Welding gases

One or more of the gases argon, helium, CO₂, Oxygen, nitrogen and hydrogen are used as shielding gases in the welding process. Acetylene and oxygen are used for autogenous welding.

The welding method and the product to be welded dictate the choice of gas mixture.

The gases are supplied as standard mixtures or are specially prepared. The gas most used is Hydro Secure 18 (argon with 18% CO₂) for wire, and MAG for carbon steel. Argon is the gas most commonly used for TIG welding. For MIG/MAG welding of rustproof materials, gases with a low CO₂ content are used, typically 2%, along with argon. In addition, purging gas is used for welding rustproof pipes and containers in order to maintain good corrosion resistance. Argon or nitrogen, with or without the addition of hydrogen, is used for this purpose.