Table of Contents

Preface xiii


I INTRODUCTION 1


1 Fusion Welding Processes 3


2 Heat Flow in Welding 37


3 Chemical Reactions in Welding 65


Further Reading 95


Problems 95


4 Fluid Flow and Metal Evaporation in Welding 97


4.1 Fluid Flow in Arcs 97


4.2 Fluid Flow in Weld Pools 103


4.3 Metal Evaporation 114


4.4 Active Flux GTAW 116


References 117


Further Reading 119


Problems 120


5 Residual Stresses, Distortion, and Fatigue 122


5.1 Residual Stresses 122


5.2 Distortion 126


5.3 Fatigue 131


5.4 Case Studies 137


References 140


Further Reading 141


Problems 141


II THE FUSION ZONE 143


6 Basic Solidification Concepts 145


6.1 Solute Redistribution during Solidification 145


6.2 Solidification Modes and Constitutional Supercooling 155


6.3 Microsegregation and Banding 160


6.4 Effect of Cooling Rate 163


6.5 Solidification Path 166


References 167


Further Reading 168


Problems 169


7 Weld Metal Solidification I: Grain Structure 170


7.1 Epitaxial Growth at Fusion Boundary 170


7.2 Nonepitaxial Growth at Fusion Boundary 172


7.3 Competitive Growth in Bulk Fusion Zone 174


7.4 Effect of Welding Parameters on Grain Structure 174


7.5 Weld Metal Nucleation Mechanisms 178


7.6 Grain Structure Control 187


References 195


Further Reading 197


Problems 197


8 Weld Metal Solidification II: Microstructure within Grains 199


8.1 Solidification Modes 199


8.2 Dendrite and Cell Spacing 204


8.3 Effect of Welding Parameters 206


8.4 Refining Microstructure within Grains 209


References 213


Further Reading 213


Problems 214


9 Post-Solidification Phase Transformations 216


9.1 Ferrite-to-Austenite Transformation in Austenitic Stainless Steel Welds 216


9.2 Austenite-to-Ferrite Transformation in Low-Carbon, Low-Alloy Steel Welds 232


References 239


Further Reading 241


Problems 241


10 Weld Metal Chemical Inhomogeneities 243


10.1 Microsegregation 243


10.2 Banding 249


10.3 Inclusions and Gas Porosity 250


10.4 Inhomogeneities Near Fusion Boundary 252


10.5 Macrosegregation in Bulk Weld Metal 255


References 260


Further Reading 261


Problems 261


11 Weld Metal Solidification Cracking 263


11.1 Characteristics, Cause, and Testing 263


11.2 Metallurgical Factors 268


11.3 Mechanical Factors 284


11.4 Reducing Solidification Cracking 285


11.5 Case Study: Failure of a Large Exhaust Fan 295


References 296


Further Reading 299


Problems 299


III THE PARTIALLY MELTED ZONE 301


12 Formation of the Partially Melted Zone 303


12.1 Evidence of Liquation 303


12.2 Liquation Mechanisms 304


12.3 Directional Solidification of Liquated Material 314


12.4 Grain Boundary Segregation 314


12.5 Grain Boundary Solidification Modes 316


12.6 Partially Melted Zone in Cast Irons 318


References 318


Problems 319


13 Difficulties Associated with the Partially Melted Zone 321


13.1 Liquation Cracking 321


13.2 Loss of Strength and Ductility 328


13.3 Hydrogen Cracking 328


13.4 Remedies 330


References 336


Problems 338


IV THE HEAT-AFFECTED ZONE 341


14 Work-Hardened Materials 343


14.1 Background 343


14.2 Recrystallization and Grain Growth in Welding 347


14.3 Effect of Welding Parameters and Process 349


References 351


Further Reading 352


Problems 352


15 Precipitation-Hardening Materials I: Aluminum Alloys 353


15.1 Background 353


15.2 Al–Cu–Mg and Al–Mg–Si Alloys 359


15.3 Al–Zn–Mg Alloys 367


15.4 Friction Stir Welding of Aluminum Alloys 370


References 371


Further Reading 372


Problems 372


16 Precipitation-Hardening Materials II: Nickel-Base Alloys 375


16.1 Background 375


16.2 Reversion of Precipitate and Loss of Strength 379


16.3 Postweld Heat Treatment Cracking 384


References 390


Further Reading 392


Problems 392


17 Transformation-Hardening Materials: Carbon and Alloy Steels 393


17.1 Phase Diagram and CCT Diagrams 393


17.2 Carbon Steels 396


17.3 Low-Alloy Steels 404


17.4 Hydrogen Cracking 410


17.5 Reheat Cracking 418


17.6 Lamellar Tearing 422


17.7 Case Studies 425


References 427


Further Reading 429


Problems 430


18 Corrosion-Resistant Materials: Stainless Steels 431


18.1 Classification of Stainless Steels 431


18.2 Austenitic Stainless Steels 433


18.3 Ferritic Stainless Steels 446


18.4 Martensitic Stainless Steels 449


18.5 Case Study: Failure of a Pipe 451


References 452


Further Reading 453


Problems 454


Index 455

About the Author

SINDO KOU, PhD, is Professor and Chair of the Department of Materials Science and Engineering at the University of Wisconsin. He graduated from MIT with a PhD degree in metallurgy. He is a Fellow of American Welding Society and ASM International. He is the author of Transport Phenomena and Materials Processing, also published by Wiley.

Reviews

"?well presented, comprehensive, and accurate?a welcome
addition to the bookshelves of metallurgists, academics,
postgraduate students, as well as non-specialized engineers?"
(JOM, February 26, 2004)
"The second edition, a valuable resource for practitioners,
researchers and students, contains more exercises and offers a
solution manual upon request..." (Materials Evaluation,
February 2003)


"For many years this review has been looking, without success,
for a book on the metallurgy of welding. This...second edition
fulfills all those needs and expectations...all those who need a
basic understanding of...welds will greatly benefit...a valuable
acquisition?highly recommended." (Choice, Vol. 40, No.
7, March 2003)