Weld Cracking in Ferrous Alloys

574 Pages·2008·9.37 MB·English

by  R. Singh

i
Weld cracking in ferrous alloys
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Related titles:
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Fatigue is a mechanism of failure that involves the formation of cracks under the action
of different stresses. Stresses can be a wide range of magnitudes. To avoid fatigue it is
essential to recognise at the design stage that the loading is such that fatigue may be a
possibility and to design the structure with inherent fatigue strength. However, fatigue
strength is not a constant material property. It may be assessed by fracture mechanics, but
such characteristics are based on quantitative analysis and mere assumption. Fatigue
cracks are exceedingly difficult to see, particularly in the early stages of crack growth.
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This volume outlines theoretical treatments on heat transfer, solid mechanics and materials
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and distortion. The approaches for computational methods and analysis methodology are
described so that even non-specialists can follow them. There are chapters discussing the
various techniques for control and mitigation of residual stress and distortion. Residual
stress and distortion results for various typical welded structures are also provided. The
second half of the book looks at case studies and practical solutions, and provides insights
into the techniques, challenges, limitations and future trends of each application. The
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Fatigue assessment of welded joints by local approaches Second edition
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Local approaches to fatigue assessment are used to predict the structural durability of
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iii
Weld cracking in
ferrous alloys
Edited by
Raman Singh
CRC Press
Boca Raton Boston New York Washington, DC
W
OODHEAD PUBLISHING LIMITED
Cambridge New Delhi
iv
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Contents
Contributor contact details xi
Introduction xv
RK SINGH, Monash University, Australia
Part I Welding technology and design to prevent weld
cracking
1 Selection of weld-crack resistant stainless steels 3
JN DUPONT, Lehigh University, USA
1.1 Introduction 3
1.2 Types of stainless steels 3
1.3 Cracking mechanisms in stainless steel welds 17
1.4 Preventing weld cracking 24
1.5 References 30
1.6 Appendix of terms 32
2 Robust welding technologies for ferrous alloys 34
AK BHADURI, SK ALBERT and B RAJ, Indira Gandhi Centre for
Atomic Research, India
2.1 Introduction 34
2.2 Weldability of austenitic stainless and other steels 35
2.3 Weldability evaluation of austenitic stainless steels 39
2.4 Weldability of modified chromium–molybdenum ferritic
steels 47
2.5 Dissimilar metal welding 55
2.6 Improving welding in practice: development of special
purpose electrodes 73
2.7 Hardfacing of austenitic stainless steel components 78
2.8 Conclusions 92
2.9 References 94
vi Contents
3 Design against cracking in ferrous weldments 96
P CHELLAPANDI and SC CHETAL, Indira Gandhi Centre for Atomic
Research, India
3.1 Introduction 96
3.2 Weld design rules for pressure vessel components
(ASME section VIII division 1) 97
3.3 Weld design rules for nuclear power plant pressure vessels
(ASME section III division 1) 102
3.4 Design rules for welds as per RCC-MR 113
3.5 Design of welds with crack-like defects 115
3.6 Effect of mismatch creep properties on weld design 122
3.7 Conclusions 125
3.8 References 125
4 A discussion of the current procedures for design
of welds against fatigue 127
JWH PRICE, Monash University, Australia
4.1 Introduction 127
4.2 Weld failures and design problems 127
4.3 Fatigue design concepts and their influence 133
4.4 Manufacturing codes: acceptable sizes of surface cracks
caused by welding 134
4.5 Assessing the strength of welds 135
4.6 Current approaches to design against fatigue cracking at
welds 135
4.7 Case studies 142
4.8 Discussion 147
4.9 Conclusions 148
4.10 References 148
Part II Weld crack behaviour, evaluation and repair
5 Mechanical behaviour of stainless steel, ferritic
steel welds and weld joints 153
K BHANU SANKARA RAO, MD MATHEW, K LAHA, R SANDHYA and
B RAJ, Indira Gandhi Centre for Atomic Research, India
5.1 Introduction 153
