Copper alloy material for parts of electronic and electric machinery and tools

Abstract

A copper alloy material for parts of electronic and electric machinery and tools contains 1.0 to 3.0 mass % of Ni, 0.2 to 0.7 mass % of Si, 0.01 to 0.2 mass % of Mg, 0.05 to 1.5 mass % of Sn, 0.2 to 1.5 mass % of Zn, and less than 0.005 mass % (including 0 mass %) of S, with the balance being Cu and inevitable impurities, wherein the copper alloy material has: (1) a specific crystal grain diameter, and a specific ratio between the longer diameters of a crystal grain on a cross section parallel or perpendicular to a direction of final plastic working; and/or (2) a specific surface roughness after the final plastic working.

Description

[0001] This is a continuation of PCT Application PCT / JP01 / 04351, filed May 24, 2001. The prior PCT application was not published in English under PCT Article 21(2).TECHNICAL FIELD[0002] The present invention relates to a copper alloy material for parts of electronic and electric machinery and tools, in particular to the copper alloy material for parts of electronic and electric machinery and tools, which is excellent in bending property and stress relaxation property, and which can sufficiently cope with miniaturization of parts of electronic and electric machinery and tools, such as terminals, connectors, switches and relays.BACKGROUND ART[0003] Hitherto, copper alloys, such as Cu--Zn alloys, Cu--Fe-alloys that are excellent in heat resistance, and Cu--Sn alloys, have been frequently used for parts of electronic and electric machinery and tools. While inexpensive Cu--Zn alloys have been used frequently, for example, in automobiles, the Cu--Zn alloys as well as Cu--Fe alloys and Cu-...

AI Technical Summary

Benefits of technology

0033] wherein a crystal grain diameter is more than 0.001 mm and 0.025 mm or less; the ratio (a/b), between a longer diameter a of a crystal grain on a cross section parallel to a direction of final plastic working, and a longer diameter b of a crystal grain on a cross section perpendicular to the direction of final plastic working, is 1.5 or less; and a surface roughness Ra after the final plastic working is more than 0 .mu.m and less than 0.1 .mu.m, or a surface roughness Rmax is more than 0 .mu.m and less than 2.0 .mu

Problems solved by technology

While inexpensive Cu--Zn alloys have been used frequently, for example, in automobiles, the Cu--Zn alloys as well as Cu--Fe alloys and Cu--Sn alloys have been unable to currently cope with the requirements for the automobile, since recent trends urgently require the terminals and connectors to be small size, and they are mostly used under severe conditions (high temperature and corrosive environment) in an engine room and the like.

The materials are also required to be excellent in stress relaxation property, and the conventional Cu--Ni--Si alloys cannot be used for a long period of time, due to increased stress load on the material and high temperatures in the working environments.

Although improvements of bending property have been investigated in ways, it has

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