WO2009154239A1 - Electric wire conductor for wiring, electric wire for wiring, and method for manufacturing electric wire conductor for wiring - Google Patents

Abstract

Disclosed is an electric wire conductor for wiring, comprising a plurality of copper alloy wire rods which have been twisted together, the copper alloy wire rod having a composition comprising 1.0 to 4.5% by mass of Ni and 0.2 to 1.1% by mass of Si with the balance consisting of Cu and unavoidable impurities.  The copper alloy wire rod has a 0.2% proof stress to tensile strength ratio of 0.70 to 0.92 and a work hardening index of 0.04 to 0.17.  Also disclosed is an electric wire for wiring, comprising an insulating covering provided on the electric wire conductor for wiring.

Description

Wire conductor for wiring, wire for wiring, and method for manufacturing wire conductor for wiring

The present invention relates to a method of manufacturing a wire conductor for wiring, a wire for wiring, and a wire conductor for wiring for automobiles, robots, electric / electronic devices and the like.

Conventionally, as a conductor of an electric wire for wiring, an annealed copper wire as stipulated in JIS C 3102 or a stranded wire obtained by twisting a wire plated with tin is used as a conductor, and this conductor is made of vinyl chloride, crosslinked. An electric wire in which an insulator such as polyethylene is coated concentrically has been used.
When these electric wires are connected to a device, they are usually crimp-connected using terminals called crimp terminals. Crimp connection is a method of wrapping an electric wire with a plate material and connecting it by caulking.
As a method for confirming the connection state by pressure bonding, there is a measurement of pressure bonding strength. In this method, after connecting an electric wire to a crimping terminal, the electric wire and the terminal are grasped, a tensile test is performed, and the strength at the time when breakage occurs is measured. In general, the crimped section has a conductor cross-sectional area that is 20-30% smaller by caulking (hereinafter, the ratio of the cross-sectional area decreased by caulking is referred to as “cross-sectional reduction rate”), and the absolute value of the conductor strength decreases. Therefore, the breakage occurs at the caulked portion.

By the way, especially in an automobile wiring circuit, the ratio of signal current circuits for control and the like has increased, and the number and weight of electric wires used have increased.
On the other hand, from the standpoint of energy saving, etc., reduction of automobile weight has been required as one means. And as one of the countermeasures, weight reduction by reducing the diameter of the wire conductor is required. However, it has been difficult to reduce the diameter of a copper soft material, which is a conventional electric wire conductor, because the mechanical strength of the electric wire conductor itself is low, although the current carrying capacity has a sufficient margin. Even if the cross-sectional area of the conductor is reduced by caulking, there is room for the conductor itself to work and harden, so the strength of the crimped part is almost the same as that of the non-crimped part and the stability of the crimped strength However, the strength itself is low because of the soft copper.
Therefore, as a measure for improving the mechanical strength, for example, the use of a hard material of a copper alloy has been studied (see Patent Document 1).

JP 2008-16284 A

Incidentally, it is considered that the electric wire conductor described in Patent Document 1 is almost saturated in its own work hardening. In this case, since the absolute strength in the crimping portion of the wire conductor is reduced due to a reduction in the cross-sectional area due to caulking when the crimp terminal is connected to the wire conductor, there is a possibility that a stable crimp strength cannot be obtained.

In view of such problems, the present invention has been made, and it is an object of the present invention to provide a wiring electric wire conductor excellent in terminal crimping strength and a method of manufacturing the wiring electric wire conductor.

As a result of intensive studies, the present inventors have used an aging precipitation type copper alloy having a specific composition, the ratio of 0.2% proof stress to tensile strength is 0.70 to 0.92, and the work hardening index is 0.04. It has been found that by using a copper alloy wire of 0.17 or less, it is possible to produce a wire conductor for wiring that is excellent in tensile strength, has a low absolute strength during crimping, and has high terminal crimping strength. Moreover, it discovered that the said wire conductor for wiring can be obtained with sufficient reproducibility by performing the aging heat processing performed at the last process before formation of an insulation coating layer on specific conditions. The present invention has been completed based on these findings.

