Lasting Connections

MATCHLESS IN STAINLESS PRACTICE AND PRODUCTS FOR STAINLESS STEEL WELDING

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LASTING CONNECTIONS ............... 3

1. STAINLESS STEELS ...................... 16Introduction ....................................................16Austenitic stainless steels............................16Ferritic stainless steels ..................................19Duplex (austenitic-ferritic) stainless steels ................................................20Martensitic and precipitation hardening stainless steels ..........................21Physical properties of stainless and mild steels ........................................................23Importance of ferrite....................................23

2. DEFINITIONS ............................... 27Welding positions ..........................................27Weld metal ......................................................27Heat-affected zone .....................................27Heat input .......................................................28Interpass temperature .................................28Penetration and dilution .............................29Metal deposition rate ..................................29Preheating .......................................................30Post-weld heat treatment ...........................30Effect of high silicon content .....................30Cast and helix .................................................30

3. WELDING METHODS .................. 32Introduction ....................................................32Terminology and abbreviations ...............32Manual Metal-Arc with covered electrode (MMA) – flexible all-position welding .............................................................32Metal Inert Gas (MIG) or Metal Active Gas (MAG) – high productivity with both manual and automatic welding ....35Tungsten inert gas (TIG) – high quality welds ..................................................................39Submerged arc welding (SAW) – high productivity welding of thick sections ....41

Flux-cored arc welding (FCAW) – a high deposition, flexible process for all-position welding ......................................43MCAW – a high deposition all-round welding process .............................................48Plasma arc welding (PAW) – a high- energy process for automatic welding .............................................................49Laser and laser hybrid welding – high productivity and high quality ...................50

4. WELDING TECHNIQUES FOR STAINLESS STEEL ........................ 53

Fitup and tack welding ...............................53Planning the welding sequence ...............55Flame straightening .....................................63Welding stainless to mild steel ..................63Overlay welding.............................................64Repair welding ...............................................70

5. WELD IMPERFECTIONS .............. 72Introduction ....................................................72Inspection ........................................................72Lack of fusion .................................................73Incomplete penetration ..............................74Solidification and liquation cracking .....74Crater cracks...................................................76Porosity .............................................................77Slag inclusions ................................................78Spatter ..............................................................78Undercut ..........................................................79Stray arcing .....................................................80Burn-through ..................................................80Slag islands .....................................................81Excessive weld metal ...................................81Liquid metal embrittlement (LME) ............82

CONTENT

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6. WELDING PRACTICE – GUIDELINES FOR WELDING DIFFERENT TYPES OF STAINLESS STEEL ........................ 85

Introduction .................................................... 85Welding procedure design/ specification ................................................... 85Choice of welding method ......................... 85Choice of filler metal .................................... 86Shielding/backing gases ............................ 87Edge preparation and joint design ......... 87Welding parameters .................................... 87Heat input ....................................................... 87Interpass temperature ................................. 88Weldment properties ................................... 88Preheating ....................................................... 95Post-weld heat treatment ........................... 96Cleanliness ...................................................... 98Post-weld cleaning ....................................... 98Austenitic stainless steels............................ 99Ferritic stainless steels ................................105Duplex stainless steels ...............................110Martensitic and precipitation hardening stainless steels ........................ 115

7. EDGE PREPARATION .................118Introduction ..................................................118Type of joint ...................................................118Cleaning before welding ..........................118Selection of joint type................................ 119Joint preparation methods ..................... 119

8. SHIELDING AND BACKING GASES .........................................126

Shielding gas function ...............................126Shielding gas components ......................126Backing (purging) gases ...........................129Shielding gases for MAG welding ..........130Shielding gases for TIG welding ............. 131Shielding gases for FCAW.........................132Shielding gases for PAW ...........................133

Shielding gases for laser welding ..........133Shielding gases for laser hybrid welding ...........................................................134

9. POST-WELD CLEANING OF STAINLESS STEEL .......................135

Need for cleaning stainless steel ...........135Typical defects .............................................135Mechanical methods .................................136Chemical methods ......................................137Choice of method .......................................140Chemical methods in practice ................141Safe handling ...............................................149

