| 摘要 |
PROBLEM TO BE SOLVED: To guarantee superior cold working and enhance electric discharge machining speed by forming a coating layer of a plurality of layers of an a phase layer and aβphase layer. SOLUTION: A core of diameter approximately 4.2 mm formed of copper alloy of Cu-0.19 wt.%, Sn-0.20 wt.%, In is prepared, and a Cu-35 wt.% Zn alloy tape with the thickness approximately 0.86 mm is vertically added thereto. Secondly, after TIG welding a joint, a composite wire of outer diameter approximately 8.8 mm is formed, then appropriately treated by drawing die, and drawn by the heat treatment so as to have the outer diameter approximately 1.2 mm. Thirdly, after side heat treating the composite wire, the wire is drawn to have the outer diameter approximately 0.25 mm. The coating layer 2 formed on the core 1 of Cu-Sn-In alloy is formed of an inner layer 3 of anαphase layer of low Zn density and an outer layer 4 of aβphase layer of high Zn density.
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