JPH0250184B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a copper-based alloy for connectors that has excellent spring properties and moldability and is suitable as a signal microcurrent connector material used, for example, in electrical wiring for automobiles. [Conventional technology and problems] Signal microcurrent connector materials used for automotive electrical wiring, etc., especially the female terminals of the connector, have high springiness and can be processed into complex molding processes. It is necessary to have excellent partial Au plating properties in order to lower the soldering temperature, and excellent Sn plating properties in order to prevent discoloration of the material surface and maintain good solderability. However, there is currently no material that satisfies all of the above characteristics at the same time, so when used for such purposes, a spring material with good spring characteristics and a frame material with good moldability are combined and processed. There is usually one. At that time, beryllium copper (C-1720) and Cu-9Ni- are used as spring materials.
6Sn alloy etc. are used, and the frame material is brass (C-2600) with good moldability or Cu-
0.1Fe−0.03P alloy etc. were mainly used. However, such conventional technology has the following problems. (1) The contact parts of the spring material are plated with Au to reduce contact resistance, and the other parts are plated with Sn in consideration of corrosion resistance and solderability. The material is subjected to age hardening treatment at a temperature range of 315 to 450° C. after press molding to develop spring properties, and for this reason, the plating treatment is a post-plating treatment performed after pressing. For this reason, the manufacturing cost is significantly higher than the tip plating process in which plating is performed before pressing. (2) Beryllium copper has excellent moldability before hardening, but it is expensive and uneconomical to use in integrally molded products for female terminals. (3) If the spring member and frame member are manufactured from different alloys and assembled in the final process, the number of man-hours increases and the processing cost increases. (4) The operating environment for connector materials used in automobile electrical wiring, etc. has become more severe, and it is now required that the contact pressure does not change even when exposed to an atmosphere of about 150 to 200 degrees Celsius for a long time. In conventional connectors manufactured by combining two types of materials,
This condition could no longer be satisfied. (5) This combination product is not economical because the cost of separating it increases when it is reused as scrap. [Object of the Invention] The object of the present invention is to solve the above-mentioned problems and provide an economical material for a connector that has the following characteristics and can integrally mold a spring part and a frame part. It is. Specific characteristic values required for such materials include: Electrical conductivity: %IACS10-20 range, Spring limit value: 45Kgf/mm2 or ^more , Press formability: 90°W bending test (CES-M- 0002
-6) and the ratio of bending radius R to plate thickness t R/t
= 1.0, a good bending surface can be obtained. Stress relaxation property, which is an indicator of whether or not the spring maintains stable contact pressure: Stress relaxation rate is 10% even after being exposed to an atmosphere of 200℃ x 500 hours. Below, plating reliability: 150 after Au plating and Sn plating processing
The plating does not peel off even after being subjected to a 90°W bending test after being exposed to an atmosphere of ℃ x 500 hours. The purpose of the present invention is to develop a material that has the above-mentioned properties, and furthermore, by appropriately adjusting the crystal grain size (refining), it is possible to bend the material. The object of the present invention is to prevent surface roughness during drawing or drawing processing, and to prevent plating peeling during processing of plated products. [Summary of the Invention] The connector material according to the present invention, which aims to achieve the above object, contains Ni: 7-15 wt.%, Al: 1.0-1.
In addition to the basic chemical components of 2.0 wt.% and _O2 : 0.0050 wt.% or less, this is a copper-based alloy for connectors that further contains B: 0.01 to 0.1 wt.%, with the balance consisting of Cu and inevitable impurities. [Detailed Description of the Invention] In the alloy of the present invention, Ni is an essential element that functions beneficially to improve strength and corrosion resistance. In particular, by forming a fine intermetallic compound of Ni _x Al _Y with the co-added element Al and precipitating this in the copper matrix, the strength and spring limit value can be improved. However, when Ni exceeds 15 wt%, the electrical conductivity decreases and the Ni content increases, leading to an increase in material price. In addition, Ni is 7%
If the Al content is less than that, the strength and spring limit value can be improved by increasing the amount of Al, but the bending workability deteriorates. Therefore, in the copper-based alloy of the present invention
Ni is contained in a range of 7 to 15 wt.%. Al is an essential element that contributes to improving the strength and spring limit value in the copper-based alloy of the present invention.
However, if it exceeds 2.0 wt.%, bending workability deteriorates, making it impossible to form a connector integrally. Also
If it is less than 1.0 wt.%, sufficient improvement in strength and spring limit value cannot be expected, so Al is contained in a range of 1.0/-2.0 wt.%. When O ₂ exceeds 50 ppm, it reacts with Al in the alloy.