5.2 Fatigue behaviour of stainless steel weldments 155
5.3 Creep–fatigue interaction behaviour of stainless steel
welds and weld joints 160
5.4 Creep behaviour of austenitic stainless steel welds 166
Contents vii
5.5 Creep rupture strength of ferritic steel weld joints 174
5.6 Creep of dissimilar weld joints 181
5.7 Acknowledgements 182
5.8 References 182
6 Fracture toughness in the design and operation of
ferrous weldments 185
SK RAY and G SASIKALA, Indira Gandhi Centre for Atomic
Research, India
6.1 Introduction: the importance of fracture properties 185
6.2 Fracture properties for materials qualification 186
6.3 Dynamic and quasi-static fracture properties 187
6.4 Metallurgical inhomogeneities 192
6.5 Strength mismatch and residual stress 193
6.6 Characterisation of fracture properties: dynamic fracture
properties 197
6.7 Quasi-static fracture toughness 205
6.8 Subcritical crack growth characterisation of welds 212
6.9 Conclusions 215
6.10 References 216
7 Testing and evaluation of weld cracking in ferrous
alloys 222
B RAJ, T JAYAKUMAR and P PALANICHAMY, Indira Gandhi Centre for
Atomic Research, India
7.1 Introduction 222
7.2 Quality assurance and qualifications 224
7.3 Testing and evaluation of welds 229
7.4 Non-destructive tests 230
7.5 Semi-destructive testing: metallography 258
7.6 Hardness testing 259
7.7 Destructive testing 264
7.8 Testing methods for corrosion assessment 271
7.9 Measurement of residual stresses in weldments 277
7.10 On-line weld monitoring and intelligent welding 294
7.11 Welding codes and standards 302
7.12 Conclusions 305
7.13 Acknowledgements 305
7.14 References and further reading 305
Appendix 7.1: compilation of standards on weld testing 307
Appendix 7.2: ASTM material specifications for welded
components with NDT requirements 310
viii Contents
Appendix 7.3: standards for semi-destructive and
destructive techniques 311
8 Lessons learnt from failures in ferrous weldments 314
B RAJ, KV KASIVISWANATHAN, N RAGHU, NG MURALIDHARAN and
V KARTHIK, Indira Gandhi Centre for Atomic Research, India
8.1 Introduction 314
8.2 Welding processes for ferrous alloys 315
8.3 Major failure mechanisms associated with ferrous
weldments 317
8.4 Reducing failures in weldments 322
8.5 Case studies in failure investigation 328
8.6 References 351
9 Cracking in high performance superduplex stainless
steel welds 353
A COMER, Dublin City University, Ireland
9.1 Introduction 353
9.2 Microstructure of superduplex stainless steel welds 354
9.3 Toughness and corrosion resistance of superduplex
stainless steel welds 361
9.4 Hydrogen embrittlement 364
9.5 Corrosion fatigue cracking of stainless steel welds 366
9.6 Crack propagation in a benign environment 372
9.7 Crack propagation in seawater under high electrochemical
potential 378
9.8 Crack propagation in seawater under negative imposed
electrochemical potential 381
9.9 Future trends 387
9.10 Sources of further information and advice 388
9.11 References 389
10 Weld metal cracking in cellulosic girth welds of
pipelines 393
D DUNNE, University of Wollongong, Australia and D NOLAN,
BlueScopeSteel, Australia
10.1 Introduction 393
10.2 Keyhole welding 394
10.3 Cellulosic welding 395
10.4 Pipeline construction 396
10.5 Hollow bead defect 398
Contents ix
10.6 Solidification cracking 406
10.7 Cold cracking 421
10.8 Conclusions 428
10.9 Acknowledgements 430
10.10 References 430
11 Repair of weld cracks 433
R IBRAHIM, Monash University, Australia
11.1 Introduction 433
11.2 Weld defects 434
11.3 Weld cracks 434
11.4 Crack locations 436
11.5 Other welding defects 440
11.6 Resultant welding process microstructures 441
11.7 Repair welding 444
11.8 Welding heat treatment 445
11.9 Techniques for tempering and grain refinement of the
HAZ without PWHT 447
11.10 Conclusions 455
11.11 References 456
12 Measurement of residual stresses in weld repairs
in steels 459
J PRICE, Monash University, Australia, A M PARADOWSKA, Rutherford
Appleton Laboratory, UK and T FINLAYSON, University of
Melbourne, Australia
12.1 Introduction 459
12.2 Experimental procedure 461
12.3 Residual stress measurement 462
12.4 Residual stress estimation 465
12.5 Results and discussion 468
12.6 Conclusions 472
12.7 Acknowledgements 473
12.8 References 473
Part III Environment-assisted weld cracking
13 Corrosion issues in ferrous weldments 477
RK DAYAL, H SHAIKH and N PARVATHAVARTHINI, Indira Gandhi
Centre for Atomic Research, India
13.1 Introduction 477