plate/grid and tubulardesignsare widely used in motive power batteries. In tubular-design cells, the positive tubular plates consist of a series of parallel porous tubes, each having a centralized lead conductor surrounded by active material. The negative plates are of standard flat-plate construction. A separator envelope wraps around either the positive or negative plate. The Hat-plate-design motive power cells are similar to SLI batteries, but the electrode plates are thicker and more robust. The cells are built with three layers of separator, consisting of a perforated spacer, a glass mat, and a microporous plastic separator. The higher surface area and the larger quantity of acid in tubular cells lead to higher utilization of the active material and a higher energy density than flat-plate cells. However, the flatplate designs usually have ahighercycle life and durability than tubular cells. Tubular cells also have a lower self-discharge rate, as the conducting grid is buried within the active material; impurities, such a s antimony, released as a result of corrosion during service are adsorbed by the lead dioxide and contamination of the negative plate is reduced. This also results in more stable voltage characteristics and a higher voltage at the top of the charge in tubular cells. The capacity of these batteries is usually quoted at the S-h rate of discharge in North America and at the 6-11 rate in Europe. Electric vehicle batteries are usually assembled in 6- or 12-V monoblock units a s distinct from the more usual 2-V cells used in motive power battery arrays, giving a further improvement in energy density. Unlike the standard traction cell, they are usually rated at the 3-h rate of discharge. The General Motors EV1 electric vehicle, which has been offered in the North American marketsince 1996, has an electrical traction powersystem that provides power at 3 12 V from 26 maintenance-free valve-regulated leadacid (VRLA) batteries (361,3631. The battery pack consists of Delphi Automotive 12 V VRLA battery monoblocks. The lightweight and sleek vehicle (Fig. 12) has a dent/corrosion-resistant composite exterior body panels and

Chapter 4

450

g

l

Figure 12 GeneralMotors EVl electric car [361]. (Courtesy of General Motors Corporation, Detroit.)

a rigid, welded, and bonded aluminum alloy frame [361]. The vehicle has an electronically regulated top speed of 80 mph and the EVl prototype has set the land-speed record for electric cars at 183 mph. The car has a 0-60 mph acceleration in less than 9 S . The estimated range of this vehicle at 85% of battery charge is 70 miles in the city and 90 miles on the highway. The charging times with 15% capacity remaining are approximately 3 h using a 22O-volt/6.6-kW charger. A regenerative breaking system recovers kinetic energy to help recharge batteries. The battery pack weight is 533 kg and the total vehicle weight is only 1350 kg. Advanced designs for the electric vehicle involve increasing specific energy through the reduction of inert components and improving active material utilization [360,361,363]. The increaseinspecificpower is being achieved through the minimization of internal resistance by (1) developing thinner plates withhigh surface areas, (2) improving current collection schemes with new grid designs, (3) increasing gridhop-lead conductivity by the use of composites, (4) developing low-resistance separator materials, and (5) minimizing current pathways. However,efforts to increase specific power and recharge capabilities are generally incompatible with cycle life. Dualbattery concepts in which one unit is optimized for range (specific energy) andthe other unitoptimized for accelerationand hill climbing (specific power) are also being considered.

3.

StandbyBatteries

Standby batteries are used to power essential equipment, critical computer systems, alarms, and emergency lighting when there is a breakdown in the main power supply.Reliability and long service life are critical. In the recent years, the standby battery market has grown rapidly with an increasing demand for unintermptable power systems (UPS) and power systems for new telecommunication networks. For a long time, standby batteries were made


