JPH0551676A - Conductive high strength copper alloy with excellent elongation properties - Google Patents

Abstract

(57) [Abstract] [Purpose] Improves elongation characteristics, does not cause a significant decrease in conductivity, has high strength against mechanical shock, reduces wire breakage due to tension and bending at the crimp terminal, and is lightweight. To measure [Composition] When the ratio of Ni to Si is in the range of 4 to 5, 1.0 to 2.0 wt% of Ni and 0.2 to 0.2 of Si are used.
0.5 wt%, and In of 0.05 to 0.5
wt% and Sn of 0.4 to 1.0 wt% are contained, and the balance is basically composed of copper.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper alloy, and particularly when used as a conductor of an electric wire for an automobile,
It has high strength against mechanical shock without causing a significant decrease in conductivity, can reduce wire breakage due to pulling and bending in the crimp terminal, and can improve elongation characteristics. The present invention relates to a conductive high strength copper alloy.

[0002]

2. Description of the Related Art Conventionally, annealed copper wire has been mainly used as a conductor for automobile electric wires. In recent years, AT
(Auto Transmission) With the spread of vehicles, carburetors are being replaced with electronic fuel injection devices, and electronic devices such as various instruments are being installed electronically. With the computerization of such in-vehicle devices, the number of electric and electronic wiring circuits in the automobile has significantly increased, the space occupied in the automobile has increased, and the total weight of the automobile due to the electric wires for the automobile has increased. ..

However, it is desirable that the body of an automobile is lightweight in terms of improving fuel efficiency, and an increase in the amount of electric wires used for an automobile is against the weight reduction of the vehicle body. Therefore, in order to reduce the weight of the vehicle body, even if the number of wiring circuits in the vehicle increases, there is an increasing demand for a narrow space in the vehicle and suppression of an increase in the total weight of the electric wires for the vehicle. There is.

An electric wire having an extremely small diameter is sufficient for a lead wire or the like which is connected to a microcomputer or the like mounted on an automobile and passes a minute electric current. However, the vibration and shock generated while driving a car is extremely large, and the engine room has an abnormally high temperature.If it does not have sufficient mechanical strength, the joint may come off, the wire may break, and the car may be hindered. Therefore, a conductor having a diameter larger than an electrically required diameter has been conventionally used.

However, in order to secure a sufficient mechanical strength, a conductor having a diameter larger than an electrically necessary diameter is used. Therefore, when the number of wiring circuits is increased, an electric wire for an automobile used for an electric or electronic wiring circuit is used. It is not possible to reduce the weight and space of the space.

[0006] Therefore, in order to reduce the weight of the electric wire for automobiles, a hard copper wire which can secure the mechanical strength even if the outer diameter of the conductor is made small has been studied, but the hard copper wire has a remarkably small elongation in terms of material. .. Therefore, even if the terminals are crimp-bonded to each other by using a hard copper wire, the joint may be damaged when a mechanical load is applied to the joint due to an external force of a vibration impact generated while the vehicle is running. When the terminals are crimp-bonded using the hard copper wire in this way, the terminal crimping point becomes a mechanical weak point, which easily causes wire breakage due to external impact, resulting in poor reliability.

Further, it is possible to reduce the use weight of the electric wire for automobiles by reducing the diameter of the conductor, but in the case of the conventional hard copper wire, reducing the outer diameter of the conductor results in mechanical reduction. The strength will decrease. Therefore, in recent years, mechanical strength can be secured even if the outer diameter of the conductor is reduced,
Ni-Ti copper alloys, Ni-Si copper alloys and the like have been invented as copper alloys having relatively good repeated bending strength and conductivity.

[0008]

This Ni-Ti copper alloy improves the tensile strength by precipitating a Ni-Ti intermetallic compound in a copper matrix without significantly reducing the conductivity. It is a thing. However, this Ni-Ti copper alloy cannot obtain sufficient tensile strength to withstand a mechanical load due to an external force such as a vibration impact generated while the vehicle is running, and thus has insufficient elongation characteristics and bending resistance. I have a problem.

Further, the Ni-Si copper alloy is one in which the intermetallic compound of Ni-Si is deposited in the copper matrix to improve the tensile strength without significantly reducing the conductivity. However, this Ni-Si copper alloy can obtain a tensile strength sufficient to withstand a mechanical load due to an external force such as a vibration impact generated while a vehicle is running, and has insufficient elongation characteristics and bending resistance. Have a point.

The first and second inventions of the present application have improved elongation characteristics, have a high strength against mechanical impact without causing a significant decrease in conductivity, and reduce disconnection due to tension and bending in the crimp terminal portion. It is an object of the present invention to provide a conductive high-strength copper alloy which has excellent elongation characteristics and can be made lightweight.

