Aluminum Alloy Castings: Properties, Processes, and Applications (#05114G)

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Aluminum Alloy Castings

Properties, Processes, and Applications

J. Gilbert Kaufman

Elwin L. Rooy

American Foundry Society 1695 N. Penny Lane ா Schaumburg, IL 60173-4555 ASM International www.afsinc.org Materials Park, OH 44073-0002 www.asminternational.org © 2004 ASM International. All Rights Reserved. www.asminternational.org Aluminum Alloy Castings: Properties, Processes, and Applications (#05114G)

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First printing, December 2004

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Prepared under the direction of the ASM International Technical Books Committee (2003-2004), Yip-Wah Chung, FASM, Chair.

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Library of Congress Cataloging-in-Publication Data

Kaufman, J. G. (John Gilbert), 1931- Aluminum alloy castings properties, processes and applications/J. Gilbert Kaufman, Elwin L. Rooy. p. cm. Includes bibliographical references and index. ISBN 0-87170-803-5 1. Aluminum alloys—Mechanical properties. 2. Aluminum castings. I. Rooy, Elwin L. II. title.

TA480.A6K33 2004 620.1'86—dc22 2004052923

ISBN: 0-87170-803-5 SAN: 204-7586

ASM International௡ Materials Park, OH 44073-0002 www.asminternational.org

Preface

This book is intended to provide a comprehensive summary of the generously provided extensive previously unpublished production and physical and mechanical properties of most types of aluminum alloy cast- property data from their archives, adding significantly to the industry’s ings. It includes discussion of the factors that affect those properties, shared knowledge base. We wish, especially, to thank R.R. Sawtell and R.J. including composition, casting process, microstructure, soundness, heat Bucci of Alcoa for their cooperation in arranging the release of this ma- treatment, and densification. Extensive previously unpublished technical terial. We are pleased that the American Foundry Society has been credited data including aging response, growth, fatigue, and high- and low- as co-publisher of this book. The AFS Aluminum Division Review Com- temperature performance have been consolidated with existing and up- mittee provided substantive and constructive suggestions; the members of dated materials property characterizations to provide a single authoritative the committee are listed in these pages. In addition, Laura Moreno and source for most performance evaluation and design needs. Joseph S. Santner of AFS provided content from AFS publications and The consideration of casting process technologies is intentionally lim- arranged for the necessary permissions to reproduce information as needed. ited to typical capabilities and to their influence on property performance. We would also like to thank Joseph C. Benedyk of the Illinois Institute of Many excellent references are available for more detailed information and Technology for his helpful comments, and John C. Hebeisen of Bodycote guidance on production methods and on important aspects of melting, melt for his assistance in providing the results of recent studies in hot isostatic processing, solidification, and structure control. Interested readers are re- processing. The North American Die Casting Association and the Non- ferred to the publications of the American Foundry Society (AFS), the Ferrous Founders’ Society also gave us permission to cite, with appro- North American Die Casting Association (NADCA), and the Non-Ferrous priate references, information from their publications. We also acknowl- Founders’ Society (NFFS). Many of these publications are included in the edge the support and assistance of theAluminumAssociation, Inc., notably, reference lists at the end of each chapter. permission to include information from their publications covering alu- It is also beyond the scope of this book to provide more than generalized minum casting alloys. economics of aluminum casting production. J. Gilbert Kaufman The authors gratefully acknowledge the support and assistance of sev- Elwin L. Rooy eral organizations and individuals in developing this volume. Alcoa, Inc.