According to the present invention, the following means are provided:
(1) A plurality of copper alloy wires containing 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, and the balance of Cu and inevitable impurities are twisted together. A wire conductor for wiring, wherein the ratio of 0.2% yield strength and tensile strength of the copper alloy wire is 0.70 or more and 0.92 or less, and the work hardening index is 0.04 or more and 0.17 or less. A wire conductor for wiring, characterized by
(2) It contains 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, 0.005 to 1.0% by mass of Sn, and 0.005 to 0. 0% of Fe. 2 mass%, Cr 0.005-0.2 mass%, Co 0.05-2 mass%, P 0.005-0.1 mass%, Ag 0.005-0.3 mass% A wire conductor for wiring comprising at least one selected from the group consisting of a plurality of copper alloy wires having a composition comprising Cu and inevitable impurities, the balance being 0.2% of the copper alloy wire A wire conductor for wiring, wherein the ratio of proof stress and tensile strength is 0.70 or more and 0.92 or less, and the work hardening index is 0.04 or more and 0.17 or less,
(3) The composition of the copper alloy wire further includes at least one selected from the group consisting of 0.01 to 0.5% by mass of Mn and 0.05 to 0.5% by mass of Mg. The wire conductor for wiring according to (1) or (2),
(4) The wire conductor for wiring according to any one of (1) to (3), wherein the composition of the copper alloy wire further contains 0.1 to 1.5% by mass of Zn. ,
(5) The electric wire conductor for wiring according to any one of (1) to (4) above, wherein the cross-sectional area is 0.03 to 0.13 mm ² ;
(6) The electric wire for wiring according to any one of the above (1) to (5), wherein the electric wire conductor for wiring has an insulating coating around it,
(7) A copper alloy containing 1.0 to 4.5% by mass of Ni and 0.2 to 1.1% by mass of Si, with the balance being composed of Cu and inevitable impurities, A solution treatment is applied to the lump or the round bar obtained from the lump, and this is drawn to a predetermined wire diameter to obtain a copper alloy wire, and a plurality of the copper alloy wires are twisted and further compressed. A method of manufacturing a wire conductor for wiring, comprising each step of performing aging annealing at 550 ° C. for 1 minute to 5 hours; and
(8) It contains 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, 0.005 to 1.0% by mass of Sn, and 0.005 to 0.005% of Fe. 2 mass%, Cr 0.005-0.2 mass%, Co 0.05-2 mass%, P 0.005-0.1 mass%, Ag 0.005-0.3 mass% A copper alloy containing at least one selected from the group consisting of a composition consisting of Cu and inevitable impurities, and a solution treatment is applied to the resulting ingot or a round bar obtained therefrom. A copper alloy wire is obtained by wire drawing to a wire diameter of 2 mm, and a plurality of the copper alloy wires are twisted, further compressed, and then subjected to aging annealing at 350 to 550 ° C. for 1 minute to 5 hours. The manufacturing method of the electric wire conductor for wiring characterized by these.
Here, the ingot includes billets.

The wire conductor for wiring of the present invention is excellent in terminal crimping strength.
Moreover, the electric wire conductor for wiring according to the present invention can be prevented from hot cracking when the conductor is produced, and can be excellent in workability when the wire is drawn into a small diameter.
According to the method for manufacturing a wire conductor for wiring of the present invention, a wire conductor for wiring having the above-described excellent physical properties can be manufactured.
The wiring wire of the present invention can reduce the weight of the conductor by reducing the diameter of the conductor, and is suitable as a wiring wire for other signal wires for automobiles and robots, and electric / electronic devices.
According to the method for manufacturing a wiring wire of the present invention, a wiring wire having the above-described excellent characteristics can be manufactured.
These and other features and advantages of the present invention will become more apparent from the following description.

A preferred embodiment of the copper (Cu) alloy wire used for the wiring conductor of the present invention will be described in detail. First, the effect of each alloy element and the range of its content will be described.

Nickel (Ni) and silicon (Si) improve the strength of the copper alloy by forming Ni—Si precipitates (Ni ₂ Si) in the matrix by controlling the content ratio of Ni and Si, thereby strengthening the precipitation. It is an element to be contained.

Ni content is 1.0 to 4.5% by mass, preferably 1.2 to 4.2% by mass. If the amount of Ni is too small, the precipitation hardening amount is small and the strength is insufficient. If the amount is too large, grain boundary precipitation occurs during heat treatment, and the strength decreases.

It is known that when the Si is calculated by mass%, the strengthening amount becomes the largest (strength is improved) when the Ni content is about 1/4. In the present invention, the Si content is 0.2 to 1.1% by mass, preferably 0.3 to 1.0% by mass.

