What is the main function of a 'flux' in welding processes?

In welding processes, the main function of a flux is to prevent oxidation and improve fusion between materials. When metals are heated to their melting points during welding, they can react with oxygen in the air, leading to the formation of oxides that can compromise the quality of the weld. By applying flux, these chemical reactions are minimized as the flux creates a protective layer that shields the molten weld pool from atmospheric contaminants.

Additionally, flux can enhance the flow of molten material and promote better wetting between the base metal and the filler material, leading to a more robust joint with good mechanical properties. This function is critical in ensuring a successful weld that maintains structural integrity under load.

While cleaning materials before welding is an important preparatory step, it is not the primary role of flux during the welding process itself. Similarly, increasing the melting point or reducing the weight of the weld does not define the fundamental purpose of flux. Instead, the focus remains on oxidation prevention and improving the bonding between the materials being joined.