JP2594249B2 - Copper base alloy for connector and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper base alloy for a connector and a method for producing the same. More specifically, for example, a small current connector for signals used for electrical wiring of transportation equipment, a pressure contact type connector used for electronic equipment, and an IC
The present invention relates to a copper base alloy for a connector which is excellent in strength, elasticity, electric conductivity and excellent in moldability, stress relaxation resistance, plating reliability and the like suitable for sockets and the like, and a method for producing the same.

[0002]

2. Description of the Related Art For example, the internal mounting of electronic equipment
With the rapid integration in C, LSI, and VLSIs, the density has been increased, and the connectors and IC sockets required for it have been increasingly required to have more functions and higher reliability. In addition, the electrical wiring of transportation equipment is becoming more and more dense, and there is also a demand for weight reduction, and connectors used for this purpose are also becoming multifunctional, highly reliable, and miniaturized.

[0003] As a method of connecting a terminal to an electric wire, pressure welding is often used to rationalize the connection in response to an increase in the number of electric wires due to a high density, and therefore, the material used for the terminal must have high strength and elasticity. Required. Also, in order to ensure electrical reliability, it is necessary to increase the contact force of the spring and not change with time. For that purpose, the terminal material must have strength, elasticity, electrical conductivity, stress relaxation resistance, corrosion resistance. It is necessary to be excellent.
Further, it is necessary to have moldability that can withstand complicated machining. In addition, the contact portion is often plated from the viewpoint of the stability of the contact resistance. Therefore, the material is not only excellent in plating property, but also between the material and the plating layer due to the influence of the use environment and heat generated by heat generation. In some cases, plating is peeled off from the fragile portion due to diffusion, and it is also required that such plating be not peeled off.

The number of pins in IC sockets has increased due to the improvement in the degree of integration, and the mounting method has shifted from DIP type to pinglit arrays and chip carriers. It is widely used for ROM writers and IC testers for burn-in and aging, etc., and the materials that make it up are the same as those required for terminal materials, such as strength, elasticity, electrical conductivity,
It is necessary to have excellent heat resistance and stress relaxation resistance.

[0005]

Conventionally, phosphor bronze and beryllium copper have been mainly used as connector materials for the above applications. However, phosphor bronze has insufficient strength and elasticity to be used as a press-fit type connector, and has insufficient stress relaxation resistance and heat resistance to be used for IC sockets, particularly for burn-in and aging of IC testers. Yes, there is a problem in reliability and durability. In addition, even when used as a general connector, stress relaxation resistance,
There was a problem of plating peeling and reliability was sometimes lacking.

For this reason, beryllium copper has recently tended to be used for this type of application. However, beryllium copper is required to have 300-
It is necessary to perform aging treatment at 350 ° C., and the process is complicated and costly, and there is a problem in terms of economy. In the case of post-plating, which is performed after the aging treatment after the forming process, plating is difficult to electrodeposit uniformly on the complicated processed portion, plating unevenness is likely to occur, and the first plating performed before the forming process is performed. In this case, plating with a low melting point such as Sn or Sn—Pb cannot be performed, and there is a problem that the plating type is limited.

In order to solve the above problems, the applicant has
Japanese Patent Application No. 62-84653, Japanese Patent Application No. 62-209839, Japanese Patent Application No. 62-306993
Cu-Ni-Al-based or Cu-Ni-
An Al-B based copper alloy for connectors and a method for manufacturing the same have been proposed. But Cu-Ni-Al system, Cu-Ni-A
Since the problem of the reaction between the carbon mold and the additive element Ni in continuous casting is remarkable in the presence of Al, the l-B alloy has a remarkable decrease in the yield during casting, a solution treatment, and an aging treatment. Among the material properties of the plate material obtained by the combination of the above and the processing, there is a problem that the spring limit value particularly varies greatly.

Accordingly, the present invention provides strength, elasticity, and electrical conductivity suitable for a microcurrent connector for signals used for electric wiring of transportation equipment, a press-contact type connector, an IC socket, etc. used for electronic equipment and the like. An object of the present invention is to provide a copper-based alloy for a connector that is excellent and has excellent moldability, stress relaxation resistance, plating reliability, and the like, and a method for producing the same.

