Flux Cored Arc Welding (FCAW) is quite similar to MIG/MAG welding as far as operation and equipment are concerned. However, the electrode is not solid but consists of a metal sheath surrounding a flux core.
The electrode begins life as a flat metal strip, which is formed first into a ‘U’ shape. Flux and alloying materials are deposited into the ‘U’, which is then closed into a tube by a series of forming rolls.
As in MIG/MAG welding, the flux cored process depends on a gas shield to protect the weld zone from atmospheric contamination. The gas is either applied separately, in which case the electrode is referred to as a gas shielded flux cored electrode, or it is generated from the decomposition of gas forming ingredients contained in the flux core (self shielding). In addition to the gas shield, the flux cored electrode produces a slag covering for further protection of the weld metal as it cools. This is subsequently removed.GTAW/TIG
Gas-Shielded Tungsten Arc Welding (also known as gas tungsten arc or TIG welding) is a process, which uses a non-consumable solid tungsten electrode. The electrode, the arc and the area surrounding the molten weld puddle are protected from the atmosphere by an inert gas shield. If a filler metal is necessary, it is added to the leading edge of the molten puddle.
TIG welding produces exceptionally clean, high quality welds. As no slag is produced, the chance of slag inclusions in the weld metal is eliminated and the finished weld requires virtually no cleaning. TIG welding may be used for welding almost all metals and the process lends itself to both manual and automatic operation. TIG welding is most extensively used for welding aluminium and stainless steel alloys where weld integrity is of the utmost importance. It is widely used for high quality joints in the nuclear, chemical, aircraft and food industries.