Applied Metallurgy and Corrosion Control (eBook)

Dr Amiya Kumar Lahiri is presently a freelance consultant in materials, corrosion and inspection providing services to process industries. He has devoted himself to the cause of development and implementation of corrosion science for more than 60 years. Having graduated in Metallurgy in 1953 from Banaras Hindu University, he obtained his Ph.D from the same university. Dr Lahiri started his career at National Metallurgical Laboratory Jamshedpur, and established a strong Corrosion Group. The specific areas of specialization of Dr Lahiri include research and development in stress corrosion cracking, high temperature oxidation and acid inhibition. An all India plan on atmospheric corrosion was prepared and implemented throughout India based on which Corrosion Map of India was prepared.  In recognition of his work on corrosion at the National Metallurgical Laboratory, he was awarded in 1970 “National Metallurgist Day Award” by Govt. of India, Ministry of Steel and Heavy Industry. Dr Lahiri joined Engineers India Ltd, a leading global engineering consultancy and EPC company, in 1972. During his tenure in EIL, he has to his credit completion of several assignments which included selection of material of construction and corrosion control measures in grass root refineries, petrochemicals and oil & gas processing projects; assisting operating plants in upgrading metallurgy, introducing or modifying corrosion control measures and recommending inspection and repair techniques of stationary equipment, and failure investigation. He was also team leader for the UNDP Project for development of maintenance and inspection system at Homs Refinery, Syria. He was assigned as UNIDO expert in Kuwait and Philippines to set up Corrosion Control and Monitoring Laboratory and assistance in setting up a Core Group to help industry, respectively. After retirement from EIL in 1989, Dr Lahiri has been providing consultancy to the hydrocarbon industry in India and Middle East. He has undertaken health assessment of a petrochemical plant in India and two refineries in Germany and USA against corrosion damage and review of MOC for the purposes of their relocation. Further he has worked as consultant to the World Bank aided Component Integrity Evaluation Program at National Metallurgical Laboratory. He has also been consultant to Nickel Institute. Dr. Lahiri throughout his carrier has been active in increasing awareness about metallurgy and corrosion and has organized short courses and conducted over 80 training programs on Applied Metallurgy, Corrosion, and Materials Failure Analysis in India, Middle East and Malaysia. He has published / presented over 30 technical papers in National and International Journals and Conferences. Dr Lahiri had been a member and Accredited NACE Corrosion Specialist, Fellow of Institute of Metallurgists, London and Fellow of The Institution of Corrosion Science and Technology, UK. He has also undertaken Advance Corrosion Training in UK and USA under Colombo Plan and US Aid Program respectively. In recognition of his selfless service to the industry in the field of corrosion, NACE International India Section conferred on Dr Lahiri the Lifetime Achievement Award on behalf of the entire professional fraternity on the occasion of the 5th National Convention on Corrosion in 1999.

Series Editors’ Preface 7
About the Indian Institute of Metals 7
Genesis and History of the Series 7
Current Series Information 8
About This Book 8
Preface 10
Acknowledgements 12
Contents 13
About the Author 21
1 Introduction 22
Abstract 22
