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 and electrode are protected from oxidation or other atmospheric contamination by an inert shielding gas (argon or helium). A filler metal is normally used, though some welds, known as autogenous welds, or fusion welds do not require it. When helium is used, this is known as heliarc welding. 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 a 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.
Sandwell is a metropolitan borough of the West Midlands county in England. The borough is named after the Sandwell Priory, and spans a densely populated part of the West Midlands conurbation. According to Sandwell Metropolitan Borough Council, the borough comprises the six amalgamated towns of Oldbury, Rowley Regis, Smethwick, Tipton, Wednesbury, and West Bromwich, although these places consist of numerous smaller settlements and localities. Sandwell's Strategic Town Centre is designated as West Bromwich, the largest town in the borough, while Sandwell Council House (the headquarters of the local authority) is situated in Oldbury.
Bordering Sandwell is the City of Birmingham to the east, the Metropolitan Borough of Dudley to the south and west, the Metropolitan Borough of Walsall to the north, and the City of Wolverhampton to the north-west. Spanning the borough are the parliamentary constituencies of West Bromwich West, West Bromwich East, Warley, and part of Halesowen and Rowley Regis, which crosses into the Dudley borough.
At the 2011 census, the borough had a population of 309,000 and an area of 86 square kilometres (33 sq mi).