Shielding gases are inert or semi-
inert gases that are commonly used in several welding processes, most notably
gas metal arc welding and
gas tungsten arc welding (GMAW and GTAW, more popularly known as MIG and TIG, respectively). Their purpose is to protect the weld area from
oxygen, and
water vapour. Depending on the materials being welded, these atmospheric gases can reduce the quality of the weld or make the welding more difficult. Other arc welding processes use other methods of protecting the weld from the atmosphere as well –
shielded metal arc welding, for example, uses an
electrode covered in a
flux that produces carbon dioxide when consumed, a semi-inert gas that is an acceptable shielding gas for welding steel.