Which gas is used for gas welding?

Which gas in MIG / MAG welding?

MIG / MAG welding is characterized by the use of a consumable electrode made of wire, a filler or solid wire and a shielding gas. The protective gases in the MIG process are inert like argon or helium. In MAG processes, the gases are active such as carbon, oxygen or argon / carbon mixtures. How do you choose the right shielding gas?

Different demands on the shielding gas

The shielding gas protects the weld metal from other gases such as oxygen from the atmosphere. Otherwise, unwanted reactions from the weld pool could be expected all the time. When choosing the protective gas it comes up

  • the welding process.
  • the metal to be welded
  • the welding work itself (large, small, thick, thin).

The different metals require different protective gases.

The gases have this specification:

Argon: This gas is inert. It is particularly suitable for MIG / MAG welding of aluminum and stainless steel. There are certain standard parameters in gas mixtures.
Helium: Helium-argon mixtures are popular shielding gases for quickly producing successful seams when welding aluminum and stainless steel.
Oxygen: The active oxygen makes the arc particularly stable. This active gas is preferably used as an additive in MAG welding.
Carbon dioxide: The active gas is often an additive in gas mixtures.
Nitrogen: Nitrogen can especially protect the welding wire and the melt from the influence of oxygen.

Typical mistakes when choosing the protective gas

The general choice is made like this:
MIG welding process - inert gases such as argon, helium or mixtures are used here. MAG welding process - active gases with carbon dioxide (MAGC welding) and a mixture of argon with carbon dioxide (e.g. "Corgon 18") and / or oxygen (MAGM welding).
The wrong choice is often made with high-alloy metals. Pay close attention to the parameters here:
Highly alloyed material requires mixed gas 2 (2% to 2.5% CO2 share), for example "CRONIGON 2" for stainless steel. If you were to use a universal mixed gas 18 such as Corgon 18 instead, the higher proportion of carbon dioxide can lead to rusting weld seams. CORGON 18, on the other hand, is the right shielding gas for steel and other unalloyed / low-alloy metals.

Remember that you are using the chosen shielding gas among other things

  • the spatter loss
  • the penetration
  • the drop size
  • the arc

act.

The arc itself is important in the context of the sheet thickness and seam types. The choice of shielding gas also has a direct impact on the cost-effectiveness of welding.