451

using the Plant@cell design because of long life, in excess of 20 years. Plant6 cells are still used to some extent in electricity-generating stations. Both tubular and flat-plate designs similar to traction cells are also widely used. These batteries have life expectations of over 1 0 years. In recent years, sealed valve-regulated batteries are increasingly used i n telecommunication and UPS applications. These batteries have service lives of more than I O years, do not require water maintenance, are claimed to be small i n size, pose no risk of acid spill, and can be located in offices without special venting requirements, as they release only small amounts of gas. These cells occupy 70% less space than Plant6 cells of equivalent capacity. The capacities of these batteries are usually quoted at a 3-11 rate of discharge. The available standby time at either constant current or constant power discharge depends on the end of discharge voltage specitied. In certain applications, such as telecommunications, the load is driven directly from the direct-current (DC) output of a rectifier and stabilizing circuit. Across this output is a bank of batteries to drive the load in the event of supply failure. The rectifier serves both the functions of driving the load and of charging the batteries. Telecommunication equipment usually operates on a nominal 24-V or 50-V DC supply with typical tolerances i n the region of + 5% to - 10%.

4.

Portable Batteries

The use of portable sealed valve-regulated lead-acid batteries for use in electrical appliances and electronic equipment have increased significantly in recent years. The critical requirements in these batteries are that they must be transportable and usable in any position without leakage. The cells are made i n cylindrical, prismatic forms or flat-pack forms. The electrolyte immobilized by absorption of electrolytes in porous glass mat or by gelling of electrolytes. All cells with these designs are sealed with a pressure-relief valve located below the external cover. These batteries deliver 1-30 A h and are used as single cells and as 12-V monoblocks. Operational temperature, discharge rate, depth of discharge, and charging method affect the service life of these batteries, in common with other lead-acid battery designs.

G.

Large-scale Energy Storage for Load Leveling

The consumption patterns of electric power varies widely depending on the time of the day or the time of the year. A constant consumption of power would allow utility companies to utilize the installed power-generation capacity more efficiently by having high load factors. Given the reality of varying demands for power, utility companies often employ energy storage procedures at off-peak periods (e.g., when demand for electricity is low-

452

Chapter 4

during the night and weekends). The stored energy is used during the peak demands for power or during the intermediate period when the utility brings on-line the intermediate-load,oil-tired(or gas-fired) combustionturbines during extended peak demands. Among the possible energy storage schemes that utilities may use are pumped hydroelectric systems, compressed-air energy storage facilities, and battery energy storage plants 1364-3681. Woodbridge [366] proposed the use of battery storage plants in various generation/distribution environments as early as 1907. BEWAG, the oldest public utility i n Germany, installed the first battery storage plant in 1893. The total capacities of these plants were 100 MW and they were used in parallel with the DCsupplysystems. With increasing use ofAC power supplysystems, the use of battery storagedecreased and the use of gas turbines for load managementbecameattractive,extensively a s backup power-generation systems and to meet peak demands [367]. The rapid development of power electronics and control engineering has led to the availability of highly sophisticated static power conditioning systems at reasonable costs. This allows the use of batteries within AC systems. An Electric Power Research Institute (EPRI) funded study compared the cost of variousenergystorageschemes that included compressed air, pumped hydro,combustionturbines, and lead-acid batteries. The study showed that lead-acid batteries are the lowest-cost option for duties of about 1 h, with combustionturbines being most cost-effectivefor 2-S h, and compressed air the preferred option for longer periods [36S]. In power-generatingutilities, the battery storage plants are used for load leveling, load frequency control, and instantaneous reserve. The random load fluctuations superimposed on the general trend of the load curve have tobe within thepowermarginfor regulation and thepermissiblepower gradient that is a function of permissible frequency fluctuation. Typical values for power margin and power gradient corresponding to a power-generating utility in West Berlin are 40 MW and I O MW/s,respectively, for a system peak load of 2000 MW and a permissible systems frequency within the range 49.8-50.2 Hz [367]. For economical reasons, generating units in small interconnected systems tend to be large. The faults occurring within the unit or interconnected systems can cause significant imbalance of generated power and load. This can cause large deviations in the system frequency. Subsequent to a fault at a power-generating utility or in transmission,quick-actingreserve units called a“spinningreserve” must come on-line immediately. Their power must be delivered for a time interval sufticient to start up and synchronize a spare generating unit. As electric utilities must provide sufficient emergency power-generating capacity at all times to replace their largest unit in case of failure(known as spinningreserve),


