41 00... Welding Steel Components

IMPORTANT: Comply with the following topics from "Body, General":
Safety regulations . See 41 00... SAFETY AT WORK or 41 00... INFORMATION ON HAZARDS .
Handling electrical/electronic equipment, airbags and restraint systems See 41 00... HANDLING AIRBAGS AND RESTRAINT SYSTEMS or 41 00... HANDLING ELECTRICAL AND ELECTRONIC EQUIPMENT .

1. General information

The following procedures are used for repairs:
- MAG welding (M etal Ac tive G as welding)
- Resistance pressure spot welding (referred to in the following and in the repair instructions as spot welding).
Take the number and location of weld spots and MAG weld seams from the separated part. Replace areas inaccessible to spot-welding tongs with MAG plug/spot welds at the same distance. Diameter of bores for plug/spot welds 8 mm.
In the case of emissions extraction, observe a minimum distance of 30 cm for MAG welding during the welding process. Otherwise the inert gas would be drawn off.
Follow the equipment manufacturer's instructions for use.

2. Work materials

MAG welding:
- Steel welding apparatus (see WORKSHOP EQUIPMENT ).
- Steel welding wire - G3SI1 (SG2) or alternatively G4SI1 (SG3)
- Welding mask
- Gas bottle containing inert gas (82 % argon, 18 % CO₂ )
Resistance pressure spot welding:
- Spot-welding apparatus (see WORKSHOP EQUIPMENT ).
- Protective goggles

3. Preparations for MAG and spot-welding

Remove the paint coating in an area of approx. 30 mm around the weld seam or spot.
- The zinc coating underneath must be removed during the MAG welding operation.
- It is not necessary to remove the zinc coating underneath during spot-welding.
Remove the paint coating on the reverse side of the weld seam or spot.
- Contaminants will otherwise enter the weld pool via the root of the weld seam.
- An insufficient electron flow prevents an optimum spot-weld joint.
Coat all metal overlaps and weld spot flanges with welding primer.
To determine the optimum electrode contact force for spot-welding, carry out spot-weld shear tests on sample metal sheets.
In order to keep the electron flow short during MAG welding on the body, you must if possible attach the ground terminal directly to the component to be welded.

4. Welding

During MAG welding, the weld gap must be kept as small as possible. The larger the weld gap, the lower will be the strength of the joint.
During spot-welding, the metal flanges to be joined must be placed as close together as possible without gaps.
The larger the gap, the lower will be the strength of the joint.

Minimum gap between welding spots 25 mm.

5. Subsequent treatment of weld joints:

When grinding a weld seam, do not grind thin the base material next to the seam.
After joining, clean all weld seams and spots with a stainless steel wire brush.
Remove burnt paint with a stainless steel wire brush.
All weld joints sealed off with body sealing compound in original state must be primed and sealed off again thoroughly after repairing. Replace damaged or removed anti-drumming layers.