Metallurgy and Mechanics of Welding: Processes and Industrial Applications

Preface xiii

Chapter 1. Traditional Welding Processes 1
Guy MURRY and Dominique KAPLAN

1.1. Introduction 1

1.2. Conditions to create metallic bonding 1

1.2.1. Activation of surfaces 2

1.2.2. Elimination of obstacles to bond creation 3

1.2.3. How can we classify the various welding processes? 4

1.3. Industrial welding processes 5

1.3.1. Processes using local fusion of components without mechanical action 5

1.3.2. Processes using local fusion of components with mechanical action 22

1.3.3. Processes using heating without fusion but with mechanical action 27

1.3.4. Processes using mechanical action without heating 29

1.4. Bibliography 30

Chapter 2. High Density Energy Beam Welding Processes: Electron Beam and Laser Beam 31
Abdelkrim CHEHAÏBOU and Jean-Claude GOUSSAIN

2.1. Welding properties using high density energy beams 31

2.2. Laser beam welding 33

2.2.1. History 33

2.2.2. Principle 34

2.2.3. Various laser types 35

2.2.4. Laser systems 41

2.2.5. Implementation of laser beam welding 48

2.3. Electron beam welding 52

2.3.1. History 52

2.3.2. Principle 53

2.3.3. Equipment 54

2.3.4. Design and preparation of the parts 60

2.4. Metallurgy of high density energy beam welding 61

2.4.1. Steels 61

2.4.2. Aluminum alloys 67

2.4.3. Nickel-based alloys 70

2.4.4. Titanium-based alloys 72

2.4.5. Zirconium-based alloys 73

2.4.6. Copper-based alloys 73

2.5. Mechanical properties of welded joints 75

2.6. The quality of the assemblies 76

2.6.1. Weld defects 76

2.6.2. Weld inspection methods 78

2.6.3. Standardization and qualification of the welding operating mode 79

2.7. Economic aspects 79

2.7.1. Cost of an electron beam machine 79

2.7.2. Cost of a laser beam machine 80

2.8. Safety 82

2.9. Examples of industrial applications 83

2.9.1. Electron beam welding 83

2.9.2. Laser beam welding 84

2.10. Development prospects 84

2.11. Bibliography 86

Chapter 3. Thermal, Metallurgical and Mechanical Phenomena in the Heat Affected Zone 89
Dominique KAPLAN and Guy MURRY

