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.
St Neots /sɛnʔ ˈniːəts/[b] is a town and civil parish in the Huntingdonshire District of the county of Cambridgeshire, England, approximately 50 miles (80 km) north of central London. The town straddles the River Great Ouse and is served by a railway station on the East Coast Main Line. It is 14 miles (23 km) west of Cambridge, to which it is linked by the A428 arterial road. It is the largest town in Cambridgeshire and had a population of 30,811 in the 2011 census.[c]
The town is named after the Cornish monk Saint Neot, whose bones were moved to the Priory here from the hamlet of St Neot on Bodmin Moor in around 980 AD. Pilgrimage to the priory church and parish church brought prosperity to the settlement and the town was granted a market charter in 1130. In the 18th and 19th centuries the town enjoyed further prosperity through corn milling, brewing, stagecoach traffic and railways.
After the Second World War the town and its industry were chosen for rapid growth as London councils paid for new housing to be built to rehouse families from London. The first London overspill housing was completed in the early 1960s and new housing has continued at a slightly lower rate such that the population, including the areas transferred from Bedfordshire, is approximately four times that of the 1920s.