The process, as the name implies, uses a tungsten electrode to create an arc, while the prefix “gas” implies a shielding gas used to prevent oxidation of materials melted during welding. Shielding gas flows around the arc, which shields atmospheric gas from coming near the arc and prevents the reaction between the atmospheric gas and arc-metal interaction zones. Shielding gas is generally an inert gas (Ar or He) but can also be a mixture of inert and non-inert gases. Since it is the same gas from which an arc is formed, it serves the dual purpose of shielding and arc-creating. Besides, the arc type depends upon the gas type. Therefore, its selection does not depend upon the sole purpose of shielding but on the arc type needed.