Brazing flux serves the purpose of dissolving or combining and slowing down the formation of oxides and other unwanted by-products in the brazing process. Brazing flux comes in powder, paste or liquid form. A good flux has the lower melting point, its less viscous and can be displaced by the filler metal. It protects the joints till the material has set and the joint is secured. It also protects the base metal from oxidation and corrosion to certain degree.
Brazing flux also acts as the cleaning agent for the base metal. It helps in removing impurities that might be present at the surface before the brazing process. Brazing is economical and a preferred method of joint creation in critical engineering applications.