[0009]

According to the present invention, Ni is 5 to 15% and Al is 0.5 to 2.0% in weight%, but the ratio of the weight percentage of Ni / Al is in the range of 3 to 10;
n: 0.1 to 3.0%, oxygen: 50 ppm or less, balance Cu
And a copper base alloy for a connector consisting of unavoidable impurities; or Ni: 5 to 15%, Al: 0.5% by weight.
2.0% where the ratio of the weight percentage of Ni / Al is 3
10, Sn: 0.1-3.0%, B: 0.005
An object of the present invention is to provide a copper-based alloy for a connector comprising 0.1 to 0.1%, oxygen: 50 ppm or less, the balance being Cu and inevitable impurities, and a method for producing the same.

[0010] One feature of the copper-based alloy of the present invention is Ni.
And the addition of an appropriate amount of Al provides a structure in which the Ni-Al intermetallic compound is finely precipitated in the Cu matrix. Therefore, the present invention also provides a method for advantageously producing the high-strength copper alloy which comprises (1)
i: 5 to 15%, Al: 0.5 to 2.0% where Ni /
Al percentage by weight in the range of 3 to 10, Sn: 0.
1 to 3.0%, and in some cases, B: 0.005 to
A process of producing a copper-based alloy material plate containing 0.1%, oxygen of 50 ppm or less, the balance being Cu and inevitable impurities by continuous casting, and rolling the material plate at a cold working rate of 50% or more; At a temperature of 750-950 ° C.
A step of performing a solution treatment for 0 to 600 seconds, a step of cold rolling the obtained solution treated material in a range of 30 to 90%, and a step of applying a solution to the obtained cold rolled material at a temperature of 300 to 600 ° C. at a temperature of 5 to 360 °. A method for producing a copper-based alloy for a connector, which comprises a step of performing an aging treatment for 30 minutes;
The production method according to (1), wherein the aging treatment is performed at a temperature of 0 to 550 ° C for 5 to 360 minutes; and the production method according to (1) or (2), wherein the solution treatment step is performed at least twice. Things.

[0011]

The contents of the present invention will be specifically described below.

First, the outline of the reason for selecting the range of the content of the additive element in the alloy of the present invention will be described as follows.

[0013] The copper-based alloy of the present invention has a basic feature in that precipitation strengthening by a Ni-Al intermetallic compound is aimed at.
Therefore, Ni and Al are indispensable elements in the alloy of the present invention.

Ni forms a compound with Al and has strength, elasticity,
It is an element that contributes to improvement of heat resistance and stress relaxation resistance.
Further, there is an effect that the casting structure is made fine and crystal grains are not coarsened during the solution treatment. In order to exhibit such an effect, the content must be 5% (% by weight, hereinafter the same) or more. However, if the content exceeds 15%, the electric conductivity is significantly reduced, and the carbon mold is continuously cast. In the case of using, there is a disadvantage that the reaction with the mold becomes remarkable, the soundness of the ingot is impaired, and the solution treatment temperature becomes high, which is disadvantageous in production. Further, the material cost is also increased and the cost is increased. Therefore, the Ni content is in the range of 5 to 15%.

When the Al content is less than 0.5%, the effect of improving strength, elasticity and heat resistance is small even in the presence of Ni. On the other hand, when the Al content exceeds 2.0%, the precipitates become excessively large, and the ductility, formability and plating property of the alloy are reduced, and the castability is reduced, which is economically disadvantageous. The amount ranges from 0.5 to 2.0%.

The object of the present invention is advantageously achieved when Ni and Al are precipitated as a Ni-Al intermetallic compound. In order to sufficiently exert the strengthening by the Ni-Al-based intermetallic compound, when the Ni / Al ratio is smaller than 3, A
If 1 is larger than 10, the amount of Ni dissolved in the Cu matrix becomes excessively large, lowering the electric conductivity and failing to efficiently improve the strength and elasticity. Therefore, the ratio of the weight percentage of Ni to Al (Ni
/ Al) is in the range of 3 to 10.