The copper alloy material used in the present invention may contain at least one of tin (Sn), iron (Fe), chromium (Cr), cobalt (Co), phosphorus (P), and silver (Ag). preferable. These elements have a similar function in terms of improving strength, and when included, at least one selected from Sn, Fe, Cr, Co, P, and Ag, The total amount is preferably 0.005 to 2% by mass, more preferably 0.01 to 1.5% by mass.

Sn can be dissolved in copper and the strength can be improved by distorting the lattice. However, when there is too much content of Sn, electrical conductivity will fall. Therefore, the preferable content range when Sn is added is 0.005 to 1.0% by mass, and more preferably 0.05 to 0.2% by mass.
Fe and Cr combine with Si to form an Fe—Si compound and a Cr—Si compound, thereby improving the strength. In addition, there is an effect of improving the conductivity by trapping Si remaining in the Cu matrix without forming a compound with Ni. On the other hand, since Fe—Si compounds and Cr—Si compounds have low precipitation hardening ability (age hardening ability), it is not a good idea from the viewpoint of improving strength to produce more of these compounds than necessary. Further, when the content of Fe and Cr is too large, the strength decreases. From these viewpoints, the contents in the case of containing Fe and Cr are preferably 0.005 to 0.2% by mass, more preferably 0.03 to 0.15% by mass, respectively.
Co, like Ni, forms a compound with Si and improves the strength. Since Co is more expensive than Ni, the wire conductor for wiring as a preferred embodiment of the present invention uses a Cu—Ni—Si-based alloy. A —Si alloy or a Cu—Ni—Co—Si alloy may be selected. Cu-Co-Si alloys tend to be slightly better in strength and conductivity than Cu-Ni-Si alloys when aged. Therefore, it is effective for applications that place importance on these. From the above viewpoint, the content in the case of containing Co is preferably 0.05 to 2% by mass, and more preferably 0.08 to 1.5% by mass.
P has the effect of increasing strength. However, if a large amount is contained, the electrical conductivity is lowered, and grain boundary precipitation is promoted to lower the strength. Therefore, the preferable content range when P is added is 0.005 to 0.1 mass%, more preferably 0.01 to 0.05 mass%.
Ag improves the strength. If the Ag content is too small, the effect cannot be obtained sufficiently. If the Ag content is too large, the effect is saturated but the effect is saturated, and the cost increases. From these viewpoints, the content when Ag is contained is preferably 0.005 to 0.3% by mass, and more preferably 0.01 to 0.2% by mass.

Furthermore, in this invention, it is preferable to contain at least 1 sort (s) of magnesium (Mg) and manganese (Mn). These elements have similar functions in that they prevent embrittlement during heating and improve hot workability. In particular, in the present invention, the copper alloy wire is used with a reduced diameter. However, when the embrittled portion is inherent in the material, it cannot be drawn to a smaller diameter, so it is preferable to contain these elements. . When Mg or Mn is contained, it is preferable to contain at least one of Mg and Mn in a total amount of 0.01 to 0.5% by mass, preferably 0.05 to 0.3% by mass. It is more preferable.
The content of Mg is preferably 0.05 to 0.5% by mass, and more preferably 0.09 to 0.3% by mass. If the content is too small, the effect is small. If the content is too large, the electrical conductivity is deteriorated, the cold workability is further reduced, and the wire drawing cannot be performed to a small diameter.
If the content of Mn is too small, the effect is small. If the content is too large, not only an effect commensurate with the content cannot be obtained, but also the conductivity can be deteriorated. Accordingly, the Mn content is preferably 0.01 to 0.5% by mass, and more preferably 0.1 to 0.35% by mass.

Furthermore, in the present invention, it is preferable to contain zinc (Zn). Zn has an effect of preventing a decrease in adhesion between the copper alloy wire and the solder due to heating. In the present invention, inclusion of Zn significantly improves the embrittlement of the interface when the copper alloy wire is soldered to other conductors or the like at the end. In the present invention, the Zn content is preferably 0.1 to 1.5% by mass, and more preferably 0.4 to 1.2% by mass. If the content is too small, the above effect is not obtained, and if the content is too large, the electrical conductivity may decrease.

