JP2002038246A - Forming and heat treatment process for copper alloy electric connector material and copper alloy for electric connector material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming and heat treatment process for an electric connector material with spring properties and a copper alloy suitable for electric connector material. SOLUTION: This is a forming/heat treatment process for a copper alloy used for electric connector components wherein heat treatment is provided subsequent to forming process. The electric connector alloy material is formed into a spring component maintaining the change in the hardness of spring portion less than 10 in terms of Vickers hardness (Hv) before and after it is formed. It is followed by heat treatment in which the change in the hardness of spring portion is maintained less than 10 in terms of Vickers harness (Hv) before and after the heat treatment. The heat treatment is preferably performed at the temperature range of 200-800 degrees Centigrade for 5-10,000 seconds.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heat-treating a copper alloy for an electric connection member including a spring used for an electric terminal, a switch, and the like, and a copper alloy for the electric connection member.

[0002]

2. Description of the Related Art A member for an electric connection member utilizing the spring characteristics of a metal material is generally used. A so-called electric connection mechanism of a terminal or a switch is brought into firm contact with a counterpart material with the spring property of a metal. In most cases, an electrical connection is obtained. A box-shaped terminal that is often used in automobiles and the like typically has a structure as shown in FIG. 1, in which the tongue piece 42 of the female terminal 4 serves as a spring and the male terminal 2 is inserted. When the spring is bent, the contact force with the male terminal 2 is obtained by the reaction force.

Various approaches have been taken to increase the reliability of electrical contacts, and for example, techniques such as surface modification by plating or the like and enhancement of contact force (hereinafter referred to as "joining") are widely used. ing. This contact pressure is not always constant, and "sagging" occurs in the spring portion due to repeated insertion / removal, and a sufficient contact pressure cannot be obtained, or a metal portion creeps, and the contact pressure gradually decreases ( Stress relaxation phenomenon)
Often.

In recent years, in particular, with the miniaturization of equipment, the electrical connector itself has also become smaller and thinner, and the thickness of the metal plate used has been decreasing. Even if the same contact pressure is obtained, it is necessary to increase the amount of deflection of the spring if the plate material becomes thinner, and the maximum stress applied to the plate material is so high that it does not become comparable to before. As a result, sag due to insertion / extraction tends to occur.

[0005] In addition, especially in the case of a connector for an automobile, the environment temperature in which the connector is used becomes high, so that stress is more easily alleviated. In view of such a situation in which the contact pressure tends to change with time, the initial contact pressure is designed to be particularly high so that the necessary minimum contact pressure can be maintained for a long period of time.

On the other hand, the number of poles of the connector tends to increase due to an increase in the number of input / output terminals, and an increase in insertion / extraction force at the time of insertion / extraction of the connector has become a problem. That is, even if the contact pressure of each pair of contacts becomes slightly higher, the insertion / removal force required when inserting / removing the connector in a multi-pole connector is greatly changed. For example, when assembling an automobile, a connector is usually fitted by a human hand. However, a high insertion / extraction force causes an increase in load at the time of assembly and a deterioration in work efficiency.

[0007] As described above, the present situation is such that a dilemma arises in the conflicting desire to increase the initial contact pressure but to reduce the insertion / extraction force. Naturally, surface modification is being promoted in order to obtain a low friction coefficient in order to keep the insertion force low while keeping the contact pressure high.However, a technology that achieves both electrical reliability and a low friction coefficient has been developed. Absent.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above.
It is an object of the present invention to provide a metal spring member for an electric connection member in which the contact pressure does not change with time without increasing the initial contact pressure.

[0009]

According to a first aspect of the present invention, there is provided a method of working and heat-treating a copper alloy for an electric connection member, wherein the copper alloy is formed from a material as a spring. The Vickers hardness (Hv) of the processed part before and after processing is processed so that the change is 10 or less, and then, when heat treatment is performed, the Vickers hardness (Hv) change of the part before and after the heat treatment is set to 10 or less. This is a method of working and heat-treating a copper alloy for an electric connection member, wherein the heat treatment is performed.

A second aspect of the present invention is a thermomechanical heat treatment method, wherein the heat treatment after the forming is performed at a temperature of 200 to 800 ° C. for 5 to 10,000 seconds.

