JP5150908B2 - Copper alloy for connector and its manufacturing method - Google Patents

Description

The present invention relates to a copper alloy having strength and conductivity suitable as a material for electrical and electronic parts such as connectors and having a small Young's modulus, and a method for producing the same.

With the recent development of electronics, the electrical wiring of various machines has become more complex and highly integrated, and along with this, the number of copper products used for electrical and electronic parts such as connectors has increased.
In addition, electrical and electronic parts such as connectors are required to be lightweight, highly reliable, and low in cost. Therefore, in order to satisfy these requirements, the copper alloy material for connectors is thinned and pressed into a complicated shape, so that the strength, elasticity, conductivity and press formability must be good.

Specifically, in the terminal, the tensile strength in the rolling direction is 600 N / mm ² or more, preferably 700 N / mm ² as strength against buckling or deformation at the time of insertion / extraction or bending, and strength against crimping and holding of the electric wire. above, the spring limit value is 450 N / mm ² or more, 500 N / mm ² or more if possible is preferred. Furthermore, in order to suppress the generation of Joule heat due to energization, the conductivity is preferably 18% IACS or more. Further, the demand for press formability becomes stricter due to the miniaturization of the terminals, and workability is required so that the ratio R / t of the bending portion radius (R) to the plate thickness (t) satisfies 1 or less.

Conventionally, connectors have been downsized, and it has been required that the Young's modulus of the material be large so that a large stress can be obtained with a small displacement. Or, the management standards such as the thickness of the material and the variation of the residual stress became stricter, and the cost was increased. Therefore, recently, there has been a demand for a design that uses a material having a small Young's modulus and has a structure in which the displacement of the spring is large, and can tolerate variation in dimensions. Accordingly, it has been demanded that the Young's modulus in the rolling direction is 120 kN / mm ² or less, preferably 115 kN / mm ² or less.

In addition to the above, the frequency of maintenance of molds is a large part of the cost and has been highlighted. Tool wear is a major factor in mold maintenance. When a material is pressed (punched or bent), tools such as punches, dies, strippers, etc. wear, leading to burrs on the workpiece and dimensional defects.
At this time, the influence on the wear of the material itself is great. Accordingly, there is an increasing demand for improvement on the material side with respect to mold wear.

Furthermore, it is necessary to have excellent corrosion resistance and stress corrosion cracking resistance, and the female terminal must be excellent in stress relaxation resistance because a thermal load is applied.
Specifically, it is desirable that the stress corrosion cracking life is at least three times that of a conventional brass, the stress relaxation rate is 150 ° C. × 500 hours, and the relaxation rate is 25% or less, which is half that of a brass.

Conventionally, brass, phosphor bronze, and the like have been generally used as connector materials. Brass is used as a low-cost material, but the tensile strength in the rolling direction does not exceed 600 N / mm ² even when the grade is EH, and is inferior in corrosion resistance, stress corrosion cracking resistance, and stress relaxation characteristics. . Phosphor bronze has an excellent balance of strength, corrosion resistance, stress corrosion cracking resistance, and stress relaxation resistance. However, for example, the phosphor bronze for springs is as small as 12% IACS and is disadvantageous in terms of cost. Therefore, many copper alloys have been researched, developed and proposed. However, many proposed copper alloys are obtained by adding a small amount of additive elements to copper and balancing the properties such as strength, electrical conductivity, and stress relaxation resistance, and the Young's modulus is 120 to 120 in the rolling direction. It was a large value of 135 kN / mm ² and the cost was high.

Here, for both brass and phosphor bronze, the Young's modulus in the rolling direction is 110 to 120 kN / mm ² , and the small Young's modulus meets the requirements of the above-mentioned design, and these materials have recently been reviewed. Therefore, in the near brass price, the rolling direction of the spring limit value 450 N / mm ² or more, a tensile strength of 600N / mm ² or more, conductivity of 18% IACS or more, a Young's modulus of 120 kN / mm ² or less, preferably 115KN / Materials that are mm ² or less are highly desired.

