Uses MIG welding flux

MSG soldering

Gas-shielded metal brazing (MSG brazing) is an alternative to MAG welding that is suitable for thin and coated steel sheets.

This article provides information on the following topics:

Description of the procedure

Gas-shielded metal brazing (MSG brazing) is an alternative to MAG welding of thin (s <1.0 mm) and coated steel sheets, which was adopted as a production technique for galvanized thin sheets at the beginning of the 1980s. Initially with welding consumables based on CuAl. Later the alloy CuSi3 was clearly preferred.

The following prerequisites are the basis for the economic use of the process:

  • Freely programmable welding power sources
  • Welding in pulse technology
  • Use of multi-component mixed gases
  • Increasing active gas content of O2 / CO2 / H2 increases the heat input during welding
  • Welding speed ~ 1.5 m / min
  • With correspondingly mechanized to automated systems, values ​​of up to 5.0 m / min are possible in the meantime

Advantages of the procedure

  1. lower heat input
  2. and less burn-off of the coating
  3. minimal spattering
  4. almost no corrosion of the seam
  5. low delay
  6. good gap bridging
  7. no corrosion of the solder seam
  8. low burn-off of the coating
  9. cathodic protection

Which gas is required for MSG soldering?

In MSG soldering, mixtures are used as protective gas argon, Carbon dioxide and hydrogen used. The composition can vary depending on the requirements.

Required equipment

Process gases for MSG soldering

(Recommendation for the solder material according to ISO 24373 CU 6560 (CuSi3Mn))

Soldering speedSpatter preventionSeam appearanceWetting behaviorUniversal application


+Comparatively high / good
-Comparatively low / low

MIG brazing of coated sheets

Steel sheets can get through extremely thin zinc layers can be effectively protected against corrosion by only a fraction of a millimeter (approx. 1 to 20 micrometers).
The use of galvanized sheet metal is interesting because of the low price. If the protective zinc layer is damaged, the component will still not rust. Due to the "cathodic protection", the corrosion protection is maintained at a distance of approx. 2 millimeters.
Areas of application can be found in automotive engineering, in air conditioning and ventilation technology, in the construction industry, etc.

Zinc has an evaporation temperature of around 900 ° C, so that the surface coating burns over a large area during conventional welding of galvanized sheet metal.
The evaporating zinc as well as the oxides lead to pore formation, cracks and lack of bonding. The arc burns extremely unstably.

These problems can largely be avoided by using MIG soldering. A bronze filler material with a low melting point (compared to steel wire) of only approx. 1000 ° C is used here. The workpieces are no longer melted, a soldered connection is formed. Due to the lower heat input, only a little zinc evaporates and the component distortion is also reduced. Despite the soldered connection, the strength values ​​are relatively high. The seam does not corrode because the filler material is made of bronze.

Material:electrolytically galvanized sheet steel
Material thickness:1.5 mm
Filler material:CU-SI 3, 0.8 mm
Seam:Overlap seam with approx. 1 mm gap, position B

Behind the term MIG soldering there is one Brazing processthat is carried out with MIG / MAG or Pulse-Arc inert gas welding machines. It is used to join coated metal sheets.

With MIG soldering, it is not the base material that is melted, but one Brazed joint of the workpieces. Wires with low melting points (at approx. 1000 ° C) are used as solder.

Wire:CuSi3CuAl8 (AlBz8)
Work pieces:galvanized sheets

aluminized sheets

aluminized sheets - steel

aluminized sheets - stainless steel

Shielding gas:argon
Power sources:Various
Wire equipment:

DV rollers for steel

Teflon core (steel core possible)

Application areas:

Control cabinet construction

Automotive industry

Automotive supplier

Ventilation and air conditioning

Surface application for plain bearings (CuAl8)


low melting temperature

low material distortion

low evaporation / burning of the surface coating

Sea water and corrosion resistance

MIG / MAG soldering is therefore an interesting alternative to MAG welding of thin and coated sheets. The welding heroes wish you good luck trying out this technique!

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