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.
Bolsover is a market town and the administrative centre of the Bolsover District, Derbyshire, England. It is 145 miles (233 km) from London, 18 miles (29 km) from Sheffield, 26 miles (42 km) from Nottingham and 54 miles (87 km) from Manchester. It is the main town in the Bolsover district.
The civil parish for the town is called Old Bolsover. It includes the town and the New Bolsover model village, along with Carr Vale, Shuttlewood, Stanfree, Oxcroft, and Whaley. Its population at the 2011 UK Census was 11,673.
Bolsover, along with several nearby villages, is situated in the north east of the county of Derbyshire. It is the main town in the District of Bolsover, which is an electoral constituency and part of Derbyshire.