A third aspect of the present invention is a Vickers hardness (Hv) before and after forming a spring from a material.
Any one of the following component compositions for performing a heat treatment so that the change in the Vickers hardness (Hv) of the site before and after the heat treatment before and after the heat treatment is performed so that the change is within 10 A copper alloy for electrical connection members containing one or more species, the balance being Cu and unavoidable impurities ("0 wt%" means no addition in the following). Sn: 0 to 10 wt%, Zn: 0 to 40 wt%, Ni: 0 to 10 wt%, Fe: 0 to 3 wt%, Cr: 0 to 1 wt%, Mn: 0 to 1 wt%, P: 0 to 0.5 wt% , Si: 0 to 1 wt%, Mg: 0 to 1 wt%, Zr: 0 to 0.5 wt%, Ti: 0 to 1 wt%, Co: 0 to 1 wt%, Ag: 0 to 1 wt%, Al: 0 to 5 wt %, B: 0 to 0.5 wt%, Rare earth element: 0 to 0.5 wt%.

In a fourth aspect of the present invention, there is provided a copper alloy for an electrical connection member, wherein the heat treatment performed after the forming is performed at a temperature of 200 to 800 ° C. for 5 to 10,000 seconds.

According to a fifth aspect of the present invention, the copper alloy for an electric connection member is a copper alloy composed of Ni: 1 to 4 wt%, Si: 0.1 to 1.0 wt%, and the balance being Cu and unavoidable impurities. It is a copper alloy for electric connection members characterized by the above-mentioned.

According to a sixth aspect of the present invention, the copper alloy for an electric connection member comprises: Ni: 1-4 wt%, Si: 0.1-1.0 wt%, and further Sn, Mn, M
g, Zn, Ag and at least one selected from Ag in a total amount of 0.005 to
A copper alloy for electric connection members, characterized in that the copper alloy contains 1 wt% and the balance is Cu and unavoidable impurities.

In a seventh aspect of the present invention, the copper alloy for an electric connection member is a copper alloy comprising Sn: 0.5 to 3 wt%, P: 0.005 to 0.5 wt%, and the balance being Cu and unavoidable impurities. It is a copper alloy for electric connection members characterized by the above-mentioned.

According to an eighth aspect of the present invention, the copper alloy for an electric connection member comprises: Sn: 0.5 to 3 wt%, P: 0.005 to 0.5 wt%, Ni, Mn, F
e, at least one selected from Cr, Mg and Zn in a total amount of 0.005 to
A copper alloy for electric connection members, characterized in that it is a copper alloy containing 2 wt% and the balance being Cu and unavoidable impurities.

A ninth aspect of the present invention is characterized in that the copper alloy for an electric connection member is a copper alloy comprising Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, and the balance being Cu and unavoidable impurities. It is a copper alloy for electrical connection members.

[0018] In a tenth aspect of the present invention, the copper alloy for an electrical connection member is composed of Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, Ni, Fe
And a copper alloy containing 0.005 to 2 wt% in total of at least one selected from Zn and Zn, with the balance being a copper alloy comprising Cu and unavoidable impurities.

According to an eleventh aspect of the present invention, the copper alloy for an electrical connection member is a copper alloy comprising Zn: 5 to 35 wt%, and the balance being Cu and unavoidable impurities. It is a copper alloy.

In a twelfth aspect of the present invention, the copper alloy for an electric connection member contains Zn: 5 to 35 wt%, and further contains at least one selected from Sn, Ni and Fe in a total amount of 0.005 to 2 wt%. The copper alloy for electric connection members, the balance being a copper alloy comprising Cu and unavoidable impurities.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Copper alloys for electrical connection members include:
Excellent spring characteristics are required. The spring characteristic is evaluated by a spring limit value, which is a bending stress value corresponding to a proof stress obtained from a tensile test, and is defined as follows. The spring limit value (Kb) is 3 when the surface stress due to bending is 3
This is the surface maximum stress that causes permanent deformation equivalent to elastic deformation when E / 8 × 10 ⁴ .

