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A Practical Guide to Welding Solutions. Overcoming Technical and Material-Specific Issues. Edition No. 1

  • Book

  • 344 Pages
  • February 2019
  • John Wiley and Sons Ltd
  • ID: 5185588
As critically important as welding is to a wide spectrum of manufacturing, construction, and repair, it is not without its problems. Those dependent on welding know only too well how easy it is to find information on the host of available processes and on the essential metallurgy that can enable success, but how frustratingly difficult it can be to find guidance on solving problems that sooner or later arise with welding, welds, or weldments.

Here for the first time is the book those that practice and/or depend upon welding have needed and awaited. A Practical Guide to Welding Solutions addresses the numerous technical and material-specific issues that can interfere with success. Renowned industrial and academic welding expert and prolific author and speaker Robert W. Messler, Jr. guides readers to the solutions they seek with a well-organized search based on how a problem manifests itself (i.e., as distortion, defect, or appearance), where it appears (i.e., in the fusion zone heat-affected zone, or base metal), or it certain materials or situations.

Table of Contents

Preface xi

1 Introduction 1

Further Reading 6

2 Categorization of Welding and Weld Problems 7

2.1 What Is Welding? 7

2.2 Microstructural Zones of Welds 13

2.3 Origin of Problems in Welding and Welds 19

2.4 How Problems Can Be Logically Categorized? 20

References 21

Further Reading 21

Part I Manifestation of Problems with Welds and Weldments 23

3 Problems with Joint Setup and Weld Joints 25

3.1 Joint Efficiency 25

3.2 Weld Joint Types and Weld Configurations 26

3.3 Joint Setup Problems 31

3.4 Problems with Weld Profile 35

3.5 Troubleshooting Guide 42

References 45

Further Reading 45

4 Shape Distortion, Dimensional Shrinkage, and Geometric Instability 47

4.1 Thermal Versus Mechanical Stresses in a Structure 47

4.2 Residual Stresses Versus Distortion 48

4.3 Origin and Effect of Volumetric Shrinkage 48

4.4 Origin and Effect of Thermal Contraction 52

4.5 Problems from Nonuniform Thermal Contraction and CTE Mismatches 57

4.6 Problems from Distortion and from Residual Stresses 60

4.7 Distortion Control and Residual Stress Reduction 60

4.8 Troubleshooting Guide 65

References 65

Further Reading 66

5 Porosity 67

5.1 The Most Common Problem in Welds 67

5.2 Types of Weld Porosity 70

5.3 Gases in Molten Weld Metal 73

5.4 The Many Possible Causes of Porosity in Welds 79

5.5 Attempting to Minimize Porosity Formation in Fusion Welds 84

5.6 Troubleshooting Porosity Problems in Welds 85

References 87

Further Reading 87

6 Cracks 89

6.1 The Most Dreaded Defect in Welds 89

6.2 Classification of Cracking and Cracks in Welds and Welding 90

6.3 Hot Cracking and Cracks 91

6.4 Cold Cracking and Cracks 98

6.5 Other Weld-Related Cracking and Cracks 101

6.6 Crack-Prone Metals and Alloys 102

6.7 Troubleshooting Cracking Problems in Welds 105

References 106

Further Reading 107

7 Nonmetallic and Metallic Inclusions 109

7.1 Solid Versus Gas Inclusions 109

7.2 Nonmetallic Inclusions in Welds 110

7.3 Metallic Inclusions in Welds 114

7.4 Troubleshooting Problems with Inclusions in Welds 115

References 116

Further Reading 116

8 Weld Appearance 117

8.1 Can You Judge a Book by Its Cover? Is Beauty Only Skin Deep? 117

8.2 Weld Crown Bead Faults 118

8.3 Weld Root Bead Faults 121

8.4 Fillet Weld Faults 123

8.5 Reading Weld Ripple Marks 124

8.6 Weld Spatter 126

8.7 Arc Strikes 128

8.8 Weld Heat Tint 129

8.9 Troubleshooting Weld Appearance Problems 132

References 133

Further Reading 134

Part II Location of Problems in Welds 135

9 Fusion Zone of Fusion Welds 137

9.1 A Refresher on Microstructural Zones in and Around Welds 137

9.2 Gas Porosity in the Fusion Zone of Welds 141

9.3 Cracking in the Fusion Zone of Welds 143

9.4 Inclusions in the Fusion Zone of Welds 151

9.5 Macrosegregation in the Fusion Zone of Welds 152

9.6 Troubleshooting Problems in the Fusion Zone of Welds 153

References 155

Further Reading 156

10 Partially Melted Zone of Fusion Welds 157

10.1 Origin and Location of the PMZ in Fusion Welds 157

10.2 Conventional Hot Cracking in the PMZ 161

10.3 Constitutional Liquation Cracking in the PMZ 161

10.4 Cold Cracking in the PMZ 164

10.5 Overcoming Cracking Problems in the PMZ 166

10.6 Troubleshooting Problems in the PMZ 167

References 167

Further Reading 168

11 Heat-Affected Zone of Fusion Welds 169

11.1 Origin and Location of the HAZ for Fusion Welds 169