453

battery energy storage systems can dedicate part of their capacity as emergency spinning reserve, especially during off-peak and mid-peak hours. Battery storage schemes have the benetit that they can be virtually any size, can be located anywhere within the distribution system, and can operate at any of the system voltages. Battery storage also allows operation of the main generating unit at efficient operating points. The ability to site batteries at major load centers, such as substations, enables deferral of costs for transmission and distribution equipment, increases transformer bank life, and reduces power-line losses. As the stored battery power is availablealmost instantaneously (even while the battery system is being recharged), the system stability and security can be enhanced by the fast-acting battery response. Operating within the distribution system means that load management can be localized, enabling the peak factor within a specitic region to be reduced. Because equipment ratings are based on peak demand. any reduction allows these to be more conservative 1364,365,3671. Energy storage by means of lead-acid batteries offers many other operating benefits to an electric utility. They allow the purchase of economy power during minimum loading conditions and storage for later use to manage peak loads. Battery energy storage systems allow expansion or downsizing as the local or system peak load requirements change, by adding (or removing) individual batteries. Shorter lead times are required to design and install a battery energystorage facility ( 2 yearsorless). Battery energy storage systems do not contribute to acid rain, fly ash, or noise because they are clean and quiet and can be operated in ordinary building enclosures. The economy of a load-leveling battery storage system is largely dependent on the prevailing load-curve characteristics. The limits of economical utilization of battery storage for industrial consumers have been described by Hagen 13691. Depending on the shape of the load peaks and the tariff situation, reasonable load reductionsrange from 5% to 15% of the peak load for peaking periods shorter than 3 h. At the present time, many battery energystorage plants are in use. Most of these plants are using lead-acid technologies of different contigurations, including flooded electrolyte cells, VRLA, automotive, or submarine batteries. Table 2 lists the different large-scale installations worldwide 13641. The choice of lead-acid cells for these applications is due to the attractive feature it provides at lower cost. Table 3 compares the properties of competing storage battery systems in large-scale energy storage [361].

H. Storage of Renewable Energy There is considerable interest in the use of lead-acid batteries to store energy from the power produced by renewable energy sources such as photovoltaic,

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Table 2

Large-Scale Battery Energy Storage Plants Worldwide [363] _ _ _ _ _ ~

~

Companyllocation Southern California Edison. Chino. CA, U.S.A. Crescent Electric Member Cooperative, Statesville, NC. U.S.A. Delco Remy, General Motors, Muncie, IN, U.S.A. BEWAG AG, Berlin, Germany Kansai Electric Power Company, Tatsunii, Japan Elektrzitatswerk Hammermuhle. Selters, Germany Hagen Batterie AG, Soest, Germany San Diego Gas and Electric, San Diego, CA, U.S.A. Puerto Rico Electric Power Authority, San Juan, PR Pacific Gas and Electric, San Ramon, CA, U.S.A. Pacific Gas and Electric, various sites in CA. U.S.A. Hawaii Electric Light Company, Island of Hawaii (Big Island), HI, U.S.A. Chugach Electric Association, Anchorage, AK, U.S.A. Golden Valley Electric Association, Fairbanks, AK, U.S.A. Oglethorpe Power Corporation, Atlanta. GA, U.S.A.

Size

Operation application

Date

10 MW/4O MW h 500 kWl500 kW h

Utility energy storage demonstration Peak shaving

1988 1987

300 kWl600 kW h 17 MW/14 MW h

Peak shaving Frequency regulation/spinning reserve Multipurpose demonstration Load leveling Load leveling Transit peak shaving Frequency regulation Distributed peak shaving Distributed peak shaving. T & D deferral Frequency regulation/spinning reserve Frequency regulationlspinning reserve Frequency regulation/spinning reserve Power quality

1987 1986

1 MW/4 MW h 400 kW/4OO kW h 500 kW/7 MW h 200 kWl400 kW h 20 MW/14 MW h 250 kWl167 kW h 500 kW/1 MW h (up to 4 units) 10 MW/15 MW h

20 MW110 MW h 70 MW/17 MW h 2 MW/IO s

I 9x6 1980 1986 I992 1994 1993 1994 1994 199s 1995

P

b 9, ii' 0

Table 3 Status of Battery Systems in Competition with Lead-Acid Batteries 13611. (Courtesy of John Wiley and Sons, Chichester, UK.)