1.1 Material Engineering 22
1.2 Considerations in Material Selection 23
1.2.1 Material Degradation 23
1.2.2 Mechanical and Physical Properties 24
1.2.3 Equipment Fabrication 24
1.2.4 Type of Equipment 25
1.2.5 Material Maintenance 25
1.2.6 Design Philosophy 26
1.3 Steps in Selection of Material 26
1.3.1 Steps in Material Selection 27
1.3.2 Design and Operational Considerations 28
1.4 Some Failure Examples 29
1.4.1 A Case of Correct MOC But Wrong Specification and Repair Procedure 29
1.4.2 Selection of Control Valve of Wrong Design 31
1.4.3 Catastrophic Failure Due to Inadequate Piping Stress Analysis 31
1.4.4 Capsize of Semi-submersible Offshore Platform Because of Poor Workmanship 32
1.4.5 Rupture of Pipe in Crude Distillation Unit Due to Wrong Specification 34
1.4.6 Failure of Thick Low Alloy Steel Vessel Due to Inadequate PWHT 35
References 35
2 Classification of Metallic Engineering Materials 37
Abstract 37
2.1 Introduction 37
2.2 Ferrous Materials 39
2.2.1 Cast Irons 39
2.2.1.1 Alloy Cast Irons 40
2.2.2 Plain Carbon Steels 40
2.2.3 Low and Medium Alloy Steels 41
2.2.4 High Alloy Steels 43
2.2.4.1 Wrought Austenitic, Ferritic and Martensitic Stainless Steels 43
2.2.4.2 Cast Stainless Steels 45
2.2.4.3 Duplex Stainless Steel (DSS) 46
2.2.4.4 High Performance Ferritic and Austenitic Stainless Steels 48
2.2.4.5 Comparison of Different Stainless Steels 48
2.3 Non-ferrous Materials 50
2.3.1 Aluminium and Aluminium Alloys 50
2.3.2 Copper and Copper Alloys 50
2.3.3 Nickel and Nickel Alloys 51
2.3.4 Lead and Lead Alloys 51
2.3.5 Titanium and Titanium Alloys 52
2.3.6 Other Non-ferrous Metals 53
2.4 Unified Numbering System 53
2.5 Material Specification 54
2.5.1 Material Standard 54
2.5.2 Purpose of Specification 54
2.5.3 Preparation of Standards 55
2.5.3.1 Broad Coverage Under Specifications 56
2.5.4 Dual Certification 58
References 59
3 Production and Working of Metals and Alloys 60
Abstract 60
3.1 Metal Production 60
3.1.1 Metal Purification 61
3.2 Iron and Steel Making 62
3.2.1 Pig Iron 62
3.2.2 Conventional Steel Making 63
3.2.2.1 Basic Oxygen Process (BOP) 63
3.2.2.2 Electric Arc Furnace Steel Making 64
3.2.2.3 Deoxidation and Ladle Treatment of Steel 65
3.2.3 Modern Steel Making by Ladle Treatment 66
3.2.3.1 Desulfurization 66
3.2.3.2 Ladle Decarburization 67
3.2.3.3 Ladle Degassing 67
3.2.4 Summary 67
3.3 Ingot Casting and Forming 68
3.3.1 Conventional Casting 68
3.3.2 Continuous Casting 68
3.4 Shaping of Metal and Alloys 69
3.4.1 Casting 69
3.4.1.1 Advantages and Disadvantages of Casting 69
3.4.1.2 Centrifugal Casting 71
3.4.2 Shaping by Mechanical Working 72
3.4.2.1 Workability 72
3.4.2.2 Surface Finish 73
3.4.3 Types of Forming Processes 73
3.4.3.1 Rolling 73
3.4.3.2 Extrusion 75
Cold Extrusion 75
Hot Extrusion 76
3.4.3.3 Forging 76
Closed Die Forging 77
Open-Die Forging 77
Cold Forging 78
Seamless Rolled Ring Forging 78
3.4.3.4 Manufacture of Pipes and Tubes 80
Fusion Welded Pipe 80
Spiral Welded Pipe 80
Electric Resistance Welded (ERW) Pipe 81
Seamless Pipe 82
Extrusion 83
UOE Process for Production of Pipe 84
3.4.3.5 Drawing 85
3.4.4 Production of Clad/Lined Material 85
3.4.4.1 Strip Lining 85
3.4.4.2 Roll Cladding 87
3.4.4.3 Weld Cladding 89
3.4.4.4 Explosion Cladding/Welding 89
Advantages and Disadvantages of Explosion Welding 91
3.4.5 Surface Defects of Worked Product 91
3.4.6 Forming of Plates 92
3.4.6.1 Cold Forming 92
3.4.6.2 Warm Forming 93
3.4.6.3 Hot Forming 93
3.4.6.4 Forming of Clad Plate 94
3.4.7 Cutting Operation 94
3.4.7.1 Oxy-flame Cutting 94
3.4.7.2 Plasma Cutting 95
3.4.7.3 Laser Cutting 95
3.4.7.4 Water Jet Cutting 95
References 96
4 Structure of Metals and Alloys 97
