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.