PROCESS DESCRIPTION
MSG-welding is the most widely used welding process. Depending on the base material being welded and the shielding gas used, the process is divided into:
- Metal-Active-Gas welding (MAG)
- Metal-Inert-Gas welding (MIG)
In both cases the procedure is the same. An endless wire electrode is fed to the arc by a wire conveyor and melted under a shielding gas jacket. The diagram illustrates the structure of an MSG welding process.
The shielding gases have different properties depending on their composition, and therefore different effects on the weld result. Their main task is to shield the liquid melt from the atmosphere. The atmosphere contains nitrogen, oxygen and moisture, which depending on the material being welded can have a negative effect on the weld or lead to a failed welding attempt.
Shielding gases influence:
- The nature of metal transfer
- Melt flow properties
- Ignition characteristics of the arc
- Arc stability
- Heat transfer
- Weld penetration profile
- Chemical composition of the weld metal
- Spatter frequency and size