Abstract 97
4.1 Crystal Structure 97
4.1.1 Introduction 97
4.1.2 Structural Changes 101
4.2 Phase Diagram 101
4.2.1 Solid Solution 103
4.2.2 Grain Boundaries 104
4.2.3 Iron–Carbon Phase Diagram 106
4.2.4 Binary Iron Alloys 107
4.2.5 Ternary Phase Diagrams 109
References 109
5 Mechanical Behaviour of Metals and Alloys 110
Abstract 110
5.1 Mechanical Properties 110
5.1.1 Deformation 111
5.1.1.1 Deformation Mechanism 111
5.1.2 Strengthening Mechanisms 113
5.1.2.1 Solid Solution Strengthening 113
5.1.2.2 Grain Boundary Strengthening 114
5.1.2.3 Dispersion Strengthening 115
5.1.2.4 Work Hardening 116
5.1.3 Fracture Mode 116
5.1.4 Ductility of Material 117
5.1.4.1 Test Methods 117
5.1.4.2 Ductile to Brittle Transition 119
5.1.4.3 Practical Uses 119
5.1.5 Fracture Mechanics 120
5.1.6 Tensile Properties 121
5.1.7 Hardness 123
5.1.7.1 Field Hardness Tester 125
Advanced Field Hardness Testing Instruments 125
5.1.8 Fatigue 126
5.1.9 Creep 129
5.1.9.1 Effect of Alloying Elements 132
5.1.9.2 Creep Based Design 132
References 133
6 Heat Treatment 134
Abstract 134
6.1 Introduction 135
6.2 Heat Treatment of Ferritic Steels 135
6.2.1 Constant Temperature Transformation 136
6.2.1.1 Factors Affecting TTT Curves 139
6.2.2 Transformation on Continuous Cooling 140
6.2.3 Important Heat Treatment Processes 142
6.2.3.1 Annealing 142
Annealing Temperature and Time 143
Recrystallization 143
6.2.3.2 Normalizing 144
6.2.3.3 Quench Hardening 145
Hardenability 146
Tempering of Hardened Steel 149
Temper Embrittlement 150
6.2.3.4 Age Hardening 151
6.3 Surface Hardening 152
6.3.1 Carburizing 152
6.3.1.1 Heat Treatment After Carburizing 153
6.3.2 Nitriding 153
6.4 Heat Treatment of Stainless Steels 153
6.4.1 Austenitic Stainless Steels 154
6.4.1.1 Solution Heat Treatment 154
6.4.1.2 Stabilizing Heat Treatment 154
6.4.2 Duplex Stainless Steel (DSS) 154
6.5 Other Surface Treatment Processes 155
6.5.1 Shot Peening 155
6.5.2 Laser Peening 156
References 156
7 Metallurgical Aspects of Welding 158
Abstract 158
7.1 Introduction 159
7.2 Welding of Ferritic Steels 159
7.2.1 Structure of Weld Deposit 159
7.2.2 Cold Cracking 160
7.2.2.1 Carbon Equivalent 162
7.2.2.2 Prevention of Cold Cracking 164
Post Weld Heat Treatment (PWHT) 166
Intermediate (IPWHT) and Low-Temperature Dehydrogenation Heat Treatment (LTDHT) 167
7.2.3 Stress-Relief Cracking 168
7.2.4 Other Methods of Reducing Weld Residual Stresses 169
7.2.4.1 Peening 169
7.2.4.2 Vibratory Stress Relief 170
7.2.5 Residual Stress Measurement in Weldments 171
7.2.6 Avoiding PWHT 171
7.2.6.1 Preheating Method 172
7.2.6.2 Temper Bead Welding 172
7.2.6.3 Buttering Technique 175
7.2.6.4 Friction Stitch and Seam Welding 175
7.3 Underwater Welding 177
7.4 Welding of Components Showing Magnetism 179
7.4.1 Causes for Magnetism of Plant Piping 179
7.4.2 Remedies for Magnetic Arc Blow 181
7.5 Welding of Austenitic Stainless Steels 181
7.5.1 Weld Defects in Austenitic Stainless Steels 181
7.5.1.1 Role of Ferrite on Welding of Austenitic Stainless Steel 182
7.5.1.2 Ferrite Number 183
HAZ Cracking 184
7.5.2 Selection of Filler Metal for Welding of Austenitic Stainless Steels 185
7.6 Welding of Dissimilar Metals (DMW) 186
7.6.1 Considerations in DMW Welding 186
7.6.1.1 Ferritic to Ferritic Steel 186
7.6.1.2 Austenitic Stainless Steel to Ferritic Steel 188
7.7 Welding of Duplex Stainless Steels 189
7.8 Welding of Titanium 190
7.9 Corrosion of Weld 191
7.9.1 Austenitic Welds 191
7.9.2 Carbon Steel 191
References 192
8 Material Degradation 194
Abstract 194
8.1 Fundamentals of Aqueous Corrosion 195
8.1.1 Electrochemical Nature of Aqueous Corrosion 195