11.2 Manifestation of Problems in the HAZ of Fusion Welds 170

11.3 Precipitation-Hardening Alloy HAZ Problems 171

11.4 Sensitization in the HAZ of Austenitic Stainless Steels 176

11.5 Transformation-Hardening Steel HAZ Problems 179

11.6 Reheat Cracking 183

11.7 Troubleshooting Problems in the HAZ of Fusion Welds 186

References 187

Further Reading 188

12 Unaffected Base Metal Cracking Associated with Welding 189

12.1 Weld-Related Problems in the Unaffected Base Metal 189

12.2 Lamellar Tearing in Thick Steel Weldments 189

12.3 Corrosion Cracking Caused by Fusion Welding 192

12.4 Fatigue Cracking Outside Fusion Welds 195

12.5 Troubleshooting Weld-Related Problems in the Unaffected Base Metal 199

References 200

Further Reading 201

13 Discontinuities in Multi-pass Welds 203

13.1 Needs for Multi-pass Welding and Welds 203

13.2 Various Functions of Multi-pass Welding and Welds 205

13.3 Defects Found in Multi-pass Welds 207

13.4 Composition Adjustment with Multi-pass Welding 210

13.5 Property Alteration with Multi-pass Welding 213

13.6 Troubleshooting Problems in Multi-pass Welding and Welds 216

References 217

Further Reading 217

14 Problems with Non-fusion Welding and Non-fusion Welds 219

14.1 Non-fusion Welding Processes Versus Fusion Welding Processes 219

14.2 Overview of Non-fusion Processes 220

14.2.1 Pressure Welding Processes 222

14.2.2 Friction Welding Processes 222

14.2.3 Diffusion Welding Processes 222

14.2.4 Solid-State Deposition Welding 223

14.3 Problems with Non-fusion Welds and Non-fusion Welding Processes 223

14.4 Inspection and Repair Challenges with Non-fusion Welds 229

14.5 Troubleshooting Problems with Non-fusion Welds 230

References 230

Further Reading 231

Part III Material-Specific Weld-Related Problems 233

15 Embrittlement of Carbon and Low- and Medium-alloy Steels 235

15.1 The Importance of Steel 235

15.2 Four Causes of Embrittlement in Carbon and Low- and Medium-alloy Steels 238

15.3 Hydrogen Embrittlement: A Misnomer in Steels 239

15.4 Secondary Hardening in Steels 240

15.5 Ductile-to-Brittle Transition in Steels 241

15.6 Compromise of Fatigue and Impact Behavior by Residual Stresses in Steels 243

15.7 Troubleshooting Problems from Embrittlement of Steels by Welding 244

References 245

Further Reading 245

16 Sensitization or Weld Decay and Knife-line Attack in Stainless Steels 247

16.1 A Primer on the Metallurgy of Stainless Steels 247

16.2 Sensitization of Austenitic Stainless Steels by Welding 249

16.3 Sensitization of Other Grades of Stainless Steel 252

16.4 Knife-line Attack in Stabilized Austenitic Stainless Steels 252

16.5 Troubleshooting Problems from Sensitization or Knife-line Attack 254

References 255

Further Reading 255

17 Stress Relief Cracking of Precipitation-Hardening Alloys 257

17.1 Different Names, Same Phenomenon 257

17.2 Stress Relief Cracking in Ferritic Alloy Steels 260

17.3 Stress Relaxation Cracking in Stainless Steels 265

17.4 Strain-age Cracking in Ni-Based Superalloys 267

17.5 Troubleshooting Problems from Stress Relief or Strain-age Cracking 270

References 271

Further Reading 271

18 Loss of Properties in Cold-Worked Metals and Alloys 273

18.1 Cold Work, Recovery, Recrystallization, and Grain Growth 273

18.2 Cold-Worked Metals and Alloys in Engineering 278

18.3 Avoiding or Recovering Properties Loss from Fusion Welding 281

18.4 The Worked Zone in Pressure-Welded Metals and Alloys 284

18.5 Troubleshooting Welding Problems in Cold-Worked Metals and Alloys 285

References 285

Further Reading 286

19 Embrittlement with High-chromium Contents 287

19.1 Phase Formation and Structure 287

19.2 Adverse Effects of σ-Phase 291

19.3 Susceptible Alloys 291

19.4 Guidelines for Avoiding or Resolving Problems from σ-Phase 293

19.5 Troubleshooting Problems with σ-Phase Associated with Welding 294

References 295

Further Reading 295

20 Weld Dilution and Chemical Inhomogeneity 297

20.1 The Designer’s Druthers 297

20.2 Chemical Inhomogeneity in Welds 300

20.3 Weld Dilution 302

20.4 The Unmixed Zone in the Weld Metal 304

20.5 Impurities in the Weld Metal 307

20.6 Troubleshooting Problems from Weld Dilution and Chemical Inhomogeneity 307

References 308

Further Reading 308

21 Dissimilar Metal and Alloy Welding 309

21.1 Joining Dissimilar Materials 309

21.2 The Need for Welding Dissimilar Metals and Alloys 311

21.3 Chemical Incompatibility 311

21.4 Mechanical Incompatibility 315

21.5 Thermal Incompatibility 315

21.6 Troubleshooting Problems with Dissimilar Metal and Alloy Welding 318

References 318

Further Reading 319

Closing Thoughts 321

Index 323

Authors

Robert W. Messler, Jr. Rensselaer Polytechnic Institute, Troy, New York.