TIG stands for Tungsten Inert Gas and is technically called Gas Tungsten Arc Welding or GTAW. The process uses a non-consumable tungsten electrode that delivers the current to the welding arc. The tungsten and weld puddle are protected and cooled with an inert gas, typically argon.
Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a non-consumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by an inert shielding gas (argon or helium) and a filler metal is normally used, though some welds, known as autogenous welds do not require it. A constant-current welding power supply produces electrical energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as plasma.
GTAW is most commonly used to weld thin sections of stainless steel and non-ferrous metals such as aluminum, magnesium and copper alloys. The process grants the operator greater control over the weld than competing processes such as shielded metal arc welding and gas metal arc welding allowing for stronger higher quality welds. However, GTAW is comparatively more complex and difficult to master and furthermore, it is significantly slower than most other welding techniques. A related process, plasma arc welding, uses a slightly different welding torch to create a more focused welding arc and as a result is often automated.
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 1940's 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.