Tungsten inert gas (TIG) welding is the process of blending together reactive metals, such as magnesium and aluminum. During the welding process, an arc is formed between a pointed tungsten electrode and the area to be welded. A shielding gas is used to help create a clean weld, as it prevents oxidization from occurring. The welding method became popular and useful in the early 1940s and, as a result, has greatly propelled the use of aluminum for welding and structural processes. It is commonly used for both high quality and manual welding.
The type of gas shielding typically used for TIG welding is argon, helium, or a combination of both. When combined, these two gases can ensure a higher welding speed and welding penetration. Argon is usually preferred by most welders simply because it is heavier than air and provides better coverage when welding.
Using the TIG welding process, a person can perform a variety of weld types on a number of different metals, although steel and aluminum are the most widely used. A filler rod, usually made from the same material as the base metal, is used for reinforcing joints and welding heavy metals.
There are several different types of joints designed for use with this method of welding, including the butt joint, lap joint, corner joint, and t-joint. The butt joint, which can be welded without the assistance of a filler rod, involves two pieces of metal being joined together along the seams. With a lap joint, the top edge is welded to the bottom piece in an area between the two overlapping metals. A corner joint involves welding one piece of metal at a right angle to the edge of a second piece of metal in order to form a corner. The t-joint is created by placing one piece of metal perpendicular to another piece of metal to form a T shape, and it does require a filler rod. This type of welding is done along either side of the perpendicular seam.