JPH04236736A - Copper-base alloy for terminal and terminal using the same - Google Patents

Abstract

PURPOSE:To offer a terminal having high performance and high reliability by regulating its compsn. contg. specified wt.% of Ni, Sn and P and the balance Cu and providing it with specified properties of tensile strength, spring limit value, stress relaxation rate and electric conductivity. CONSTITUTION:The compsn. of a copper-base allay for a terminal is regulated to a one contg., by weight, 0.5 to 3.0% Ni, 0.5 to 2.0% Sn, 0.005 to 0.20% P and the balance Cu with inevitable impurities. Then, the allay is provided with the properties of >=50kgf/mm<2> tensile strength, >=40kgf/mm<2> spring limit value, <=10% stress relaxation rate and 30% IACS electric conductivity. The copper- base alloy is furthermore incorporated with 0.01 to 2.0% Zn. The terminal is incorporated with a spring material. In this way, the terminal excellent in low voltage-low current resistance value and stress relaxation properties can be offered.

Description

Description: FIELD OF INDUSTRIAL APPLICATION The present invention relates to a copper-based alloy used in connector terminals for automobiles, etc., and its terminals. [Prior Art] Regarding copper-based alloys for terminals in automobiles, etc.,
Traditionally brass and phosphor bronze, and even Cu-Sn-Fe
-P-based copper-based alloys have been used. [0003]Problems to be Solved by the Invention With the recent development of electronics, terminals for connectors such as automobiles are required to have higher density, smaller size, lighter weight, and improved reliability. . Furthermore, as the performance of engines increases, the temperature inside the engine room is also rising. Along with this, the copper-based alloy for terminals, which is a conductive material used therein, is also required to have higher reliability and heat resistance. However, brass, which has been conventionally used as a copper-based alloy for terminals, is inexpensive but has low conductivity, for example, C2600 has an IACS of 27%, and also has problems in corrosion resistance and stress relaxation properties. In addition, phosphor bronze has excellent strength but low conductivity; for example, C521
0, the IACS was about 12%, and there were also problems in stress relaxation resistance, and the price was also high, making it uneconomical. C
The u-Sn-Fe-P alloy was developed to compensate for the drawbacks of these two alloys. For example, Cu-2.
0 Sn-0.1 Fe-0.03P, conductivity is 35%
Although it is IACS and has excellent strength, it could not be said that its stress relaxation resistance was sufficiently satisfactory as an alloy for terminals. [0004] Furthermore, in order to improve the reliability of terminals for automobiles, the copper-based alloy used therein has high strength and
It is necessary to have excellent spring limit value and electrical conductivity, and also to not cause stress relaxation or corrosion even after long-term use, but conventional brass, phosphor bronze, and even Cu-Sn-Fe-P
None of the series alloys satisfied the above characteristics. [0005] Furthermore, with respect to terminals manufactured using these copper-based alloys for terminals, the characteristics of these materials are directly linked to the characteristics of the terminal. Terminals made of brass, phosphor bronze, and Cu-Sn-Fe-P alloys do not have both electrical conductivity and stress relaxation resistance.
Self-heating of the terminals can cause oxidation, peeling of plating, stress relaxation, voltage drop in the circuit, and softening or deformation of the housing. Therefore, it is an object of the present invention to provide a copper-based alloy for terminals that is excellent in all of tensile strength, spring limit value, electrical conductivity, and stress relaxation resistance, and to provide at least a spring portion made of this alloy. The purpose of the present invention is to provide a terminal with excellent low voltage, low current resistance and stress relaxation properties. [Means for Solving the Problems] In order to achieve the above object, the present inventors have conducted intensive studies on the above-mentioned problems, and have developed a Cu-Ni-Sn-P based copper-based alloy as the copper-based alloy. and Cu-Ni-Sn-P-Z with further addition of Zn
Through repeated testing and research on n-based alloys, we discovered that by selecting the component composition, satisfactory properties can be obtained in terms of tensile strength, electrical conductivity, and even stress relaxation rate.
We have discovered that a terminal with a built-in spring made from this copper-based alloy, or whose entire body including the spring is made integrally with the copper-based alloy, has excellent performance, and has thus arrived at the present invention. That is, the present invention firstly provides Ni
:0.5-3.0%, Sn:0.5-2.0%
, P: 0.005 to 0.20%, the balance being Cu
It has a composition consisting of unavoidable impurities, and has a tensile strength of 50
kgf/mm2 or more, spring limit value is 40kgf/mm
2 or more, stress relaxation rate is 10% or less and electrical conductivity is 30%
Provided is a copper-based alloy for terminals characterized by having characteristics superior to IACS. The present invention secondly provides that, in weight %, Ni:0
．． 5 to 3.0%, Sn: 0.5 to 2.0%, P
: 0.005 ~ 0.20%, Zn: 0.01 ~ 2.0
%, with the balance consisting of Cu and unavoidable impurities, with a tensile strength of 50 kgf/mm2 or more, a spring limit of 40 kgf/mm2 or more, a stress relaxation rate of 10% or less, and an electrical conductivity of 30% IACS or more. Provided is a copper-based alloy for terminals, which is characterized by having the following characteristics. The third aspect of the present invention is that Ni: 0.5 to 3.0%, Sn: 0.0% by weight.