System Acidic aqueous solution Lead-acid Alkaline aqueous solution Nickel/cadmium NickeI/iron Nickel/zinc Nickel/metal hydride Alurninum/air Iron/air Zinc/air Flow Zincbromine Vanadium redox Molten salt Sodium/sulfur Sodiurn/nickel chloride Lithiumhron sulfide (FeS) Organic/lithium Lithium ion

P,

Specific energy (W h k g )

Peak power Wkg)

Energy efficiency Cycle life

Selfdischarge (W48 h)

ill nl

Q

35-50

1 50-400

40-60 50-60 55-75 70-95 200-300 80- 120 100-220

80- 150 80- 150 170-260 200-300

70-85 20-30 150-240

>80

75 65 70 70

500- 1000

0.6

120- 150

800

1 3 1.6 6

250-350 200-400 100-300 200-350

1500-2000 300 750- 1200+

160

<so

90 30-80

60 60

500 + 600 +

90-1 10 I10

65-75 75-85

500-2000

90- 120 100-130

230 130- 160 1 50-250

85 80 80

800+ 1200+

0 0"

1000+

?

250-450 230-345 110

80- 130

200- 300

>95

1 ooo+

0.7

200

"No self-discharge. but some energy loss by cooling.

?

9

?

.?

>

50 90- 120 200-250 400-450

-

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456

Chapter 4

wind, hydro, and tidal systems.These energy sources provide fluctuating output. The use of lead-acid batteries is attractive to store excess energy as a way of normalizing output or to get a substantial reserve. Lead-acid batteries with a good deep cycling capability and long life are required. Maintenance intervals are usually a minimum of 6 months, and the cell design must accommodate the necessary amount of electrolyte or be fitted with an automatic watering device. Plant6 cells, tubular cells, and flat-plate cells may allbeused for this application. The discharge times are long. The photovoltaic-based RAPS system on Coconut island, Torres Strait, Australia that provides continuous AC power to 130 inhabitants is a good example of the benefits of the RAPS system [370]. One of the largest projects in Remote Area Power Supplies for the storage and delivery of solar energy using lead acid batteries is being planned for the Amazon region in Peru [371]. A study to assess the potential for RAPS in the Amazon region is funded by ILZRO; this study attempts to define the specific activity to install the first RAPS systems following the agreement signed in June 1997 between the ministry of Energy and Mines (MEM) in Peru, the Solar Energy Industries Association (SEIA) and ILZRO. The project involves the design, manufacture, management, installation, operation, and financing of the first RAPS systems in the Amazon region of Peru. The funding for the project is to be obtained from multilateral financiers, most specifically the Global Environmental Facility at the World Bank. The project will consist of installing six 150-kW h/day power modules into two community power RAPS systems at Padre Cocha (300 kW h/day) and Indiana (600 kW h/day). The project is expected to cost US $1.875 million for these systems, although options are provided for additional or alternative systems. The modular community power RAPS systems will be integrated into existing electric networks and diesel-generator sets; the project is scheduled for completion within 1 1 months after start. RAPS power modules are to be assembled in Peru. The power system will use modular building blocks. These building blocks include gelled VRLA batteries, a power conditioning system, a 15 kW of photovoltaic array, and a local control/monitoring system. A typical community power system will consist of oneormore of these building blocks, along with an interface to the existing diesel generator, a supervisory control system, and a remote monitoring system. The project load increases could shorten this payback considerably. The system has 25% of the fuel consumption and 15% of the maintenance costs of an equivalent system based on a prime diesel generator. The RAPS system, when completed, will eliminate nearly 19,000 tons of COz and over 900,000 lbs of NO,, compared with an equivalent prime diesel generator. The total value for these savings is $2.7 million over the 20-year life of the project. The RAPS system will


457

provide much needed electricity for economic development, reduce emissions in the Amazon region, and (with a payback period of 12.8 years or less for the project cost) reduce the costs to the Peruvian government for supplying fuel and electricity to these remote villages.

