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.
South West Englandis one of nine officialregions of England. It consists of the counties ofBristol,Cornwall(including theIsles of Scilly),Dorset,Devon,Gloucestershire,SomersetandWiltshire. Large cities and towns in the region includeBristol,Bournemouth,Cheltenham,Exeter,Gloucester,PlymouthandSwindon. It is geographically the largest of the nine regions of England covering 9,200 square miles (23,800 km2),but the third least-populous, with approximately five million residents.
The region includes theWest Countryand much of the ancient kingdom ofWessex. It includes two entirenational parks,DartmoorandExmoor(a small part of theNew Forestis also within the region); and fourWorld Heritage Sites:Stonehenge, theCornwall and West Devon Mining Landscape, theJurassic Coastand theCity of Bath. The northern part of Gloucestershire, nearChipping Campden, is as close to the Scottish border as it is to the tip of Cornwall.The region has by far the longest coastline of any English region.
The region is at thefirst levelofNUTSforEurostatpurposes. Key data and facts about the region are produced by theSouth West Observatory. Following the abolition of theSouth West Regional AssemblyandGovernment Office, local government coordination across the region is now undertaken bySouth West Councils.
The region is known for its richfolklore, including the legend ofKing ArthurandGlastonbury Tor, as well as its traditions and customs. Cornwall has its own language,Cornish, and some regard it as aCeltic nation. The South West is known forCheddar cheese, which originated in theSomersetvillage ofCheddar; Devoncream teas,crabs,Cornish pasties, andcider. It is home to theEden Project,Aardman Animations, theGlastonbury Festival, theBristol International Balloon Fiesta,trip hopmusic and Cornwall'ssurfingbeaches. The region has also been home to some of Britain's most renowned writers, includingDaphne du Maurier,Agatha ChristieandEnid Blyton, all of whom set many of their works here, and the South West is also the location ofThomas Hardy's Wessex, the setting for many of his best-known novels.