Mitsubishi MOTORS Lancer Evolution 2008, Body Repair Manual, Page: 71 / 186

WELDING
TSB Revision
BASE OF BODY REPAIR
9-11
CONTINUOUS WELDING
There are several types of continuous welding: fillet (lap joint)
welding, butt welding, T joint welding, gap welding, etc.; these
are called short-circuit arc welding, and provide a stable arc at
a relatively low current.
.
Torch angle and welding technique
There are two welding techniques: forehand welding and back-
hand welding.
Forehand welding: Penetration is shallow and the bead is flat.
Backhand welding: Penetration is deep and the bead has a
convex shape.
The angle of the torch should be 15
−
30 degree angle for
either technique, and the tip should be maintained at a distance
of 6
−
10 mm (0.24
−
0.39 inch) from the surface being welded.
.
Preventing warping
1. Backhand technique
Because the direction for each weld pass and that for the
fusion progression are opposite, the residual stress is
evenly distributed.
2. Symmetrical technique
Because the welds are made in symmetrical positions in
relation to the center of the joint, the residual stress is also
symmetrical.
3. "Stepping stone" technique
Because the welds are made at random positions, the
residual stress is the most evenly distributed; however, the
possibility of flaws at the starting and stopping points is rela-
tively high.
AB200041
AB301457
15 – 30˚ 15 – 30˚
Forehand
technique
Backhand
technique
AD
AB200043AD
Anti-Warp Welding Techniques
1.
2.
3.
Backhand technique
Symmetrical technique
"Stepping stone" technique
5 4 3 2 1
5 4 3 2 1
4 3 2 1