In FCAW, what function does the flux serve?

In Flux-Cored Arc Welding (FCAW), the flux serves multiple important roles, one of the primary functions being to prevent oxidation during the welding process. When metals are heated, they can react with atmospheric elements, particularly oxygen, leading to defects such as porosity or a weakened weld. The flux forms a protective barrier or gas that shields the molten weld pool from the atmosphere, which is crucial for ensuring a strong and durable weld.

Additionally, while some fluxes can contribute to enhancing the weld quality and might have other functions, such as slag formation to protect the weld bead, the central purpose is to ensure that oxidation does not occur. This protection is essential for achieving the necessary mechanical properties of the finished weld, thus contributing to the overall integrity and strength of the welded joint.