8.1.2 Thermodynamics of Aqueous Corrosion 197
8.1.3 Kinetics of Aqueous Corrosion 199
8.1.3.1 Polarization 199
8.1.3.2 Passivation 200
8.2 Forms of Corrosion 201
8.2.1 Uniform or General Corrosion 201
8.2.2 Galvanic Corrosion 203
8.2.2.1 Potential Difference 203
Resistivity of Medium 203
8.2.2.2 Area Effect 203
8.2.2.3 Cathodic Polarization Characteristics 205
Polarization Characteristics of Metal 206
Polarization Effect of Biofilm 206
8.2.2.4 Prevention of Galvanic Corrosion 206
8.2.3 Pitting Corrosion 208
8.2.3.1 Pitting of Stainless Steel 210
8.2.4 Crevice Corrosion 210
8.2.4.1 Controlling Pitting and Crevice Corrosion in Stainless Steels 212
8.2.5 Stress Corrosion Cracking (SCC) 215
8.2.5.1 Prevention of Stress Corrosion Cracking 217
8.2.5.2 Some Practical Considerations in Use of Stainless Steels 218
Chloride Concentration and Temperature Limits 219
Cooling Water System 220
Process Plant Equipment 221
8.2.5.3 External Stress Corrosion Cracking (ESCC) of Insulated Stainless Steel 222
Prevention Against (ESCC) of Stainless 223
8.2.5.4 ESCC of Non-Insulated Stainless Steel 225
8.2.6 Intergranular Corrosion (IGC) 225
8.2.6.1 Austenitic Stainless Steel 225
8.2.6.2 Knife Line Attack 227
8.2.6.3 Remedial Measures 227
8.2.6.4 Ferritic Stainless Steel 228
8.2.7 Erosion–Corrosion 228
8.2.7.1 Prevention of Erosion Corrosion 229
8.2.8 Cavitation Damage 230
8.2.8.1 Prevention of Cavitation Damage 230
8.2.9 Fretting Corrosion 230
8.2.9.1 Prevention of Fretting Corrosion 231
8.2.10 Corrosion Fatigue 231
8.2.10.1 Prevention of Corrosion Fatigue 232
8.2.11 Dealloying Corrosion 232
8.2.12 Microbiologically Influenced Corrosion (MIC) 232
8.3 Corrosion Control 233
8.3.1 Corrosion Resistant Materials 234
8.3.1.1 Metals and Alloys 234
8.3.1.2 Non-metals 234
8.3.2 Alteration of Environment 234
8.3.2.1 Lowering Temperature 235
8.3.2.2 Decreasing Velocity 235
8.3.2.3 Removing Oxygen or Oxidizing Agent 236
8.3.2.4 Changing Concentration 236
8.3.2.5 Neutralization 236
8.3.2.6 Inhibition 236
Adsorption-Type Inhibitors 237
Passivators 238
Vapour-Phase Inhibitors 238
Oxygen Scavengers 238
8.3.3 Electrochemical Protection 239
8.3.3.1 Cathodic Protection 239
Methods of Applying Protective Current 240
Anodes Used for Cathodic Protection (Added This Portion) 241
Protective Potential 241
Magnitude of Applied Current 242
Checking Effectiveness of Cathodic Protection 243
Typical Applications of Cathodic Protection 244
8.3.3.2 Anodic Protection 245
8.3.4 Coatings 246
8.3.4.1 Metallic and Other Inorganic Coatings 246
Electrodeposited Coating 247
Flame-Sprayed Coating 247
Hot Dipped Coating 247
Vapour Deposited Coating 248
Diffusion Coating 248
Chemical Conversion Coating 248
8.3.4.2 Non-Metallic Coatings 248
8.3.4.3 Organic Paint Coatings 249
Surface Preparation 249
Selection of Paint System 249
Maintenance Painting 252
8.3.4.4 Coating and Wrapping of Pipeline 253
8.3.5 Precautions During Design and Construction 254
8.4 Corrosion Monitoring 255
8.4.1 Analysis of Process Stream 255
8.4.2 Coupon Test 256
8.4.3 Electrochemical Techniques 257
8.4.3.1 Electrical Resistance Technique (ER) 258
8.4.3.2 Linear Polarization Resistance Technique (LPR) 258
8.4.4 Hydrogen Probe 260
8.4.4.1 Electrochemical Hydrogen Patch Probe 260
8.4.4.2 Hydrogen Pressure Probe 261
8.4.5 Field Signature Method (FSM) 261
8.4.6 Sand Probe 262
8.4.7 Bio-Probe 263
8.5 Metallurgical Degradation 264
8.5.1 Spheroidization/Carbide Coarsening 264
8.5.2 Graphitization 265
8.5.3 Phase Transformation/Phase Precipitation 266
8.5.3.1 Sigma Phase Formation 266
8.5.3.2 Carbide Precipitation 267
8.5.3.3 Chi Phase Formation 268
8.5.3.4 Other Intermetallics 268