The amount of Al required to form Al ₂ O ₃ and improve strength decreases. Furthermore, the dispersion of Al ₂ O ₃ in the structure causes the problem of shortening the life of the press die. Therefore, it is necessary to regulate O ₂ to less than 50 ppm. As described above, the copper alloy of the present invention contains Ni: 7 to 15 wt.
%, Al: 1.0 to 2.0 wt.%, O ₂ : 0.0050 wt.% or less as basic chemical components, and the feature is that B: 0.01 to 0.1 wt.% is further included in this basic component system. There is. That is, B functions to prevent coarsening of crystal grains during solution treatment of the alloy of the present invention. The alloy of the present invention is solution-treated,
After the necessary processing, aging treatment is performed to finely precipitate the Ni-Al intermetallic compound mentioned above, thereby achieving the desired characteristics. Refinement is also advantageous in exhibiting these properties, and by making the crystal grains finer, it is possible to improve bending workability and prevent surface roughness during drawing, and it also improves plating during bending after plating. peeling can be prevented. Furthermore, since coarsening of crystal grains during solution treatment is suppressed by the addition of B, the optimum range of treatment conditions for solution treatment is expanded, making the solution treatment itself easier. Even if the amount of B added exceeds 0.1wt.%, this effect will be saturated and it will be economically wasteful, and if the amount of B added is less than 0.01wt.%, this effect will be small. The amount of addition is preferably 0.01 to 0.1 wt.%. In order to manufacture a connector material made of the copper-based alloy according to the present invention having the above-mentioned composition, a slab having the above-mentioned composition is hot-rolled to form a hot-rolled plate, and the hot-rolled plate is It is practical to cold-roll the material to form a plate material. Then, it is preferable to perform solution treatment during this process. Solution treatment can also be applied to hot-rolled sheets, but when cold-rolling a hot-rolled sheet several times to reduce its thickness, intermediate annealing is performed between cold-rolling. It is also possible to perform a solution treatment that also serves as a solution treatment. The solution treatment conditions include heat treatment at 800 to 1000°C for 1 to 120 minutes, preferably heat treatment at 900 to 950°C for 1 to 30 minutes. Further, the aging treatment is preferably performed after the final cold rolling, and the aging treatment may be performed after processing into the final product. This aging treatment is performed at 350-600℃
The temperature is preferably 400 to 500°C for about 30 minutes. The characteristics of the alloy of the present invention will be specifically shown below by way of Examples. Example 1 An alloy with the basic composition shown in Table 1 is melted in a high-frequency vacuum melting furnace, and a 40 mm (width) × 40
It was cast into an ingot of mm (thickness) x 150 mm (length). After face-cutting this ingot, it was heated to 900°C, homogenized, hot-rolled, and immediately after hot-rolling, it was rapidly cooled. This hot-rolled plate was then repeatedly subjected to cold rolling and solution treatment at 900°C to obtain a plate material with a thickness of 0.8 mm. This 0.8 mm cold rolled sheet was solution treated at 900°C for 20 minutes, immediately cooled in water, final cold rolled to 0.4 mm at a processing rate of 50%, and aged at 500°C for 30 minutes. Test pieces were taken from each of the obtained plates and examined for mechanical strength, elongation, hardness, spring limit value, electrical conductivity, and bending workability. The results are also shown in Table 1. In addition, the measurement of mechanical strength and elongation is based on JIS-Z-
2241, conductivity was measured in accordance with JIS-H-0505, hardness was measured in accordance with JIS-Z-2244, and spring limit value was measured in accordance with JIS-H-3130. The bendability is
It was evaluated by a 90°W bending test according to CES-M-0002-6. Bending radius R = 0.4mm, plate thickness = 0.4
mm, R/t=1.0. In the table, GW is the test result when the bending axis is perpendicular to the rolling direction, and BW is the test result when the bending axis is parallel to the rolling direction.
A good bending surface was evaluated as ◯, a case with wrinkles on the bending surface as △, and a case with cracks on the bending surface as ×. As can be seen from the results in Table 1, all of the basic composition alloys No. 1 to 5 of the present invention simultaneously satisfy the target properties such as spring limit value, electrical conductivity, and bending workability described in the text. it is obvious. On the contrary
In Comparative Examples No. 6 and No. 7, in which Al was added in a larger amount than the amount stipulated in the present invention, even if Ni was added (Comparative Example No.
6), and at least (Comparative Example No. 7) the bending workability is poor. Further, in Comparative Example 8, in which the amount of Al is smaller than the amount specified in the present invention, the strength, spring limit value, and hardness are low, and the conductivity and bending workability are also insufficient.
Furthermore, a comparative example in which O ₂ is greater than the amount specified in the present invention
In No. 9, the bending workability was poor even though Al was within the range specified by the present invention (Ni was also within the range specified by the present invention).

