| 摘要 |
PROBLEM TO BE SOLVED: To obtain a copper alloy or electrical and electronic parts, excellent in shearing property as well as in characteristics of strength, electric conductivity, solderability, plating suitability, etc. SOLUTION: This copper alloy has a composition consisting of, by weight, 1.0-8.0% Ni, >0.1-2.0% Si, 0.05-5.0% Zn, <=300ppm O, and the balance essentially Cu with inevitable impurities and containing, if necessary, 0.0001-1.0%, in total, of one or >=2 elements among Mn, Mg, and Ca and also has a structure in which Ni-Si compounds are precipitated. In this case, grains of <0.03μm grain size (small grains) and grains of 0.03-100μm grain size (large grains) are present, and the ratio between the number of the small grains and that of the large grains is regulated to >=1 and also the ratio between the grain size (median) of the small grains and that of the large grains is regulated to <=0.5.
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