Sn improves the continuous castability of the alloy of the present invention using a carbon mold. Specifically, N in the presence of Al
It efficiently prevents the reaction between i and carbon, and contributes to improving the soundness of the ingot and extending the life of the carbon mold. In addition, Sn forms a solid solution in the matrix to improve strength and elasticity, and particularly has an effect of reducing the variation of the spring limit value in the present invention. Such an effect is obtained when the Sn content is 0.1%.
If the Sn content is less than 3.0%, spinodal decomposition occurs in the coexistence with Ni to produce a heterophase. By this, the strength and elasticity can be further improved, but the moldability is significantly reduced, and the heat treatment becomes complicated, resulting in an increase in cost. Therefore, the Sn content is set in the range of 0.1 to 3.0%.

B contributes as a deoxidizing agent at the time of melting and casting of the alloy of the present invention, and also functions to prevent the crystal grains from becoming coarse during the solution treatment. If the B content is less than 0.005%, such an effect is not sufficient, and if it exceeds 0.1%, the moldability deteriorates and it is economically disadvantageous.

If the O ₂ content is more than 50 ppm in the alloy, Al having a high affinity for oxygen is oxidized to Al ₂ O ₃ , and the plating property, the plating reliability, and the life of the press die decrease. For example, the characteristics may be degraded. If the oxygen content is large, hydrogen embrittlement may occur on the surface and inside when H ₂ gas is used in the production process of the alloy. Therefore, the O ₂ content is in the range of 50 ppm or less.

The copper-based alloy of the present invention adjusted to such a component composition is a material having various characteristics required for recent connector materials by finely depositing a Ni-Al intermetallic compound. be able to.

First, Ni: 5 to 15%, Al: 0.5 to
2.0% where the ratio of the weight percentage of Ni / Al is 3 to 1
0, Sn: 0.1 to 3.0%, and in some cases, B: 0.005 to 0.1%, oxygen 50 ppm or less, the balance being a copper-based alloy material plate composed of Cu and unavoidable impurities. Manufactured by continuous casting. The melting casting is desirably performed in an inert gas or reducing gas atmosphere. The material of the mold for continuous casting is preferably carbon from the viewpoint of cooling, consumption, reaction with molten metal, and running cost. After casting, it is desirable that the ingot be rapidly cooled by secondary cooling. However, the quenching start temperature is desirably 800 ° C. or higher.

Next, the ingot is rolled at a cold working ratio of 50% or more. Although hot rolling may be used instead of cold rolling, heating and rolling in an oxidizing atmosphere cause Al as an additional element to be internally oxidized to form Al ₂ O ₃ , a strong film is formed, and hot cracking occurs. It is easy to occur and is not desirable. 50% cold working rate
If it is less than 50%, the time required for eliminating segregation at the time of casting in the subsequent solution treatment step becomes extremely long. Therefore, the cold working ratio is set to 50% or more.

Next, 750 to 950
Solution treatment is performed at a temperature of 10C for 10 to 600 seconds. 750
When the temperature is lower than 950 ° C., the solution is not sufficiently dissolved, and when the temperature is higher than 950 ° C., the crystal grains are coarsened in a short time. Therefore, the processing temperature is in the range of 750 to 950 ° C.
If the time is less than 10 seconds, segregation at the time of casting remains and the solution is not sufficient, and if the time exceeds 600 seconds, the crystal grains become coarse and it is not economical. The obtained solution-treated material may be pickled, if necessary, after 30 to 9 days.
Cold rolling is performed in the range of 0%. If the working ratio is less than 30%, the working strain imparted by the working is small, and the strength and elasticity in the aging precipitation in the subsequent aging treatment step are not sufficiently improved. It becomes remarkably directional (anisotropic) in mechanical properties and deteriorates moldability. Therefore, the cold rolling before the aging treatment material is in the range of 30 to 90%.

Next, aging treatment is performed at 300 to 600 ° C.
At a temperature of 5 to 360 minutes. If the temperature is lower than 300 ° C., the time required for precipitation is too long, which is not economical. If the temperature is higher than 600 ° C., overaging occurs, and further improvement in properties cannot be expected. Therefore, the aging temperature is in the range of 300 to 600 ° C. If the aging time is less than 5 minutes, the formation of precipitates is insufficient, and if the aging time is longer than 360 minutes, it is not preferable from the viewpoint of growth of the precipitates and from the viewpoint of economic efficiency. Range.

