JPH07113143B2 - Method for producing high strength copper alloy - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a high-strength copper alloy having good fatigue characteristics, which is particularly suitable for applications in which cyclic stress related to switches and relays is applied. .

[Conventional technology]

A typical example of high-strength copper alloys that have been commonly used in the market, for example, is the Journal of Copper and Copper Technology, Vol.
There is a C1720 alloy (beryllium copper alloy) shown in 9 (1970) P109 to P116, but this alloy has a problem in terms of cost because it contains expensive Be, which is a scarce resource and does not easily receive a stable supply. On the other hand, as an inexpensive spring material, there is a phosphor bronze-based alloy containing Sn and a small amount of P in Cu, and its mechanical properties are, for example, published: ASTM Spec.Tech.Pub.No.183 (1956).
As also shown, it has a tendency to increase with increasing Sn content. However, when the Sn content is large, the workability becomes extremely poor due to the crystallization of hard and brittle compound phases with poor ductility, such as the δ and β phases, and the appearance of the reverse segregation phenomenon of Sn. It cannot be processed and has the drawback that it can only be used as a phosphor bronze casting. Therefore, the maximum Sn content of the alloy currently used as a spring material in this alloy system is only about 9%. For this reason, there is a large difference in characteristics from the C1720 alloy, and the emergence of an alloy that fills this gap is desired.

[Problems to be solved by the invention]

Conventionally, phosphor bronze-based alloys that can be stably supplied without using expensive Be, which is a scarce resource and difficult to receive a stable supply, have mechanical properties,
There was a problem in that it was not possible to obtain a material with excellent workability and sufficient properties as a spring material.

The present invention has been made to solve the above problems, and aims to improve the structure and cold workability of a phosphor bronze alloy without using Be, which is a resource scarce and does not easily receive a stable supply, The purpose is to obtain a high-strength copper alloy having sufficient properties as a spring material.

[Means for solving problems]

The high-strength copper alloy of the present invention contains Sn in an amount of more than 12% by weight and 20% by weight or less and 0.01 to 0.5% by weight of P, and the balance of the molten metal consisting of Cu is 10 ² ℃ / sec or more and 10 ⁵ ℃ / It is manufactured by rapid solidification at a cooling rate of less than sec.

[Action]

10 ² ℃ / sec or more 10 ⁵ ℃ / s
By quenching and solidifying at a cooling rate less than ec, the occurrence of reverse segregation can be suppressed and the compound phase can be finely and uniformly dispersed in the matrix, improving the structure and cold workability.

〔Example〕

 Examples of the present invention will be described below.

The invented material was produced using an experimental rapid solidification facility consisting of cast iron twin rolls with a diameter of 200 mm and capable of internal water cooling. The manufacturing conditions are (1) the rotation speed of the cooling roll is 10 rpm,
(Ii) The pouring temperature to the roll is 50 from the melting point of the alloy.
Higher at ℃, (iii) Roll gap was set to 1 mm. The obtained thin plate ingot had a thickness of 1.8 mm and a width of 100 mm. This ingot is faster than conventional continuous casting and batch casting.
^The continuous rapid solidification at a cooling rate of ² ° C / sec or more and less than 10 ⁵ ° C / sec suppresses the appearance of dendrite structure and reverse segregation, and the compound phase is finely dispersed uniformly in the matrix. The workability is extremely good. The thickness of these ingots is 0.3 mm at a stretch without homogenizing and annealing.
Cold rolled to 500 ° C, followed by 1 hour pheasant annealing
Finished to a thickness of 0.2 mm with a cold working rate of 33%. Then 250
A low temperature annealing treatment was performed at 1 ° C. for 1 hour to obtain a sample for measuring various characteristics.

Table 1 summarizes the characteristic values of the invention material and the comparative material.

As is clear from these results, Sn exceeding 12 wt%
The cold workability is remarkably improved by producing a Cu-Sn alloy containing Cu by rapid solidification as in the present invention.
It can be seen that a high-strength copper alloy suitable as a spring material can be obtained. For example, the C5210 alloy of Sample No. 1 (comparative material, Japanese Patent Laid-Open No. 5-112324, etc.), which is generally widely used as a spring material, and Sample No. 3 containing about twice that amount of Sn (the present invention). Material)
Comparing the characteristics of Sample No. 3, the tensile strength of Sample No. 3 is about 50.
%, The spring limit value has increased by about 110%. On the other hand, improvement is also observed for the fatigue characteristics are important as a spring member, 32 kg in fatigue strength at the repetition rate N = 10 ⁷ times f /
A value of mm ² was obtained, and the level is at the intermediate position between the C5210 alloy and the C1720 alloy.