5 to 2.0%, P: 0.005 to 0.20%, and the balance is Cu and unavoidable impurities, and is processed through hot and cold rolling. To provide a terminal which has a built-in spring made of material or whose entire body including the spring is integrally made of this spring material. Fourthly, the present invention provides Ni: 0.5 to 3.0 in weight%.
%, Sn: 0.5 to 2.0%, P: 0.005
~0.20%, Zn: 0.01~2.0%,
A built-in spring made of a spring material made from a copper-based alloy with the remainder consisting of Cu and unavoidable impurities and processed through hot and cold rolling, or the whole body including the spring made of this spring material. Provides a terminal with a unique configuration. [Function] Next, the function of the additive elements of the Cu-Ni-Sn-P system and Cu-Ni-Sn-P-Zn system copper-based alloy in the present invention and the reason for limiting the range of the components will be explained. [0010] Ni forms a solid solution in the Cu matrix to improve strength, spring limit value, and stress relaxation resistance, and further improves electrical conductivity by forming a compound with P and precipitating in a dispersed manner. Improves strength, spring limit and stress relaxation properties. However, if it is less than 0.5%, the desired effect cannot be obtained, and if it exceeds 3.0%, the effect is saturated, so the preferred range of Ni is as follows:
It is 0.5 to 3.0 wt%. [0011] Sn forms a solid solution in the Cu matrix to improve strength, spring limit and corrosion resistance. However, 0
．． If it is less than 5%, the desired effect cannot be obtained, and if it exceeds 2.0%, the effect is saturated, so the preferred range of Sn is 0.5 to 2.0 wt%. [0012] P acts as a deoxidizing agent for the molten metal, and
By forming a compound with Ni and precipitating it in a dispersed manner, conductivity is improved, and strength and stress relaxation resistance are improved. However, if it is less than 0.005%, the desired effect cannot be obtained, and if it exceeds 0.20%, the effect is saturated, so the preferable range of P is 0.005 to 0.2.
It is 0wt%. Zn, which can be added as a subcomponent, has the effect of improving plating weather resistance. However, 0.
If the Zn content is less than 0.01%, the desired effect cannot be obtained, and if it exceeds 2.0%, the effect is saturated. Therefore, the preferred range of Zn is 0.01 to 2.0 wt%. Next, the characteristics of the terminal in the present invention will be explained. [0015] The insertion/extraction force indicates the coupling force between the male terminal and the female terminal in the terminal, and if it is too strong, it will be difficult to easily insert the male terminal. In particular, as the number of terminals increases due to higher integration, this poses a problem to normal assembly work. On the other hand, if it is too weak, an oxide film is likely to form due to vibration etc. due to the low contact load, resulting in unstable contact resistance and a lack of electrical reliability as a connector. Therefore, the initial insertion/extraction force is 0.2k.
It is desirable that the gf is greater than or equal to 3 kgf, and for that purpose, the terminal material used therein should have a tensile strength of 50 kgf/mm.
2. It is necessary to use a material with a spring limit value of 40 kgf/mm2 or more and a stress relaxation rate of 10% or less. Furthermore, the initial low voltage and low current resistance value is preferably as small as possible, preferably 3 mΩ or less. The magnitude of the contact electrical resistance value is influenced by the magnitude of the decrease in the contact load of the joint due to thermal cycling, but it is also influenced by the stress relaxation caused by the self-heating of the material, as well as the temperature in the engine room and around the exhaust gas system of the automobile. The contact load also decreases due to the stress relaxation caused by the influence of this, and the contact electrical resistance value increases accordingly. For this purpose, the stress relaxation rate of the material itself must be 1
10% or less at 50°C x 1,000 hours, tensile strength of 50kgf/mm2 or more, and spring limit of 40k.
gf/mm2 or more, the conductivity of the material is preferably 30% IACS or more, and the stress relaxation rate after processing into a spring is preferably 20% or less. EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples. [Example 1] An alloy having the composition shown in Table 1 was melted using a high-frequency melting furnace, heated to 850°C, and then melted to a thickness of 5.0 m.
It was hot rolled to a thickness of m. Next, the surface was milled to 4.8m.
m, repeated cold rolling and heat treatment, final processing rate 67%
A plate material having a thickness of 0.2 mm was obtained. Next, the tensile strength, elongation,
In addition to measuring the spring limit value, bending workability, stress relaxation characteristics, etc. were investigated. These results are shown in Table 1 in comparison with conventionally used brass, phosphor bronze and Cu-Sn-P-Fe alloys. [0021] Measurement of tensile strength, electrical conductivity, and spring limit value is carried out by J.
IS H 2241, JIS H 0505, JIS
Compliant with H 3130. [0022] The bending workability was evaluated by a 90°W bending test. The test was conducted in accordance with CES-M0002-6, with a 90°W bending process using a jig with R = 0.1 mm, the condition of the central peak surface was examined, and those with cracks were marked as ×,