Further, if necessary, an aging treatment may be performed at a temperature of 300 to 550 ° C. for 5 to 360 minutes before cold rolling after the soaking. This aging treatment can be expected to further improve strength, elasticity, and electrical conductivity. 300 ℃
At a temperature lower than 550 ° C., the time required for precipitation is too long to be economical. At a temperature higher than 550 ° C., overaging occurs and further improvement in properties cannot be expected. Therefore, the aging temperature is in the range of 300 to 550 ° C. When the time is less than 5 minutes, the formation of precipitates is insufficient,
A long time exceeding 0 minutes is not preferable from the viewpoint of growth of precipitates and economical efficiency.
The range is 360 minutes. However, the cold working ratio after the pre-aging treatment is desirably 30 to 70%. If the working ratio is less than 30%, the strength and elasticity after the subsequent aging treatment are insufficient, and if it exceeds 70%, the moldability is significantly reduced.

If necessary, the solution treatment step may be performed twice or more. By performing the solution treatment twice or more,
The effects of uneven structure and segregation during casting can be almost eliminated. If the influence of the casting structure is left, further improvement in the elasticity and formability of the alloy cannot be expected.

Through the above processing and heat treatment, N
A thin plate of a copper-based alloy having a structure in which an i-Al-based intermetallic compound is finely precipitated in a matrix can be manufactured, which has high strength, high elasticity, and high conductivity as shown in Examples described later,
In addition, since they are excellent in moldability, plating properties, stress relaxation resistance, and the like, they are suitable as connector materials used in recent electric and electronic parts, transport equipment, and the like.

[0028]

Example 1 Copper base alloys No. 1 to No. 10 whose chemical component values (% by weight) are shown in Table 1 were melted using a high-frequency melting furnace and cast into a 10 × 100 × 10000 (mm) ingot. Was continuously cast. However, the melting and casting atmosphere of the alloys No. 1 to No. 9 was completely shielded by Ar gas, and the alloy of No. 10 was melted and cast in the atmosphere. Further, carbon was used as the material of the mold, and the drawing was performed at an average drawing speed of 100 mm / min by a pulse method. The surface of the obtained ingot was observed, and those having no defect were marked as O and those having a defect were marked as X in Table 1.

[0029]

[Table 1] The obtained ingot was rolled by cold rolling to a thickness of 2 mm (working rate: 80%), and was subjected to a solution treatment at a temperature of 850 ° C. for 180 seconds. Next, cold rolling was performed to a thickness of 0.6 mm (working rate: 70%), and a solution treatment was performed at a temperature of 850 ° C. for 150 seconds. Pickling the obtained solution-treated material,
After buffing, cold rolling to a thickness of 0.2 mm (working rate 6
7%) and subjected to aging treatment at a temperature of 500 ° C. for 60 minutes. In the above-described heat treatment, the atmosphere was set to an inert gas or reducing gas atmosphere to suppress oxidation of the material surface and the inside as much as possible.

Using the obtained test material, hardness, tensile strength, spring limit value, conductivity, bending workability, solderability,
The results of examining the characteristic variations are also shown in Table 1.

The hardness, tensile strength, spring limit value and conductivity were measured according to JISZ2224 and JISZ224, respectively.
1. Performed according to JIS H3130 and JIS H0505. The bending workability is 90 ° w bending test (CES-M0
002-6, R = 0.2mm, bending axis parallel to rolling direction)
Were evaluated, and those having a good mountain surface at the center were evaluated as ○, and those having cracks were evaluated as x. Solder adhesion was measured by solder plating (dip: Sn-40 wt% Pb, 260 ° C × 5 sec.
After weakly active rosin flux was used, the specimen was heated at a temperature of 150 ° C. for 500 hours, and then the test piece was bent 90 ° w (R =
0.2 mm) and a peeling test was performed using a cellophane tape. Variations in characteristics were obtained by repeating trial production in the same process three times and measuring the tensile strength and spring limit value of the obtained test material, and all the variations in the measured values were within 5% of the average value. Was evaluated as ○, and those exceeding 5% were evaluated as ×.

The stress relaxation characteristics of the alloy No. 2 of the present invention and a commercially available phosphor bronze (C5210EH, 0.2 mm) were measured, and the results are shown in Table 2. In the test, the test piece was bent in an arch shape so that the stress at the center of the test piece was 40 kgf / mm ² , and the bending after holding at 150 ° C. and 200 ° C. for 500 hours was calculated as the stress relaxation rate by the following equation.

