PURPOSE: To possess the sufficient strength for the high load in spot welding on the inner layer by forming with the outer layer of a precipitation hardening type copper alloy and the inner layer of Ti material or Ti-Cu composite material having a Ti high hardening core part an by joining with diffusion the outer layer and inner layer with the extrusion at high temp. hydrostatic pressure.
CONSTITUTION: The inner layer 3 formed by a high strength member is formed at the inner part of the outer layer 2 formed by a precipitation hardening type copper alloy and the inner layer and outer layer are joined integrally by the diffusion joining by the high temp. hydrostatic extrusion metallurgically. The Ti high hardness core part hardened by cold work is formed over the axial direction of the tip on the inner layer 3. The material for excepting the core part of the inner layer 3 is preferably Ti member or Ti-Cu composite member.
IWAI AKIRA
SAITO AKIO
FURUYA MASAHARU