Those with wrinkles were rated △, and those with good wrinkles were rated ○. However, the bending axis is parallel to the rolling direction (Bad Wa
y). In addition, in the stress relaxation test, arch bending was performed so that the stress at the center of the specimen was 40 kgf/mm2, and the stress relaxation rate was calculated using the following equation as the bending pattern after being held at a temperature of 150°C for 1,000 hours. Calculated by. Stress relaxation rate (%) = {(L1 - L2)
/(L1 -L0)}×100 (However, L
0: Jig length (mm),
L1: Sample length at start (mm)
L2: Horizontal distance between sample edges after processing (
mm)) [0024] From the above results, sample No. according to the present invention
．． All alloys 1 to 4 have a tensile strength of 50 kgf/mm2
, the spring limit value is 40 kgf/mm2, the electrical conductivity is 30% or more, and the bending workability is also good. Furthermore, the stress relaxation rate is 10% or less, and the stress relaxation resistance is excellent. Therefore, it can be seen that this alloy is extremely excellent as a copper-based alloy for terminals in automobiles and the like. [0025] [Table 1] [0026] [Example 2] Further, the characteristics of a terminal using the copper-based alloy of the present invention will be specifically explained with reference to an example. For evaluation as a terminal, the material of the present invention was pressed and evaluated for stress relaxation properties, which is the aim of the material of the present invention. Using the alloy of the present invention, a female terminal 1 having a spring portion 2 shown in FIG. 1 was pressed. After the material was pressed, it was heat treated to improve its spring properties. The heat treatment conditions include Sn as a surface treatment for the terminal.
In order to perform plating, the temperature was 180℃ x 3 in consideration of surface deterioration.
After performing the treatment for 0 minutes, a stress relaxation property evaluation test was conducted. For comparison with conventional products, female terminals made of Cu-Sn-Fe-P and brass materials were also heat treated under the same conditions and evaluated at the same time. [0030] The initial insertion and removal forces of the terminals are both 0.5 to 0.
．． 6kgf, initial low voltage low current resistance value is 1.5~2
．． It was 0 mΩ. [0031] As a stress relaxation characteristic test, a male terminal was mated with a female terminal, a heat resistance test was conducted, and the contact load before and after the test was measured. In addition, the heat resistance conditions are 120℃, 3
The conditions are 00 hours. The stress relaxation rate was calculated using the following formula. Stress relaxation rate (%) = {(F1 − F2 )
/F1}×100 (F1: initial contact load (gf); F2: contact load after test (gf)) 00
32] The test results are shown in FIG. Conventional product Cu-Sn-F
The stress relaxation rate of the e-P female terminal was about 30%, which was greater in reducing the contact load than that of the female terminal made of the present invention material, and that of the brass material was about 50%. On the other hand, the material of the present invention had a stress relaxation rate of about 12%, satisfying a stress relaxation rate of 20% or less, and was recognized to be superior. In addition, for the electrical performance test, using the same sample as above, a standing test was conducted at 120° C. for 300 hours, and the low voltage and low current resistance values were measured before and after the test. The results are shown in FIG. From the above results, it is clear that the material of the present invention has better electrical performance than the conventional product Cu-Sn-Fe-P.
Superiority was recognized compared to steel and brass materials. Spring portion 2 using copper-based alloy for terminals of the present invention
When a female terminal 1 with a built-in terminal was molded as shown in FIG. 2 and tested in the same manner as in the case of the terminal in FIG. 1, test results equivalent to those in the case of the terminal in FIG. 1 were obtained. From the above, it can be seen that the terminal according to the present invention is very excellent as a terminal for automobiles and the like. The copper-based alloy for terminals of the present invention and terminals using the same can be used not only for automobiles but also for aircraft, ships, etc. Effects of the Invention The copper-based alloy for terminals of the present invention has high tensile strength,
It has excellent spring limit value, electrical conductivity, and stress relaxation properties.Furthermore, terminals made of the above alloy and having internal springs have excellent low voltage, low current resistance, and stress relaxation properties. , which has remarkable industrial effects. That is, according to the present invention, a copper base for a terminal is provided which has the following properties: an electrical conductivity of at least 30% IACS, a high tensile strength and a high spring limit value, and a stress relaxation rate of 10% or less. In addition to obtaining the alloy, the spring made of the copper-based alloy is built in, or the whole including the spring is made of the copper-based alloy.The initial performance is 0.2 kgf or more and 3 kgf of insertion/extraction force is appropriate. Hereinafter, a terminal having characteristics such as a low voltage and low current resistance of 3 mΩ or less and a stress relaxation rate of 20% or less can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an example of a terminal of the present invention.

