Mitsubishi Evolution X. Manual — part 2

WELDING

TSB Revision

BASE OF BODY REPAIR

9-5

NOTES REGARDING WELDING

1. Selection of the electrode tips

• Select the electrode tips according to the

thickness of the panels to be welded.
D = 2t + 3 mm (D = 2t + 0.1 inch)

• The angle of the tip should be between 90

degree angle and 120 degree angle.

• To always keep the end of tip in the correct

shape, use a tip cutter, file or similar tool to
shape it if it becomes worn.

2. Alignment of the electrode tips

• Adjust the arms so that the upper and lower

electrode tips are in a straight line.

3. Alignment and length of the arms

• Adjust the electrode tips so that the upper and

lower arms are parallel.

• Select an appropriate arm length. Note, how-

ever, that the arm length should not be more
than 350 mm (13.8 inches) in order to ensure
nugget strength.

4. The weld points

• The overall strength will increase as the pitch

decreases; however, if the pitch decreases
too much, the current will be short-circuit
diverted to the previous weld point and the
strength of the individual nuggets will be insuf-
ficient.

• Make the spot welds at the center of the

flanges to provide sufficient adhesion. When
welding at an edge, make the spot welds at
least 5 mm (0.2 inch) from the edge of the
flange.

• The number of spot weld points should be the

same as, or slightly more than the number of
original repair welds.

• When spot welding three or more panels

together, if painted surfaces cause a loss of
conductivity, make the welds at the same
places as the factory welds. If this is done,
extra welds will not be necessary, but if extra
welds are necessary, switch to plug welding.

.

WELDING REQUIREMENTS

Standard steel plate (SPCC, etc.)

CAUTION

If the total thickness of the plates at the weld
places is 3 mm (0.12 inch) or more, use plug
welding, because spot welding will not provide
sufficient welded strength.

Example

• Center pillar (outer): plate thickness 1.4 mm

(0.055 inch), material SPCC

• Center pillar (inner): plate thickness 1.5 mm

(0.059 inch), material SPCC

AB301455AE

90 – 120˚

D
t

:
:

Diameter of the electrode tip
Thickness of the panel

t

D

WELDING

TSB Revision

BASE OF BODY REPAIR

9-6

The number of weld points are as below when the
outer and inner center pillars are repaired by weld-
ing.

NOTE: *: For welding steel plates of different thickness, conform to the welding conditions for the thinner
plate.

.

AB200031AE

Factory welds (F)

8 Points

8 Points

11 Points

11 Points

Repair welds (R)

As shown by the Welding Requirements table, the number of repair welds is as follows.
8 (points)

× 130 (%) = 10.4 (points)

The number of weld points should, therefore, be ten or eleven.
If, however, a pitch of 26 mm (1.02 inch) or more cannot be maintained, the plug
welding method (eight weld points) should be used.

Panel
thickness*
[mm (in)]

Number of repair weld (percentage of factory weld)

Safety
equipment
area

1.0 (0.04) or
less

100% Same number as factory welds

1.2 (0.047)

150% Maintain pitch of at least 22 mm (0.87 inch); if not possible, plug weld.

1.4 (0.055) or
more

100% Same number as factory welds; plug welding

Other
area

1.2 (0.047) or
less

100% Same number as factory welds

1.4 (0.055)

130% Maintain pitch of at least 26 mm (1.02 inch); if not possible, plug weld.

1.6 (0.063) or
more

100% Same number as factory welds; plug welding

WELDING

TSB Revision

BASE OF BODY REPAIR

9-7

GALVANIZED STEEL PLATE (SECC)

CAUTION

If the total thickness of the plates at the weld
places is 3 mm (0.12 inch) or more, use plug
welding, because spot welding will not provide
sufficient welded strength.

NOTE: *: For welding steel plates of different thicknesses, conform to the welding conditions for the thinner
plate.

.

USING A TEST PIECE TO CHECK NUGGET
FORMATION

Weld a test piece of the same type of steel plate as the panels
to be welded. Try to twist the piece, and also check the nugget
diameter.
Using the weld point as an axis, apply force in the direction indi-
cated by the arrows in the illustration, and determine the
strength of the weld.

1. Good (The welded part remains at one side).
2. and 3.

The weld conditions are unsatisfactory; adjust the welding
current, the current application time, and/or the applied
pressure.

.

Panel
thickness*
[mm (in)]

Number of repair weld (percentage of factory weld)

Safety
equipment
area

0.9 (0.035 or
less

100% Same number as factory welds

1.0 (0.04)

200% Maintain pitch of at least 18 mm (0.71 inch); if not possible, plug weld.

1.2 (0.047) or
more

100% Same number as factory welds; plug welding

Other area 0.9 (0.035) or

less

100% Same number as factory welds

1.0 (0.04)

140% Maintain pitch of at least 18 mm (0.71 inch); if not possible, plug weld.

1.2 (0.047) or
more

100% Same number as factory welds; plug welding

AB200032AB

WELD POINT

1

2

3

WELDING

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BASE OF BODY REPAIR

9-8

CHECKING NUGGET STRENGTH FOLLOWING
SPOT WELDING

CAUTION

• Stop wedging the tip or the chisel or flat-tipped screw-

driver as soon as the size of the nuggets can be deter-
mined; do not wedge it in more than 30 mm (1.18
inches).

• After checking the nugget diameter, correct the place

where the checking was done.

Wedge the tip of a chisel or flat-tipped (-) screwdriver into the
space between two weld points.

• The nuggets should not break apart.

• The nugget diameter should be 3 mm (0.12 inch) or more.

GAS SHIELD ARC WELDING

M4090003000043

Gas shielded arc welding is one method of arc weld-
ing. In this method, while the area to be welded is
shielded from the air by a layer of inert gas (such as
argon) or carbon dioxide gas, the filler metal (wire) is
fed from the torch nozzle at a constant rate and an
electric arc is generated between the tip of the wire
and the area being welded, thus generating heat to

fuse the area. There are two types of gas shielded
arc welding, classified according to the gas they use
as the shield gas: carbon dioxide (CO

2

) gas shielded

arc welding, and MIG welding, which uses an inert
gas (such as argon).
However, herein we will refer to all gas shielded arc
welding as MIG welding.

AB200033AC

3 mm (0.12 in)

AB200033

AB301456

Nozzle

Wire

Contact tip

Metal vapor

Shield gas

AD

AB301456