Next, the manufacturing process and mechanical properties of the copper alloy wire used in the present invention will be described.
The copper alloy used in the present invention is an aging precipitation type alloy. For example, the copper alloy wire can be obtained as follows. First, an ingot obtained by casting by a conventional method so as to have an alloy composition specified in the present invention, a round bar obtained from the ingot by hot extrusion, hot forging, or rough drawing wire (hereinafter referred to as these The ingot, round bar, and rough wire are also referred to as wire material), and the solution wire material is drawn to a specified diameter (wire diameter) and then subjected to aging heat treatment. Apply. In the aging heat treatment, the above-described precipitation of Ni ₂ Si occurs, and the strength and conductivity are improved. At the same time, the strain introduced by the wire drawing process is released, so that the tensile strength (T) is zero. The ratio of 2% proof stress (Y) (this is called Y / T ratio) decreases. The aging heat treatment conditions for decreasing the Y / T ratio vary depending on the degree of wire drawing (η), but in the present invention, the aging heat treatment conditions are preferably maintained at 350 to 550 ° C. for 1 minute to 5 hours. When the diameter of the wire material before wire drawing is D ₀ (mm) and the diameter of the wire after wire drawing is D (mm), the degree of wire drawing is η = 2 × ln (D ₀ / D). It is represented by For example, when the wire drawing degree (η) is 0, the preferred aging heat treatment temperature is 450 to 550 ° C., and when the wire drawing work degree (η) is greater than 0, the preferred aging heat treatment temperature is 380 to 500 ° C. It is. In the latter case, when the wire drawing degree (η) is greater than 0 and 4 or less, the preferable aging heat treatment temperature is 400 to 500 ° C., and the wire drawing degree (η) is larger than 4 (usually from 4). In the case of large (15 or less), the preferable aging heat treatment temperature is 380 to 480 ° C.

In the present invention, this Y / T ratio is 0.70 to 0.92, preferably 0.72 to 0.90. By setting the Y / T ratio within this range, it is possible to increase the work hardening of the conductor itself at the time of crimping the terminal, and it is possible to obtain a wiring electric wire conductor with little reduction in strength of the crimped portion. Under the aging heat treatment conditions such that the Y / T ratio is less than 0.70, the strength decreases due to overaging, and it is not suitable for use as an electric wire. In addition, when the Y / T ratio exceeds 0.92, the strain is not sufficiently released, so that the conductor itself has a small work hardening at the time of crimping, and the component or manufacturing process reduces the strength after aging heat treatment. In such a case, even if the cross-sectional reduction rate of the crimp terminal is 40% or less, the strength reduction of the crimp portion becomes large.
The cross-sectional area reduction rate at the time of crimping is the ratio at which the cross-sectional area is reduced by caulking at the time of crimping, and the cross-sectional area of the entire conductor strand before crimping is A ₀ (mm ² ). When the area is A (mm ² ), it is represented by (A ₀ -A) / A ₀ . If the cross-section reduction rate exceeds 40%, the decrease in absolute strength tends to be large regardless of the Y / T ratio. Therefore, the cross-section reduction rate of the crimp terminal is preferably 40% or less, more preferably 30% or less. . Also, if the cross-section reduction rate during crimping is less than 5%, the conductor portion is likely to come out from the crimped portion of the terminal, and the electrical connection that is the original purpose becomes insufficient. Is 5% or more, more preferably 10% or more.

In the present invention, the wire material may be subjected to an aging heat treatment after a wire drawing process and then a twisting process. Further, a compression process may be added after the stranded wire process and before the aging heat treatment. In addition, the compression may be performed after the aging heat treatment. In that case, it is preferable that the cross-section reduction rate of the crimping is 40% or less in consideration of the cross-section reduction in the compression.

The work hardening index (hereinafter referred to as n value) is a value representing workability, and the relationship (curve) between stress σ and strain ε in a plastic region above the yield point is σ = Cε ⁿ (C is a coefficient) Is the index n when approximated by. The larger the n value, the easier the strain distribution is averaged. In the present invention, as a result of intensive studies, in this alloy system, the Y / T ratio satisfies the range of 0.70 to 0.92, and excellent crimp strength is obtained when the n value is 0.04 to 0.17. It was found that it can be obtained.

In the present invention, there is no restriction on the method for producing the wire material. For example, the material of the copper alloy wire constituting the wire conductor for wiring of the present invention can be manufactured by any of manufacturing methods such as hot extrusion of billets, hot forging of ingots, or continuous casting.