FIG. 2 is a perspective view of another example of the terminal of the present invention.

FIG. 3 is a graph showing stress relaxation characteristics of the terminal of the present invention and a conventional product.

FIG. 4 is a graph showing the electrical characteristics of the terminal of the present invention and a conventional product.

[Explanation of symbols]

1.Female terminal 2. Spring part

Claims (4)

[Claims] [Claim 1] Ni: 0.5 to 3.0 in weight%
%, Sn: 0.5 to 2.0%, P: 0.005 to
0.20%, with the balance consisting of Cu and unavoidable impurities, tensile strength is 50 kgf/mm2 or more, spring limit value is 40 kgf/mm2 or more, stress relaxation rate is 10% or less, and electrical conductivity is 30%. A copper-based alloy for terminals that is characterized by having properties that are better than IACS. [Claim 2] Ni: 0.5 to 3.0 in weight%
%, Sn: 0.5 to 2.0%, P: 0.005 to
0.20%, Zn: 0.01-2.0%, the balance is Cu and unavoidable impurities, the tensile strength is 50 kgf/mm2 or more, and the spring limit is 40 kgf.
/mm2 or more, stress relaxation rate of 10% or less, and electrical conductivity of 3
A copper-based alloy for terminals characterized by having characteristics of 0% IACS or higher. [Claim 3] Ni: 0.5 to 3.0 in weight%
%, Sn: 0.5 to 2.0%, P: 0.005 to
0.20%, with the balance consisting of Cu and unavoidable impurities. A terminal whose entire structure including the spring is integrated. Claim 4: Ni: 0.5 to 3.0 in weight%
%, Sn: 0.5 to 2.0%, P: 0.005 to
0.20%, Zn: 0.01~2.0%, and the balance is Cu and unavoidable impurities. A terminal that has a built-in spring built-in, or is made entirely of this spring material, including the spring.