1.

Recycling of Lead from Batteries

Nearly 71% of thelead produced today is consumed in the production of batteries 13721. Fortunately, for the benefit of the lead industry and environmental protection, batteries are now completely recyclable [373]. Because of the complications involved in determining recovery rates, detailed calculations of recovery rates are not available. Recovery rates of industrial batteries are nearly loo%, whereas the recovery rates for consumer batteries is somewhat less. Conservative estimates suggested a 98% recovery rates in the United States in 1990. Recovery rates in Europe were higher than 85% i n 1993. These rates have steadily increased with improvements in collection schemes for spent batteries, and today, nearly 100% of batteries are recycled and, as mentioned in Chapter 1, more than 50% of lead produced in the world comes from recycled lead. Lead is probably the most recycled element today. Besides Pb and PbO, the plastic cases and other material are also recycled. Batteries represent a relatively concentrated source of lead. Both pyrometallurgical and hydrometallurgical recycling schemes have been pursued. Modern recycling facilities include a first-stage automated breakup, from which polypropylene case material is extracted and reclaimed.Cell parts consisting of grid metal, lead oxide/lead sulfate paste, top lead parts, and separators form the feedstock for the furnace together with controlled amount of lime. The refining stages differ from primary lead production, as few of the natural ore impurities are present in recycled lead. The limits of toxic elements in gas emissions, slag, and effluent water is a major factor in the recycling processes being adopted. Hydrometallurgical recycling schemes are also available. The elements in grid alloys that cause problems in recycling are As, Se, Ag, Cd, Sn, and Cu [374]. The elements that enter the recycling stream from posts and straps in batteries are As, Se, Cu, Ni, Sn, and Ag. Cd is fumed from the metal to dust.Cdemissionhas to be controlled to very low PEL (personnel exposurelimit)levels. Cd is extremely soluble as lead sulfate and causes problems in wastewater. Copper is a major producer of dross in lead refining. About a half of the refining time and treatments involve copper removal. An even higher effort occurs in obtaining low copper levels. Nickel causes drossing and plugging of lines in die casting. It causes gassing even at low levels in VRLA batteries and should be removed to low levels. Nickel enters the stream as stainless-steel nuts and parts. Arsenic is fumed from grid material as As203and can go

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458

through bag houses using high-temperature bags (gas at 193°C). I t can react with chlorides and fluorides to produce low-boiling-point materials, such as ASCI, (63"C), AsF, (-63°C). The low PEL makes it a difficult element with which to deal. It causes problems in TCLP leach test for slags. Se is fumed from grid materials as SeO, in the furnace. This is also a problem element in TCLP leach tests for slags. It is a problem element in SO, scrubbers producing soluble selenates (Na,Se,03)in scrubber solutionsand wastewater. Sn must be removed by pyrometallurgical refining and most of the Sn is lost in slag. Sn recycling circuits are not adequately developed at the present time. Ag cannot be removed economically at low levels from recycled lead. Buildup can exceed specification limits in lead for pure oxide production. Ag transferred from the positive to the negative grid causes negative voltage changes. Higher Ag content in recycled lead will affect all producers for several years [374]. The future design of batteries and choice of materials for grids and other components will thus be determined by recycling considerations. Some of the suggestions for the future include the elimination of the use of Sb and Cd in battery grids, the reduction and restriction of As to low levels in Pb-Sb grids and strap alloys, the restriction of copper from grids and posts, the substitution ofAg a s an alloying element in positive grids,and the development of Sn-recovery circuits.

