What is the function of flux in FCAW (Flux-Cored Arc Welding)?

The function of flux in Flux-Cored Arc Welding (FCAW) is primarily to help create shielding gas and slag. During the welding process, the flux within the core of the filler wire is heated and undergoes a chemical reaction that produces a shielding gas. This gas protects the molten weld pool from atmospheric contamination, which can lead to defects and weakened welds.

In addition to providing this shielding, the flux also forms a layer of slag over the weld; this slag acts as an insulator, cooling the weld more slowly and minimizing oxidation. The presence of slag can help improve the mechanical properties of the weld by preventing impurities from settling in the weld area as it solidifies. Overall, the flux plays a critical role in ensuring the quality and integrity of the weld in FCAW applications.