8.5.4 Temper Embrittlement 269
8.6 High Temperature Degradation 272
8.6.1 Oxidation 272
8.6.1.1 Electrochemical and Morphological Aspects of Oxidation 272
8.6.1.2 Growth of Oxide Scale 273
8.6.1.3 Effect of Alloying 274
8.6.2 Catastrophic Oxidation/Fuel Ash Corrosion 276
8.6.2.1 Prevention of Fuel Ash Corrosion 276
8.6.3 High Temperature Hydrogen Attack 277
8.6.3.1 Prevention of High Temperature Hydrogen Damage 278
Blister Formation 278
High Temperature Hydrogen Attack (HTHA) 278
Performance of Cr–0.5Mo Steel 278
Dearburization 279
8.7 Cost of Corrosion to Society 279
8.7.1 Estimation of Cost of Corrosion 279
8.7.2 Formation of World Body 280
References 281
9 Material Selection and Performance in Oil and Gas Industry 285
Abstract 285
9.1 Introduction 285
9.2 Summary of Oil and Gas Production Facilities 288
9.3 Corrosion Damage in Oil and Gas Production 290
9.3.1 Corrosivity of Reservoir Well Fluid 290
9.3.1.1 Carbon Dioxide 291
9.3.1.2 Hydrogen Sulphide 293
9.3.1.3 Bicarbonates 294
9.3.1.4 Chlorides 295
9.3.1.5 Effect of Acetic Acid 295
9.3.1.6 Role of Oil–Water Ratio 296
9.3.1.7 Elemental Sulphur 297
9.3.1.8 Mercury Corrosion 297
Prevention Against Mercury Corrosion 298
9.3.1.9 Oxygen 298
9.3.1.10 Microbial-Induced Corrosion (MIC) 298
9.3.1.11 Glycol/Methanol 299
9.3.1.12 Flow Rate 299
9.3.2 Embrittlement Effect of Hydrogen Sulphide 299
9.3.2.1 Controlling Hydrogen Related Damage 301
SSSC and SOHIC 301
Blistering and HIC 302
9.3.3 Development of CO2 Corrosion Model 303
9.3.3.1 CO2 Corrosion in Multi-phase System 303
9.3.3.2 Corrosion in Gaseous Phase 305
9.4 Material Selection and Corrosion Control for Gas and Oil Wells 308
9.4.1 Well Completion 309
9.4.2 Corrosion Control in Oil and Gas Wells 311
9.4.2.1 Casing 311
9.4.2.2 Production Tubing 312
Protection by Inhibitors 312
Application of Inhibitors 313
Use of Corrosion-Resistant Alloys 313
9.5 Material Selection and Corrosion Control of Gathering Lines 316
9.5.1 Application of Inhibitor in Flow Lines 316
9.5.1.1 Continuous Inhibition 316
9.5.1.2 Batch Inhibition 316
9.5.1.3 Pigging 317
9.5.2 Use of Corrosion-Resistant Alloys 317
9.5.2.1 Solid CRA 317
9.5.2.2 Clad Corrosion-Resistant Alloy (CRA) Pipeline 318
Types of Clad Pipe 319
9.5.2.3 Material Selection Standard for Oil and Gas Production 321
9.5.3 Protection of Carbon Steel Gathering Lines by Internal Coating 322
9.5.3.1 New Lines 322
9.5.3.2 Old Lines 322
9.5.4 External Protection of Gathering Lines 322
9.5.4.1 External Coating 322
9.5.4.2 Cathodic Protection of Offshore Lines 323
9.5.4.3 Cathodic Protection of Onshore-Gathering Lines 326
9.5.4.4 Galvanic Anodes for Cathodic Protection 326
Cathodic Protection in Deep-Water Installations 327
9.5.5 Non-Metallic Reinforced Thermoplastic Pipe (RTP)-Gathering Lines 327
9.5.6 Umbilical for Operation of Well Heads in Deep Water Sea Bed 328
9.5.7 Instrument, Chemical Inhibition and Other Tubing 328
9.6 Material Selection and Corrosion Control for Oil and Gas Processing 330
9.6.1 Processing Facilities 331
9.6.1.1 Oil Fields 331
Handling of Well Fluid 332
Handling of Crude 333
Handling of Associated Gas 334
Handling of Produced Water 335
9.6.1.2 Gas Field 335
9.6.2 Gas Drying 336
9.6.2.1 Corrosion Protection of Pipelines Carrying Wet Gas 337
Formation of Gas Hydrate 337
Corrosion Inhibition 338
pH Stabilization 338
Combined pH Stabilization and Corrosion Inhibition 338
Corrosion Allowance 339
Operator Variations 339
9.7 Processing of Oil and Gas 339
9.7.1 Crude Oil Processing 339
9.7.2 Gas Processing 339
9.7.2.1 NGL Extraction 340
Absorption Process 340
Cryogenic Expansion Process 340
9.7.2.2 Separation of Liquid Fractionation 340
