Welding Metallurgy and Weldability of Nickel-Base Alloys

WELDING METALLURGY AND WELDABILITY OF NICKEL-BASE ALLOYS......Page 5
CONTENTS......Page 9
Preface......Page 15
1. Introduction......Page 17
1.1.1 Commercially Pure Nickel Alloys......Page 18
1.1.2 Solid-Solution Strengthened Alloys......Page 19
1.1.3 Precipitation-Strengthened Alloys......Page 20
1.2 History of Nickel and Ni-base Alloys......Page 21
1.3 Corrosion Resistance......Page 27
1.4 Nickel Alloy Production......Page 28
References......Page 30
2.1 Introduction......Page 31
2.2 General Influence of Alloying Additions......Page 32
2.3.1 The Ni-Cu System......Page 36
2.3.2 The Ni-Cr System......Page 37
2.3.4 The Ni-Fe-Cr System......Page 38
2.3.5 Ni-Cr-Mo System......Page 40
2.4 Phase Diagrams for Precipitation Hardened Alloys—γ' Formers......Page 42
2.5 Phase Diagrams for Precipitation-Hardened Alloys—γ'' Formers......Page 46
2.6 Calculated Phase Stability Diagrams......Page 49
2.7 PHACOMP Phase Stability Calculations......Page 56
References......Page 59
3.1 Standard Alloys and Consumables......Page 63
3.2 Physical Metallurgy and Mechanical Properties......Page 67
3.3.1.1.1 Solidification Subgrain Boundaries (SSGBs)......Page 73
3.3.1.2 Elemental Segregation during Solidification......Page 75
3.3.1.3 Phase Transformation Sequence......Page 86
3.3.2 Heat Affected Zone......Page 97
3.3.3 Postweld Heat Treatment......Page 98
3.3.3.1 Stress Relief Heat Treatments......Page 99
3.3.3.2 Homogenization of Weld Metal Microstructure......Page 103
3.4.1 Hydrogen Effects......Page 107
3.4.2 Postweld Heat Treatment......Page 109
3.5.1 Fusion Zone Solidification Cracking......Page 116
3.5.2 HAZ Liquation Cracking......Page 134
3.5.3 Avoiding Solidification and Liquation Cracking......Page 139
3.5.4.1 Description of Ductility-Dip Cracking......Page 144
3.5.4.2 Proposed Mechanisms for Ductility-Dip Cracking......Page 146
3.5.4.3 Ductility-Dip Cracking in Ni-base Weld Metals......Page 147
3.6 Corrosion Resistance......Page 159
3.7.1 Pitting Corrosion in MONEL(®) Welds......Page 165
References......Page 166
4. Precipitation-Strengthened Ni-base Alloys......Page 173
4.1 Standard Alloys and Consumables......Page 174
4.2 Physical Metallurgy and Mechanical Properties......Page 177
4.3.1.1 Elemental Segregation during Solidification......Page 189
4.3.1.2 Phase Transformations—γ' Formation......Page 191
4.3.1.3 Phase Transformations—Carbide Formation......Page 198
4.3.1.4 Phase Transformations—γ'' Formation......Page 200
4.3.1.5 Effect of Nb and C......Page 203
4.3.1.6 Fusion Zone Microstructure Predictions using New PHACOMP......Page 212
4.3.2 Heat-Affected Zone......Page 217
4.3.3 Postweld Heat Treatment......Page 220
4.4 Mechanical Properties of Weldments......Page 222
4.5 Weldability......Page 223
4.5.1.1 Effect of Minor Element Additions—B and Zr......Page 224
4.5.1.2 Effect of Nb Additions......Page 226
4.5.1.3 Cast Pin Tear Test Results......Page 236
4.5.1.4 Summary of Solidification Cracking......Page 238
4.5.2 HAZ Liquation Cracking......Page 239
4.5.2.1 Composition Effects......Page 240
4.5.2.2 Effect of Grain Size......Page 242
4.5.2.3 Effect of Heat Treatment......Page 244
4.5.2.4 Effect of Thermal Stress/Strain......Page 250
4.5.3 Strain-Age Cracking......Page 251