Stress relaxation rate (%) = [(L1-L2) /
(L1-L0)] x 100 where L0: length of jig (mm) L1: length of sample at start (mm) L2: horizontal distance between sample ends after processing (mm)

[0034]

[Table 2]

The following is clear from the results in Table 1.

The alloys of Nos. 1 to 5 according to the present invention have hardness,
This alloy has excellent properties as a copper alloy for connectors, because it has excellent balance of tensile strength, spring limit value, and conductivity, and has excellent bending workability, solder adhesion and castability, and small variation in properties. is there.

On the other hand, Comparative Alloy No. 6 containing no Sn
Comparative alloy No. 7 is inferior in spring limit value, castability, and characteristic variation, and has a higher Ni content than specified in the present invention. The comparative material No. 8 having a large Ni / Al ratio has hardness, tensile strength,
Low spring limit, low conductivity and poor balance. Comparative alloy No. 9 having a Sn content larger than that specified in the present invention has conductivity,
Comparative alloy No. 10 which is inferior in bending workability, castability, and property balance and has a large oxygen content even in the Ni amount, Al amount, Ni / Al ratio, and Sn amount specified in the present invention has bending workability,
Poor solder adhesion, castability, and property balance.

It is also apparent from Table 2 that the alloy of the present invention is superior in stress relaxation resistance to phosphor bronze, which is a typical conventional connector material.

[0039]

Example 2 Alloy No. 2 of the present invention shown in Table 1 of Example 1
In the same manner as in Example 1, a solution-treated material having a thickness of 0.6 mm was obtained. This was aged at a temperature of 400 ° C. for 30 minutes, pickled, buffed, cold-rolled to a thickness of 0.2 mm, and aged at a temperature of 500 ° C. for 60 minutes. The hardness, tensile strength, spring limit value, and conductivity of the obtained test material were measured, and are shown in Table 3. However, the measurement was based on Example 1.

[0040]

[Table 3]

From Table 3, it can be seen that the hardness, tensile strength, spring limit value, and electrical conductivity of the alloy of the present invention were further improved by aging treatment after solution treatment and before cold rolling.

[0042]

As described above, the present invention provides a copper-based alloy for connectors having high strength, high elasticity, and excellent electrical conductivity, bending workability, plating reliability, and stress relaxation resistance. An object of the present invention is to provide a connector material which can sufficiently cope with recent miniaturization and weight reduction of electric components for transportation equipment, higher density of wiring, and higher density and higher reliability of internal mounting of electronic equipment.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H01B 1/02 H01B 1/02 A H01H 1/02 H01H 1/02 C H01R 13/03 H01R 13 / 03 A

Claims (3)

(57) [Claims] 1. Ni: 5 to 15% by weight, Al: 0.5 to
2.0% by weight, Sn: 0.1 to 3.0% by weight, oxygen: 5
0 ppm or less, the balance consists of Cu and unavoidable impurities, and the value of the ratio of (wt% of Ni) / (wt% of Al) is 3%.
A copper-based alloy for a connector, which is 10 to 10. 2. Ni: 5 to 15% by weight, Al: 0.5 to
2.0% by weight, Sn: 0.1 to 3.0% by weight, B: 0.
005 to 0.1% by weight, oxygen: 50 ppm or less, balance C
u and inevitable impurities, (% by weight of Ni) /
A copper-based alloy for a connector having a ratio value of (weight% of Al) of 3 to 10. 3. As essential components, Ni: 5 to 15% by weight, Al: 0.5 to 2.0% by weight, Sn: 0.1 to 3.
0% by weight and oxygen: 50 ppm or less, and if necessary, B: 0.005 to 0.1% by weight, the balance being Cu and unavoidable impurities, and (% by weight of Ni) / (A
step value of the ratio of l% by weight of) is produced by continuous casting blank of copper-based alloy is 3-10, hot the material sheet
A step of rolling at a cold working ratio of 50% or more without rolling, and further obtaining the obtained sheet material at a temperature of 750 to 950 ° C.
A step of solution-treating for 0 to 600 seconds, a step of cold-rolling the obtained solution-treated material in a reduction ratio of 30 to 90%,
The obtained cold-rolled material is heated at a temperature of 300 to 600 ° C. for 5 to 360
A method for producing a copper-based alloy for a connector, comprising a step of performing aging treatment for minutes.