The Welding Of Aluminium And Its Alloys
The Welding Of Aluminium And Its Alloys
Gene Mathers
Contents
Preface ix
1 Introduction to the welding of aluminium 1
1.1 Introduction 1
1.2 Characteristics of aluminium 4
1.3 Product forms 6
1.4 Welding: a few definitions 6
2 Welding metallurgy 10
2.1 Introduction 10
2.2 Strengthening mechanisms 10
2.3 Aluminium weldability problems 18
2.4 Strength loss due to welding 31
3 Material standards, designations and alloys 35
3.1 Designation criteria 35
3.2 Alloying elements 35
3.3 CEN designation system 36
3.4 Specific alloy metallurgy 40
3.5 Filler metal selection 46
4 Preparation for welding 51
4.1 Introduction 51
4.2 Storage and handling 51
4.3 Plasma-arc cutting 52
4.4 Laser beam cutting 58
4.5 Water jet cutting 63
4.6 Mechanical cutting 64
4.7 Cleaning and degreasing 66
v5 Welding design 69
5.1 Introduction 69
5.2 Access for welding 70
5.3 Welding speed 71
5.4 Welding position 72
5.5 Edge preparation and joint design 72
5.6 Distortion 84
5.7 Rectification of distortion 88
5.8 Fatigue strength of welded joints 89
6 TIG welding 97
6.1 Introduction 97
6.2 Process principles 97
6.3 Mechanised/automatic welding 114
6.4 TIG spot and plug welding 115
7 MIG welding 116
7.1 Introduction 116
7.2 Process principles 116
7.3 Welding consumables 130
7.4 Welding procedures and techniques 135
7.5 Mechanised and robotic welding 141
7.6 Mechanised electro-gas welding 143
7.7 MIG spot welding 144
8 Other welding processes 147
8.1 Introduction 147
8.2 Plasma-arc welding 147
8.3 Laser welding 150
8.4 Electron beam welding 155
8.5 Friction welding 160
9 Resistance welding processes 166
9.1 Introduction 166
9.2 Power sources 167
9.3 Surface condition and preparation 169
9.4 Spot welding 171
9.5 Seam welding 175
9.6 Flash butt welding 176
vi Contents10 Welding procedure and welder approval 181
10.1 Introduction 181
10.2 Welding procedures 181
10.3 Welder approval 191
11 Weld defects and quality control 199
11.1 Introduction 199
11.2 Defects in arc welding 199
11.3 Non-destructive testing methods 205
Appendix A British and ISO standards related to
welding and aluminium 216
Appendix B Physical, mechanical and chemical
properties at 20°C 226
Appendix C Principal alloy designations: cast products 227
Appendix D Alloy designations: wrought products 228
Bibliography 230
Index 235
Contents vii
age hardening see precipitation hardening
alloy elements 35–36
alloying interstitial and substitutional 14
alloy metallurgy 40–46
heat treatable 43–46
non-heat treatable 40–43
aluminium
applications 7
characteristics 4, Appendix B
history 1
backing bars and strips 78–80
butt welds definitions 75–78
cold work (strain hardening) 15–16
defects 199–205
hot cracking 24–31
oxide filming 22–24
porosity 18–22
‘suck-back’ in TIG welding 111
degreasing 66–68
mechanical cleaning 66
chemical cleaning (pickling) 67
design
backing bars and strips 78–80
edge preparations (joint design) 72–78
edge preparations (joint design) for MIG
136–139
edge preparations (joint design) for TIG
98–99
effect of position 72
for access 70–71
designations 36–40
alloy composition identification 36–38
temper designations 38–40
distortion 84–89
electron beam welding
capabilities 157, 160
process principles 155–157
fatigue 89–96
joint classification 92–94
filler metals
effect on hot cracking 29–31
selection 46–50
fillet weld definitions 74, 75
friction welding
friction stir welding 161–165
capabilities 163, 164, 165
mechanical properties 165
process principles 160–161
rotary motion 161
gamma radiography 213
GMAW see MIG
grain size 12–13
effect on hot cracking 30
GTAW see TIG
handling of parent metals 51
laser cutting 58–63
health and safety 60–63
parameters 61
principles 58–60
laser welding
arc augmented 154–155
CO2 laser welding 152–153
defects 154
Nd-YAG (solid state) welding 153–154
process principles 150–152
liquation cracking see hot cracking
mechanical cutting 64–66
MIG welding
arc starting 135
contact tip 129–130
electro-gas welding 143–144
filler wire 133–134
fine wire 124
mechanised and robotic welding 141–143
parameters (argon shielding) 136–137
parameters (helium shielding) 138
power sources 119–121
process principles 116–118
Index
235pulsed MIG 121–124
shielding gases 130–133
spot welding 144–146
terminating the weld 140–141
torches 125–126
torch positioning 138–140
twin wire 124–125
wire feeders 127–128
non-destructive testing 205–215
eddy current 207–208
penetrant 205–207
radiography 211–215
ultrasonic 208–211
penetrant examination 205–207
plasma arc cutting 52–58
health and safety 56–58
parameters 55
principles 52–54
plasma arc welding
parameters 149
plasma MIG 150
process principles 147–149
variable polarity 149
porosity 18–22
in autogenous welds 18
in parent metal 22
effect of cleanliness 21
composition 20
hose type 20
process 20
gas dew point 20
ISO classification 200
precipitation (age) hardening 16–17
resistance welding
flash butt welding 176–180
power sources 167–169
seam welding 175–176
spot welding 171–175
surface condition 169–171
236 Index
solidification cracking see hot cracking
solid solution strengthening see alloying
storage of parent metals 52
strengthening mechanisms 10–18
strength loss 31–34
in HAZ 32–34
in weld metal 31–32
TIG welding
effects of HF 100
mechanised/ automated welding 114–
115
parameters (argon shielding) 104
parameters (helium shielding) 113
process principles 97–101
shielding gas 102–106
spot and plug welding 115
torches and cables 106–107
torch manipulation 110–112
tungsten electrodes 108–109
ultrasonic examination 208–211
water jet cutting 63–64
weldability 18–31
hot cracking 24–31
oxide film 22–24
porosity 18–22
welder approval
ASME IX 193, 196, 197
BS EN 287 Pt 2 191–193
BS EN 1418 197–198
welding procedure 181–182, 183
welding procedure approval
ASME IX 188–190
BS EN 288 Pt 4 182–188
alloy grouping 184
range of approval 187–188
test regime 185–187
x-radiography 213
كلمة سر فك الضغط : books-world.net
The Unzip Password : books-world.net
تعليقات