Flux Cored Arc Welding Carbon SteelFlux cored arc welding is a process being used increasingly for welding carbon steels. It is capable of high deposition rates and has good fusion characteristics. Standard MIG welding equipment is suitable for use with cored wires, but wire feeders are normally equipped with special knurled rolls. Welding guns are often water-cooled because of the high currents and duty cycles involved. Consumables are tubular wires with a flux filling. There are three main types of cored wire, namely, gas shielded rutile, gas shielded basic, and self-shielded. Rutile wires are normally the easiest to use, basic wires generally give the toughest and cleanest welds, and self-shielded wires are ideal for site work. Shielding gases for FCA welding are either CO2 or argon-20%CO2 mixtures with or without an addition of oxygen. The weldability of the steel may impose restrictions on the choice of electrode. Steels with carbon contents above about 0.3% are hardenable, and fast cooling will produce a hard HAZ and this is liable to result in hydrogen cracking. This form of cracking can be prevented by use of preheat, basic wires and suitable welding procedures. FCA welding may present possible electrical and radiation hazards plus particulate and gaseous welding fume depending on wire type, size, and current.
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