II. USE OF LEAD IN EARTHQUAKE PROTECTION A.

Introduction

The excellent damping capacity of lead and its malleability make it a valuable material in seismic protection devices. The collapse or structural damage to buildings, bridges, and other structures and the toppling of material and equipment under the influence of seismic waves generated by an earthquake is a serious concern,particularly i n areas of the world prone to seismic activity. The economic impact of an earthquake could be devastating, as the recent earthquakes in San Francisco, CA and Kobe, Japan amply demonstrated. Designing and incorporating interfaces between the building and the earth that damp seismic wave or isolates the building and their foundations from the earth's movement could provide the structural stability and minimize the damage due to earthquakes. Such structures protected from earthquakes by isolation and damping are referred to as seismically isolated or base-isolation structures.The lead and its alloys are a key component i n these seismic isolation interfaces [ 375-3781. The isolation interface consists of isolators and dampers i n the lowest floor of the buildings. If this interface is designed appropriately, the behavior


459

of buildings during earthquakes can be controlled to a certain extent. The function of isolators is to support buildings and, in the case of an earthquake, to cause a moderate degree of lateral displacement. These are commonly made from laminated rubber. Dampers, although not effective in supporting the load of a building, are able to dissipate the energy generated by earthquakes and control the deformation of the isolation interface. Steel and lead alloys are commonly used in damping. Isolation system can be of two types: an integrated system and the independent hybrid system. In the integrated system, the damping mechanism is integrated in the isolators such a s a highdamping rubber bearing and a lead-rubber bearing (LRB). In the Independent hybrid system, the damper can be set up separately from isolators. Installing integrated devices such as LRBs is fairly straightforward, but its overall design in integrating the functions of the dampers and isolators could be very complex. If dampers and isolators are fitted separately, their functions are clearly well defined and this provides increased flexibility in design. Dampers installed separately from isolators in this way include hysteresis dampers made traditionally from steel and lead materials as well as others such as viscous oil dampers. Among these, dampers made from lead have superior performance i n dissipating energy and can sustain repeated deformation due to the superior malleability of lead and its recrystallization mechanism based on repeated deformation. There is a growing acceptance of base-isolation structures and the characteristics of base-isolation devices such as lead dampers. Since the Great Hanshin earthquake in Kobe, Japan, base-isolation systems have been installed in over 150 buildings in Japan and the number is expected to increase. A significant amount of LRB arid lead dampers is being utilized in these new base-isolated buildings and the demand for base-isolation devices using lead is consequently expected to increase. The scale of buildings and applications utilizing this base-isolation technology has greatly increased, and in 1997, a base-isolation system was installed in a nuclear power plant. Since 1987, the International Lead Zinc Organization has supported the development of lead dampers and earthquake-protection devices at Mitsubhishi Materials Corporation and Fukuoka University in Japan 1375-3781. Much of the information on the use of lead in earthquake-protection devices is a result of this effort.

B. Design of Base-Isolated Buildings In the design of structures, structural engineers always consider the various external forces on the building, such as earthquakes and typhoons. The anticipated level of external forces is difficult to decide, but it is common now to use a maximum velocity of 50 cmls (or level 2 ) for earthquake tremors

460

Chapter 4

as a likely basis. For design involving critical structures,surveys on past earthquakes and dislocation earthquakes are used to calculate the likely forces to be expected from earthquake tremors. In Japan and other earthquake-proneareas, it is very important to consider the strength and characteristics of earthquake tremors and the buildings' response to earthquakes and to grasp the ultimate perfonnance of buildings in advance. In base-isolated buildings, isolator interfaces composed of isolators and dampers are installed in the lower story of the building to isolate it from ground excitation. It has been possible to accurately confirm the basic features and performance limits of isolators and dampers through laboratory experiments. Thus, it is possible to accurately determine from these results, the characteristics of vibration of base-isolated buildings due to the reliance of such buildings on the characteristics of the isolator interface. During earthquakes, the upper structure oscillates almost rigidly. The deformation of the building and ground acceleration are extremely small and the deformation of the structure is reduced to within the range of elasticity. Because of the reliance on base isolators, uncertainty in the behavior of foundations is reduced. The response behavior of base-isolated buildings during an earthquake can be measured with a high degree of precision, which also allows one to verify earthquake observation results to date. That their probable behavior during an earthquake can be predicted is indeed what makes baseisolated buildings unique structures. Base-isolation systems using rubber include those systems ( I ) where lead plugs are pressed into the core of laminated rubber where the functions of isolator and damper are integrated and (2) where rubber laminate isolators and lead dampers are not integrated. The response of base-isolated buildings during earthquakes is controlled to a large extent by the characteristics of the isolators (period characteristics) and dampers (damping amounts). In the design and selection of isolation members, it is necessary to carry out stringent engineering tests on the ultimate performance limits and characteristics of a structure.

