JPH0123542B2 - - Google Patents

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 use in electrical and electronic components. 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 connector parts.
However, this brass has the drawbacks of being susceptible to stress corrosion cracking and having poor creep resistance. The present invention maintains the excellent properties of brass described above, has strength equivalent to that of brass, has electrical conductivity equivalent to or higher than that of brass, and has stress corrosion resistance and cracking resistance higher than that of brass. The purpose of the present invention is to provide a high-strength conductive copper alloy that has high strength and creep resistance. The characteristics of the high-strength conductive copper alloy according to the present invention are: Zn5.0-12.5wt%, Sn0.2-2.0wt%,
It contains 0.02 to 0.50 wt% of Fe, 0.01 to 0.1 wt% of P, and the balance 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 strength will not be improved sufficiently, and if the Zn content exceeds 12.5 wt%, the stress corrosion cracking resistance will increase. Therefore, the Zn content is set to 5.0 to 12.5 wt%. If the Sn content is less than 0.2 wt%, the strength will not be improved sufficiently, and if the content exceeds 2.0 wt%, the electrical conductivity will decrease significantly. Therefore, the Sn content is
The content should be 0.2-2.0wt%. When Fe and P are contained together, an intermetallic compound of Fe and P (iron phosphide) is formed, which improves strength and conductivity compared to when Fe and P are contained alone, and , stress corrosion cracking resistance is improved. If the Fe content is less than 0.02wt%, even if it coexists with P, it will not be effective in improving the strength, electrical conductivity, and stress corrosion cracking resistance, and if the content exceeds 0.50wt%, the intermediate annealing material will not be effective. The rate of improvement in strength decreases, and work hardening becomes severe, resulting in deterioration of workability. Therefore, the Fe content is set to 0.02 to 0.50 wt%. If the content of P is less than 0.01wt%, it has no effect on improving strength and stress corrosion cracking resistance even if Fe coexists; The amount of P present in the phase decreases, resulting in decreased electrical conductivity and stress corrosion cracking resistance. Therefore, the P content is set to 0.01 to 0.1 wt%. Next, examples of high-strength conductive copper alloys according to the present invention will be described. Example

[Table] *: Comparative alloy The present invention alloy and comparative alloy were adjusted by the method described below so that the components and component ratios shown in Table 1 were obtained. That is, high-purity copper is melted using a Kryptor electric furnace, and Fe is added while the surface of the molten metal is covered with charcoal.
After confirming that Fe is completely dissolved, Zn and Sn are added in that order, and finally P is added as a Cu-15wt%P alloy and dissolved, and then 45mmt x 70mmw x 200mm
It was cast in a mold of 1 (6KgX/1ch). After facing the ingot of the alloy of the present invention, it was hot rolled at 900°C to a thickness of 15 mm, heated at 850°C for 1 hour, and then rapidly cooled in water to equalize the temperature at the end of hot rolling. Thereafter, it was cold rolled to a thickness of 0.46 mm, and at this stage the sample was subjected to a precipitation treatment at 500°C for 2 hours. after that,
Further cold rolling was performed to adjust the sample thickness to 0.32 mmt. At this 0.32 mm thickness, tensile strength, electrical conductivity,
Stress corrosion cracking resistance and creep resistance were adjusted. Table 2 shows the tensile strength and electrical conductivity of the alloys of the present invention and comparative alloys.

【table】

[Table] *: Comparative alloy As is clear from Table 2, the invention alloy (No.
6, No. 8) is superior to the comparative alloys in both tensile strength and electrical conductivity, and the invention alloy (No.
Nos. 1, 2, 3, 4, 5, and 7) are superior to the comparative alloys in either tensile strength or electrical conductivity. Next, the present invention alloy No. 6 and comparative alloy shown in Table 1
No. 9 was adjusted to have the characteristics shown in Table 2. Each sample was 0.33 mm thick x 12.7 mm wide x 150 mm long (holes with a diameter of 5 mmφ were drilled at 6.35 mm from both ends) Five test pieces each were made, and the center of the test piece in the longitudinal direction had a diameter of 19 mmφ as shown in Figure 1.
Bend the specimen 160° around the round rod and secure it with vinyl-coated copper wire so that both ends of the specimen touch. Next, the test piece was placed in a desiccator kept at a constant temperature of 35°C, and after 24 hours, the knot was untied and the distance l ₁ between both ends of the test piece was measured to see the effect on the initial creep value. Separately, dilute 28% ammonia water with an equal volume of distilled water to make 11, and place it in a 51-capacity desiccator and keep it at 35°C. A test piece with both ends fixed is suspended in this ammonia vapor, the knot is untied at a fixed time, and the distance l ₂ between both ends of the test piece is measured. Repeat this to calculate the stress relaxation rate (DH.
Thompson's method). Stress relaxation rate (%) = l ₁ - l ₂ / l ₁ × 100 l ₁ : Distance between both ends of the test piece before exposure to ammonia l ₂ : Distance between both ends of the test piece after exposure to ammonia Shown in the table.

[Table] It can be seen that the alloy of the present invention exhibits stress corrosion cracking resistance that is much superior to that of the comparative alloy. Furthermore, the invention alloy No. 6 and comparative alloy No. 6 in Table 1.
9, the stress relaxation rate was measured at 125°C and the results are shown in Figure 2. This test method uses a jig made of titanium holders 1 and 1 that are tightened with bolts 2 as shown in Figure 3.
% bending stress was applied and the test was started after being kept at room temperature for 24 hours in this state (N=5). The stress relaxation rate in this case is expressed as stress relaxation rate=L ₁ −L ₂ /L ₁ −L ₀ ×100. L ₀ : Length of the jig L ₁ : Length at the start L ₂ : Length of the sample after a certain period of time In this case as well, Invention Alloy No. 6 is superior to Comparative Alloy No. 9. I understand. As explained above, since the high-strength conductive copper alloy according to the present invention has the above-mentioned structure, its strength and conductivity are equal to or superior to that of brass, and it also has high durability. Its stress corrosion cracking resistance and creep resistance are higher than that of brass, and therefore, as a material for electrical and electronic parts, stress corrosion cracking is less likely to occur, and the reliability of equipment is improved, such as reducing the deterioration of fitting force over time. This has the effect of widening the usable range.

[Brief explanation of drawings]

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

Claims (1)

[Claims] 1 Zn5.0~12.5wt%, Sn0.2~2.0wt%, Fe0.02
~0.50wt%, P0.01~0.1wt%, and the balance essentially consists of Cu.