TIG, MIG, and MAG are gas-shielded welding processes : A gas displaces the ambient air from the weld pool and prevents oxygen and nitrogen from damaging the weld. The main difference lies in the type of electrode and the composition of the shielding gas.
TIG (tungsten inert gas, international TIG)
The electric arc burns between a non-consumable tungsten electrode and the workpiece. The filler material is supplied separately as a rod, if required. An inert gas , usually argon, which does not chemically participate in the process, serves as a shielding gas.
Because the arc and material feed are decoupled, the heat input can be precisely controlled. This results in clean, spatter-free welds of high quality – with comparatively low melting rates. TIG welding is the standard process for thin-walled stainless steel, for root passes, and for welds in contact with the product.
MIG (Metal Inert Gas)
Here, the filler material itself is the electrode: A wire is continuously melted and automatically fed. The shielding gas is inert (argon, helium, or mixtures).
MIG is primarily used on non-ferrous metals, especially aluminum and copper alloys.
MAG (Metal Active Gas)
The setup is similar to MIG welding, but the shielding gas is active : it contains components of carbon dioxide or oxygen and intervenes in the arc process – it influences penetration and droplet transfer.
MAG is the dominant process for unalloyed and low-alloy steels. It offers high melting rates and is suitable for thicker sheets and long welds.
Comparison
| WEDGE | MIG | MAG | |
|---|---|---|---|
| Electrode | Tungsten, non-melting | wire, meltable | wire, meltable |
| Additive material | separately, manually | = electrode | = electrode |
| Protective gas | inert (Argon) | inert | active (with CO₂/O₂) |
| Melting capacity | low | hoch | hoch |
| splash | practically none | low to medium | medium |
| Typical materials | Stainless steel, aluminum, thin sheets | Aluminum, copper | Steel, structural steel |
classification
The choice depends on the requirements: Where weld quality, surface finish, and controlled heat input are paramount—for example, in hygienic pipelines or thin-walled stainless steel—TIG welding is used. Where productivity and melting performance are key, MIG/MAG welding is employed. For automated circumferential welds on pipes, orbital welding offers a mechanized variant of the TIG process.