TIG: arc welding with gas protection and tungsten electrode

TIG welding is a process that uses an arc between a non-melting electrode, generally made of tungsten, and the workpiece as a heat source. The molten bath is protected by an inert shielding gas: argon, helium or a mixture of the two. The process can be used with or without filler metal.

In the nomenclature of standard NF EN ISO 4063, tungsten arc welding in an inert atmosphere is numbered 14.

The initials TIG come from the English name for the "Tungsten Inert Gas" process. This acronym is used in France and Great Britain. In Germany, the metal tungsten is called wolfram, so the process is known as "Wolfram Inert Gas", or WIG. In the USA, the process is still referred to as GTAW for Gas Tungsten Arc Welding.

The TIG process is a major industrial process for producing high-quality welds on a wide variety of materials.

Historically, the process originated during the Second World War, when it was widely used, with spectacular results in some countries, notably the USA. It was used to weld materials used in military applications (aluminum, magnesium). A number of improvements have been made to the original process, mainly to enhance productivity while maintaining a high level of quality.

This article provides a comprehensive description of the welding process and its variants, as well as its possible uses, weldable materials and joint preparations.

A glossary and a table of acronyms and symbols are provided at the end of the article.