TIG Welder
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.
Devon(/ˈdɛvən/, also known asDevonshire) is acountyofEngland, reaching from theBristol Channelin the north to theEnglish Channelin the south. It is part ofSouth West England, bounded byCornwallto the west,Somersetto the north-east andDorsetto the east. The city ofExeteris thecounty town. The county includes the districts ofEast Devon,Mid Devon,North Devon,South Hams,Teignbridge,TorridgeandWest Devon.PlymouthandTorbayare each geographically part of Devon, but are administered asunitary authorities.[4]Combined as aceremonial county, Devon's area is 6,707 km2(2,590 square miles)[5]and its population is about 1.1 million.
Devon derives its name fromDumnonia(the shift frommtovis a typicalCeltic consonant shift). During theBritish Iron Age,Roman Britainand theearly Middle Ages, this was the homeland of theDumnoniiBrittonicCelts. TheAnglo-Saxon settlement of Britainresulted in the partial assimilation of Dumnonia into theKingdom of Wessexduring the eighth and ninth centuries. The western boundary with Cornwall was set at theRiver TamarbyKing Æthelstanin 936. Devon was later constituted as ashireof theKingdom of England.
The north and south coasts of Devon each have both cliffs and sandy shores, and the county'sbayscontainseaside resorts,fishing townsandports. The inland terrain is rural, generally hilly and has a lower population density than many other parts of England.Dartmooris the largest open space in southern England, at 954 km2(368 square miles);[6]itsmoorlandextends across a large expanse ofgranitebedrock. To the north of Dartmoor are theCulm MeasuresandExmoor. In the valleys and lowlands of south and east Devon the soil is more fertile, drained by rivers including theExe, theCulm, theTeign, theDartand theOtter.
As well as agriculture, much of theeconomy of Devonis based ontourism. The comparatively mild climate, coastline and landscape make Devon a destination forrecreation and leisure in England. Visitors are particularly attracted to the Dartmoor and Exmoornational parks; its coasts, including the resort towns along the south coast known collectively as theEnglish Riviera; theJurassic CoastandNorth Devon's UNESCO Biosphere Reserve; and the countryside including theCornwall and West Devon Mining Landscape.