About the Authors

J.G. (Gil) Kaufman has a background of almost fifty years in the aluminum and materials information industries and remains an active consultant in both areas. In 1997, he retired as vice president, technology, for the Aluminum Association, Inc., headquartered in Washington, D.C., and is currently president of his consulting company, Kaufman Associates. Earlier in his career, he spent twenty-six years with the Aluminum Company of America and five with ARCO Metals, where he was vice president, R&D. He also served as president and CEO of the National Materials Property Data Network, establishing a worldwide online network of more than twenty-five materials databases. Mr. Kaufman is a Fellow and Honorary Member of ASTM, and a Fellow and Life Member of ASM International. He has published more than 125 articles, including four books, on aluminum alloys and materials data systems. Elwin Rooy retired after thirty-five years with the Aluminum Company of America, where he was corporate manager of metallurgy and quality assurance, to form a consulting firm specializing in aluminum process and product technologies, quality systems, and industry relations. He has been active in committees of the Aluminum Association, American Foundry Society, American Die Casting Institute, The Institute of Scrap Recycling Industries, Society of Die Casting Engineers, ASM In- ternational, and TMS. He has served as chairman of the TMS Aluminum Committee, chairman of the AFS Light and Reactive Metals Division, director and chairman of the Northeast Ohio chapter of AFS, regional director of the Foundry Education Foundation, and charter member of the Drexel/WPI Advanced Casting Research Laboratory. Mr. Rooy’s honors include the AFS award for Scientific Merit, The TMS/AIME Distinguished Service Award, the M.C. Flemings Award for contributions in the field of solidification, and the Arthur Vining Davis Award for technical achievement. He has served on the editorial boards of the Journal of Metals and Advanced Materials & Processes, published more than thirty articles and papers, edited Light Metals 1991, and authored or coauthored articles in the ASM Handbook series.

American Foundry Society Aluminum Division Review Committee

James Boileau John Miller Joe Santner FordMotor Company JMA Services American Foundry Society

Paul Crepeau Paul Niskanen Al Torok General Motors Corporation Alion Science andTechnology Kaiser Aluminum & Chemical Corporation Yemi Fasoyinu Randy Oehrlein Canada Centre for Mineral and Energy Carley Foundry Inc. Jim Van Wert Technology Amcast Industrial Corporation Tom Prucha Jerry Gegel INTERMET Corporation Dave Weiss Material & Process Consultancy Eck Industries Inc. Steve Robison David Jakstis American Foundry Society Jacob Zindel Boeing Commercial Airplanes Group FordMotor Company