3.1. Thermal aspects related to welding 89

3.1.1. Maximum temperature attained in the HAZ 95

3.1.2. Cooling parameter in the HAZ 97

3.2. Microstructural modifications in the HAZ: metallurgical consequences of the thermal cycles of welding 102

3.2.1. Transformations in the HAZ during heating 102

3.2.2. Transformations in the HAZ during cooling 107

3.2.3. Case of multipass welding 110

3.2.4. Cold cracking 112

3.2.5. Lamellar tearing 117

3.3. Influence of the thermal cycles on the mechanical properties of the HAZ 118

3.3.1. Modifications of the mechanical properties of hardness or traction in the HAZ 119

3.3.2. Toughness properties of the HAZ 120

3.3.3. Residual stresses associated with welding 123

3.3.4. Influence of residual stress relieving heat treatments in the HAZ 125

3.4. Bibliography 126

Chapter 4. Molten Metal 133
Christian BONNET

4.1. Metallurgical reminders 133

4.2. Molten metal 135

4.2.1. Thermal aspect 135

4.2.2. Chemical aspect 136

4.2.3. Microstructures in ferritic steel welds: relationship with impact strength characteristics 139

4.3. Principal welding defects 149

4.3.1. Hot cracking 149

4.3.2. Cold cracking 157

4.3.3. Reheat cracking 160

4.3.4. Porosities 162

4.4. Bibliography 166

Chapter 5. Welding Products 169
Christian BONNET

5.1. Coated electrodes 169

5.1.1. Constitution of coatings: consequences 169

5.1.2. Basic electrodes and diffusible hydrogen 172

5.2. Fluxes for submerged arc welding 175

5.2.1. Fused fluxes and granular fluxes: advantages and disadvantages 175

5.2.2. Roles of flux: metallurgical aspects 177

5.3. Welding gases 181

5.3.1. Welding processes under a gas flux with an infusible electrode 181

5.3.2. Welding processes under a gas flux with a fusible electrode 184

5.4. Cored wires 191

5.4.1. Manufacturing processes 191

5.4.2. Types of cored wires 192

5.4.3. The titanium/boron effect in relation to rutile cored wires 194

5.5. Choice of welding products 195

5.6. Welding products and the welder’s environment 197

5.6.1. Coated electrodes 197

5.6.2. Gas mixtures for TIG welding 199

5.6.3. Gas mixtures for GMAW 201

5.6.4. Cored wires 204

5.7. Bibliography 205

Chapter 6. Fatigue Strength of Welded Joints 207
Henri-Paul LIEURADE

6.1. Fatigue strength 207

6.1.1. Introduction 207

6.1.2. Fatigue failure of the principal welded joints 208

6.1.3. Concept of nominal stress 212

6.1.4. Factors in welded joint endurance 213

6.2. Dimensioning of joints in mechanized welding 227

6.2.1. Position of the problem 228

6.2.2. General method (current regulations) 230

6.2.3. Verification methods 231

6.2.4. Geometric structural stress method 232

6.3. Bibliography 237

Chapter 7. Fracture Toughness of Welded Joints 239
Marc BOUSSEAU

7.1. Ductile fracture and brittle fracture 239

7.2. Evaluation of fracture risks in metallic materials 241

7.2.1. Determination of the ductile-brittle transition temperature 241

7.2.2. Determination of a fracture criterion in the elastic linear field 245

7.2.3. Fracture criteria in the elasto-plastic field 249

7.3. Evaluation of fracture risks in welded joints 253

7.3.1. Heterogenities of the weld bead 253

7.3.2. Conditions of specimen taking 255

7.3.3. Determination of the ductile-brittle transition temperature 256

7.3.4. Various methods of toughness evaluation 258

7.4. Consequences of heterogenities on the evaluation of fracture risks 262

7.4.1. Mismatching effects 263

7.4.2. Influence of the base material 266

7.4.3. Influence of filler metals 269

7.4.4. Importance of welding conditions 269

7.4.5. Evaluation and taking account of residual stresses 270

7.5. Bibliography 273

Chapter 8. Welding of Steel Sheets, With and Without Surface Treatments 279
Gilles RIGAUT, Olivier DIERAERT, Pascal VERRIER and Joël CLAEYS

8.1. Spot welding 280

8.1.1. Principle 280

8.1.2. Tests of spot weldability 281

8.1.3. Spot weldability of thin steel sheets 284

8.2. Seam welding 292

8.2.1. Mash seam welding 292

8.2.2. Overlapping seam welding 293

8.2.3. Example applications studied or handled with customers 294

8.3. Laser welding of thin sheets 295

8.3.1. Principle of keyhole laser welding 296

8.3.2. Butt welding 298

8.3.3. Lapped welding 304

8.4. Arc welding 306

8.4.1. TIG welding 306

8.4.2. MAG welding 307

8.5. Bibliography 311

Chapter 9. Welding of Steel Mechanical Components 313
Yves DESALOS and Gérard PRADERE

9.1. Introduction 313

9.2. Specificities of welded bonds in mechanical components 315

9.2.1. Standard welding processes and general recommendations 315

9.2.2. Metallurgical defects in the molten zone and the HAZ 317

9.2.3. Weldability limits for welding with and without remelting 320

9.3. Principal types of welding for mechanical components 323

9.3.1. Electric arc welding and alternatives 324

9.3.2. Welds with reduced HAZ using high density energy sources: laser beam, EB, plasma 327

9.3.3. Friction welding 333

9.3.4. Butt welding by the Joule effect 337

9.3.5. Diffusion welding in the solid phase 341

9.4. Specifications and quality control of the weldings for these components 344

9.4.1. Weld quality specifications 345

9.4.2. The quality assurance plan of the weld 349

9.5. Developments and trends 353

9.5.1. Evolution of the context 353

9.5.2. Favored processes 353

9.6. Conclusions 355

9.7. Bibliography 356

Chapter 10. Welding Steel Structures 359
Jean-Pierre PESCATORE and Jean-Henri BORGEOT

10.1. Introduction 359

10.1.1. History 359

10.1.2. Applications 361

10.2. Steels for steel structures 362

10.2.1. Grades and qualities 362

10.2.2. Steels used 363

10.3. Steel construction welding processes and techniques 364

10.3.1. Table of the usual processes 364

10.3.2. Preliminary operation: tack weld 365

10.3.3. Particular welding techniques 365

10.3.4. Usual welding positions 367

10.3.5. Edge preparation 367

10.4. Welding distortion 369

10.4.1. Precautions in execution 369

10.4.2. Straightening 371

10.5. Defects and their prevention 371

10.5.1. Cracks 371

10.5.2. Fracture 372

10.5.3. Other thermal and mechanical precautions 373

10.6. Specificities of non-destructive testing of steel structures 374

10.7. Developmental perspectives 374

Chapter 11. Welding Heavy Components in the Nuclear Industry 375
François FAURE and Léon DUNAND-ROUX