In general, low-temperature annealing is known as a method for increasing the spring limit value. The reason why low-temperature annealing improves the spring limit value is considered to be that dislocations generated by plastic working before low-temperature annealing rearrange by heat treatment. Therefore, in the present invention, an appropriate plastic working is performed in advance to disturb the arrangement of dislocations, and then appropriate low-temperature annealing is applied to obtain a copper alloy member for an electrical connection member having excellent spring characteristics. is there.

A basic aspect of the present invention is a method of working and heat-treating a copper alloy for an electric connection member, which is subjected to a forming process and a heat treatment thereafter, wherein the copper alloy for an electric connection member is formed from a material such as a plate or a rod / wire by a spring. The Vickers hardness (Hv) change of the processed part before and after the forming process is made to be within 10 and then, when the heat treatment is performed, the Vickers hardness (Hv) change of the part before and after the heat treatment is changed by 10 This is a thermomechanical treatment method for performing a heat treatment within the range. Here, when the degree of spring working is determined, refining is performed by appropriate plastic working or heat treatment in advance so that the change in hardness is within 10 when predetermined working is performed.

The part acting as a spring is work-hardened during bending and changes in Vickers hardness (Hv). Even the heat treatment applied cannot sufficiently improve the characteristics as a spring. This is because the rearrangement of dislocations cannot be sufficiently performed by the subsequent low-temperature annealing.

Next, the reason why the heat treatment temperature is generally limited to 200 to 800 ° C. as a condition of the low temperature annealing as the heat treatment will be described. If the temperature is lower than 200 ° C., the characteristics of the spring portion cannot be improved, and if the temperature is higher than 800 ° C., the work material is excessively softened, which is not appropriate. Processing time 5
The reason for setting to 10000 seconds is that even if the temperature is as high as about 800 ° C., a sufficient property improving effect is not recognized if the time is less than 5 seconds. This is because of saturation.

Desirable conditions for the above-mentioned processing temperature and processing time differ depending on the material of the copper alloy used as the spring member, and typical materials and processing conditions will be described below. As a copper alloy used for a connector, there is a Cu-Ni-Si alloy (also called a Corson alloy). 1-4 wt% N
i, an alloy containing 0.1 to 1.0 wt% of Si and the balance substantially consisting of copper is known. In addition to the above alloy,
1 selected from n, Mn, Mg, Zn, Ag, and Co
There is also known a copper alloy spring member containing at least 0.005 to 2 wt% of seeds and the balance substantially consisting of copper. For these, the optimal temperature is 300-750 ° C., and 5-10
A processing time of 000 seconds is preferred. When the treatment is performed at a temperature lower than 300 ° C., the properties of the spring portion are not sufficiently improved. On the other hand, when the temperature exceeds 750 ° C., the hardness becomes 10 or more before and after the heat treatment, which is not desirable.

The brass-based material most frequently used as a copper alloy will be described. For a spring member containing 5-35 wt% Zn and the balance substantially consisting of copper,
The optimum temperature is from 00 to 600 ° C., and a treatment time of from 5 to 10,000 seconds is preferred. When the treatment is performed at a temperature lower than 200 ° C., the characteristics of the spring portion are not sufficiently improved. On the other hand, when the treatment is performed at a temperature higher than 600 ° C., the hardness becomes 10 or more before and after the heat treatment.

Next, the heat treatment performed after the forming process including the bending process will be described. Strictly, the heat treatment conditions differ depending on the material to be processed. However, if the Vickers hardness change before and after the heat treatment is -10 to 10 in general, a good member having little change with time in the contact pressure can be manufactured. Here, the hardness before the heat treatment is the hardness of the portion where the bending process is performed, and the hardness must be compared with the hardness of the same portion after the heat treatment. If the Vickers hardness change is more than 10 and becomes soft, it is unsuitable because both the set and the stress at the time of insertion and removal become too large.

Further, there is a metal material such as beryllium copper which is subjected to a heat treatment for causing age hardening after forming including bending. If these metal materials are further subjected to bending after age hardening, they are too hard, causing cracks in the bent portions, and cannot be processed normally. Therefore, to prevent cracking, an age hardening treatment is performed after bending, but in this case, there is a significant hardness change of 50 or more in Vickers hardness (Hv). The technology of age hardening after the bending is different from the present invention also in its technical meaning, and the technology is not included in the present application.