[0011]

In order to achieve the above object, in the conductive high-strength copper alloy of the first invention of the present application, which is excellent in elongation characteristics, the ratio of Ni to Si is in the range of 4 to 5. , Ni of 1.0 to 2.0 wt%, Si of 0.
2 to 0.5 wt%, and In of 0.05 to
It contains 0.5 wt% and 0.4 to 1.0 wt% Sn, and the balance is basically made of copper.

That is, in order to achieve the above object, in the conductive high-strength copper alloy having excellent elongation characteristics of the first invention of the present application, an intermetallic compound of Ni and Si is precipitated in the copper matrix, and The tensile strength is improved without significantly lowering the conductivity, and the addition of In further increases the tensile strength, improves the bending resistance, and improves the elongation.

In the first invention of the present application, the Ni content is set to 1.0 to 2.0 wt%, because when the Ni content is less than 1.0 wt%, the intermetallic compound with Si precipitates. Little improvement in tensile strength, Ni content 2.0
This is because when the content exceeds wt%, the tensile strength is improved, but the amount of Ni that forms a solid solution in the Cu mother phase is increased, the conductivity is significantly impaired, and the workability of fine wire processing is deteriorated.

Further, in the first invention of the present application, the Si content is set to 0.2 to 0.5 wt% because the Si content of less than 0.2 wt% results in an intermetallic compound with Ni. The improvement in tensile strength due to precipitation is small, and when the Si content exceeds 0.5 wt%, the tensile strength improves but Cu
This is because the amount of Si that forms a solid solution in the mother phase is increased and the conductivity is significantly reduced.

Further, in the first invention of the present application, the content ratio of Ni and Si (ratio in wt%) is set such that the content of Ni is 4 to 5 with respect to the content of Si. _{This is} to precipitate ₂ Si or Ni ₅ Si ₂ and effectively improve the tensile strength.

Further, in the first invention of the present application, the In content is set to 0.05 to 0.5 wt%. The reason is that when the In content is less than 0.05 wt%, the tensile strength and bending resistance are low. Effect is small, and the In content is 0.5 wt.
This is because if the content exceeds 0.1%, the effect of improving the tensile strength is low relative to the amount of In added, the amount of In dissolved in the Cu matrix increases, and the conductivity is significantly reduced, leading to higher costs.

Furthermore, in the first invention of the present application, S
The content of n is set to 0.4 to 1.0 wt% because Sn is
If the content of Sn is less than 0.4 wt%, the effect of improving elongation and flex resistance is small, and the Sn content is 1.0 wt%.
This is because if it exceeds, the conductivity is significantly reduced.

In order to achieve the above object, in the conductive high-strength copper alloy excellent in elongation property of the second invention of the present application, S
When the ratio of Ni to i is in the range of 4 to 5, Ni
1.0-2.0 wt%, Si 0.2-0.5 wt
%, In, 0.1 to 0.5 wt% In, Sn
Of 1.0 to 2.0 wt% and P of 0.1 to 0.5 wt% with the balance basically made of copper.

That is, in order to achieve the above object, in the conductive high-strength copper alloy of the second invention of the present application, which is excellent in elongation characteristics, an intermetallic compound of Ni and Si is precipitated in the copper matrix, whereby The tensile strength is improved without significantly lowering the conductivity, and by adding In, the tensile strength is further increased and the flex resistance is improved.
Elongation and flex resistance are improved by precipitation of an intermetallic compound of n and P.

In the second invention of the present application, Ni, Si, I
The content of n is the same as that in the first invention of the present application.

Further, in the second invention of the present application, the Sn content is set to 1.0 to 2.0 wt% because the intermetallic compound with P is less than 1.0 wt% when the Sn content is less than 1.0 wt%. Small, the effect of improving elongation and bending resistance is small, and Sn
This is because if the content of P exceeds 2.0 wt%, the conductivity is significantly reduced.

Further, in the second invention of the present application, the content of P is set to 0.1 to 0.5 wt% because most of P is less than 0.1 wt% as a deoxidizing agent. This is because the intermetallic compound with Sn is not formed,
This is because if the P content exceeds 0.5 wt%, the amount of P that forms a solid solution in the Cu mother phase increases, and the conductivity decreases significantly.

[0023]

When the conductive high-strength copper alloy having excellent elongation characteristics as constructed above is used, the conductivity can be almost the same as that of the conventional conductive high-strength copper alloy.

When the conductive high-strength copper alloy having excellent elongation properties as constructed above is used, the tensile strength is about 1.3 times or more that of hard copper, which is remarkably strong. Even if compared with the conventional conductive high-strength copper alloy, it does not decrease.