  With the development of electronics, the present invention has the above-mentioned characteristics required for materials for electrical and electronic parts such as connectors, that is, strength, conductivity, Young's modulus, stress relaxation resistance, and stress corrosion cracking resistance. The present invention provides a copper alloy for connectors excellent in press formability, cost, and the like, and a method for producing the same.

  The present invention provides various properties as described above required for materials for electrical and electronic parts such as connectors by limiting the composition and heat treatment conditions while reducing the cost by adding components cheaper than copper. That is, the present invention provides a copper alloy for connectors excellent in strength, electrical conductivity, Young's modulus, stress relaxation resistance, stress corrosion cracking resistance, press formability, cost, and the like.

That is,
(1) Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass% , the balance is made of Cu and inevitable impurities, the tensile strength in the rolling direction is 600 N / mm ² or more, the conductivity is 18% IACS or more, A copper alloy for connectors having a Young's modulus of 120 kN / mm ² or less and a spring limit value of 450 N / mm ² or more.

(2) Including Zn: 24-30 mass%, Sn: 0.7-1.3 mass% , Ni: 0.1-5.0 mass%, P: 0.01-0.3 mass% and satisfying the following formula:
5.0 ≦ Ni / P ≦ 50
However, Ni: Ni content (mass%)
P: P content (mass%)
The balance is made of Cu and inevitable impurities, the tensile strength in the rolling direction is 600 N / mm ² or more, the conductivity is 18% IACS or more, the Young's modulus is 120 kN / mm ² or less, and the spring limit value is 450 N / mm ² or more. A copper alloy for connectors.

(3) The connector as described in (1) or (2) above, wherein in the copper alloy for connectors, Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass% , and satisfying the following formula: Copper alloy.
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)

(4) The connector according to (1) to (3) above, wherein the surface of the metal material made of the copper alloy is subjected to a surface treatment of Cu base: 0.3 to 2.0 μm, Sn: 0.5 to 5.0 μm. Copper alloy.

(5) Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass% , Ni: 0.1 to 5.0 mass%, P: 0.01 to 0.3 mass%, including Ni and P satisfying the following formula,
5.0 ≦ Ni / P ≦ 50
However, Ni: Ni content (mass%)
P: P content (mass%)
After the heat treatment for 1 to 360 minutes at a temperature of 300 to 750 ° C. and the cold working at a processing rate of 10% or more, the copper alloy material consisting of the remainder consisting of Cu and inevitable impurities is then cold processed at 200 to 600 ° C. for 5 seconds to 180 minutes. The copper alloy for connectors having a tensile strength in the rolling direction of 600 N / mm ² or more, an electrical conductivity of 18% IACS or more, a Young's modulus of 120 kN / mm ² or less, and a spring limit value of 450 N / mm ² or more. Manufacturing method.

(6) Zn: 24-30 mass%, Sn: 0.7-1.3 mass% , Ni: 0.1-5.0 mass %, P: In the range of 0.01-0.3 mass% and satisfying the following formula, Ni: P is included,
5.0 ≦ Ni / P ≦ 50
However, Ni: Ni content (mass%)
P: P content (mass%)
After the heat treatment for 1 to 360 minutes at a temperature of 300 to 750 ° C. and the cold processing at a processing rate of 10% or more, the copper alloy material consisting of Cu and inevitable impurities as the balance is 200 to 600 ° C. for 5 seconds to 180 minutes. After heat treatment, the tensile strength in the rolling direction is 600 N / mm ² or more, the electrical conductivity is 18% IACS or more, the Young's modulus is 120 kN / mm ² or more, and the spring limit value is 450 N / mm ² or more. The copper for connector, characterized by subjecting the surface of the copper alloy material to a Cu base: 0.3-2.0 μm and Sn: 0.5-5.0 μm, followed by heat treatment at a temperature of 100-280 ° C. for 1-180 minutes Alloy manufacturing method.