C. Lead Dampers The lead dampers used are made from pure lead that has the advantages of being corrosion resistant and having superior plastic deformation and crystallization ability. Thedeformable section could have different shapes. In order to improve the characteristic of the force-displacement relationship, four different damper shapes have been evaluated under an ILZRO program: I-shaped (hourglass), C type, J type, and U type. Nomenclature used to refer to the lead dampers is of the form A-nn where A refers to the type and nn refers to diameter in mm. For example, C75 refers to a C-type damper of 75 mm diameter. Sketches of the four types of dampers are shown in Figure


461

Steel plate

Steel plate

I - Type

Steel plate

C - Type

Steel plate

Steel plate J - Type

U - Type

Figure 13 Profiles of l-type, C-type, J-type, and U-type dampers 13771.

13 [377]. Earthquake simulation test equipment was used toevaluate the performance of the dampers. The schematic and the actual test equipment are shown in Figs. 14a and 14b, respectively 1375,3771. Specimens were attached to upper and lower H-shape angles by high-tension fasteners. Various wave-pattern forces were applied to specimens by sliding the upper movable angle. Forces were applied in two directions, parallel to the bending plane of the specimens (P direction) and orthogonal to the plane (0 direction), to investigate the force versus displacement hysteresis loop changes depending on the directions. In the case of Fig. 14, the direction of applied force is the P direction. For testing in the 0 direction, the same H-shape angles as shown in Fig. 14 are used, but the specimen orientation is rotated by 90" about the y direction (vertical). Applied forces were measured with actuator load cells and the displacements were measured with linear voltage differential-transformer-type gauges (LVDT). The I-shaped and U-type dampers showed the same yield strength in both directions, whereas the C and J types showed different strengths. The areas of hysteresis loops were plotted versus damper diameter for each type and showed the highest areas (greatest damping) for the C type, followed by the J and U types. The hysteresis area was related to the third or fourth power of the damper diameter, meaning that small diameter adjustments give large changes in damping. The I type has lower damping because a greater proportion of its deformation is tensile strain rather than shear strain.

D. Performance

of U-Type Dampers

There are many U-type lead dampers in use today. There has been a steady increase in the scale,size, and capacity in the use of these U-type lead dampers in base-isolated buildings. The largest U-type lead damper in use, the U 180, has a shaft diameter of 180 mm. Itis possible to shape lead dampers quite freely by gravity die casting and it is also quite straightforward to develop lead dampersappropriate to the particular properties of

462

Chapter 4

Figure 14 Earthquake simulation test equipmentfor the evaluationof the dampers. (a) Schematic and (b) actual test equipment t375.3771.

base-isolated buildings.The challenge one faces today is to begin to develop even larger lead dampers. Dynamic tests using an actual-size Ul80-type damper and a one-quarter size model have confirmed the basic capabilities of dampers, including ultimate deformation, energy dissipation capabilities, and yield strength. Figures 15a and 15b show a schematic indicating the dimensions of the U180type damper and an actual U180-type lead damper [376]. Table 4 gives the specifications of different U-type lead dampers [376]. The lead damper is strengthened at those sections where it is most weak, namelythe deformable section, where the damper has been bent into a U-shaped curve (diameter

463

Applications of Lead Attached flange

-

I Actualsize test plece

Model test plece

(W

Figure 15 (a) A schematic diagram of a U180-type lead damper and (b) an actual size damper [376].

