| 摘要 |
PROBLEM TO BE SOLVED: To provide a copper alloy for electrical and electronic equipment, improved in structure and excellent in strength, electric conductivity, and punchability, by subjecting an alloy, having a composition in which specific amounts of Cr, Zr, rare earth elements, Pb, Bi, etc., are added to Cu, to hot working, to annealing, and then to cold working. SOLUTION: A molten Cu alloy, having a composition containing, by weight, 0.1-0.4% Cr, <0.2% (including 0%) Zr, 0.002-O.2% rare earth element, such as misch metal composed essentially of La, Ce, etc., and 0.002-0.2% of at least either of Pb and Bi, is cast, and the resultant ingot is hot-worked at 800-1000 deg.C. After rapid cooling, cold working and heat treatment consisting of heating at 350-600 deg.C for 30 sec-6 hr are repeatedly applied one or more times, and final cold working is performed at <=60% draft. By the above procedure, the size of crystallized substances and precipitates in a structure is regulated to <3μm, and a recrystallized structure of <20μm crystalline grain size is obtained. By this method, the copper alloy having excellent properties required of a copper alloy for electrical and electronic equipment can be obtained.
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