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.
Norfolk (/ˈnɔːrfək/) is a county in East Anglia in England. It borders Lincolnshire to the northwest, Cambridgeshire to the west and southwest, and Suffolk to the south. Its northern and eastern boundaries are the North Sea and to the northwest, The Wash. The county town is the city of Norwich. With an area of 2,074 square miles (5,370 km2) and a population of 859,400, Norfolk is a largely rural county with a population density of 401 per square mile (155 per km2). Of the county's population, 40% live in four major built up areas: Norwich (213,000), Great Yarmouth (63,000), King's Lynn (46,000) and Thetford (25,000).
The Broads is a network of rivers and lakes in the east of the county, extending south into Suffolk. The area is not a national park although it is marketed as such. It has similar status to a national park, and is protected by the Broads Authority.