Argon arc welding, also known as tungsten inert gas (TIG) welding, is a welding process that uses a non-consumable tungsten electrode to create an electric arc to join metals together. Using a round tungsten needle in argon arc welding (TIG welding) allows for accurate and efficient welding, making it a popular choice for various industrial and artistic applications. When performing TIG welding, a round tungsten needle (tungsten electrode) is used as the electrode. The electrode is the part that carries the current and generates the arc. The electrode is made of pure tungsten or tungsten alloy and is available in different diameters. The choice of electrode diameter depends on the specific welding application and the thickness of the metal being welded.