9.7.3 Natural Gas (NG) 341
9.7.4 Material Selection for Sub-zero and Cryogenic Temperatures 341
9.7.5 Gas Sweetening 342
9.7.5.1 Amine Process 342
Amine Degradation 343
Amine Reclamation 344
Corrosion Control 344
Stress Corrosion Cracking 346
9.8 Offshore Platform 347
9.8.1 Protection of Offshore Platform Against Corrosion 347
9.8.1.1 Cathodic Protection 348
9.8.1.2 Coating 349
9.8.1.3 Sheathing of Legs and Risers 350
9.8.1.4 Corrosion Fatigue of Platform Structure 351
9.9 Protection of Long-Distance Cross-Country Pipeline 351
9.9.1 Cathodic Protection 351
9.9.2 Soil Side SCC 352
9.10 Corrosion Monitoring 354
9.10.1 Iron Count 355
9.10.2 Coupons and LPR and ER Probes 355
9.10.3 NDE Techniques 355
9.10.4 Special Techniques 355
9.10.5 Monitoring of Cathodic Protection 356
9.10.6 Assessing Corrosion of Underground and Subsea Transmission Line Using In-line Intelligent or Smart Pig 356
9.10.6.1 Magnetic Flux Leakage (MFL) Tool 357
9.10.6.2 Ultrasonic Tool (UT) 358
9.10.6.3 Combined MFL and UT Tool 360
References 360
10 Material Selection and Performance in Refining Industry 364
Abstract 364
10.1 Short Outline of Processes 364
10.2 Considerations in Material Selection 366
10.3 Problems Related to High-Temperature Service 366
10.3.1 High-Temperature Sulphur Attack 366
10.3.1.1 Corrosive Constituents in Crude 366
10.3.1.2 Prediction of Sulphur Corrosion 367
10.3.2 High-Temperature Naphthenic Acid Attack 369
10.3.2.1 Naphthenic Acid 369
10.3.2.2 Control of Naphthenic Acid Corrosion (NAC) 370
10.3.2.3 Role of Sulphur in Naphthenic Acid Corrosion 372
10.4 Material Selection for Different Processing Units 373
10.4.1 Atmospheric Crude and Vacuum Distillation Units 374
10.4.1.1 Low Sulphur Crude 375
10.4.1.2 High-Sulphur Crude 375
Exchangers 375
Heater Tubes 376
Atmospheric Distillation Column 377
Pumps and Valves 378
10.4.2 Processing High TAN Crude 378
10.4.2.1 Controlling Naphthenic Acid Corrosion by Material Upgradation 378
Materials Resistance to NAP 378
Furnace Tubes and Transfer Lines 379
Atmospheric and Vacuum Column 380
Side-Cut Piping 380
Pumps and Valves 380
10.4.2.2 Other Methods for Controlling Naphthenic Acid Corrosion 380
10.4.2.3 Summary of MOC 382
10.4.3 Visbreaker and Coking Units 384
10.4.3.1 Process Outline 384
10.4.3.2 Materials of Construction 384
10.4.3.3 Specific Problems Experienced in Coking Units 386
Vapour Lines 386
Bulging of Drums 387
Coke Drum Life 389
Failure of Skirt and Skirt to Shell Weld 390
API Surveys 391
Monitoring of Coker Drum Damage 392
10.4.4 Fluid Catalytic Cracking 392
10.4.4.1 Process Outline 392
10.4.4.2 Material Selection 393
10.4.4.3 Refractory Lining 394
10.4.5 Catalytic Reforming Unit 394
10.4.5.1 Process Outline 394
10.4.5.2 Selection of MOC 395
10.4.5.3 Problems Experienced in CCRU 395
10.4.6 Hydro-desulphurizer and Hydrocracker Units 397
10.4.6.1 Process Outline 397
10.4.6.2 Role of Hydrogen in High-Temperature Sulphur Attack 398
10.4.6.3 MOC Used in Hydro-desulphurizer 398
10.4.6.4 MOC of Hydrocracker 400
Advanced Cr–Mo–V Alloys for Hydrocracker 401
Advantages of Vanadium-Modified 2.25Cr–Mo Steel 402
Hydrogen Embrittlement of Reactors 403
Minimum Pressurization Temperature (MPT) 404
10.5 Problems Related to Low-Temperature Service 405
10.5.1 Corrosive Constituents 405
10.5.1.1 Acid Corrosion 405
10.5.1.2 Alkaline Corrosion 406
10.5.2 Overhead Corrosion Control System in Different Units 406
10.5.2.1 Crude and Vacuum Unit 407
Source of Hydrochloric Acid 407
Source of Hydrogen Sulphide 408
Source of Organic Acids 408
Other Acids/Acidic Salts 408
Corrosion Control Measures 409
Neutralization 410
Inhibition 412
Water Wash 412
