Copper-based alloy and method of manufacturing same

Abstract

This invention is a copper-based alloy for use in connectors, lead frames, switches and relays and the like that has a superior balance of conductivity, tensile strength and workability in bending and method of manufacturing same. The alloy is manufactured by taking an ingot of a copper-based alloy containing Ni, Sn, P and also at least one or more elements selected from a group consisting of Zn, Si, Fe, Co, Mg, Ti, Cr, Zr and Al in a total amount of 0.01-30 wt. % with the remainder being Cu and unavoidable impurities, performing a combination process of cold rolling followed by annealing at least one time and then performing cold rolling at a percent reduction Z that satisfies the following Formula (1): Z<100−10X−Y  (1) [where Z is the percent cold reduction (%), X is the Sn content (wt. %) among the various elements, and Y is the total content (wt. %) of all elements other than Sn and Cu] followed by low-temperature annealing performed at a temperature below the recrystallization temperature. This causes dispersion and precipitation of Ni—P compounds so that a precipitation-strengthened type copper-based alloy with an x-ray diffraction intensity ratio of the surface SND as given by the following formula is 0.05≦SND≦0.15 [provided that SND=I{200}÷[I{111}+I{220}+I{311}], where I{200} is the x-ray diffraction intensity of the {100} plane, {111} is the x-ray diffraction intensity of the {111} plane, I{220} is the x-ray diffraction intensity of the {110} plane, and {311} is the x-ray diffraction intensity of the {311} plane] and a superior balance of conductivity, tensile strength, 0.2% yield strength, springiness, Vickers hardness and bending workability is obtained.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] This invention relates to a copper-based alloy that has a superior balance of conductivity, tensile strength and bending workability and to a method of manufacturing same, and more specifically to a copper-based alloy for use in consumer products, for example, for forming blanks for narrow-pitch connectors for use in telecommunications, blanks for automotive harness connectors, blanks for semiconductor lead frames and blanks for compact switches and relays and the like and a method of manufacturing same. [0003] 2. Background Art [0004] Against the background of recent developments in portable and mobile electronic equipment, where the pin thickness and pin width of connectors mounted in computers, mobile phones, digital video cameras and the like are typically 0.10-0.30 mm, there is a trend for these to become even thinner and narrower as the final product is made more compact. As a result of higher volumes of infor...

AI Technical Summary

Benefits of technology

[0008] An object of the present invention is therefore to control the crystal orientation of the material and thus provide a copper-based alloy that has a superior balance of conductivity, tensile strength and bending workability. and a method of manufacturing same.

[0017] The present invention provides a copper-based alloy that has a superior balance of conductivity, tensile strength, 0.2% yield strength, springiness, hardness and bendability and is suitable for use in connectors, switches, relays and the like, and thus satisfies the demand for material that can be made into thinner sheet and finer wire in response to recent high-density mounting in consumer electronics, telecommunications equipment and automotive components. Particularly, the present invention is able to improve remarkably the bending workability of high strength / high springiness copper based alloy.

Problems solved by technology

Moreover, some of the pins are used for supplying power, so the material used for them must have a reduced conductor resistance, namely a high conductivity, and thus the development of copper alloys to replace low-conductivity brass and phosphor bronze has become an urgent task.

Accordingly, if one wishes to improve conductivity even while achieving both good strength / springiness and bending workability, this cannot be achieved with brass or phosphor bronze or other materials that are solid-solution strengthened by the addition of large amounts of additive elements.

Precipitation strengthening of materials is one example of a method of increasing the conductivity while also obtaining high strength and high springiness, but if precipitation strengthening is used, deterioration of the ductility and bending workability of the material is ordinarily not negligible, and when it is attempted to avoid this, the control of the amount of elements added and the working and heat treatment processes required to control the size and distribution of precipitates becomes complex and as a result the manufacturing costs become higher (as in patent document JP2000-80428A, for example).

As one method still remaining for solid-solution strengthened materials, measures can be taken to suppress the amount of solid-soluble elements added that lead to decreased conductivity, and to modify the machining and heat-treatment processes, but reducing the solid-solution strengthening elements leads to reduced strength so one must rely on that much more on work hardening, so decreased ductility and formability are unavoidable.

At any rate, there has been a need to establish methods of evaluation from unconventional standpoints and adopt measures that extend the field of view to standpoints based on studies of texture, but no dramatic improvements have been achieved.