| 摘要 |
PROBLEM TO BE SOLVED: To provide a copper-alloy sheet material which is remarkably improved in bendability and fatigue characteristics while maintaining high electric conductivity and high strength, and suitable for electrical/electronic parts. SOLUTION: The copper-alloy sheet material is obtained by applying repeated bending to a cold rolled stock of a precipitation-strengthened copper alloy using a tension leveller so as to make its both surface layer parts softer than its central part in such a way that average hardness Hs (HV) in a position at a depth of 1/8 in the sheet-thickness direction and average hardness Hc (HV) in a position at a depth of 1/2 in the sheet-thickness direction satisfy inequality (Hs-Hc)/Hc×100≤-5. As an example of alloy composition, a composition consists of, by mass, 0.4 to 4.8% Ni, 0.1 to 1.2% Si and the balance essentially Cu, containing, if necessary,≤0.3% Mg or≤15% Zn and further contains, if necessary,≤3%, in total, of one or more elements among Sn, Co, Cr, P, B, Al, Fe, Zr, Ti and Mn. COPYRIGHT: (C)2007,JPO&INPIT
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