| 摘要 |
PROBLEM TO BE SOLVED: To provide a copper base alloy for terminal capable of realizing a copper base alloy bar for terminal excellent in strength, spring characteristics, electrical conductivity, bending workability and stress relaxation resistance, to provide the alloy bar and to provide a method for producing the alloy bar. SOLUTION: This alloy is composed of a Cu-Co-P series and a Cu-Co-Sn-P series having prescribed composition. This alloy bar has the composition of the alloy, and in which the tensile strength, spring critical value, electrical conductivity, minimum bend radius ratio and stress relaxation rate are controlled to prescribed levels or more. This producing method comprises a first stage where an ingot of the alloy is prepared, a second stage where the hot rolling is performed at prescribed starting temperature and finishing temperature and is rapidly cooled, a third stage where the final intermediate cold rolling is performed at a prescribed rolling ratio at the time of subjecting the alloy to intermediate cold rolling and next to process annealing at prescribed temperature, a fourth stage where the finish cold rolling is performed at a prescribed rolling ratio and a fifth stage where the low temperature annealing is performed at prescribed temperature.
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