TIG welding is the process of using a tungsten electrode in conjunction with a gas, such as argon, during welding. The tungsten electrode warms the metal being welded while the gas protects it from contamination from the air.
TIG welding is capable of welding a large number of metals and alloys, including steel, aluminum, magnesium and brass. When a clean metal is welded, TIG welding produces no sparks, smoke or fumes. TIG welding is possible from a variety of welding positions including flat, horizontal, vertical and overhead welds. Types of tungsten electrodes used in TIG welding include ceriated CeO2, thoriated ThO2, lanthanated La2O3 and zirconiated ZrO2.
Initially, two pieces of metal are butted together and grounded to complete an eventual electric circuit. Opening a valve on a gas bottle starts a flow of gas, commonly argon or helium, to the tip of an electrode. When the electrode is placed close to the joint, a spark is formed that melts both pieces of metal. A welding rod is then melted into the seam creating a solid joint. Because of the coordination involved, TIG welding is more difficult to learn than other types of welding.
TIG welding differs from other types of welding by the use of a tungsten electrode tip, which is shaped for different applications. The sharpness of the tip determines the concentration of the spark and the temperature of the arc. Round or blunt tips provide a lower arc temperature, which is preferred for welding nonferrous metals, such as aluminum. Versatility of application gives TIG welding an advantage over other types of welding.