| 摘要 |
PURPOSE:To make the production of a blank material contg. a brazing material easy and to decrease the use of noble metals considerably, by disposing the brazing material in a base material of base metals and providing noble metals around the same thereby forming the material clad with >=3 layers contg. the brazing material. CONSTITUTION:A brazing material 4 is inserted at 3-10% area percent in the central part of a circular columnar material 3 of Cu, Cu alloys, Ni or base metals contg. Ni to form a primary composite body. The outside circumference of the primary composite material is enclosed with a thin sheet 5 consisting essentially of noble metals to form a billet. The billet is formed to a bar shape by extrusion working and is then subjected repeatedly to cold drawing and heat treatments, whereby the billet is finished to the desired sizes. |
