Duplex Stainless Steels

Preface xiii

Chapter 1. Process: Hot Workability 1
Isabel GUTIERREZ and Amaia IZA-MENDIA

1.1. Introduction 1

1.2. As-cast microstructure 1

1.3. Microstructural evolution during hot working 4

1.4. Mechanical behavior under hot working 16

1.5. Static softening 28

1.6. Hot workability 31

1.7. Conclusions 39

1.8. Acknowledgments 39

1.9. References 39

Chapter 2. Corrosion Resistance Properties 47
Jacques CHARLES

2.1. Introduction 47

2.2. The duplex grades and pitting resistance equivalent numbers 48

2.3. Some fundamentals concerning stainless steel corrosion resistance 50

2.4. The different forms of corrosion 60

2.5. Some complex corrosion behaviors encountered in industrial applications 100

2.6. Conclusions 111

2.7. References 111

Chapter 3. Phase Transformation and Microstructure 115
Angelo Fernando PADILHA and Ronald Lesley PLAUT

3.1. Introduction 115

3.2. Phase diagrams and typical phases 117

3.3. Solidification 120

3.4. Austenite precipitation 121

3.5. Phase changes occurring below 1,000°C 123

3.6. Cold working and annealing 132

3.7. Final remarks 134

3.8. References 135

Chapter 4. Welding Processes, Microstructural Evolution and Final Properties of Duplex and Superduplex Stainless Steels 141
Franco BONOLLO, Alberto TIZIANI and Paolo FERRO

4.1. Introduction 141

4.2. ƒÏ-ferrite ƒÏƒnaustenite transformation 142

4.3. Secondary and intermetallic phases precipitation during welding processes 145

4.4. Welding processes for DSS and SDSS 147

4.5. Final remarks 155

4.6. References 155

Chapter 5. Thermal Embrittlement of Cast Duplex Stainless Steels: Observations and Modeling 161
Andre PINEAU and Jacques BESSON

5.1. Introduction 161

5.2. Composition, elaboration, microstructure, and mechanical properties 163

5.3. Thermal embrittlement of the ferrite phase in DSS 170

5.4. Materials investigated and embrittlement heat treatments 181

5.5. Damage and rupture 186

5.6. Scale effect and scatter 189

5.7. Modeling of rupture 192

5.8. Conclusion 201

5.9. References 201

Chapter 6. Low-Cycle Fatigue at Room Temperature 209
Iris ALVAREZ-ARMAS

6.1. Introduction 209

6.2. Cyclic hardening/softening process 210

6.3. Uniaxial cyclic plasticity in DSSs 219

6.4. Final remarks 236

6.5. Acknowledgments 237

6.6. References 237

Chapter 7. Multiaxial Low-Cycle Fatigue Behavior at Room Temperature 241
Suzanne DEGALLAIX-MOREUIL

7.1. Introduction 241

7.2. Multiaxial LCF – introduction 242

7.3. Biaxial LCF of a DSS type 25-07 248

7.4. Conclusions 270

7.5. Acknowledgments 270

7.6. References 270

Chapter 8. Partition of Cyclic Plasticity in the 25Cr-7Ni-0.25N Duplex Stainless Steel Investigated by Atomic Force Microscopy 275
Jean-Bernard VOGT, Daniel SALAZAR and Ingrid PRORIOL SERRE

8.1. Introduction 275

8.2. Material 277

8.3. Experimental procedure 278

8.4. Cyclic behavior at a low strain range 280

8.5. Cyclic behavior at a high strain range 289

8.6. Conclusions 300

8.7. References 300

Chapter 9. Macro- and Micromodeling of the Monotonic and Cyclic Mechanical Behavior of a Forged DSS 303
Veronique AUBIN and Pierre EVRARD

9.1. Introduction 303

9.2. Macroscopic modeling of the mechanical behavior 304

9.3. Micromechanical modeling 318

9.4. General conclusion 332

9.5. References 334

Chapter 10. Low-Cycle Fatigue at Intermediate Temperatures 339
Alberto F. ARMAS

10.1. Introduction 339

10.2. Materials studied 342

10.3. UNS S32900 DSS 345

10.4. UNS S32750 SDSS 352

10.5. Temperature influence on the fatigue life 361

10.6. Final remarks 363

10.7. Acknowledgments 364

10.8. References 364

Chapter 11. Industrial Processing and Fatigue Response of DSSs 367
Nuri AKDUT

11.1. Introduction 367

11.2. Morphological aspects 369

11.3. The role of morphological texture on the fatigue response 372

11.4. The role of nitrogen-content on the fatigue response of DSSs 375

11.5. Cyclic plasticity and fatigue of nitrogen-alloyed DSSs – effects of cyclic softening 383

11.6. Summary and conclusions 395

11.7. References 396

Chapter 12. Applications 403
Mats LILJAS and Fredrik SJOHOLM

12.1. Introduction 403

12.2. Historical review 404

12.3. Current (modern) DSS grades 408

12.4. Modern applications 409

12.5. Conclusions 422

12.6. References 422

Appendix 425

List of Authors 429

Index 433