TIG Plate Welding Practice Test

An inert shielding gas is used in GTA welding to create a protective blanket around the arc and the weld pool, keeping air away from the hot tungsten and molten metal. Air contains oxygen and nitrogen that would react with the hot metal, causing oxidation, porosity, and contamination, and could also oxidize the tungsten electrode. The inert gas (usually argon or helium) is nonreactive at welding temperatures, so it prevents these undesired reactions while helping to stabilize the arc and improve weld quality.