COMPOSITE CLAD BRAZING FILLER METAL HAVING EXCELLENT OXIDATION RESISTANCE AND COLD WORKABILITY

摘要

PURPOSE:To improve oxidation resistance and to prevent the generation of work cracking by forming a core material of a copper alloy contg. Ag and Si and constituting a sheath material of tough pitch copper. CONSTITUTION:The core material is constituted by preparing the copper alloy contg. about 5-40% Ag, about 2.5-13% Si, etc. and incorporating further about 1-10%=1 kinds of Sn and In or about 0.001-0.8%=1 kinds of B and Li therein. A thin oxygen-free copper plate is held in place in the copper material and the material in this state is loaded into a mild steel case. The case is subjected to hot rolling in a vacuum heating state. The clad plate material is subjected, successively to cold rolling after annealing in a hydrogen atmosphere, by which the thin-sheet-shaped clad brazing filler metal is obtd. Since the tough pitch copper as the sheath material coats thoroughly the core material, the oxidation of the core material is prevented in the stage of annealing and brazing. The work cracking in the stage of cold working is thus prevented and the oxidation resistance is improved.