As a metal material to which the above-mentioned thermomechanical treatment can be applied, there is a copper alloy having the following composition. That is, a copper alloy for an electric connection member containing any one or more of the following component compositions and the balance consisting of Cu and unavoidable impurities ("0 wt%" in the following means no addition). Sn: 0 to 10 wt%, Zn: 0 to 40 wt%, Ni: 0 to 10 wt%, Fe: 0 to 3 wt%, Cr: 0 to 1 wt%, Mn: 0 to 1 wt%, P: 0 to 0.5 wt% , Si: 0 to 1 wt%, Mg: 0 to 1 wt%, Zr: 0 to 0.5 wt%, Ti: 0 to 1 wt%, Co: 0 to 1 wt%, Ag: 0 to 1 wt%, Al: 0 to 5 wt %, B: 0 to 0.5 wt%, Rare earth element: 0 to 0.5 wt%.

The above alloys have been described comprehensively.
However, more specifically, it is desirably applied to a copper alloy having the following composition. Ni: 1-4 wt%, Si: 0.1-1.0 wt%, the balance being a copper alloy composed of Cu and unavoidable impurities. This alloy is an alloy called a so-called Corson alloy.

Further, as the copper alloy for the electric connection member, Ni: 1-4 wt%, Si: 0.1-1.0 wt%, and Sn, Mn, M
g, Zn, Ag and at least one selected from Ag in a total amount of 0.005 to
It is also desirable to use a copper alloy containing 1 wt%, with the balance being Cu and unavoidable impurities.

Further, as the copper alloy for an electric connection member, a copper alloy comprising Sn: 0.5 to 3 wt%, P: 0.1 to 1.0 wt%, and a balance of Cu and unavoidable impurities is desirable.

Further, as the copper alloy for the electric connection member, Sn: 0.5 to 3 wt%, P: 0.1 to 1.0 wt%, Ni, Mn, F
e, Cr, Mg, at least one selected from Zn, 0.005 to 2 in total amount
It is also desirable to use a copper alloy containing wt%, with the balance being Cu and unavoidable impurities.

Further, as the copper alloy for electric connection members, Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, and the balance can be applied to a copper alloy composed of Cu and unavoidable impurities.

Further, the copper alloy for an electric connection member comprises: Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, and Ni, Fe
And a copper alloy containing at least one selected from Zn and 0.005 to 2 wt% in total, with the balance being Cu and unavoidable impurities.

Further, as the copper alloy for the electric connection member, a copper alloy consisting of Zn: 5 to 35 wt% and the balance consisting of Cu and unavoidable impurities can be used.

Further, the copper alloy for an electric connection member contains Zn: 5 to 35 wt%, and further contains at least one selected from Sn, Ni and Fe in a total amount of 0.005 to 2 wt%, with the balance being Cu and unavoidable. Copper alloys composed of chemical impurities can also be used.

[0039]

Example 1 A copper alloy (A: Corson alloy, B, C: bronze, D: brass) having the composition shown in Table 1 shown in FIG.
A 0.25mm thick material is processed into a female terminal with the shape shown in Fig. 1,
After processing, heat treatment was performed under the conditions shown in Table 2 shown in FIG. In the conventional example, no heat treatment is performed, and in the comparative example, the temperature or the heat treatment time is inappropriate. The heat treatment was performed in a sealed small electric furnace capable of rapid heating and rapid cooling. The test was performed in a non-oxidizing atmosphere with a thermocouple attached to a non-processed material.

In the evaluation of the characteristics, the hardness, the set of the spring portion, and the stress relaxation characteristics were evaluated. Each evaluation method is described. <Hardness> It is necessary to perform the measurement at a bent portion that acts as a spring. In order to measure the hardness of the bent portion, the work was buried in a resin, and the measurement was performed on the polished cross section. The measurement was made at three locations in the cross section of the bent portion at a portion radially outward from the center of the plate thickness in the bending direction. In addition, three places where no bending was performed were also measured, and a change in hardness before and after the bending was calculated based on an average value of each of the three parts. Next, the Vickers hardness (Hv) after the heat treatment was measured. The hardness measuring section is the above-mentioned bending section. The change in hardness before and after the heat treatment was determined from the difference between the averages of the three points.

