JP2010177055A - Method for manufacturing cu-ag alloy wire, and cu-ag alloy wire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a Cu-Ag alloy wire for manufacturing an extra-fine Cu-Ag alloy wire at sufficient productivity, and the extra-fine Cu-Ag alloy wire. <P>SOLUTION: The extra-fine wire with a finished wire diameter of 0.05 mm or below is manufactured by drawing a cast material including Ag of 0.5-15.0 wt.%. The cast material wherein foreign bodies of more than 0.2 μm related to disconnection of a wire are very few is used. A surface layer of the wire with a wire diameter ϕ of 1.0 mm or below is removed at a wire which is in a halfway stage of wire-drawing to a finished wire diameter. Removal of the surface layer is performed so as to make thickness t of the surface layer to be removed satisfy t/r≥0.02 when one half of a wire diameter ϕ of the wire before removing the surface layer is set up to be r. The obtained extra-fine Cu-Ag alloy wire and a strand wire twisting the Cu-Ag alloy wire are suitably used for a center conductor of a coaxial cable. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an extra fine wire made of a Cu-Ag alloy, a stranded wire using the extra fine wire as a strand, a coaxial cable using the extra fine wire or the stranded wire as a conductor, and a method of manufacturing the extra fine wire.

  In recent years, along with demands for reducing the size and weight of various electronic devices, it is desired to reduce the diameter of conductors such as coaxial cables used in electronic devices (Patent Document 1). As an ultrafine conductor material, a Cu-Ag alloy wire having high conductivity and higher strength than copper has been proposed (Patent Document 2).

  An extra fine wire used for an extra fine conductor is generally manufactured by drawing a cast material. In the manufacturing process, foreign materials that are considered to be derived from constituent materials such as crucibles and molds used in the processes from melting to casting and molds that connect these may be mixed into the material. It is difficult to avoid this contamination even if a high-purity raw material is used. Further, even in the wire drawing process, wrinkles may be generated on the surface of the material or foreign substances may be caught on the surface of the material. The presence of such foreign matters and surface flaws causes disconnection when manufacturing the fine wire, and decreases the productivity of the fine wire. Patent Document 1 discloses the use of chemical dissolution in reducing the diameter from the wire diameter of the drawn wire to the final wire diameter in order to make it difficult to cause disconnection.

Japanese Patent Laid-Open No. 2002-140935 JP 2001-040439 A

  However, it is hard to say that the conventional technology can produce an ultrafine Cu-Ag alloy wire of 0.05 mm or less with high productivity.

  Patent Document 1 discloses performing electrochemical dissolution on a copper element wire drawn to a wire diameter of 20 μm (0.02 mm). However, with the conventional method, it is difficult to produce a long ultrafine wire by drawing it to 0.05 mm or less, so many breaks occur during drawing to a wire diameter of 0.02 mm, resulting in a long copper wire. It is difficult to obtain a strand. In addition, since the absolute value of the foreign substance diameter does not change, when removing the surface layer of a wire with a wire diameter of 0.02 mm, the ratio of the foreign substance diameter to the wire diameter increases, so the foreign substance is completely removed if the removal amount is small. However, if the removal amount is increased in order to completely remove foreign matter, the amount of waste (the weight of the wire after removing the surface layer / the weight of the wire before removing the surface layer) increases. As described in Patent Document 1, when a strand having a wire diameter of 20 μm is reduced to a wire diameter of 14 μm, the yield is about 50% and half of the wire is discarded. Since this waste is a part added to the cost of processing to 0.02 mm, there is a problem that discarding this part results in poor yield and high cost.

  The present invention has been made in view of the above circumstances, and one of its purposes is to reduce the disconnection during wire drawing and to produce a Cu-Ag alloy wire having a wire diameter of 0.05 mm or less with high productivity. An object of the present invention is to provide a method for producing a Cu-Ag alloy wire. Another object of the present invention is to provide a highly conductive and high-strength ultra-fine Cu-Ag alloy wire, a stranded wire obtained by twisting the ultra-fine wire, and a coaxial cable having the ultra-fine wire or the stranded wire as a central conductor. Is to provide.

  Since the present inventors have a limit to the reduction of foreign matter contained in a cast material by using a high-purity raw material, what is the amount of foreign matter contained in the cast material? It was examined from the viewpoint of acceptability as a material. As a result, a part of the cast material is obtained as a sample, the concentration of the contained foreign matter is measured, and if the amount of foreign matter having a certain diameter or more is a predetermined value or less, the foreign matter involved in the disconnection is very small. I found it to be a cast material. And since this cast material was hard to break at the time of wire drawing, the knowledge that an ultrafine wire could be manufactured with high productivity was acquired. Moreover, the knowledge that this cast material can be manufactured by casting under specific conditions was obtained.