(7) In the above copper alloy for connectors, Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass% , and satisfying the following formula, (5) or (6) Manufacturing method of copper alloy for connectors.
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)

(8) The method for producing a copper alloy for connectors according to the above (5) to (7), wherein the heat treatment is performed at a temperature higher than a heat treatment temperature at which the spring limit value reaches a peak.

(9) In the above manufacturing method, when the stamped scrap of the material obtained by surface-treating Sn is used as a raw material in the above-mentioned alloy, the temperature is 300 to 600 ° C. for 0.5 to 24 hours in the air or in an inert gas atmosphere in advance. The method for producing a copper alloy for connectors according to the above (5) to (8), wherein the copper alloy is melted after heat treatment.

Next, the contents of the present invention will be specifically described.
First, the reason for limiting the amount of components in the copper alloy of the present invention will be described.
Zn:
Addition of Zn improves strength and springiness and is cheaper than Cu, so it is desirable to add a large amount. However, if it exceeds 41 mass%, workability, corrosion resistance, and stress corrosion cracking resistance are reduced. Further, the plating property and solderability are deteriorated. On the other hand, if it is less than 20 mass%, strength and springiness are insufficient, Young's modulus is increased, and when scraps with Sn surface treatment are used as raw materials, hydrogen gas occlusion increases during melting, and ingot blowholes are generated. It becomes easy to do. Moreover, there is little inexpensive Zn and it becomes economically disadvantageous. Therefore, Zn should just be the range of 20-41 mass%. A preferable range is 22 to 38 mass%. Furthermore, as a preferable range, when it is 24 to 30 mass%, it is possible to suppress hot cracking that occurs due to the balance between the solidification structure during hot casting and hot rolling.

Sn:
Sn is effective in improving mechanical properties such as strength and elasticity in a small amount. Moreover, a small Young's modulus can be satisfied in the presence of Zn as compared with many copper alloy systems. Furthermore, it is preferable to contain it as an additive element also from the point of reuse of the material which surface-treated Sn, such as Sn plating. However, when the Sn content is increased, the conductivity is drastically lowered and the hot workability is also lowered. In order to ensure the electrical conductivity of 18% IACS, it must be within a range not exceeding 4.0 mass%. Further, if the amount is less than 0.1 mass%, the above effect cannot be expected. Therefore, Sn should just be the range of 0.1-4.0 mass%. A preferable range is 0.5 to 2.0 mass%. Furthermore, as a preferable range, when it is 0.7 to 1.3 mass%, it is possible to suppress hot cracking that occurs due to the balance between the solidification structure and hot rolling during melting and casting.

Ni:
Ni is dissolved in the Cu matrix to improve strength, elasticity, and stress relaxation resistance. In addition, by forming a compound with P to disperse and precipitate, the electrical conductivity is also improved. However, if it is less than 0.1 mass%, the desired effect cannot be obtained, and if it exceeds 5.0 mass%, the electrical conductivity is lowered, which is economically disadvantageous. A more preferable range is 0.2 to 2.0 mass%.

P:
P improves the corrosion resistance of the Zn-containing alloy and forms a compound with Ni to disperse and precipitate, thereby improving strength, elasticity, stress relaxation resistance, stress corrosion cracking resistance, and electrical conductivity. If the amount is less than 0.01 mass%, the above effects cannot be obtained sufficiently. If the amount exceeds 0.3 mass%, the electrical conductivity and solder weatherability are severely deteriorated, which adversely affects castability and hot workability. Specifically, when Zn, Sn and P coexist, hot workability is remarkably lowered. For this reason, addition of Ni is necessary. Even in the presence of Ni, excessive P significantly reduces the productivity as described above. Therefore, it is set to 0.01 to 0.3 mass%. A more preferable range is 0.02 to 0.1 mass%.