Contents

Chapter 1: Introduction ...... 1 2.5.20 Tin ...... 16 1.1 Background and Scope ...... 1 2.5.21 Titanium...... 16 1.2 History ...... 1 2.5.22 Zinc ...... 17 1.3 Advantages and Limitations of Aluminum Castings ...... 2 2.6 Alloy Groupings by Application or Major Characteristic ..... 17 1.4 Major Trends Influencing Increased Use of Aluminum 2.6.1 General-Purpose Alloys...... 17 Castings ...... 3 2.6.2 Elevated-Temperature Alloys ...... 19 1.4.1 Technology...... 3 2.6.3 Wear-Resistant Alloys ...... 19 1.4.2 Recycling ...... 5 2.6.4 Moderate-Strength Alloys with Low Residual Stresses.. 19 1.5 Selecting the Right Aluminum Alloy and Casting Process..... 5 2.6.5 Bearings ...... 20 2.6.6 High-Strength Alloys...... 20 Chapter 2: Aluminum Casting Alloys ...... 7 2.1 General...... 7 Chapter 3: Aluminum Casting Processes...... 21 2.2 Specifications...... 7 3.1 History ...... 21 2.3 Alloy Designations...... 8 3.2 Casting Process Selection ...... 21 2.3.1 The Aluminum Association (AA) Casting Alloy 3.2.1 Casting Design...... 21 Designation System ...... 8 3.2.2 Specification Requirements ...... 21 2.3.2 Aluminum Association Casting Temper Designation 3.2.3 Volume of Production...... 22 System...... 9 3.2.4 Costs...... 22 2.3.3 Evolution of Designation System; Cross-Reference to 3.2.5 Quality...... 22 Older Designations ...... 9 3.3 Casting Process Technology ...... 22 2.3.4 The UNS Alloy Designation System...... 9 3.3.1 Expendable and Nonexpendable Mold Processes ...... 22 2.3.5 International Casting Alloy Designations ...... 9 3.3.2 Pressure versus Gravity...... 22 2.3.6 Nomenclature System for Aluminum Metal-Matrix 3.3.3 Gating and Risering...... 22 Composites...... 9 3.4 Expendable Mold Gravity-Feed Casting Process and 2.4 Composition Groupings ...... 13 Its Variations...... 23 2.4.1 Aluminum-Copper ...... 13 3.4.1 Sand Casting...... 23 2.4.2 Aluminum-Silicon-Copper ...... 13 3.4.2 Evaporative (Lost-Foam) Pattern Casting (EPC) ...... 24 2.4.3 Aluminum-Silicon...... 13 3.4.3 Shell Mold Casting...... 25 2.4.4 Aluminum-Silicon-Magnesium ...... 14 3.4.4 Plastic Casting ...... 25 2.4.5 Aluminum-Magnesium...... 14 3.4.5 Investment Casting ...... 25 2.4.6 Aluminum-Zinc-Magnesium ...... 14 3.4.6 Vacuum Mold (V-Mold) Casting ...... 26 2.4.7 Aluminum-Tin ...... 14 3.5 Nonexpendable (Permanent) Mold Gravity Feed Casting 2.5 Effects of Alloying Elements...... 14 Process and Its Variations...... 26 2.5.1 Antimony ...... 14 3.5.1 Permanent Mold Casting...... 26 2.5.2 Beryllium ...... 15 3.5.2 Low-Pressure Die Casting (LP), Pressure Riserless 2.5.3 Bismuth...... 15 Casting (PRC)...... 27 2.5.4 Boron...... 15 3.5.3 Vacuum Riserless Casting (VRC)...... 28 2.5.5 Cadmium...... 15 3.5.4 Centrifugal Casting...... 28 2.5.6 Calcium...... 15 3.5.5 Squeeze Casting...... 29 2.5.7 Chromium ...... 15 3.5.6 Semisolid Forming ...... 29 2.5.8 Copper...... 15 3.6 Pressure Die Casting and Its Variations...... 29 2.5.9 Iron...... 15 3.6.1 Acurad Die Casting Process...... 31 2.5.10 Lead...... 15 3.6.2 High-Integrity Pressure Die Casting...... 31 2.5.11 Magnesium...... 15 3.6.3 Pore-Free Pressure Die Casting ...... 31 2.5.12 Manganese ...... 15 3.6.4 Vacuum Die Casting...... 31 2.5.13 Mercury...... 16 3.6.5 Rotor Casting...... 31 2.5.14 Nickel...... 16 3.7 Premium Engineered Castings...... 31 2.5.15 Phosphorus...... 16 3.7.1 Melt Processing ...... 32 2.5.16 Silicon ...... 16 3.7.2 Melt Quality Assessment...... 32 2.5.17 Silver...... 16 3.7.3 Solidification...... 32 2.5.18 Sodium ...... 16 3.7.4 Solidification Rate ...... 32 2.5.19 Strontium...... 16 3.7.5 Mold Materials ...... 32

