Page 16 - Welding of Aluminium and its Alloys

8 The welding of aluminium and its alloys

Table 1.2 (cont.)

Process Application

Manual metal arc Limited application; uses a flux-coated consumable
electrode; non- or lightly stressed joints;
obsolescent.
Oxy-gas Low-quality weld metal; unstressed joints;
obsolescent.
Electron beam High-quality, precision welding; aerospace/defence
welding and electronic equipment; high capital cost;
vacuum chamber required.
Laser welding High-quality, precision welding; aerospace/defence
and electronic equipment; high capital cost.
Electro-gas, electro-slag, Limited applications, e.g. large bus bars; porosity
submerged arc problems; largely obsolescent.
Welding with fusion and pressure
Magnetically impelled Butt joints in pipe; capital equipment required but
arc butt welding lower cost than flash butt; fully automated.
Resistance and flash welding
Spot, projection spot Lap joints in sheet metal work, automotive,
seam welding holloware, aerospace industry; high capital cost;
high productivity.
Weld bonding Combination of spot welding through an adhesively
bonded lap joint; automotive industry; very good
fatigue strength.
High-frequency Butt joints; production of pipe from strip; high capital
induction seam cost; high production rates.
Flash butt welding In line and mitre butt joints in sheet, bar and hollow
sections; dissimilar metal joints, e.g. Al-Cu; high
capital cost; high production rates.
Stud welding
Condenser, capacitor Stud diameters 6mm max, e.g. insulating pins, pan
discharge handles, automotive trim, electrical contacts.
Drawn arc Stud diameters 5–12mm.
Solid phase bonding
Friction welding Butt joints in round and rectangular bar and hollow
sections; flat plate and rolled section butt welds
(friction stir); dissimilar metal joints; capital
equipment required.
Explosive welding Field pipeline joints; dissimilar metal joints,
surfacing.
Ultrasonic welding Lap joints in foil; thin to thick sections; Al-Cu joints
for electrical terminations.
Cold pressure welding Lap and butt joints, e.g. Al-Cu, Al-steel, Al sheet and
wire.
Hot pressure welding Roll bonded lap joints, edge to edge butt joints.