The improvement of these mechanical properties is due to the fact that the Sn content is increased and the solid solution hardening ability and work hardening ability are increased compared with the conventional product, and the fine compound is uniformly dispersed in the matrix. In particular, the improvement of fatigue properties is considered to be due to the fact that fine compounds dispersed in the matrix prevent the propagation of fatigue cracks. If the Sn content is 12 wt% or less, the mechanical properties are insufficient, and if the Sn content is 20 wt% or more, the mechanical properties are improved, but the cost merit becomes thinner and the workability decreases as compared to the C1720 alloy. The range of more than 12% by weight and 20% by weight or less is desirable, and the range of 12.4 to 20% by weight is preferable. Further, if the P content is 0.01% by weight or less, there is practically no effect as a deoxidizer, and if it is 0.5% by weight or more, the effect does not change. The range of 0.01 to 0.5% by weight is preferable.

Table 2 shows the effect of a small amount of additional element.

When compared with the sample No.4 based on Cu-Sn-P, the tensile strength, spring limit value and fatigue strength of sample No.5 were compared. Since there is almost no difference in either case, Mn,
Zn and B do not adversely affect these properties, indicating that they are effective as deoxidizers. However, the higher the amount added, the more brittle it becomes and the workability and conductivity are affected. Therefore, the upper limit is set. On the other hand, when comparing No.6 to No.9 samples, the additive elements of Ni, Fe, Co, Ti, and Zr contribute to the refinement of crystal grains and increase in strength, and especially to the improvement of fatigue properties. On the other hand, the effect was recognized, and the upper limit was limited in terms of moldability. The content of these trace elements is 1.0% by weight
If the above content is included, the conductivity will be reduced, so the total practical value is 0.01.
It is desirable to be 1.0% by weight or less. In view of the above, the content of each trace element is practically desirable within the following range.

Ni …… 0.01 to 0.5 wt% Zn …… 0.01 to 0.35 wt% Fe …… 0.01 to 0.15 wt% Ti …… 0.01 to 0.5 wt% B …… 0.001 to 0.1 wt% CO …… 0.01 to 0.5 wt% Mn… … 0.05 ～ 0.4wt% Zr …… 0.01 ～ 0.5wt% The cooling rate of molten metal was 10 ² ℃ / s as a result of various experiments.
If it is less than ec, the ingot structure is the same as that obtained by the conventional casting method and good workability cannot be obtained. If it is 10 ⁵ ° C / sec or more, the plate thickness that can be manufactured is too thin and it is put to practical use. Since it becomes difficult, a range of 10 ² ° C / sec or more and less than 10 ⁵ ° C / sec is preferable.

In addition, for reference, the manufacturing method according to the alloy of the present invention is not limited to Cu-Sn alloys, but Ni-Be-Al, Cu-Ni- which is known as a difficult-to-process material that easily crystallizes a compound phase with poor ductility Mn, Cu
The same effect can be obtained even when applied to a Ti-based alloy or the like.

〔The invention's effect〕

As described above, according to the present invention, Sn of more than 12 wt% and 20 wt% or less and 0.01 to 0.5 wt% of P are contained, and the balance Cu
By rapidly solidifying molten metal consisting of 10 ² ℃ / sec or more and less than 10 ⁵ ℃ / sec, the cold workability of the structure is remarkably improved, and spring materials such as switches,
It has the effect that a stable supply suitable for applications in which relay-related repetitive stress is applied can be received, and a low-strength, high-strength copper alloy with excellent fatigue resistance can be obtained.

Claims (3)

[Claims] 1. Sn of more than 12% by weight and 20% by weight or less and 0.01-
The molten metal containing 0.5% by weight of P and the balance of Cu was 10
^A method for producing a high-strength copper alloy produced by rapid solidification at a cooling rate of ² ° C / sec or more and less than 10 ⁵ ° C / sec. 2. The method for producing a high-strength copper alloy according to claim 1, wherein the molten metal contains 12.4 to 20% by weight of Sn. 3. Molten metal is Ni, Zn, Fe, Ti, B, Co, Mn and Zr.
The method for producing a high-strength copper alloy according to claim 1 or 2, further comprising 0.01 to 1.0 wt% of at least one of them.