The wire conductor for wiring of the present invention is not only suitable as a wire conductor but also suitable as a wire for wiring provided with an insulating coating. As the material for the insulating coating, olefin resins such as polyethylene and polypropylene, or polyvinyl chloride (PVC) resins are preferable. In addition, regarding the olefin-based resin, a flame retardant, a cross-linking agent, or the like may be added to these to improve flame retardancy, mechanical strength, or the like.
In the electric wire for wiring of the present invention, there is no particular limitation on the number of copper alloy wires as conductor wires to be twisted and the diameter of each strand, and the layer thickness of the insulating coating layer disposed on the strands, It can be determined as appropriate according to the use of the wire for wiring. For example, 7 to 100 copper alloy wires having a diameter of 0.1 to 0.4 mm can be twisted to provide an insulation coating having a thickness of 0.1 to 1.0 mm.

The concept of the present invention can be applied to an aging precipitation type alloy other than the Cu—Ni—Si system of the present invention. For example, when the electrical conductivity is more important than the strength, an aging precipitation type alloy such as Cu—Fe or Cu—Cr may be employed.

Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited thereto.

Example 1
An alloy having the composition shown in Table 1 was melted in a high frequency melting furnace, and each billet was cast. Next, the billet was hot extruded at 900 ° C. and immediately quenched in water to obtain a round bar (diameter 16 mm). Next, the round bar was drawn cold to obtain a copper alloy wire having a circular cross section with a diameter of 0.14 mm. The drawing work degree (η) from the round bar to the drawing was 9.5 (note that the drawing work degree was the same in the following Example 2, Comparative Example, and Reference Example). Seven wires were twisted and further compressed to obtain a stranded wire having a cross-sectional area of about 0.1 mm ² . The stranded wire was subjected to an aging heat treatment at 430 ° C. for 2 hours, and further covered with an insulator (polyethylene) to produce a wiring wire having a length of 1 km.

For each copper alloy wire and wiring wire thus obtained, [1] Tensile strength, [2] 0.2% yield strength, [3] Crimp strength, and [4] n value were examined by the following methods. It was. The measurement method for each evaluation item is as follows.
[1] Tensile strength According to JIS Z 2241, three specimens were measured for each type of copper alloy wire, and the average value was taken as the tensile strength (MPa).
[2] 0.2% Yield Strength According to the offset method described in JIS Z 2241, the stress when permanent elongation of 0.2% occurs was determined. Three test materials were measured for each type of copper alloy wire, and the average value was defined as 0.2% proof stress (MPa).
[3] Terminal crimping strength The obtained wiring electric wire was connected to the crimping terminal by a conventional method, and the tensile test was conducted by grasping the electric wire and the terminal to determine the strength when the breakage occurred. The cross-sectional reduction rate of the crimping was 20%. In practice, if the pressure bonding strength is less than 50 N, there is a high possibility of disconnection during or after wiring.
[4] n Value The stress-strain diagram obtained in the tensile test of [3] above was converted into a true stress-true strain diagram, and the n value was read from the slope.
The results are shown in Table 1. In either case, the Y / T ratio is 0.70 or more and 0.92 or less, the n value is 0.04 or more and 0.17 or less, and the compression strength of 50 N or more which is practically acceptable is obtained.

(Example 2)
Table 2 shows the results of the crimping strength when the cross-sectional reduction rate of crimping is 10, 20, 30, and 40% for inventive examples 4 and 11 in Table 1. As the cross-sectional reduction rate of crimping increases, the crimping strength decreases, but in both cases, a practically satisfactory 50N or more is obtained as the crimping strength.

(Comparative example, reference example)
Table 3 shows examples 4 and 11 of the present invention in Table 1, with the aging heat treatment conditions after twisting being changed as follows, with Y / T ratios of 0.93 and 0.69, and n value 0.03 and 0.18 respectively, and comparative examples in which both are outside the scope of the present invention, and reference examples when the cross-section reduction rate of crimping is 50% and 60% are shown together with the test results, respectively. It is. The aging heat treatment conditions were 390 ° C. for 2 hours in Comparative Examples 1 to 4, and 500 ° C. for 2 hours in Comparative Examples 5 to 8.
In the case where the Y / T ratio is 0.93 (Comparative Examples 1 to 4), the crimping strength that is the same as that of the present invention is obtained when the cross-section reduction rate of the crimping is 10 to 30%. The decrease in absolute strength due to the decrease in area is greater than 50N. In addition, in the examples where the Y / T ratio is 0.69 (Comparative Examples 5 to 8), the crimping strength is 50 N or more until the cross-section reduction rate of crimping is 10 or 20%, but in the case of 30 or 40%. Below 50N.
Reference examples 1 to 4 in which the cross-section reduction rate of the crimping is 50% and 60% are also shown, but these all have a crimping strength of less than 50N.