【table】

[Table] Example 2 Ni: 11wt.%, Al: 1.7wt.%, ₀₂ : 0.0050wt.%
Below, the copper-based alloy of the basic composition system of the present invention, the balance of which is Cu and unavoidable impurities, is melted in a high-frequency melting furnace and cast to 10 mm (thickness) x 50 mm by horizontal continuous casting method.
An ingot of (width) x L (length) was cast. A plate with a thickness of 0.4 mm was produced from the obtained ingot in the same manner as in Example 1, and heated at 500°C for 30
Aged for 1 minute. Then, the characteristic values were investigated in the same manner as in Example 1, and the results are shown in Table 2. For comparison, commercially available phosphor bronze for springs (C-
5210) EH material and beryllium copper (C-1720)
Table 2 also shows the characteristic values of the 1/4H material that was heat-treated at 315°C for 2.5 hours. From the results in Table 2, it can be seen that the basic component alloy of the present invention has better bending workability than phosphor bronze or beryllium copper. Next, the stress relaxation properties of the three types of alloys were investigated.
In the stress relaxation property test, a load is applied to the test piece so that a maximum bending stress of 60Kgf/ ^mm2 acts on it, the test piece is bent, and after being held at 200℃ for a specified period of time (up to 500 hours), the load is released and the test piece is The evaluation was made by measuring the amount of deformation (%). The results are shown in Figure 1. As is clear from the results in Figure 1, phosphor bronze (C-5210) EH material has the worst stress relaxation properties;
It can be seen that the stress relaxation rate of the heat treated material of beryllium bronze (C-1720) 1/4H becomes 10% or more after 200°C x 100 hours. However, the basic composition alloy of the present invention has stress relaxation properties of about 5% even after 500 hours at 200°C, and it is clear that it exhibits stable contact pressure when used as a spring under such conditions. . In addition, a plating reliability test was conducted on the three types of alloys. First, each of the three types of alloys was subjected to Au plating or Sn plating treatment. Au plating is electrolytically degreased and pickled, then copper strike plating is applied and a wax bath is applied.
After applying Ni plating, alkaline degreasing and pickling again, Au plating was applied to a thickness of 0.2μ in an acid bath. Sn
After electrolytic degreasing and pickling, some are made of Cu.
One was plated with a base plating, and the other was without a Cu base plating, and a 2μ thick matte Sn plating was applied on top of it in a sulfuric acid bath. In all cases of plating, the plating properties of the three alloys were good. Next, each plated product obtained was heated at 150℃×500Hr.
After being subjected to heat treatment, a 90°W bending test was conducted to investigate the adhesion of the plating on the bent surface, and to determine whether the adhesion was good or bad. The results are shown in Table 3. As seen in the results in Table 3, the basic composition alloy of the present invention has been subjected to Cu underplating treatment and Sn
Adhesion was good except for those that were plated. In the case of Sn plating with a Cu base plating, an intermetallic compound of Cu and Sn was formed at the plating interface, and it is presumed that the intermetallic compound was peeled from there, and this is thought to be due to the properties of the plating itself. On the other hand, the Sn plating of the heat-treated phosphor bronze (C-5210) EH material and beryllium copper (C-1720) 1/4H material was completely peeled off regardless of the presence or absence of the Cu base plating. As described above, it has been found that the basic component alloy of the present invention has very good plating properties.