4.5.3.1 Mechanism for Strain-Age Cracking......Page 253
4.5.3.2 Effect of Residual, Thermal and Aging Stresses, and Joint Restraint......Page 258
4.5.3.3 Composition Effects......Page 260
4.5.3.5 Preweld Condition of the Base Metal......Page 261
4.5.3.7 Effect of Postweld Heat Treatment......Page 262
References......Page 264
5.1.1 Physical and Mechanical Metallurgy......Page 271
5.1.2 Welding Metallurgy......Page 275
5.2.1 Physical and Mechanical Metallurgy......Page 284
5.2.2.1 Elevated Temperature Cracking......Page 288
5.2.2.2 Hot Ductility Behavior......Page 290
5.2.3 Summary of the Weldability of Nickel Aluminide Alloys......Page 292
References......Page 294
6.1 Solid-Solution Strengthened Alloys......Page 297
6.2 Precipitation-Strengthened Alloys......Page 299
6.2.1.1 Effect of δ-phase Formation......Page 300
6.2.1.2 Rejuvenation Heat Treatments......Page 308
6.2.1.3 Summary of Repair Weldability of Alloy 718......Page 310
6.2.2 Waspaloy......Page 311
6.3 Single Crystal Superalloys......Page 314
6.3.1 Control of Single Crystal Weld Repairs......Page 318
6.3.2 Solidification Cracking......Page 330
6.3.3 Optimizing Processing Parameters......Page 333
References......Page 340
7.1 Application of Dissimilar Welds......Page 343
7.2 Influence of Process Parameters on Fusion Zone Composition......Page 344
7.3 Carbon, Low Alloy and Stainless Steels......Page 347
7.3.1 Determining Weld Metal Constitution......Page 348
7.3.2 Fusion Boundary Transition Region......Page 350
7.3.3.1 Solidification Cracking......Page 358
7.3.3.3 Creep Failure in the HAZ of Carbon Steel or Low Alloy Steel......Page 361
7.3.3.4 Postweld Heat Treatment Cracking......Page 362
7.4 Postweld Heat Treatment Cracking in Stainless Steels Welded with Ni-base Filler Metals......Page 363
7.5 Super Austenitic Stainless Steels......Page 365
7.7.1 Physical Metallurgy of 9%Ni Steels......Page 373
7.7.2 Hot Cracking of Ni-base Deposits......Page 377
7.8 Super Duplex Stainless Steels......Page 379
7.9.1 Postweld Heat Treatment Cracking of Thick Section Welds in Alloy 800H Made with ENiCrFe-2 Filler Metal......Page 380
7.9.2 Alloy 925 Welded with ERNiCrMo-15 (INCO-WELD 725NDUR) for Manufacturing Vacuum Insulated Oil Patch Tubing......Page 383
7.9.3 Corrosion-Fatigue of Alloy 625 Weld Overlays......Page 385
7.9.4 Overlay of “Safe-End” Welds using High-Cr, Ni-base Filler Metals......Page 389
References......Page 392
8.1 Introduction......Page 395
8.1.2 Types of Weldability Test Techniques......Page 396
8.2 The Varestraint Test......Page 397
8.2.1 Technique for Quantifying Weld Solidification Cracking......Page 399
8.2.2 Technique for Quantifying HAZ Liquation Cracking......Page 402
8.3 Modified Cast Pin Tear Test......Page 404
8.4 The Sigmajig Test......Page 408
8.5 The Hot Ductility Test......Page 410
8.6 The Strain-to-Fracture Test......Page 415
8.7 Other Weldability Tests......Page 417
References......Page 418
Appendix A Composition of Wrought and Cast Nickel-Base Alloys......Page 419
Appendix B Composition of Nickel and Nickel Alloy Consumables......Page 425
Appendix C Corrosion Acceptance Testing Methods......Page 431
Appendix D Etching Techniques for Ni-base Alloys and Welds......Page 435
Author Index......Page 439
Subject Index......Page 447