JPS5931839A - High-strength electrically-conductive copper alloy - Google Patents

Abstract

PURPOSE:To improve the strength, electric conductivity, stress corrosion cracking resistance and creep resistance of the resulting Cu alloy by providing a specified composition consisting of Zn, Sn, Fe, P and the balance essentially Cu. CONSTITUTION:This high-strength electrically-conductive Cu alloy has a composition consisting of, by weight, 5.0-12.5% Zn, 0.2-2.0% Sn, 0.02-0.50% Fe, 0.01-0.1% P and the balance essentially Cu. The Cu alloy is comparable to brass in strength, comparable or superior to brass in electric conductivity, and superior to brass in stress corrosion cracking resistance and creep resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a high-strength conductive copper alloy, and more particularly to a high-strength conductive copper alloy with good electrical conductivity suitable for electrical and electronic parts.

In general, brass has excellent strength, appropriate conductivity, and good workability, so it is widely used as a material for electrical and electronic parts such as terminals and funector parts.

However, this brass has the drawbacks of being susceptible to stress corrosion cracking and having poor creep resistance.

The present invention retains the excellent properties of brass explained in Section 2,
Furthermore, it is a high-strength conductive copper alloy that has strength equivalent to brass, conductivity equivalent to or better than brass, and stress corrosion cracking resistance and creep resistance superior to that of brass. It provides:

The characteristics of the high strength conductive copper alloy according to the present invention are as follows:
Zn 5.0-12.5u+L%, Sn0.2-2.0
u+t%, Fe O, 02-0, 50wL%, P O,
01-0.1u+L%, and the remainder essentially consists of Cu.

In the high-strength conductive copper alloy according to the present invention, the contained components and component ratios thereof will be explained.

If the Zn content is less than 5 wt%, the improvement in strength will not be sufficient, and if the content exceeds 12.5 wL%, the stress corrosion resistance and cracking susceptibility will be very low. Therefore, the Zn content will be 5.
0-12.5111t%.

If the Sn content is less than 0.2 wt%, the strength will not be improved sufficiently; If the content exceeds OwL%, the conductivity will decrease significantly. Therefore, the Sn content is 0.2~
It is set as 2.0%.

When Fe and P are contained together, an intermetallic compound (iron phosphide) of Fe and P is formed, which improves strength and conductivity compared to when they are contained alone. , stress corrosion cracking resistance is improved. And Fe
If the content is less than 0.0211IL%, even if it is the same as 11, it will not be effective in improving the strength, conductivity, and stress corrosion cracking resistance, and if the content exceeds 0.50u+L%, the intermediate annealing material The rate of improvement in strength decreases, and work hardening becomes severe, resulting in deterioration of workability. Therefore, the Fe content is 0.
02~0.50u+L%.

If the P content is less than 0.01u+t%, even if Fe coexists, it has no effect on improving strength and stress corrosion cracking resistance, and 0,
], if the content exceeds u+L%, the amount of P present in the Cu-Fn phase increases without forming a compound with 1:'e, which impairs conductivity and stress corrosion cracking resistance. )
The amount of honor is 0.01~OA, 1llL%.

Next, examples of high-strength conductive copper alloys according to the present invention will be described.

Example ×: Comparative alloy The side and bottom t were adjusted so that the contained components and component ratios shown in Table 1
The invention alloy and comparative alloy were prepared by the method described in .

That is, high-purity copper was melted using a cryptoluminium electric furnace, Fe was added with the surface of the molten metal covered with charcoal, and after confirming that 1.e was completely dissolved, Z++ and S++ were added in that order, and finally Add P as C, u 15% P alloy and melt, then 45+n+ntX70n+u+u+X
It was cast into a 200m+nl mold (6Kg/1ch).

The ingot of the alloy of the present invention has 15+nIn at 900°C after the face side.
850'CX 1. To perform hot rolling to the thickness and to equalize the temperature at the end of hot rolling. After l+r heating, it was rapidly cooled in water. Thereafter, it was cold rolled to a thickness of 0.46 m+o, and at this stage the sample was subjected to a precipitation treatment at 500°C x 21+r.

After that, further cold rolling is performed to obtain a sample thickness of 0.32+n+
Adjusted to nL.

Tensile strength, electrical conductivity, stress corrosion cracking resistance, and creep resistance were investigated in this 0.32+n+aL thickness state.

Table 2 shows the tensile strength and electrical conductivity of the alloys of the present invention and comparative alloys.

It is clear from Table 2 that the alloys of the present invention (No. 6, No. 6,
No. 8) has tensile strength and electrical conductivity that are one fold lower than the comparative alloy, and the alloy of the present invention (No. 1.
2.3.4.5.7) is superior to the comparative alloys in terms of tensile strength or electrical conductivity.

Next, the present invention alloy No. 6 shown in Table 1 and the comparative alloy No.
, 9, the sample was bent into a loop shape as shown in Figure 1, both ends of the sample were fixed with copper wire, bending stress was applied, left for 24 hours, exposed to 35°C ammonia vapor, and then fixed. Release both ends of the test piece! Measure 11 distances (D,
H, T bo+ol+soB+ method).

11: lli distance of both ends of the test piece before exposure to ammonia 1
2: Distance between both ends of the test piece after exposure to ammonia The results of this measurement are shown in Table 3.

It can be seen that the alloy of the present invention exhibits stress corrosion cracking resistance that is far superior to that of the comparative alloy.

Furthermore, the present invention alloy No. 6 in Table 1 and the comparative alloy No.
9, the stress relaxation rate was measured at 125° C. The results are shown in FIG. This test method consists of a titanium holder 1.1 tightened with bolts 2 as shown in Figure 3.
A bending stress of 80% of the yield strength is applied to the sample S using the jig, and the test is started after keeping the sample S at 24br room temperature in this state (N = 5).

The stress relaxation rate in this case is It is indicated by.

Ll, 2 Length of the jig 1, : Length at the start I-2 2 Length of the sample after a certain period of time In this case as well, the alloy No. 6 of the present invention is superior to the comparative alloy No. 9. It can be seen that

As explained above, since the high-strength conductive i-Si 1 alloy according to the present invention has the above-mentioned structure, its strength and conductivity are equal to or superior to that of brass. 1)
In addition, the stress corrosion cracking resistance and creep resistance are better than that of brass, so as a material for electrical and electronic parts, stress corrosion cracking is less likely to occur (1), and (the deterioration of the clamping force over time is also reduced), etc. This has the effect of improving reliability and widening the usable range.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the stress corrosion cracking test method, FIG. 2 is a diagram showing stress relaxation rate and elapsed time, and FIG. 3 is a diagram showing a stress relaxation rate measurement jig. 1. Titanium holder, 2. Bolt, 3. Sample.

Claims (1)

[Claims] Zn 5.0-12.5u+t%, SnO,
2-2, OwL%, FeO,02=0.50+uL
%, PO,01-0.11IIL%, the balance consisting essentially of Cu.