Further, when the conductive high-strength copper alloy having the above-mentioned constitution and excellent in elongation characteristic is used, the elongation is smaller than that of the annealed copper, but it is 11 in the first invention of the present application as compared with the hard copper.
Double, the second invention of the present application has an elongation of 15 times or more, and it is possible to obtain the repeated bending strength of annealed copper or more. Further, the elongation is twice as high in the first invention of the present application and more than three times as high in the second invention of the present application as compared with the conventional conductive high-strength copper alloy.

For the above-mentioned reasons, when the conductive high-strength copper alloy having the excellent elongation property constructed according to the present invention is used for the electric wire for automobiles, the characteristics suitable for the conductor of the electric wire for automobiles are obtained. Therefore, it is possible to secure the mechanical strength against the small outer diameter of the body and reduce the disconnection due to the tensile load and the bending at the terminal crimping portion. Therefore, it is preferable to use the conductive high-strength copper alloy having the above-described excellent elongation property as a conductor of an electric wire for wiring in an electronic device, a lead wire material of a semiconductor, and the like.

[0027]

EXAMPLES Specific examples of the first and second inventions of the present application will be described below in comparison with a conventional example.

<< First Invention of the Present Application >> As an embodiment of the first invention of the present application, Ni, In, and Sn are dissolved in a melting furnace kept in an inert gas atmosphere after melting copper under the coating of graphite particles. Pure metal and Si were added in the form of a master alloy to obtain a uniform molten metal, which was continuously cast to obtain the composition of each Example 2 as shown in Table 1.
A 0 mmφ cast rod was prepared. These were cold-rolled and wire-drawn to 3.2 mmφ, and then about 9 mm in an inert gas atmosphere.
After heating and holding at 00 ° C. for 1 hour, it was rapidly cooled for solution treatment. After that, the wire was drawn to 1.0 mmφ and further subjected to an aging treatment at a temperature of 420 ° C. to 480 ° C. for 6 hours in an inert gas atmosphere, and the tensile strength, elongation, conductivity, and repeated bending strength were measured. The comparative example also uses the same manufacturing method.

In the bending test, as shown in FIG. 1, the sample material 2 is clamped in the jig 1 and the other end is subjected to a tensile load W of 2 kg. ) → (C) →
(D) and 90 ° bending to the left and right were repeated once until fracture, and the number of times was taken as the repeating bending strength.

Table 1 shows the characteristics of the conductive high-strength copper alloy having excellent elongation characteristics according to the first invention of the present application.
Together with the examples, the compositions and characteristic values of the comparative example and the conventional example are shown.

The alloys No. 4 to No. 6 of the comparative examples have the same composition as Ni, Si, In and Sn as in the first invention of the present application, but the content of each composition is different from that of the present invention.

[0032]

[Table 1]

As is clear from the comparison between the examples (No1 to No5) of Table 1 and the comparative examples (No1 to No6), according to the first invention of the present application, the intermetallic compound of Ni--Si is deposited in the copper matrix. As a result, the tensile strength can be improved without significantly reducing the conductivity.

Further, according to the first invention of the present application, since In is solid-dissolved in the Cu mother phase, I in the Cu mother phase is dissolved.
Although the solid solution of n and Sn causes some decrease in conductivity, a slight improvement in tensile strength and bending resistance and a dramatic improvement in elongation characteristics can be achieved. This conductivity is compared with that of a comparative example (No by the alloy element In dissolved in the copper matrix).
Approximately 43% IACS was secured, though there was a slight decrease compared to 1), and the tensile strength was markedly improved over hard copper (about 1.
5 times), the flexural strength is far superior to that of annealed copper, and the elongation rate is about twice that of the comparative example (No. 1).
Even when compared with other comparative examples, a marked improvement can be seen.

As described above, the conductive high-strength copper alloy according to the first invention of the present application has excellent elongation, which is about 11 times or more that of hard copper. Although the rate is slightly lowered, by precipitating a part of the additional element, the reduction is suppressed to about 43% IACS as much as possible, the tensile strength is improved as compared with the comparative example, and the cyclic bending strength is much better than that of annealed copper. Far superior.

Therefore, the conductive high-strength copper alloy excellent in elongation property according to the first invention of the present application has a property suitable for a conductor of an electric wire for an automobile, and is a machine capable of reducing the outer diameter of the conductor and reducing its weight. It is possible to secure the desired strength and reduce the disconnection due to the pulling and bending in the crimp terminal portion. From this, it is preferable to use the conductive high-strength copper alloy having the above-described excellent elongation characteristics as the conductor of the electric wire for the electronic device internal wiring, the lead wire material of the semiconductor, and the like.

