The Furukawa Electric Co., Ltd.

Yoshimasa Ohyama

Shoji Shiga

Takayuki Usami

Takao Hirai

Shigeo Shinozaki

Makoto Asai

Tohru Tanigawa

A copper alloy with excellent punchability, comprising 0.2 to 0.35 wt % of Cr, 0.1 to 0.5 wt % of Sn, and 0.1 to 0.5 wt % of Zn, the balance being made of Cu and unavoidable impurities, wherein, in a Cu matrix, a precipitation phase A of Cr or a Cr compound of 0.1 to 10 &mgr;m in maximum diameter, is provided, at a density in number of 1&times;10 to 3&times;10 /mm , and a precipitation phase B of Cr or a Cr compound of 0.001 to 0.030 &mgr;m in maximum diameter, is provided, at a density in number that is 10 times or more of that of the precipitation phase A.

Copper alloy with punchability, and a manufacturing method thereof

A copper alloy for electronic instruments is disclosed which comprises 2.0 to 7.0 wt. % of Sn, 1.0 to 6.0 wt. % in total amount of at least one kind of Ni, Co and Cr, o.1 to 2.0 wt. % of Si, and the remainder of Cu and unavoidable impurities, thereby further the content of O.sub.2 in unavoidable impurities being not more than 50 ppm, the content of S being not more than 20 ppm, and the average particle diameter of precipitates being not larger than 10 .mu.m. As the uses of such copper alloys, lead material for semiconductor elements and connector, socket, spring and terminal for electronic and electric instruments are claimed.

Copper alloy for electronic instruments

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Tokyo, Japan

Yoshimasa Ohyama