| 摘要 |
PROBLEM TO BE SOLVED: To provide a copper alloy which does not comprise elements harmful to the environment such as Be, and has satisfactory various performance such as electric conductivity, tensile strength and high temperature strength. SOLUTION: The copper alloy comprises two or more of Cr, Ti and Zr, the balance being Cu and impurities, wherein the particle diameter (X)(μm) of precipitates and inclusions being present in the alloy and having particle diameter of 1 m or more and the total number (N) (pieces/mm<SP>2</SP>) of the precipitates and inclusions satisfy the following formula (1): logN≤0.4742+17.629×exp(-0.1133×X). The copper alloy may further comprise Ag, P, Mg or the like in place of a part of Cu. The method comprises cooling a cast piece at a cooling rate of 0.5°C/s or more at least in the temperature range from the temperature immediately after the casting to 450°C. It is desirable that after the cooling, the cast piece is worked in the temperature range of 600°C or lower or is subjected to a heat treatment wherein it is held in the temperature range of 150 to 750°C for 30 s or longer. It is most desirable that the work and the heat treatment are repeated. COPYRIGHT: (C)2006,JPO&NCIPI
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