| Brazing 720 is the silver-copper eutectic composition and in melting it acts like a metallic element, i.e. it melts completely at a single temperature, thus it will quickly flow into long narrow joints. On either silver base of copper base alloys, Braze 720 exhibits a decreased fluidity and an increased remelt temperature due to the solution of either silver or copper in the eutetic. Brazing time and temperature should be minimized to prevent excessive diffusion and erosion of the base metal. This filler metal has limited wetting ability on iron and/on nickel base alloys. The wetting ability it does have is derived from its copper content. Both iron and nickel have practically no solubility in silver, while nickel is readily soluble in copper and the solubility of iron in copper is sufficient to provide wetting. It is an observed fact that the wetting obtained in good hydrogen atmospheres is superior to that derived from flux protection. Applications: Braze 720 is generally used to join silver, copper and nickel base alloys in reducing or inert atmospheres or vacuum. It is also widely used to join metallized ceramics to metals in vacuum. Specifications: This filler metal conforms to the following specifications: AWS A5.8 BAg-8, ASME Boiler & Pressure Vessel Code, Sec. II-C, SFA 5.8 BAg-8 Information provided by Lucas-Milhaupt, Inc. |
