Copper, copper alloy, and manufacturing method therefor

Abstract

Copper and copper alloy comprises: a structure having fine crystal grains with grain size of 1 μm or less after a final cold rolling with a reduction η, wherein η is expressed in the following formula and satisfying η≧3; and an elongation of 2% or more in a tensile test.η=ln(T0 / T1)T0: plate thickness before rolling, T1: plate thickness after rolling.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application is a continuation of U.S. patent application Ser. No. 10 / 105,454, filed Mar. 26, 2002, which parent application is incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to copper and to copper alloys having fine crystal grains, and relates to a manufacturing method therefor, and more particularly, the resent invention relates to a technology for enhancing the characteristics in bending or other working when used for electronic devices such as terminals, connectors, and lead frames for semiconductor integrated circuits.[0004]2. Description of the Related Art[0005]Recently, electronic devices such as terminals and connectors and their parts are reduced in size and thickness, and copper and copper alloy used as materials thereof are demanded to have high strength. In terminal and connector material, the contact pressure must be increased ...

AI Technical Summary

Benefits of technology

The present invention provides a method for manufacturing copper and copper alloy with fine crystal grains and good bending properties. By controlling the rolling process and adding stress relief annealing, the final cold rolling reduction and elongation can be achieved. The method includes a final cold rolling with a reduction of more than 40%, followed by dynamic continuous recrystallization annealing at temperatures between 400 and 600°C. The resulting material has uniform crystal grain sizes of 1 μm or less and an elongation of 2% or more. The method can be used for mass production of copper and copper alloy.

Problems solved by technology

However, first of all, strength and ductility are inversely related to each other, and in each alloy system, when rolling is processed in order to increase the strength by work hardening, the ductility declines, and preferable workability is not obtained by rolling alone.

In this method, however, when the annealing temperature is lowered in order to reduce the grain size, non-crystallized grains remain in part, and there is substantially a limit to obtaining recrystallized grains of about 2 to 3 μm, and a technique for further reducing the grain sizes has been demanded.

Furthermore, by recrystallization alone, the strength level is usually low, and it is not practical, and therefore a certain rolling process is needed in a later step, which has led to reduction of ductility.

This process, however, causes lowered strength once obtained in the rolling process, and sufficient ductility is not obtained after stress relief annealing, and it was difficult to satisfy the recent extremely severe demand for bending deformation performance.

In these processing methods, however, a mass quantity sufficient to be used as materials for electronic devices cannot be manufactured, and there are not suited to industrial production.

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