Chapter 4

464

Table 4

Main Specifications for U-Type Lead Dampers [376]

Name of test piece

Diameter of deformable section 10 (mm)]

Height of deformable section [ H (mm)]

Length of deformable section [ L (mm)]

50 75 100

550 560 560 560 560

680 73 0 700 638 660

U50 type U75 type U 100 type U 140 type U180 type

140

180

"Calculated values.

180 mm) and at both ends, where the diameter is at its greatest. The maximum diameter of the strengthened sections at the ends of the damper is 360 mm, or twice that of the deformable section. The strengthened sections and flanges are homogeneously bonded and the deformable and reinforced sections are cast together using a special mold. Lead of purity higher than 99.99% is used, and by the virtue of lead being extremely malleable and able to recrystallize even at extremely low temperatures, its repeated deformation capacity is extremely high. For the evaluations of the dampers, both static and dynamic tests have been carried out on the actual size damper. Sine waves were used for applying vibrations in the dynamic testing. For the application of large-deformation vibrations, an actuator able to apply vibrations (load of +50 tons and a displacement of ? 150 mm) was used. The standards for the deformation offset were set at 0 mm, 200 mm, or 400 mm and the amplitude of the vibrations were -1-50 mm. The vibration period was 3 S. In the static tests, monotonic loading from one direction with a displacement of up to 700 mm was used. The loading speed was approximately 1 mm/s. Figures 16a and 16b show the load versus displacement curves of an actual size damper tested in the P and 0 directions, respectively 13751. Both static and dynamic test results are shown in these figures. During an earthquake, there will be repeated dynamic forces and, thus, a need to experimentally prove to what degree the damper can withstand repeated deformation. Figures 17a and 17b show deformation caused by the dynamic tests in the P direction after 30 and 135 cycles, respectively, for a deformation amplitude of 150 mm [376]. Energy dissipated as a function of accumulated plastic deformation is shown in Fig. I 8 13761. The deformation of the lead damper depends on the loading frequency and amplitude, as the yield strength varies with cyclic loading frequency and amplitude of vibration (Figs. 19a and 19b, respectively) 13761.

465


.;............... Static

................... .i.....................

................... i......................

......................

J

................

.......... ......

.................

E

.......... ......

-2 0

.................

.................................... 79cyclcs ,

,

I

I

,

I

,

0

I

I

200

,

,

400

I

L

i 600

Lateral displacement (mm)

(4 ..........................................

I .................

................... :...................... D y n m c ics1

:..................

..,........

x

...........

-0 1 0 : . m 0

7L5

............

0 L.

..,........ 91cyc1cs

...........

.................. {.-.- ............ 1oocyc I oocyc I es 1

"

'

1

0

"

1

'

'

1

'

200

1

1

400

600

Lateral displacement (mm)

(b)

Figure 16 Load-displacement curves of an actual size U180 damper in (a) the P direction and (b) the 0 direction [375].

In the scale-up of dampers, the law of similitude as shown in the Table 5 are used [376]. However, one must bear in mind that the generation of heat arising from repeated deformation will have an influence on the properties of lead.

E.

Energy DissipationCapability

The damper must ultimately dissipate all of the input energy brought about by an earthquake. The total energy input can be expressed as E = M(V,)'/

Chapter 4

466

l

(W

Flgure 17 Deformation in the U180 damper by the dynamic tests in the P direction after (a) 30 cycles and (b) 135 cycles [375].


467

Pdircctit~ll.2 0 c m ~ I I I S C I , 11x1 limes Pdirucllotl. W c ~ n t ) ~ r s c ~79 . II~IC)

...................

.._

Amount of accumulated plastic deformation (cm)

Figure 18 Encrgy dissipated uctunl size test pieces 13761.

;IS

a function of accumulated plastic tleformation

of

2, where the equivalent velocity is V,

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