Oite the Ni and P copper alloy according to the present invention the composition ratio of, the added Ni, a part of the P form a Ni-P compound, which is electrically conductive and by dispersedly precipitated uniformly finely strength , Elasticity, stress relaxation resistance, and stress corrosion cracking resistance can be improved. Therefore, it is desirable to limit the ratio of Ni and P. If the ratio of Ni and P is less than 5.0, the desired effect cannot be obtained, and hot workability is remarkably reduced. If it is greater than 50, Ni—P compounds are coarsely precipitated, and the strength, conductivity, and molding process are reduced. Adverse effects such as decreased sex.

About formula (1)
6.0 ≦ 0.25X + Y ≦ 12 (1)
However, X: Zn content (mass%)
Y: Sn content (mass%)
In addition , when the value of the formula is less than 6.0 in the formula (1), the strength such as the tensile strength is lowered and a desired Young's modulus cannot be obtained, and when it is larger than 12, the conductivity and molding processability are lowered. It will have an adverse effect.

By limiting the range of the components as described above, the tensile strength in the rolling direction is 600 N / mm ² or more, the electrical conductivity is 18% IACS or more, the Young's modulus is 120 kN / mm ² or less, and the spring limit value is 450 N / mm ^2. Furthermore, various characteristics required for connector materials, specifically corrosion resistance, stress corrosion cracking resistance (cracking life in ammonia vapor is more than three times that of brass), stress relaxation resistance (relaxation at 80 to 120 ° C) It is possible to produce a copper-based alloy for a connector that satisfies a rate of less than half of one kind of brass, comparable to phosphor bronze), moldability (no cracking even in 90 ° W bending with R / t ≦ 1.0).

Next, the reasons for limiting the manufacturing conditions according to the present invention will be described.
This copper alloy material is heat-treated at a temperature of 300 to 750 ° C. for 1 to 360 minutes, then cold worked at a processing rate of 10% or more, and then subjected to a heat treatment at a temperature of 200 to 600 ° C. for 5 seconds to 180 minutes. If the surface of the substrate is subjected to surface treatment of 0.3 to 2.0 μm Cu base and 0.5 to 5.0 μm Sn and then heat-treated at a temperature of 100 to 280 ° C. for 1 to 180 minutes, the characteristics as a connector material are further improved. Can do.

  In the annealing before the final cold working, if the crystal grain size is controlled to 5 to 20 μm, the press formability is improved, but the processing temperature at this time is preferably 300 to 750 ° C. If the temperature is lower than 300 ° C., the temperature required for recrystallization is too low, and the treatment time becomes longer and is not economical. If the temperature exceeds 750 ° C., the crystal grains become coarse in a short time and it is difficult to control the crystal grain size.

  The time is preferably 1 to 360 minutes. If the treatment time is too short, the control of crystal grains by recrystallization is not sufficient, and if the treatment time is too long, crystal grains are likely to grow and become coarse, and this is economically disadvantageous.

  The final cold work rate is preferably 10% or more. If it is less than 10%, improvement in strength, hardness, etc. by work hardening is not sufficient. However, if the processing rate is too large, the workability deteriorates, so a preferable range is 10 to 90%.

  Thereafter, heat treatment is performed at a temperature of 200 to 600 ° C. for 5 seconds to 180 minutes. This heat treatment improves the spring limit value, stress relaxation resistance, stress corrosion cracking resistance, conductivity, and bending workability of the material. Such effects are not sufficient at temperatures below 200 ° C., and strength rapidly decreases at temperatures above 600 ° C. The time is preferably 5 seconds to 180 minutes. If the treatment time is too short, the above effect is not sufficient, and if it is too long, it is economically disadvantageous.

  At this time, by performing the heat treatment at a temperature higher than the heat treatment temperature at which the spring limit value reaches a peak, the stress relaxation resistance, the stress corrosion cracking resistance, and the workability can be improved. However, if the heat treatment temperature is too high, the tensile strength and the spring limit value are sharply lowered. Therefore, it is desirable that the heat treatment conditions are such that the spring limit value is between 70 and 100% of the peak value.