<Spring Set> Sample 5 after heat treatment
For each sample, the gap interval shown in FIG. 1 was measured a plurality of times, and the average value A was obtained. Also, after the heat treatment, the male tab was inserted as shown in FIG. 2, and after holding for 60 seconds, the gap interval was similarly measured a plurality of times for five samples from which the male tab was removed, and the average value B was obtained. Then, the difference between A and B was determined, and the spring portion after insertion and removal of the male tab was set.

<Stress Relaxation Property> A male tab was inserted into each of the five heat-treated samples, and a relaxation treatment was performed at 150 ° C. for 500 hours in this state. After the elapse of 500 hours, remove from the processing furnace, remove the male stub, measure the gap interval indicated by l, determine the average value C of 5 pieces, determine the difference between A and C, and set the amount of relaxation .

The gap was measured by embedding the terminals in a resin and observing the cross section after polishing. The measurement results are shown in Table 3 shown in FIG. In the bent portion of this example, the change in hardness before and after bending of any of the materials A to D was within 10 or less. According to Table 3 in FIG. 6, conventional example No. in which no heat treatment is performed after the forming process including the bending process. 14
Nos. 17 to 17 are inferior in the amount of settling of the spring portion and the amount of stress relaxation. Invention Example No. No. 1-13
It turns out that it shows very excellent characteristics.

In addition, No. 19, 20, 23,
The hardness after heat treatment of both 25 and 27 is 10 times higher in Hv than before treatment.
It is clear that it is softer, and the amount of relaxation and the amount of relaxation of the spring part are greatly deteriorated. As described above, it is important to perform the heat treatment to the extent that the workpiece is not excessively softened.
The optimum heat treatment conditions differ depending on the material.

[0045]

Example 2 Test pieces (a, b, c) having different hardness changes during bending of the C material were prepared, and the same test as in Example 1 was performed. The heat treatment conditions were the same as in No. 1 shown in Example 1. Performed under the same conditions as 10. The results are shown in Table 4 as FIG. No. was originally soft. In No. 30, the change in hardness before and after bending was 12, and the characteristics as a spring were No. 3 of the present invention. 28 and No. 29
Was inferior to In other words, this is an example showing that, depending on the heat treatment conditions of the test piece before bending, the hardness change in bending is different even under the same processing, and the spring characteristics are inferior under the conditions other than the present invention. Although the present invention has been described with reference to the copper alloy, the present invention can be applied to, for example, carbon steel and stainless steel in principle.

[0046]

As described above, when the thermomechanical treatment method of the present invention is applied to a copper alloy for an electric connection member, the sag of the spring portion and the stress relaxation characteristics are improved, and the contact pressure can always be kept high. It is possible. Further, since the change with time of the contact pressure is small, it is not necessary to design the initial contact pressure to be particularly high. Therefore, it is possible to contribute to a reduction in insertion force. Further, the copper alloy to which the above-mentioned thermomechanical treatment method is applied can be used as an electrical connection member for a long time. Therefore, the present invention has a remarkable industrial contribution.

[Brief description of the drawings]

FIG. 1 is a diagram showing an example of a shape of an electric connection member including a spring.

FIG. 2 is a diagram showing a state in which a male part and a female part of the electrical connection part are connected.

FIG. 3 is a diagram showing a portion where the hardness of a bent member is measured.

FIG. 4 is a diagram showing the composition of the tested alloy components as Table 1.

FIG. 5 is a table showing heat treatment temperatures tested as Table 2.

FIG. 6 is a graph showing a change in hardness, a set of a spring portion, and an amount of relaxation before and after a heat treatment tested.

FIG. 7 is a table showing a relationship between a change in hardness before and after bending and a spring characteristic when the spring is bent as a spring.