【table】

【table】

[Table] Example 3 As shown in Table 4, an alloy with an appropriate amount of B added to the basic composition alloy was melted in a high-frequency vacuum melting furnace, and the resulting material was 40 mm (width) x 40 mm (thickness). ×
Cast into a 150mm (length) ingot. After face-cutting this ingot, it was heated to 900°C, homogenized, hot-rolled, and immediately after hot-rolling, it was rapidly cooled. This hot-rolled plate was then repeatedly subjected to cold rolling and solution treatment at 900°C to obtain a plate material with a thickness of 0.6 mm. A test piece was taken from the obtained 0.6 mm cold-rolled material.
After solution treatment at 900℃ for 60 minutes, immediately cool with water.
The hardness and grain size of each alloy were measured. The results are shown in Table 5. In addition, the test piece after solution treatment can be made up to 0.3 mm.
The samples were cold rolled at a processing rate of 50% and aged at 500°C for 30 minutes, and the bending workability of the obtained samples was investigated. The results are also listed in Table 5. The bendability is
It was evaluated by a 90°W bending test according to CES-M-0002-6. Bending radius R = 0.3mm, plate thickness = 0.3
mm, R/t=1.0. In the table, GW is the test result when the bending axis is perpendicular to the rolling direction, and BW is the test result when the bending axis is parallel to the rolling direction.
A good bending surface was evaluated as ◯, a case with wrinkles on the bending surface as △, and a case with cracks on the bending surface as ×. As seen in the results in Table 5, it can be seen that in the alloys of the present invention to which B is added, as the amount of B added increases, the hardness after solution treatment increases and the grain size decreases. Furthermore, it can be seen that the bending workability after aging treatment also becomes better when B is added and the crystal grain size is fine. In addition
Comparative alloy No. 13 had excessive time in the solution treatment process, so the crystal grain size grew large and the bending workability deteriorated.

【table】

[Table] Hardness and grain size: After solution treatment Bending workability: After aging treatment As is clear from the above examples, the alloy of the present invention is required for connector materials, especially conventional connector materials for microcurrents in automobiles. It has excellent bending workability while meeting the electrical conductivity and spring limit values.
Therefore, according to the present invention, it is possible to provide a material for a connector which has an advantage over conventional materials (two-piece materials) in that the spring portion and the frame portion can be integrally molded. Furthermore, unlike beryllium-copper alloys, it does not contain expensive elements and exhibits stress relaxation properties superior to those of other alloys, so it is economically and economically superior in terms of properties, and it also has sufficient plating reliability. Since we have succeeded in increasing the operating environment of the connector to 200°C, we will provide a new, inexpensive material for the field of connector materials.

[Brief explanation of drawings]

FIG. 1 is a diagram showing changes in stress relaxation rates of the basic composition alloy of the present invention and a known alloy at 200° C. for 500 hours.

Claims (1)

[Claims] 1 Ni: 7-15wt.%, Al: 1.0-2.0wt.%, _O2 :
A copper-based alloy for connectors containing 0.01 to 0.1 wt.% of B in addition to 0.0050 wt.% or less of basic chemical components, with the remainder consisting of Cu and inevitable impurities.