  The material obtained in this manner is subjected to surface treatment with a Cu underlayer of 0.3 to 2.0 μm and an Sn surface treatment of 0.5 to 5.0 μm. If the Cu substrate is less than 0.3 μm, Zn in the alloy diffuses and oxidizes on the surface treatment layer and the surface, and is less effective in preventing an increase in contact resistance and a decrease in solderability. Saturated and not economical. However, the Cu base plating is not limited to pure Cu, but may be a copper alloy such as Cu—Fe or Cu—Ni.

  If the Sn surface treatment layer is less than 0.5 μm, the corrosion resistance, particularly hydrogen sulfide resistance is insufficient, and if it exceeds 5.0 μm, the effect is saturated and economically disadvantageous. Furthermore, if these surface treatments are carried out by electroplating, it is preferable in terms of film thickness uniformity and economy. A reflow treatment may be performed after the surface treatment to give gloss. This process is also effective for whisker countermeasures.

  This surface treatment material is heat-treated at a temperature of 100 to 280 ° C. for 1 to 180 minutes. This heat treatment improves the spring limit value and work hardening index of the material. When the work hardening index is increased, when the connector spring portion is formed by bending, the spring property is improved by hardening of the spring portion. In addition, by forming a hard Cu-Sn intermetallic compound layer on the surface treatment layer of the material, when used as a connector, it is possible to improve wear resistance and decrease insertion / extraction force, and also to prevent whisker It is valid. Such effects are not sufficient at temperatures below 100 ° C., and contact resistance, solderability, and workability deteriorate due to diffusion and oxidation at temperatures above 280 ° C. In addition, if the heat treatment time is less than 1 minute, the effect is not sufficient, and if it exceeds 180 minutes, the above-described characteristic deterioration due to diffusion or oxidation occurs, and it is not economical.

  When the stamped scrap of the surface-treated material Sn is melted as a raw material in the alloy of the present invention, it is melted after heat treatment in the air or in an inert atmosphere at a temperature of 300 to 600 ° C. for 0.5 to 24 hours. When the temperature is lower than 300 ° C., the press oil adhering to the press scrap is not sufficiently burned, and the moisture adsorbed during storage is insufficiently dried. The hydrogen generated by the decomposition is absorbed into the molten metal and causes blowholes.

Further, at a temperature exceeding 600 ° C., oxidation rapidly proceeds and causes dross generation. This dross increases the viscosity of the melt and lowers the castability. Therefore , the heat treatment temperature is in the range of 300 to 600 ° C. If the time is less than 0.5 hours, the combustion of the press oil and the drying of moisture are not sufficient. If the time exceeds 24 hours, the base material Cu diffuses and oxidizes in the Sn surface treatment layer, and Cu—Sn—O-based oxides are formed. It forms, causes dross, and is not economical. Accordingly, the heat treatment time is in the range of 0.5 to 24 hours. In addition, the atmosphere is insufficient in the air, but sealing with an inert gas is preferable from the viewpoint of preventing oxidation.
However, when the temperature of the reducing gas is high, it is disadvantageous due to the absorption and diffusion of hydrogen due to the decomposition of moisture.

The copper-based alloy according to the present invention or the material obtained by the method of the present invention is stronger than the conventional brass, phosphor bronze, etc. in terms of strength, electrical conductivity, balance of Young's modulus and formability, as well as environmental resistance and heat resistance. It is ideal for electrical and electronic materials such as inexpensive connectors that can replace brass and phosphor bronze because of its excellent properties, stress relaxation characteristics, and mold wear.
Next, embodiments of the present invention will be described by way of examples.

Example 1
Table 1 shows the chemical composition (mass%) of copper alloy No. 1-16 were melted using a high frequency induction melting furnace and cast into a 40 × 40 × 150 (mm) ingot. However, the atmosphere during melting and casting was an Ar gas atmosphere, and water cooling was performed immediately after casting.
Then, after hot rolling each ingot, cold rolling and annealing were repeated to obtain a thickness of 0.50 mm. And after heat-processing material for 60 minutes at the temperature of 450 degreeC, water quenching was performed, and also the pickling was performed. The heat-treated material obtained as described above was cold-rolled to a thickness of 0.25 mm, annealed for 30 minutes at each temperature condition, and subjected to pickling as a test material.

