Copper alloy with high strength and excellent processability in bending and process for producing copper alloy sheet

Abstract

The present invention provides a Cu—Fe—P alloy which has a high strength, high conductivity and superior bending workability. The copper alloy comprises 0.01 to 1.0% Fe, 0.01 to 0.4% P, 0.1 to 1.0% Mg, and the remainder Cu and unavoidable impurities. The size of oxides and precipitates including Mg in the copper alloy is controlled so that the ratio of the amount of Mg measured by a specified measurement method in the extracted residue by a specified extracted residue method to the Mg content in said copper alloy is 60% or less, thus endowing the alloy with a high strength and superior bending workability.

Description

TECHNICAL FIELD[0001]The present invention relates to a copper alloy which has a high strength, a high electrical conductivity and superior bending workability, e.g., a copper alloy suitable for use as electrical or electronic part materials in household appliances, semiconductor parts such as IC lead frames for semiconductor devices or the like, printed wiring boards or the like, copper alloying element plate strips used in mechanical parts such as opening-and-closing parts, bus bars, terminals, connectors and the like. Furthermore, the present invention also relates to a method for manufacturing such a copper alloy.BACKGROUND ART[0002]Cu—Fe—P alloys which contain Fe and P have been commonly employed in the past as copper alloys in the various applications described above, beginning with semiconductor IC lead frames and the like. Examples of such Cu—Fe—P alloys include copper alloys that contain 0.05 to 0.15% Fe and 0.025 to 0.040% P (C19210 alloy) and copper alloys that contain 2....

AI Technical Summary

Benefits of technology

The present invention provides a copper alloy with both high strength and good bending workability. This is achieved by controlling the size and amount of oxides and precipitates in the alloy, as well as the grain size and the ratio of small-angle grain boundaries. The addition of specific elements such as Mn, Ca, Ni, or Co can further improve the bending workability. The invention also provides a method for controlling the grain size and the ratio of small-angle grain boundaries in the alloy.

Problems solved by technology

The addition of solid-solution reinforcing elements such as Sn or Mg, and an increase in the amount of work-hardening obtained by strong working effected by increasing the working ratio of cold rolling, which are conventional means of obtaining high-strength copper alloys, are inevitably accompanied by a deterioration in bending workability, so that it is difficult achieve both the necessary strength and the necessary bending workability at the same time.

However, in the case of such high-strength Cu—Fe—P alloys, the bending workability cannot be sufficiently improved with respect to severe bending such as the abovementioned U-bending, 90-degree bending after notching or the like merely by using structure control means such as the finer grain size, control of the disperse state of the crystallized / precipitated matter or the like described in the abovementioned patent documents 1-6 or the aggregated structure control means described in the abovementioned patent documents 7, 8.