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.
Warwick (/ˈwɒrɪk/ WOR-ik) is a market town and county town of Warwickshire, England. It lies near the River Avon, 11 miles (18 km) south of Coventry and west of Leamington Spa and Whitnash. Its population was 31,345 in 2011. Signs of Neolithic activity precede unbroken habitation to the 6th century AD. It was a Saxon burh in the 9th century; Warwick Castle was built during the Norman conquest of England. Warwick School claims to be the country's oldest boys' school. The earldom of Warwick, created in 1088, controlled the town and built its walls, of which Eastgate and Westgate survive. The castle became a fortress, then a mansion. The Great Fire of Warwick in 1694 destroyed much of the town. Warwick missed industrialisation, but the population has grown almost sixfold since 1801.