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.
Matlock is the county town of Derbyshire, England. It is situated at the south-eastern part of the Peak District, with the National Park directly to the west. The town is twinned with the French town of Eaubonne. The former spa resort of Matlock Bath lies immediately south of the town on the A6. The civil parish of Matlock Town had a population in the 2011 UK census of 9,543. The population of the wider Matlock urban area (including Darley Dale, Tansley, Hackney and Matlock Bath) is approximately 20,000.
Matlock is nine miles (14 km) south-west of Chesterfield and in easy reach of the cities of Derby (19 miles), Sheffield (20 miles) and Nottingham (29 miles); the Greater Manchester conurbation is 30 miles away. Matlock is within the Derbyshire Dales district, which also includes the towns of Bakewell and Ashbourne, as well as Wirksworth. The headquarters of Derbyshire County Council are in the town.