11.1. General presentation of a PWR pressure vessel 375

11.2. Main materials used for manufacturing 376

11.2.1. Principle of material choice – construction code 376

11.2.2. Low alloyed steels for pressure vessels 377

11.2.3. Austenitic stainless steel circuits 379

11.2.4. Nickel alloy parts 380

11.3. Welding of large low alloy steel components 381

11.3.1. Properties aimed for 382

11.3.2. Procedural description 382

11.3.3. Welding with coated electrodes 387

11.4. Cladding 387

11.4.1. Cladding method 389

11.4.2. Cladding inspection 389

11.5. Welding of stainless steel circuits 390

11.6. Dissimilar metal interfaces 393

11.7. Welding of steam generator pipes 394

11.8. Conclusions 396

Chapter 12. Welding Stainless Steels 397
Jean-Louis MOIRON

12.1. Definitions 397

12.2. Principal stainless steel families 397

12.3. Metallurgical structures 399

12.4. Constitution diagrams 402

12.4.1. Introduction 402

12.4.2. Calculation of the equivalent formulae 402

12.4.3. Constitution diagrams 403

12.5. Welding ferritic stainless steels 408

12.5.1. Introduction 408

12.5.2. Risks incurred in welding 409

12.5.3. Stabilization 410

12.5.4. Risks of embrittlement 411

12.5.5. Filler products 412

12.5.6. Shielding gases 413

12.5.7. Summary: partial conclusion 413

12.6. Welding of martensitic stainless steels 414

12.6.1. Introduction 414

12.6.2. List of martensitic stainless steels 415

12.6.3. Effect of the elements C, Cr and Ni on the y loop 415

12.6.4. Metallurgical weldability of martensitic stainless steels 416

12.6.5. Conclusion: partial summary 417

12.7. Welding of austenitic stainless steels 418

12.7.1. Introduction 418

12.7.2. Risks incurred during welding 418

12.7.3. Carbide precipitation 419

12.7.4. Hot cracking 420

12.7.5. The sigma phase 421

12.7.6. Filler products 422

12.7.7. Shielding gas 422

12.8. The welding of austeno-ferritic stainless steels (duplex) 423

12.8.1. Introduction 423

12.8.2. Risks incurred in welding 423

12.8.3. Principal austeno-ferritic stainless steels 424

12.8.4. Weldability of austeno-ferritic steels 425

12.8.5. Filler products 426

12.8.6. Shielding gases 426

12.9. Heterogenous welding 427

12.9.1. Reminder of definitions 427

12.9.2. Treatment and forecast of heterogenous welds 427

12.10. Finishing of welds 429

12.11. Glossary 430

12.12. Bibliography 431

Chapter 13.Welding Aluminum Alloys 433
Michel COURBIÈRE

13.1. Metallurgy of welding 433

13.1.1. Weldability of aluminum alloys (steels/aluminum comparison) 433

13.1.2. Filler metals 436

13.2. Welding techniques 440

13.2.1. Introduction 440

13.2.2. Arc welding processes (TIG-MIG) 441

13.2.3. Electric resistance welding 447

13.2.4. Flash welding 448

13.2.5. Friction welding and friction stir welding 449

13.2.6. Electron beam welding 451

13.2.7. Laser welding 452

13.2.8. Other techniques 453

13.3. Preparation and use of semi-finished aluminum welding products 454

13.3.1. Particularities of aluminum alloy surfaces 454

13.3.2. Storage 455

13.3.3. Surface preparation 455

13.3.4. Cleaning of the weld beads 456

13.4. Deformations 457

13.4.1. Introduction 457

13.4.2. Steel/aluminum comparison (deformation due to heating) 458

13.4.3. Shrinkage 461

13.4.4. Basic rules 461

13.5. Dimensioning of the welded structures 464

13.5.1. Static 464

13.5.2. Fatigue dimensioning 467

13.5.3. Rules governing the optimal use of welded structures 467

13.6. Welding defects 468

13.7. Health and safety 471

13.8. Bibliography 471

Chapter 14. Standardization: Organization and Quality Control in Welding 473
Jean-Paul GOURMELON

14.1. Introduction 473

14.2. Standards of general organization of quality 474

14.2.1. Presentation 474

14.2.2. Principles 475

14.2.3. Analysis 475

14.3. Standards for welding procedure qualification 479

14.4. Non-destructive testing standards 484

14.5. Conclusion 487

List of Authors 489

Index 491