41 00... Welding And Soldering Steel Components

A. Welding steel components 

1. General information 

• The following procedures are used for repairs:
  • MAG welding (M  etal A  ctive G  as w  elding)
  • Resistance pressure spot welding (referred to in the following and in the repair instructions as spot welding).
• Take the number and position of welding spots and MAG weld seams from the separated part. Replace areas inaccessible to spot-welding tongs with MAG plug weldings at the same distance. Diameter of bore holes for plug weldings 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 welder (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 ).
  • Safety 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 layer underneath must be removed during the MAG welding method.
  • It is not necessary to remove the zinc layer 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 sheet metal.
• 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 sheet 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 distance between welding spots 25 mm.

5. Subsequent treatment of welded connections 

• 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 welded connections sealed off with body sealing compound in original condition must be primed and sealed off again thoroughly after repairing. Replace damaged or removed anti-drumming layers.

B. Soldering steel components 

1. General information 

• The following procedures are used for repairs:
  • Autogenous brazing solder
  • Tinning
• The MIG soldering procedure is not used in repairs for strength reasons. MIG soldered/brazed seams used in standard production are replaced during repairs by MAG weld seams  .
• Areas brazed in vehicle production are joined during repairs with the same procedure.
• It is possible when straightening steel components to correct irregularities smaller than 2 mm with filler.

  If in exceptional cases the irregularities are in excess of 2 mm, these areas must be tinned.

  Only visible areas of the outer skin and on the carrier support must be tinned.

  All areas which have covers on the vehicle are not to be tinned.

  NOTE: Only applicable within the European Union!
  European used-vehicle regulations prohibit the use of tin containing lead in motor vehicles introduced after 01.07.2003!

2. Work materials 

• Brazing solder:
  • Tube pack and torch (autogenous torch)
  • Brazing solder
  • Gas bottles (oxygen and acetylene)
  • Welding goggles
• Tinning:
  • Tube pack and torch (torch for tinning)
  • Tinning paste
  • Tin (refer to "ELECTRONIC PARTS CATALOGUE ").
  • Gas bottle (acetylene)
  • Safety goggles

3. Preparations for brazing solder and tinning 

• Heat brazed connections to be opened with gas flame. Lift off sheet metal remnants and remove remaining brazing solder with wire brush.
• Remove the paint and zinc layer in an area of approx. 30 mm around the seam to be soldered.
• Remove the paint and zinc layer in the tin-plating area and approx. 30 mm beyond.

4. Brazing solder/tinning 

• Execute brazed seam without overheating the solder and with low heat dissipation. If necessary, use heat protecting paste.

5. Subsequent treatment of brazed connections 

• Remove burnt residual zinc completely. Straighten, grind and tin visible connection faces.
• Remove burnt paint with a stainless steel wire brush.