10. STORAGE AND HANDLING RE COMMENDATIONS FOR COVERED ELECTRODES, FLUX-CORED WIRE AND FLUXES ........................................150

Storage and transport ...............................150Recycling fluxes ........................................... 151Redrying .........................................................152

11. QUALITY ASSURANCE, THIRD-PARTY APPROVALS AND INTERNATIONAL STANDARDS ...............................154

Quality assurance .......................................154Third-party approvals ...............................154CE marking ....................................................154Guide to EN standards ..............................155

12. SELECTING FILLER METAL ........172Similar welding .............................................172Dissimilar welding .......................................172

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13. FILLER METAL AND FLUX CONSUMPTION .........................220

14. HEALTH AND SAFETY WHEN WELDING STAINLESS STEELS ...226

Radiation .......................................................226Welding fumes .............................................227Spatter and flying slag ..............................228Fire ...................................................................228Ergonomics ...................................................229Noise ...............................................................229Electrical safety ...........................................229Electromagnetic fields ..............................230Cuts (handling metal plates and filler metals) ............................................................231MSDS ...............................................................231

15. PRODUCT DATASHEETS ...........232Introduction ..................................................232Standard designations ..............................232Approvals ......................................................232

16. PACKAGING DATA .....................588Covered electrodes ....................................588MIG/MAG wire ..............................................588Flux-cored and metal-cored wire ..........589SAW wire .........................................................591Flux ...................................................................591

17. CONVERSION TABLES – EN TO IMPERIAL UNITS ............592

Length .............................................................592Packaging ......................................................592Weight .............................................................593Metric conversion factors, useful for welding applications ..................................593Temperature .................................................595Impact toughness .......................................596Tensile and yield strength .........................596Heat input .....................................................597Volume/time conversion...........................597

SYMBOLS OF THE ELEMENTS ........597

ABBREVIATIONS .............................598

INDEX, PRODUCT DATASHEETS ...600Covered electrodes ....................................600Welding wire ..................................................603Flux-cored wires ...........................................607Metal-cored wires .......................................609Wires for submerged arc welding ..........609Welding flux for stainless and nickel-alloys .................................................. 611Finishing Chemicals .................................... 611Disclaimer ...................................................... 615

INDEX ...............................................612

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INDEX

AAbbreviations: 32, 598Approvals: 154, 232Austenitic stainless steels: 16 - 19, 96, 99 – 105, 168AWS standards

» A5.4/A5.4M: 33, 164 » A5.9/A5.9M: 166 » A5.11/A5.11M: 168 » A5.14/A5.14M: 168 » A5.22/A5.22M: 44, 170 » A5.34/A5.34M: 180

BBacking gases: 55, 87, 91, 112, 129Blasting: 137Brushing: 137Burn-through: 80

CCE marking: 154Cladding: 64Cleaning: 98, 118, 136Coatings: 33Consumption: 220Conversion tables: 592Corrosion: 17, 19, 20, 22, 89 - 94Covered electrodes: 33, 35

» product datasheets: 233 – 317 » rutile: 33 – 35 » rutile-acid: 33 – 35

Crater cracks: 76

DDefinitions: 27Design: 87Dip transfer: 36Dissimilar welding: 172Distortion: 61Duplex stainless steels: 20 – 21, 87, 97, 109 – 115, 184

EEdge preparation: 87, 128, 142Electrical resistivity: 8, 23

Electrical safety: 230Electromagnetic fields: 230Electropolishing: 140Electroslag welding: 67EN ISO Standards

» 3581: 33, 155 » 14172: 162 » 14174: 158 » 14343: 158 » 17633: 155 » 18274: 162

Ergonomics: 229Excessive weld metal: 82

FFCW Flux-cored wire

» product datasheets: 454 – 506Ferrite: 18, 21, 23 – 26, 100, 110 – 116Ferritic stainless steels: 19, 105 – 110, 176Filler metals: 172 – 219