<< Second Invention of the Present Application >> As an embodiment of the second invention of the present application, Ni, In, and Sn are dissolved in a melting furnace kept in an inert gas atmosphere after melting copper under the coating of graphite particles. Pure metal, Si, and P were added in the form of a master alloy to obtain a uniform molten metal, which was continuously cast to prepare a 20 mmφ casting rod having the composition of each example as shown in Table 2. These were cold-rolled and wire-drawn to 3.2 mmφ, and after heating and holding at about 900 ° C. for 1 hour in an inert gas atmosphere, they were rapidly cooled for solution treatment. After that, the wire was drawn to 1.0 mmφ and further subjected to an aging treatment at a temperature of 420 ° C. to 480 ° C. for 6 hours in an inert gas atmosphere, and the tensile strength, elongation, conductivity, and repeated bending strength were measured. The comparative example also uses the same manufacturing method.

In the bending test, as shown in FIG. 1, the sample material 2 is sandwiched between the jigs 1 and the other end is subjected to a tensile load W of 2 kg, as shown in FIG. ) → (C) →
(D) and 90 ° bending to the left and right were repeated once until fracture, and the number of times was taken as the repeating bending strength.

Table 2 shows the characteristics of the conductive high-strength copper alloy having excellent elongation characteristics according to the second invention of the present application.
Together with the examples, the compositions and characteristic values of the comparative example and the conventional example are shown.

The alloys No. 4 to No. 6 of the comparative examples have the same composition as Ni, Si, In and Sn as the second invention of the present application, but the content of each composition is different from the present invention.

[0041]

[Table 2]

As is clear from the comparison between the examples (No1 to No5) of Table 2 and the comparative examples (No1 to No6), according to the second invention of the present application, the Ni-Si intermetallic compound is deposited in the copper matrix. As a result, it is possible to suppress a significant decrease in conductivity and improve the tensile strength.

Further, according to the second invention of the present application, since In is solid-dissolved in the Cu mother phase, In in the Cu mother phase is increased.
Although the solid solution causes some decrease in conductivity, the tensile strength is improved more than that of annealed copper, and the repeated bending strength is also much improved than that of annealed copper.

Further, according to the second invention of the present application, Sn-P
By precipitating the intermetallic compound (1) in the copper matrix, the flex resistance and the elongation are dramatically improved.

As described above, the conductive high-strength copper alloy according to the second invention of the present application, which has excellent elongation characteristics, has a remarkably excellent elongation of about 16 times or more as compared with the hard copper, and the conductivity is high. Although the rate is slightly lower than that of the comparative example, by precipitating a part of the additional element, the decrease is suppressed to about 33% IACS as much as possible, the tensile strength is maintained at the same level as the comparative example, and the cyclic bending strength is Better and much better than the extremely good annealed copper.

Therefore, when the conductive high-strength copper alloy having the excellent elongation property constructed as in the second invention of the present application is used for the electric wire for automobiles, it is possible to obtain the characteristics suitable for the conductor of the electric wire for automobiles. Therefore, it is possible to secure the mechanical strength with respect to whether the outer diameter of the body is small and to reduce the disconnection due to the tensile load and the bending at the terminal crimping portion. From this, it is preferable to use the conductive high-strength copper alloy having the above-described excellent elongation characteristics as the conductor of the electric wire for the electronic device internal wiring, the lead wire material of the semiconductor, and the like.

[0047]

EFFECTS OF THE INVENTION According to the first and second aspects of the present invention, the elongation property is improved, the electrical conductivity is not significantly lowered, the mechanical strength is high, and the tension and bending of the crimp terminal portion are high. It is possible to reduce the disconnection due to, and to reduce the weight.

[Brief description of drawings]

FIG. 1 is a diagram showing a bending test method according to an example of the present invention, a comparative example, and a conventional example.

[Explanation of symbols]

 1 …………………………………… Jig 2 …………………………………… Sample material

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhito Taki 2771 Ooka, Numazu City, Shizuoka Prefecture Yazaki Electric Cable Co., Ltd.

Claims (2)

[Claims] 1. When Ni / Si is in the range of 4 to 5, Ni is 1.
0-2.0 wt%, Si 0.2-0.5 wt%, In further 0.05-0.5 wt%, Sn 0.
A conductive high-strength copper alloy containing 4 to 1.0 wt% and the balance basically consisting of copper and having excellent elongation characteristics. 2. Ni / Si in the range of 4 to 5 has a Ni content of 1.
0-2.0 wt%, Si-0.2-0.5 wt%, In-0.1-0.5 wt%, Sn 1.0
A conductive high-strength copper alloy containing .about.2.0 wt%, P of 0.1 to 0.5 wt%, and the balance basically consisting of copper and having excellent elongation characteristics.