Mitsubishi MOTORS Lancer Evolution VIII 2003, Technical Information Manual

Page: 213 / 368

WELDING
BASE OF BODY REPAIR
9-9
FEATURES OF MIG SPOT WELDING
In comparison to resistance spot welding, MIG spot
welding has the following advantages and disadvan-
tages.
.
ITEM MIG SPOT WELDING ELECTRIC RESISTANCE SPOT WELDING
Working
characteristics
•
Light weight
•
Welding possible at various
positions (no limit upon welding
positions)
•
Although the torch with separate
transformer is lightweight, the torch
combined with transformer type is heavy.
•
The arm must be exchanged to conform
to the weld location.
Weld time/point Slow (0.5 second or more) Fast (0.5 second or less)
Treatment after
welding Necessary (grinding by grinder,
etc.) Unnecessary
Power High voltage, low current
(15 - 30 V, 50 - 200 A) Low voltage, high current
(2 - 4 V, 4 - 10 kA)
Flux material
•
CO
2
(carbonic acid gas)
•
Weld wire
Unnecessary
Weld points/10
minutes
(rate of use)
•
25 points or less
•
Arc instability and contact tip
burn if rate of use is exceeded.
•
50 - 60 points
•
Welding rod deformation and transformer
overheating if rate of use is exceeded.
Distortion caused by
welding Occurs easily Rare
Welding strength Depends on strength of welding
wire itself.
•
Same as base material
•
Little oxidation
•
Uniform welding quality
Weld traces Button head (slightly convex) Slight concave
(Almost no indentation if swivel tip
used.)
Re-repairability
(cutting away welded
area) Difficult
(Much welding trace High hardness
of weld points) Easy
(Can be separated by spot cutter.)
AB200037AB
SWIVEL TIP