» consumption: 220 – 225 » dissimilar welding: 64, 172, 192

Finishing chemicals » product datasheets: 574 – 587

Flux: 41, 66, 158 » consumption: 150, 220 » product datasheets: 567 – 573

Flux-cored arc welding: 43 – 48, 68, 132

GGlobular transfer: 37Grinding: 54, 95, 99, 102, 136

HHandling: 150, 231Health and safety: 226 – 231High-temperature steels: 103, 106

IIncomplete penetration: 74Inspection: 72

KKeyhole mode welding: 50

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LLack of fusion: 73Laser hybrid welding: 50Laser welding: 51Liquation cracking: 74Liquid metal embrittlement: 82

MMAG welding: 34 – 39, 50, 59, 112, 130Martensitic stainless steels: 21, 98, 115 – 117, 174Metal-cored arc welding: 48MMA welding: 32 – 35, 68

OOverlay welding: 64

PPackaging data: 588 – 591Passivation: 140, 148Penetration: 29, 59, 74, 111Pickling: 137 – 149Plasma: 45Plasma arc welding: 49 – 50Porosity: 77, 112, 131Post-weld cleaning: 83, 88, 91, 98, 135 – 149

» chemical methods: 137 » defects: 83, 135 » mechanical methods: 136

Precipitation hardening stainless steels: 98, 115 – 117, 184Product datasheets: 232

» electrodes: 233 – 317 » FCW: 454 – 506 » flux: 567 – 573 » MIG/MAG wire: 382 – 453 » SAW wire: 518 – 566 » TIG wire: 318 – 381

Pulsed arc: 37

QQuality assurance: 154

RRadiation: 226Redrying: 152Remelt mode welding: 50Repair welding: 70

SSafety: 226 – 231Shielding gases: 87, 112, 126 – 134

» components: 126 » FCAW: 132 » function: 126 » MAG welding: 130 » PAW: 133 » TIG welding: 131

Similar welding: 172Slag inclusions: 78Slag islands: 81Solidification cracking: 74Spatter: 78, 228Spray transfer: 37Stainless steels: 16

» austenitic: 16 – 19, 96, 99 – 104, 178 » austenitic-ferritic: 110 » duplex: 81, 97, 110 – 117, 184 » ferritic: 19, 105 – 110, 176 » martensitic: 21, 98, 115 – 117, 174 » precipitation hardening: 98, 115 – 117,

184Standards: 154

» AWS: 162 » EN ISO: 155

Storage: 150 – 152, 590Stray arcing: 55, 80Stringer beads: 57Submerged arc welding: 41 – 43, 65, 67Surfacing: 64

TTandem: 38, 42Thermal conductivity: 8, 23Thermal expansion: 8, 23TIG welding: 39 – 41, 112, 131Tungsten electrodes: 40, 228 Twin: 38

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UUndercut: 79

VVertical-down welding: 57Vertical-up welding: 57

WWeaving: 57Weld imperfections: 72 – 84Welding methods: 32

» FCAW: 43 – 48, 68, 132 » laser: 50 » laser hybrid: 51 » MIG/MAG: 35 – 39, 50, 59, 112, 130 » MMA: 32 – 35, 68 » PAW: 49 – 50 » SAW: 41 – 43, 65, 67 » terminology: 32 » TIG: 39 – 41, 111, 131

Welding positions: 27Welding practice: 85

» austenitic steels: 99 – 105 » duplex steels: 110 – 115 » ferritic steels: 105 – 110 » high-temperature steels: 103, 106 » martensitic steels: 115 – 117 » precipitation hardening steels:

115 – 117Welding techniques: 53 – 71

» backhand: 45, 59 » cladding: 63, 67, 69 » dissimilar: 64, 78 » forehand: 45, 58 » overlay: 64, 67, 69 » repair: 70 » tack: 53, 62, 91 » vertical-down: 57 – 59 » vertical-up: 57 – 58

Width: 57, 60, 65, 101 – 102

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