The flux-cored filler metals are composed of outer metal skin and inner brazing flux, and can be fabricated into various shapes such as rods, wires and preforms according to customers" requests. The products have the advantage of enhancing brazing automation and efficiency, reducing and controlling the usage of flux as well as improving the quality stability. They can be used with automatic shrink-ring and induction brazing equipment to raise productivity. Flux-cored filler metals are applied in the production of air-conditioner and valves.