JPH0788545B2 - High strength and high toughness Cu alloy with little characteristic anisotropy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention is Cu having high strength and high toughness, and having little difference in properties between the processing direction and the direction perpendicular to the processing, that is, Cu with less characteristic anisotropy. It concerns alloys.

[Conventional technology]

Generally, in% by weight (hereinafter% indicates% by weight), Ti: 2 to 5
% Cu-Ti alloy has an excellent precipitation hardening ability and, therefore, a strength comparable to that of beryllium copper is obtained. Therefore, high electrical strength and high toughness are required for electrical contacts such as connectors and switches. It is used as a spring material.

[Problems to be solved by the invention]

On the other hand, in recent years, demands for smaller and lighter parts are strict, and along with this, it is inevitable to reduce the wall thickness and increase the strength, so that the workability tends to increase. As a result, for example, rolled material and drawn material In such cases, the properties in the machining direction and the direction perpendicular to the machining show a marked difference, and such characteristic anisotropy is fatal for the spring material, especially the spring limit value and the repeated bending property. It strongly appears in.

In particular, this characteristic anisotropy is prominently exhibited in the above-mentioned conventional Cu-Ti alloys. Therefore, during processing, a large degree of processing cannot be obtained, and further, this characteristic anisotropy is increased during the processing step. It requires a special high temperature heat treatment to erase, resulting in not only complicated processing steps but also cost increase, and avoiding adverse effects such as crystal coarsening, embrittlement, and oxidation due to high temperature heat treatment. The current situation is that it is difficult to process such as problems such as not being possible.

[Means for solving problems]

Therefore, the present inventors, from the above viewpoints, pay attention to the above conventional Cu-Ti alloy having high strength and high toughness,
As a result of conducting research to improve this and reduce the characteristic anisotropy, the above-mentioned conventional Cu-Ti alloy was added as an alloy component.
When Co and Cr are contained together, the characteristic anisotropy of the processed material is drastically reduced, and the primary particles of Co-Ti intermetallic compound are effectively refined by the action of Cr component. result,
Bending workability and mating property are significantly improved,
Furthermore, they have found that the inclusion of Ni and Fe as alloy components further improves the characteristic anisotropy.

The present invention has been made based on the above findings, containing Ti: 2.2 to 5%, Co: 0.1 to 0.8%, Cr: 0.02 to 0.5%, and if necessary, Ni and Fe. It is characterized by a high-strength, high-toughness Cu alloy having a small amount of characteristic anisotropy and having a composition containing one or two of these: 0.05 to 0.6%, and the balance of Cu and unavoidable impurities.

Next, the reason why the composition of the Cu alloy of the present invention is limited as described above will be explained.

(A) Ti The Ti component has the effect of improving the strength and toughness of the alloy, but if the content is less than 2.2, the desired effect is not obtained, whereas if the content exceeds 5%. Since the hot workability suddenly decreases, its content was set to 2.2 to 5%.

(B) Co and Cr These components have the effects of relaxing the characteristic anisotropy of the processed material in the coexisting state as described above, and refining the structure to improve the bending workability and matting property. If the content is less than Co: 0.1% and Cr: less than 0.02% respectively, the desired effects cannot be obtained, while the content is Co: 0.8%.
If Cr and 0.5% are exceeded, coarse crystallized particles will be dispersed in the matrix, resulting in a decrease in bending workability and plating property.
Co: 0.1 to 0.8%, Cr: 0.02 to 0.5%, respectively.

(C) Ni and Fe These components have the function of further improving the characteristic anisotropy of the alloy and also of increasing the electrical conductivity, so they are contained as necessary, but the content is less than 0.05%. However, the desired effect of improving the above action cannot be obtained, while its content is 0.5
%, The strength will be reduced and the crystallized intermetallic compound will become coarse.
It was set at 0.6%.

〔Example〕

Next, the Cu alloy of the present invention will be specifically described by way of Examples.

Using a normal high-frequency vacuum melting furnace, prepare a molten metal having the composition shown in Table 1 in a graphite crucible, and mold it into a diameter: 60 mm ^φ × weight: 5 Kg ingot, after chamfering, A plate material with a width of 100 mm and a thickness of 6 mm was formed by hot forging and hot rolling, which was held at a temperature of 920 ° C for 1 hour, and then subjected to solution treatment under the conditions of rapid cooling in water and then cold rolling. , 360-500
Repeated intermediate annealing at a temperature within the range of ℃, performed final cold rolling with a rolling ratio of 50%, and finally performed a temperature of 360.
By applying strain relief annealing at 20 ℃ for 20 minutes, Thin sheet materials of the present invention Cu alloys 1 to 10 and comparative Cu alloys 1 to 3 each having a thickness of 0.25 mm were manufactured.

Then, with respect to these thin plate materials, the tensile properties in the rolling direction and the direction perpendicular to the rolling were measured, and the spring limit value was measured using a cantilever burr / spring limit tester, and the bending radius R was 0.2 mm. Hold the test piece in an upright position by using a tool, and place the test piece in the right and left alternately centering on the base of the sandwich.
Repeated bending was performed at 0 °, and the number of times of repeated bending (90 ° was calculated as 1 time) was measured until a crack was generated in the bent portion. The results of these measurements are shown in Table 1.

〔The invention's effect〕

From the results shown in Table 1, all of the Cu alloys 1 to 10 of the present invention have high strength and high toughness, and the anisotropy in these characteristics is extremely small.
As seen in the comparative Cu alloys 1 to 3,
In particular, it is clear that when either or both Co and Cr are not contained, the characteristic anisotropy is inferior.

As described above, the Cu alloy of the present invention has high strength and high toughness, and has very little characteristic anisotropy. Moreover, this characteristic anisotropy increases the workability to further reduce the wall thickness. Is a material that never grows in size, and is useful as a spring material.

Claims (2)

[Claims] 1. A composition comprising Ti: 2.2 to 5%, Co: 0.1 to 0.8%, Cr: 0.02 to 0.5%, and the balance being Cu and inevitable impurities (above weight%). High strength and high toughness Cu alloy with little characteristic anisotropy. 2. Ti: 2.2 to 5%, Co: 0.1 to 0.8%, Cr: 0.02 to 0.5%, and one or two of Ni and Fe: 0.05 to 0.6%. A high-strength, high-toughness Cu alloy having a small characteristic anisotropy, which is characterized in that it has a composition containing Cu and the unavoidable impurities in the balance (above weight%).