  Using the test material obtained as described above, Vickers hardness, tensile strength, Young's modulus, bending limit value and electrical conductivity in the rolling direction were measured, and stress relaxation characteristics were investigated. Regarding the bending workability, the rolling direction and the direction perpendicular to the rolling direction were investigated. The measurements of Vickers hardness, tensile strength, Young's modulus, spring limit value, and conductivity were in accordance with JIS-Z-2244, JIS-Z-2241, JIS-H-3130, and JIS-H-0505, respectively.

The stress relaxation test was calculated according to the following formula as a stress relaxation rate after bending for 500 hours at a temperature of 150 ° C. in an arch so that the stress at the center of the test piece was 400 N / mm ² .
Stress relaxation rate (%) = [(L ₁ −L ₂ ) / (L ₁ −L ₀ )] × 100
L ₀ : Jig length (mm)
L ₁ : Sample length at the start (mm)
L ₂ : Horizontal distance between sample ends after processing (mm)

  The bending workability is a 90 ° W bending test (CES-M-002-6, R = 0.2 mm, R / t = 1.0, W = 10 mm, rolling direction and vertical direction). A good one was evaluated as a mark ◯, a wrinkled one was evaluated as a △ mark, and a cracked one was evaluated as a x mark.

From the results shown in Table 1, the copper alloys of Nos. 1 to 3 and 7 to 9 according to the present invention are excellent in the balance of tensile strength, Young's modulus and electrical conductivity, and also have good bending workability. Therefore, it is a copper alloy having very excellent characteristics as an electrical / electronic material such as a connector.
In addition, the annealing temperature is increased as compared to No.5, and No.9 is improved in Young's modulus, stress relaxation resistance, and bending workability instead of decreasing the tensile strength and spring limit value. I understand that. The copper alloys of Alloy Nos. 4 to 6 were used as reference examples because the contents of Zn and / or Sn were outside the specified range of the present invention.

On the other hand, the smaller No. 10 whose Zn and Sn contents are defined by the above formula (1) is inferior to the tensile strength and Young's modulus, and the larger No. 10 whose Zn and Sn contents are defined by (1). 11 is inferior in electrical conductivity, stress relaxation rate, and bending workability.
No. 12, which has a higher Ni: P ratio than the alloy of the present invention, has a large Young's modulus and a low electrical conductivity.
Moreover, it is inferior also in bending workability. No. 13 having a smaller Ni: P ratio than the alloy of the present invention is inferior in stress relaxation rate and bending workability. It is considered that this is because the amount of P is large, the Ni: P ratio is small, the precipitation of the Ni-P compound is excessively large, and the bending workability and the stress relaxation property are deteriorated. In addition, cracks occurred during hot rolling, and it was not possible to roll to the final thickness with good yield.
No. 14, which has a larger amount of P than the alloy of the present invention, is inferior in tensile strength, spring limit value, Young's modulus, electrical conductivity, and bending workability. Furthermore, the yield was extremely poor due to a significant decrease in hot workability. No. 15 having a larger amount of Ni than the alloy of the present invention is inferior in Young's modulus and electrical conductivity.
No. 16 is a sample in which the heat treatment temperature is higher than No. 9, but the tensile strength and spring limit value are greatly reduced.