Upgradation of MOC 412
Vacuum Unit 414
10.5.2.2 Visbreaker and Coker Units 414
10.5.2.3 Fluid Catalytic Cracking (FCC) Unit 415
Carbonate Stress Corrosion Cracking 415
10.5.2.4 Catalytic Reformer 415
10.5.2.5 Hydro-desulphurizer and Hydrocracker 416
Polythionic Acid Cracking 418
10.5.3 Low-Temperature Hydrogen Damage 419
10.5.3.1 Introduction 419
10.5.3.2 Damage in Wet H2S Service in Refinery Service 420
Definition of Sour Service 423
Prevention of SSCC in Refinery Sour Service 423
10.5.3.3 Cracking of LPG Sphere 425
10.5.3.4 Blistering 426
10.5.4 Pyrophoric Iron Sulphides 427
10.5.5 Corrosion in Ethanol Service 428
10.5.5.1 General Corrosion in Ethanol Service 428
10.5.5.2 Stress Corrosion of Carbon Steel in Ethanol Service 429
References 429
11 Material Selection and Performance in Fertilizer Industry 434
Abstract 434
11.1 Introduction 434
11.2 Hydrogen Production 435
11.2.1 Process Outline 435
11.2.2 High-Temperature Section 436
11.2.2.1 Primary Reformer 436
11.2.2.2 Pigtails and Collecting Headers 441
11.2.2.3 Materials Specification for Primary Reformer Tubes 443
11.2.2.4 Secondary Reformer 445
11.2.3 Intermediate Temperature Section 446
11.2.3.1 RG Boiler 446
11.2.3.2 Shift Converter 446
11.2.3.3 Metal Dusting 446
Mechanism of Metal Dusting 447
Preventive Measures 448
11.2.4 Low-Temperature Section 449
11.2.4.1 Cooling of Reformed Gas Before Removal of CO2 449
11.2.4.2 Carbon Dioxide Removal 450
Carbonate Process 450
11.3 Ammonia Synthesis 451
11.3.1 Intermediate Temperature Section 451
11.3.1.1 Nitriding 452
11.3.1.2 Start-Up and Shutdown Procedures 453
Heating Rate 453
Pressurization Rate 453
Dehydrogenation 453
11.3.2 Low-Temperature Section 454
11.3.2.1 Pressurized Storage 454
11.3.2.2 Atmospheric Storage 455
Nature of Cracking 455
11.4 Waste Heat Boilers (WHB) 456
11.4.1 Reformed Gas Boiler 457
11.4.2 Vertical Waste Heat Boiler 458
11.5 Production of Urea 459
11.5.1 Conventional Alloys for Carbamate Service 460
11.5.2 Development of New Alloys 463
11.5.2.1 Duplex Stainless Steel 463
Improved Plant Safety with DSS 466
11.5.2.2 Bi-metallic Stripper Tube 467
Mechanically Bonded Tube 467
Metallurgically Bonded Tube 468
Zirconium Stripper Tube 468
References 468
12 Damage Assessment and Repair of Stationary Equipment 471
Abstract 471
12.1 Importance of Plant Inspection 471
12.1.1 Inspection Tools and Techniques 472
12.1.1.1 Radiography 473
12.1.1.2 Dye Penetrant (Normal or Fluorescent) 473
12.1.1.3 Wet Fluorescent Magnetic Particle Inspection (WFMPI) 474
12.1.1.4 Ultrasonic Test (UT) 474
12.1.1.5 Acoustic Emission (AE) 475
12.1.2 Inspection Planning 476
12.1.2.1 Conventional Inspection Practices 476
12.1.2.2 Risk-Based Inspection 477
12.2 Pressure Vessel Code 479
12.2.1 History of Pressure Vessel Code 480
12.2.2 American Codes 480
12.2.3 Unfired Pressure Vessels Code 481
12.2.4 Process Piping Code 482
12.2.5 Pressure Vessel Code in United Kingdom 482
12.2.6 European Pressure Vessel Codes 482
12.2.7 Some Important Aspects of ASME and EN Codes 483
12.3 Material Requirements 483
12.3.1 Thickness 483
12.3.2 Allowable/Design Stress 484
12.3.3 Carbon and Low-Alloy Ferritic Steels 484
12.3.4 Stainless Steels 485
12.3.5 Cost and Preferences Related to ASME and EN Codes 486
12.4 Heat Treatment Requirements 487
12.4.1 Post-Weld Heat Treatment 487
12.4.1.1 Post-Weld Heat Treatment Requirement in Some Other Industries 488
12.4.1.2 Post-Weld Heat Treatment Temperature 489
12.4.1.3 Post-Weld Heat Treatment Holding Time 490
12.4.1.4 Procedure for Post-Weld Heat Treatment 491
Shop Welding 491
Field Welding 491
12.4.1.5 Local Post-Weld Heat Treatment 492
Improvements in Local PWHT 492