[Explanation of symbols]

 2 Male terminal of connection part 4 Female terminal of connection part 42 Tongue of female terminal

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Claims (12)

[Claims] 1. A method for processing and heat treating a copper alloy for an electrical connection member, wherein the copper alloy for an electrical connection member is subjected to a forming process and then a heat treatment, wherein the Vickers hardness of a processed portion before and after forming the copper alloy for an electrical connection member as a spring from a material. (Hv) a process in which a change is made to be within 10 and then a heat treatment is performed so that a change in Vickers hardness (Hv) of the portion before and after the heat treatment is made to be 10 or less when the heat treatment is performed. Method for thermomechanical processing of copper alloy for connecting members. 2. The heat treatment after the forming process is performed at 200 to 800 ° C.
2. The method according to claim 1, wherein the heating is performed at a temperature of 5 to 10,000 seconds. 3. A Vickers hardness (Hv) change of a processing portion before and after forming a spring from a material so as to be within 10 and then, when a heat treatment is performed, Vickers of the portion before and after the heat treatment. Any one of the following component compositions for performing a heat treatment to change the hardness (Hv) within 10 or
Copper alloy for electric connection members containing two or more kinds, the balance being Cu and unavoidable impurities ("0 wt%" means no addition in the following). Sn: 0 to 10 wt%, Zn: 0 to 40 wt%, Ni: 0 to 10 wt%, Fe: 0 to 3 wt%, Cr: 0 to 1 wt%, Mn: 0 to 1 wt%, P: 0 to 0.5 wt% , Si: 0 to 1 wt%, Mg: 0 to 1 wt%, Zr: 0 to 0.5 wt%, Ti: 0 to 1 wt%, Co: 0 to 1 wt%, Ag: 0 to 1 wt%, Al: 0 to 5 wt %, B: 0 to 0.5 wt%, Rare earth element: 0 to 0.5 wt%. 4. The heat treatment performed after the forming process is 200
The copper alloy for an electrical connection member according to claim 3, wherein the temperature is 800800 ° C. for 5 to 10,000 seconds. 5. The copper alloy for an electrical connection member, wherein the copper alloy is Ni: 1-4 wt%, Si: 0.1-1.0 wt%, and the balance is Cu and unavoidable impurities. The copper alloy for an electrical connection member according to 3 or 4. 6. The copper alloy for an electrical connection member comprises: Ni: 1 to 4 wt%, Si: 0.1 to 1.0 wt%, Sn, Mn, M
g, Zn, Ag and at least one selected from Ag in a total amount of 0.005 to
The copper alloy for an electrical connection member according to claim 3, wherein the copper alloy contains 1 wt% and the balance is Cu and an unavoidable impurity. 7. The copper alloy for an electrical connection member is a copper alloy comprising Sn: 0.5 to 3 wt%, P: 0.005 to 0.5 wt%, and the balance being Cu and unavoidable impurities. The copper alloy for an electrical connection member according to 3 or 4. 8. The copper alloy for an electric connection member comprises: Sn: 0.5 to 3 wt%, P: 0.005 to 0.5 wt%, Ni, Mn,
0.005 or more of at least one selected from Fe, Cr, Mg and Zn
The copper alloy for an electrical connection member according to claim 3 or 4, wherein the copper alloy contains up to 2 wt% and the balance is Cu and unavoidable impurities. 9. The copper alloy for an electrical connection member is a copper alloy comprising Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, and the balance being Cu and unavoidable impurities. The copper alloy for an electrical connection member according to 3 or 4. 10. The copper alloy for an electrical connection member comprises: Sn: 3 to 10 wt%, P: 0.005 to 0.5 wt%, and further, Ni, Fe
The copper alloy for an electrical connection member according to claim 3, wherein the copper alloy contains 0.005 to 2 wt% in total of at least one selected from Zn and Zn, and the balance is a copper alloy including Cu and unavoidable impurities. 11. The electrical connection member according to claim 3, wherein the copper alloy for an electrical connection member is a copper alloy comprising Zn: 5 to 35 wt%, and the balance being Cu and unavoidable impurities. For copper alloy. 12. The copper alloy for an electric connection member contains Zn: 5 to 35 wt%, further contains at least one selected from Sn, Ni and Fe in a total amount of 0.005 to 5 wt%, and the balance is Cu and unavoidable. The copper alloy for an electrical connection member according to claim 3, wherein the copper alloy is a copper alloy comprising a temporary impurity.