Example 2
Regarding the alloy No. 2 of the present invention shown in Table 1 of Example 1 and commercially available brass 1 type (C2600-EH) and phosphor bronze 2 type (C5191-EH), the hardness in the rolling direction, the tensile strength, the Young The rate, conductivity, stress relaxation rate and stress corrosion cracking life were tested and measured. Further, the bending direction and the bending workability in the direction perpendicular to the rolling direction were adjusted.
The test for measuring the hardness, tensile strength, Young's modulus, electrical conductivity, and stress relaxation rate in the rolling direction is the same measurement method as in Example 1, and the stress corrosion cracking time is about 400 N / mm ^{2 in} the sample. This is the time when cracks occurred when stress was applied and exposed in a desiccator containing 12.5% aqueous ammonia.

  From the results shown in Table 2, the copper alloy of the present invention has strength, Young's modulus, bending workability, stress relaxation characteristics, stress corrosion resistance compared to brass, which is a conventional electrical / electronic material such as a connector. It can be seen that the cracking property is improved. Compared to phosphor bronze, it is excellent in strength, bending workability, Young's modulus, electrical conductivity, and stress relaxation characteristics. Furthermore, it can be said that it is excellent also in terms of cost from a component and a manufacturing process. Therefore, it can be said that the copper alloy of the present invention is sufficiently superior to conventional brass and phosphor bronze.

Example 3
After producing the alloy strips of the present invention shown in Table 3, Cu undercoating was performed at 0.5 μm and Sn plating was performed at 1.0 μm, and then the press-punched material was prepared as a raw material for melt casting. The target composition in the casting was shown in Table 3, and about 1 ton of press scrap was prepared as a raw material for melting, and the remainder was adjusted with electric Cu, Zn, Ni, and P to obtain six ingots of about 2 t. The components of the obtained ingot were almost the same as in Table 3.

Here, as for three pieces, the press scrap of the raw material was heated at 450 degreeC for 3 hours in air | atmosphere. The remaining three were not processed. This was rapidly melted to cast a 2 ton ingot, and hot rolling, cold rolling and annealing were repeated to finish to 0.25 mm. The total length of the material thus obtained was inspected, and the number of defects due to ingot blowholes was counted (Table 4).
From Table 4, the heat-treated press waste by the method of the present invention was excellent without defects. On the other hand, those not heat-treated have defects and it can be seen that there is a problem in yield.

Example 4
After subjecting the alloy No. 2 of the present invention shown in Table 1 of Example 1 to 0.5 μm of Cu undercoat and 1.1 μm of Sn, heat treatment was performed at 190 ° C. for 60 minutes. For this material and the one that was not heat-treated after plating, the limit value of the spring in the rolling direction was measured, and a 90 ° W bending test (R = 0.2 mm, R / t = 1.0, rolling direction) was performed. The distribution of the hardness of the cross section of the bent part of the later specimen was investigated. The same investigation was conducted on a conventional alloy (brass type 1 comparative material C2600 EH bare material).

表５より、熱処理を行なうことで本発明合金のばね限界値は更に向上していることがわかる。また、変形しなかった定常部の硬さと変形した曲げ部の最大硬さを比べると、熱処理を行わなかった場合よりも硬化が大きく、コネクタばね部に有利であることがわかる。また黄銅と比較しても本発明合金はコネクタ用銅合金として十分に優れているといえる。

From Table 5, it can be seen that the spring limit value of the alloy of the present invention is further improved by heat treatment. Moreover, when comparing the hardness of the stationary part that has not been deformed with the maximum hardness of the bent part that has been deformed, it can be seen that the hardening is greater than when the heat treatment is not performed, which is advantageous for the connector spring part. Moreover, even if compared with brass, it can be said that the alloy of the present invention is sufficiently excellent as a copper alloy for connectors.