vii © 2004 ASM International. All Rights Reserved. www.asminternational.org Aluminum Alloy Castings: Properties, Processes, and Applications (#05114G) 3.7.6 Alloys...... 32 8.3.2 Published Minimum and Design Mechanical 3.7.7 Aluminum-Silicon Eutectic Modification and Grain Properties ...... 71 Refinement ...... 34 8.3.3 Effects of Subzero and Elevated Temperatures on 3.7.8 Mold Filling...... 34 Mechanical Properties ...... 71 3.7.9 Quality Assurance...... 35 8.3.4 Influence of Premium Practices and Emerging Casting 3.7.10 Relevance of Premium Casting Engineering...... 35 Technologies on Mechanical Properties ...... 84 3.8 Other Process Technologies...... 35 8.4 Fatigue Properties of Aluminum Casting Alloys ...... 92 3.8.1 Metallurgical Bonding...... 35 8.4.1 Influence of Casting Quality on Fatigue Strength...... 97 3.8.2 Cast Aluminum-Matrix Composites...... 36 8.4.2 Influence of Stress Raisers on Fatigue Strength of 3.8.3 Hot Isostatic Pressing (HIP)...... 37 Aluminum Castings ...... 101 8.4.3 Fatigue Strengths of Welded Aluminum Castings ...... 102 Chapter 4: The Effects of Microstructure on Properties...... 39 8.4.4 Design Fatigue Strengths for Aluminum Castings...... 103 4.1 Intermetallic Phases...... 39 8.5 Fracture Resistance of Aluminum Alloys...... 103 4.2 Dendrite Arm Spacing...... 39 8.5.1 Notch Toughness and Notch Sensitivity...... 103 4.3 Grain Refinement ...... 40 8.5.2 Tear Resistance ...... 110 4.4 Aluminum-Silicon Eutectic Modification...... 40 8.5.3 Fracture Toughness...... 112 4.5 Refinement of Hypereutectic Aluminum-Silicon Alloys ...... 45 8.5.4 Interrelation of Measures of Fracture Resistance...... 114 8.6 Subcritical Crack Growth...... 114 Chapter 5: The Influence and Control of Porosity and Inclusions 8.6.1 Fatigue Crack Growth ...... 115 in Aluminum Castings ...... 47 8.6.2 Creep Crack Growth...... 116 5.1 Hydrogen Porosity...... 47 8.6.3 Stress-Corrosion Crack Growth ...... 116 5.2 Shrinkage Porosity ...... 49 8.7 Corrosion Resistance...... 116 5.3 Inclusions...... 50 8.7.1 Aluminum-Copper Casting Alloys (2xx.x)...... 116 5.4 Combined Effects of Hydrogen, Shrinkage, and Inclusions.. 51 8.7.2 Al-Si-Cu and/or Mg Casting Alloys (3xx.x) ...... 120 5.5 Radiographic Inspection...... 53 8.7.3 Aluminum-Silicon Casting Alloys (4xx.x) ...... 120 8.7.4 Aluminum-Magnesium Casting Alloys Chapter 6: Hot Isostatic Pressing ...... 55 (5xx.x)...... 120 6.1 The HIP Process...... 55 8.7.5 Aluminum-Zinc Casting Alloys (7xx.x) ...... 120 6.2 The Effect of HIP on Tensile Properties ...... 56 8.7.6 Aluminum-Tin Casting Alloys (8xx.x) ...... 122 6.3 The Effect of HIP on Fatigue Performance ...... 56 8.8 Properties of Cast Aluminum Matrix Composites...... 122 6.4 Radiographic Inspection of HIPped Castings ...... 56 Data Set 1: Aging Response Curves ...... 133 Chapter 7: Heat Treatment of Aluminum Castings...... 61 7.1 Solution Heat Treatment ...... 62 Data Set 2: Growth Curves ...... 175 7.2 Quenching...... 62 7.3 Precipitation Heat Treating/Aging ...... 64 Data Set 3: Stress-Strain Curves...... 193 7.3.1 Aluminum-Copper ...... 65 7.3.2 Aluminum-Copper Magnesium...... 65 Data Set 4: Tensile Properties at High and Low Temperatures and 7.3.3 Aluminum-Silicon-Magnesium ...... 65 at Room Temperature after High-Temperature 7.3.4 Aluminum-Zinc-Magnesium ...... 65 Exposure ...... 211 7.4 Annealing...... 66 7.5 Stability...... 66 Data Set 5: Creep-Rupture Properties ...... 243 7.6 Residual Stresses...... 66 7.7 Troubleshooting Heat Treatment Problems...... 66 Data Set 6: Rotating-Beam Reversed-Bending Fatigue Curves.. 253 7.7.1 Acceptance Criteria ...... 66 7.7.2 Diagnosis...... 67 Appendix 1: Glossary of Terms...... 293

Chapter 8: Properties and Performance of Aluminum Appendix 2: Abbreviations and Symbols...... 299 Castings ...... 69 8.1 Compositions and Inﬂuence of Composition on Appendix 3: Test Specimen Drawings...... 301 Characteristics ...... 69 8.2 Physical Properties of Aluminum Casting Alloys...... 69 8.3 Typical and Minimum Mechanical Properties of Aluminum Alloy Index...... 305 Alloy Castings...... 71 8.3.1 Published Typical Mechanical Properties...... 71 Subject Index...... 325

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