Procedure for Local PWHT 495
12.5 Repair, Alteration and Rerating 496
12.5.1 General Background 496
12.5.2 Repair Procedure 496
12.5.2.1 Salient Features of ASME PCC–2 498
Outline of a Few Repair Techniques 498
12.6 Specific Inspection Procedures 500
12.6.1 Inspection of Equipment Subjected to Hydrogen Damage 500
12.6.1.1 Equipment Operating in Sour Service 500
12.6.1.2 Equipment Operating at High-Temperature High-Pressure Service (HTHA) 500
Attenuation Measurement 501
Advanced Back-Scattered Ultrasonic Testing (ABUT) 501
Time-of-Flight Diffraction (TOFD) 501
Velocity Ratio Measurement 502
Surface Replica Test 502
12.6.2 Inspection of Tubular Items 502
12.6.2.1 Inspection of Hydrogen Reformer Tubes 503
Dimensional Changes 503
Surface Replica 503
Ferromagnetism of Tube 504
Eddy Current Examination 504
Ultrasonic Attenuation 505
H-Scan 505
Laser Profilometry 505
12.6.2.2 Corrosion Inspection Under Insulation and Fireproofing 506
12.7 Repair Welding of Equipment 506
12.7.1 Repair Welding of Ferritic Steel Equipment in Hydrogen Charging Service 507
12.7.1.1 Designation of Consumables with Respect to Diffusible Hydrogen 509
12.7.2 Avoidance of Hydrogen Embrittlement of Repair Weld 509
12.7.2.1 Control of Preheat Temperature 509
12.7.2.2 Hydrogen Bake-Out Prior to Welding 510
Guidelines for Hydrogen Bake-Out 510
12.7.2.3 Post-Heat Treatment 512
12.7.3 PWHT of Repair Weld 512
12.7.3.1 Where PWHT Is not Exempted 513
12.7.3.2 Where PWHT Can Be Exempted 513
Impact Testing Is Not a Requirement 513
Where Notch Toughness Is a Requirement 514
12.7.3.3 Effect of Multiple PWHT on Mechanical Properties of Carbon and Low-Alloy Steels 514
Use of Equivalent Parameter 515
Change in Mechanical Properties Versus LMP of Alloy Steels 515
Change in Mechanical Properties Versus LMP of Carbon Steel 516
Achieving Acceptable Property Both in Original and Simulated PWHT Conditions 517
12.7.3.4 Implementation of PWHT 517
12.7.3.5 PWHT Temperature 519
12.7.3.6 Precaution Against Physical Restraints 519
12.7.3.7 Inspection After PWHT 520
12.7.3.8 Post-Weld Cleaning of Stainless Steel 520
12.8 Post-Repair Hydrotesting 522
12.8.1 Hydrotesting of Carbon Steel with Sea water 522
12.8.2 Hydrotesting of Stainless Steel 524
12.9 Integrity Operating Window 525
References 526
13 Failure Analysis 531
Abstract 531
13.1 Introduction 531
13.2 Causes of Material Failure 532
13.3 Steps in Material Failure Analysis 533
13.3.1 Visual Examination 534
13.3.2 Operating Conditions 534
13.3.3 Investigation 535
13.3.4 Samples for Testing 536
13.3.4.1 Where Samples are Available for Destructive Examination 536
13.3.4.2 Where Samples are Not Available and Non-destructive Tests are to be Conducted 536
13.3.4.3 Where Samples can be Obtained by Semi-destructive Methods 537
13.4 Tools for Failure Analysis 537
13.4.1 Tools for Visual Examination 538
13.4.2 Chemical Analysis 538
13.4.3 Metallurgical Examination 539
13.4.3.1 Macroscopic Examination 539
13.4.3.2 Microscopic Examination 541
Optical Microscopy 542
Scanning Electron Microscopy (SEM) 545
Microanalysis by Means of SEM 546
13.4.3.3 Some Case Studies 546
13.4.3.4 Field Microscopy 548
13.4.4 X-ray Diffraction 549
13.4.5 Non Destructive Examination (NDE) Techniques 550
13.4.5.1 Dye Penetrant (DP) 551
13.4.5.2 Magnetic Particle Inspection (MPI) 551
13.4.5.3 Ultrasonic Testing Technique 552
13.4.5.4 Radiography 553
13.4.6 Mechanical Testing 553
13.5 Stages in Failure Analysis 553
13.5.1 In-plant Failure Analysis 553
13.5.2 Centralized In-house Failure Analysis 554
13.5.3 Failure Analysis by Outside Specialist 554
13.6 Analysis of Data and Recommendations 555
References 556
Index 557