Claims (11)

Zn: 24-30 mass%, Sn: 0.7-1.3 mass%, the balance is composed of Cu and inevitable impurities, and satisfies the following formula:
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)
Copper alloy for connectors characterized by a tensile strength in the rolling direction of 600 N / mm ² or more, an electrical conductivity of 18% IACS or more, a Young's modulus of 120 kN / mm ² or less, and a spring limit value of 450 N / mm ² or more . Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass%, Ni: 0.1 to 5.0 mass%, P: 0.01 to 0.3 mass%, and satisfy the following formula Ni, P included,
5.0 ≦ Ni / P ≦ 50
However, Ni: Ni content (mass%)
P: P content (mass%)
The balance is composed of Cu and inevitable impurities, and satisfies the following formula:
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)
Tensile strength in the rolling direction 600 N / mm ² Above, conductivity is 18% IACS or more, spring limit value is 450 N / mm ² The copper alloy for connectors characterized by the above. Tensile strength is 700 N / mm ² It is the above, The copper alloy for connectors of Claim 1 or 2 characterized by the above-mentioned. The copper alloy for connectors according to any one of claims 1 to 3, wherein the stress relaxation rate is 25% or less. The copper for connectors according to any one of claims 1 to 4, wherein the surface of the metal material made of the copper alloy is subjected to a surface treatment of Cu base: 0.3 to 2.0 µm, Sn: 0.5 to 5.0 µm. alloy. Zn: 24-30 mass%, Sn: 0.7-1.3 mass%, the balance consisting of Cu and inevitable impurities, and a copper alloy material satisfying the following formula
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)
The ingot obtained by melting and casting is hot-rolled, and cold rolling and annealing are repeated, and heat treatment is performed at a temperature of 300 to 750 ° C. for 1 to 360 minutes in the annealing before the final cold rolling process. After controlling the crystal grain size to 5 to 20 μm by the above, after the final cold rolling process at a processing rate of 10 to 90%, it is 200 to 600 ° C. for 5 seconds at a temperature higher than the heat treatment temperature at which the spring limit value peaks. A tensile strength in the rolling direction of 600 N / mm, characterized by heat treatment for up to 180 minutes ² Above, electrical conductivity is 18% IACS or more, Young's modulus is 120kN / mm ² Hereinafter, the spring limit value is 450 N / mm ² The manufacturing method of the copper alloy for connectors which is the above. Zn: 24 to 30 mass%, Sn: 0.7 to 1.3 mass%, Ni: 0.1 to 5.0 mass%, P: 0.01 to 0.3 mass%, and satisfy the following formula Ni, P included,
5.0 ≦ Ni / P ≦ 50
However, Ni: Ni content (mass%)
P: P content (mass%)
Copper alloy material with balance of Cu and inevitable impurities and satisfying the following formula
6.0 ≦ 0.25X + Y ≦ 12
However, X: Zn content (mass%)
Y: Sn content (mass%)
The ingot obtained by melting and casting is hot-rolled, and cold rolling and annealing are repeated, and heat treatment is performed at a temperature of 300 to 750 ° C. for 1 to 360 minutes in the annealing before the final cold rolling process. After controlling the crystal grain size to 5 to 20 μm by the above, after the final cold rolling at a processing rate of 10 to 90%, it is 200 to 600 ° C. for 5 seconds at a temperature higher than the heat treatment temperature at which the spring limit value peaks. A tensile strength in the rolling direction of 600 N / mm, characterized by heat treatment for up to 180 minutes ² Above, conductivity is 18% IACS or more, spring limit value is 450 N / mm ² The manufacturing method of the copper alloy for connectors which is the above. 8. The copper alloy for connectors according to claim 6, wherein the heat treatment after the final cold rolling is performed at a heat treatment temperature such that a spring limit value is between 70% and 100% of a peak value. Manufacturing method. The method for producing a copper alloy for connectors according to claim 8, wherein the heat treatment temperature after the final cold rolling is 250 to 300 ° C. The stress relaxation rate of the copper alloy finally obtained is 25% or less, The manufacturing method of the copper alloy for connectors in any one of Claims 6-9 characterized by the above-mentioned. The surface of the copper alloy for connectors is subjected to a heat treatment for 1 to 180 minutes at a temperature of 100 to 280 ° C. after surface treatment of Cu base: 0.3 to 2.0 μm and Sn: 0.5 to 5.0 μm. The manufacturing method of the copper alloy for connectors in any one of Claims 6-10.