(Conventional example)
Table 4 shows conventional examples together with test results.
The conventional example was manufactured by the following steps. That is, the conventional examples 1 and 2 are for soft copper (tough pitch copper), and the conventional examples 3 and 4 are for alloys having the compositions shown in Table 4 by the method described in paragraph 0032 of Patent Document 1 by a continuous casting and rolling apparatus. A rough-drawn wire was manufactured at, and then drawn in the cold to obtain a strand having a diameter of 0.14 mm. Seven strands were twisted and further compressed to obtain a stranded wire having a cross-sectional area of about 0.1 mm ² , and further covered with an insulator (polyethylene) to obtain a wiring electric wire. Conventional examples 1 and 3 were obtained by annealing the stranded wire with an electric heating device, and conventional examples 2 and 4 were obtained by performing no annealing.
Each characteristic was measured by the same method as [1] to [4] described above. In the conventional examples, the pressure bonding strength is less than 50N, which is not practical.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2008-157599 filed in Japan on June 17, 2008, which is incorporated herein by reference. Capture as part.

Claims (8)

An electric wire for wiring formed by twisting a plurality of copper alloy wires containing 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, and the balance of Cu and inevitable impurities A ratio of 0.2% proof stress and tensile strength of the copper alloy wire is 0.70 or more and 0.92 or less, and a work hardening index is 0.04 or more and 0.17 or less. Characteristic wire conductor for wiring. Containing 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, 0.005 to 1.0% by mass of Sn, and 0.005 to 0.2% by mass of Fe From the group consisting of 0.005 to 0.2% by mass of Cr, 0.05 to 2% by mass of Co, 0.005 to 0.1% by mass of P, and 0.005 to 0.3% by mass of Ag. A wire conductor for wiring formed by twisting a plurality of copper alloy wires having a composition composed of Cu and inevitable impurities, the balance being 0.2% proof stress and tensile strength of the copper alloy wires. A wire conductor for wiring, wherein the strength ratio is 0.70 or more and 0.92 or less, and the work hardening index is 0.04 or more and 0.17 or less. The composition of the copper alloy wire further contains at least one selected from the group consisting of 0.01 to 0.5% by mass of Mn and 0.05 to 0.5% by mass of Mg. The wire conductor for wiring according to claim 1 or 2. The wire conductor for wiring according to any one of claims 1 to 3, wherein the composition of the copper alloy wire further contains 0.1 to 1.5 mass% of Zn. The electric wire conductor for wiring according to any one of claims 1 to 4, wherein the cross-sectional area is 0.03 to 0.13 mm ² . A wiring electric wire according to any one of claims 1 to 5, wherein the wiring electric wire conductor has an insulating coating around it. An ingot obtained by casting a copper alloy containing 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, and the balance of Cu and inevitable impurities. The obtained round bar is subjected to a solution treatment, and this is drawn into a predetermined wire diameter to obtain a copper alloy wire, and a plurality of the copper alloy wires are twisted and further compressed, and then at 350 to 550 ° C. A method for producing a wire conductor for wiring, comprising the steps of aging annealing for 1 minute to 5 hours. Containing 1.0 to 4.5% by mass of Ni, 0.2 to 1.1% by mass of Si, 0.005 to 1.0% by mass of Sn, and 0.005 to 0.2% by mass of Fe From the group consisting of 0.005 to 0.2% by mass of Cr, 0.05 to 2% by mass of Co, 0.005 to 0.1% by mass of P, and 0.005 to 0.3% by mass of Ag. A copper alloy containing at least one selected and having the balance consisting of Cu and inevitable impurities is cast, and the obtained ingot or a round bar obtained therefrom is subjected to a solution treatment, and this is treated with a predetermined wire diameter. To obtain a copper alloy wire by wire drawing, twisting a plurality of the copper alloy wires, further compressing, and thereafter performing aging annealing at 350 to 550 ° C. for 1 minute to 5 hours A method for producing a wire conductor for wiring.