  In addition, when producing very fine Cu-Ag alloy wires of 0.05 mm or less, in addition to using a cast material with less foreign matter that can be involved in the disconnection, a specific size in the middle of wire drawing By removing a specific amount of the surface layer, it is possible to effectively reduce the disconnection at the time of wire drawing, and to produce a very fine wire of a desired size with high productivity. I got the knowledge.

Based on the above knowledge, the method for producing a Cu—Ag alloy wire of the present invention uses a specific cast material and removes a specific surface layer. Specifically, in the method for producing a Cu-Ag alloy wire of the present invention, an ultrafine wire having a final wire diameter of 0.05 mm or less is obtained by subjecting a cast material containing Ag to 0.5 mass% to 15.0 mass% to wire drawing. It is a manufacturing method, and includes the following casting process and surface layer removal process.
(1) Casting process: Melt the prepared raw material Cu and raw material Ag in a crucible made of high purity carbon, hold this mixed molten metal for 30 minutes or more above the liquidus temperature of the mixture of Cu and Ag, and mix Impurities are separated on the surface of the molten metal. Thereafter, a cast material is produced from the molten metal from which the impurities are separated, using a mold made of high purity carbon.
(2) Surface layer removal step: The surface layer of the wire in the middle of drawing until reaching the final wire diameter is removed. This surface layer removing step particularly includes a thin wire processing step for removing a surface layer of a thin wire having a wire diameter φ of 1.0 mm or less. Then, in this fine wire processing step, the removal of the surface layer is such that the thickness t of the surface layer to be removed satisfies t / r ≧ 0.02, where r is 1/2 of the wire diameter φ of the wire before the removal of the surface layer. Do as follows.

  It is conceivable to use a cast material with less foreign matter that can be involved in disconnection, and to strip the raw material before drawing to remove foreign matter and surface flaws. However, even when stripping in such an upstream process, if a very fine Cu-Ag alloy wire with a thickness of 0.05 mm or less, particularly 0.04 mm or less, especially less than 0.025 mm, is produced by wire drawing, frequent disconnections occur. As a result, it has been found that it is difficult to continuously produce extra fine wires. In other words, even if the skin is peeled upstream, only foreign matter and wrinkles present on the very surface of the material can be removed. There is. Further, even if the skin is peeled upstream, foreign matter may be newly involved in the drawing process or wrinkles may be generated, and there is a risk of disconnection, and it is difficult to continuously manufacture the fine wire. On the other hand, if the surface layer is removed in the most downstream process after wire drawing (just before the final wire diameter) as in Cited Document 1, yields and costs are likely to increase as described above. On the other hand, when the surface layer is removed after the diameter becomes 1.0 mm or less, the present inventors hardly break the wire, and even a very fine wire material of less than 0.025 mm continuously. It was possible to manufacture and gained the knowledge that productivity could be improved by reducing the number of disconnections. Therefore, in the production method of the present invention, the surface layer is removed from the thin wire rod that is in the middle of wire drawing.

  The manufacturing method of the present invention having the above-described configuration is capable of continuous wire drawing without causing disconnection in manufacturing an ultrafine Cu—Ag alloy wire of 0.05 mm or less. Therefore, according to the manufacturing method of the present invention, a long and extremely fine wire can be manufactured, and the productivity is excellent. Hereinafter, the present invention will be described in more detail.

  In the casting process, the holding time for separating impurities on the surface of the mixed molten metal is particularly important. When this holding time is shorter than 30 minutes, the separation of impurities becomes insufficient, and the foreign material contained in the cast material also increases. In particular, when the holding time is 0 to 20 minutes, the foreign material involved in the disconnection is contained in the cast material with a high probability, and by using such a cast material, disconnection is likely to occur at the time of wire drawing. The holding time may be 30 minutes or longer, and the upper limit is not particularly limited. However, considering productivity, it is preferably 10 hours or shorter.

  By the casting process, a cast material with few foreign matters that can be involved in the disconnection is obtained. Specifically, after part of the cast material is dissolved with an acid, it is filtered with a filter having a pore size of 0.2 μm, and the cast material in which the amount of Al and the amount of Si contained in the residue collected on the filter are respectively dissolved is dissolved. 1 ppm by mass or less. That is, this cast material has very little Al compound and Si compound exceeding 0.2 μm. Since there are few coarse foreign matters that cause breakage at the time of wire drawing, the use of this cast material can effectively reduce the disconnection at the time of wire drawing. In addition, when the amount of Al and the amount of Si exceed 1 ppm by mass, it is preferable to recreate the cast material and use the cast material with less foreign matter for wire drawing.

  In addition, a crucible or mold made of high-purity carbon is used to reduce foreign substances contained in the cast material. Specifically, it is preferable to use a carbon product having an impurity amount of 20 mass ppm or less, more preferably 5 mass ppm or less. Furthermore, it is preferable to use a raw material Cu or a raw material Ag having a high purity, for example, a four-nine class (purity 99.99%) or higher.

  The addition amount of the raw material Ag is adjusted so that the content of Ag in the obtained ultrafine wire is 0.5 to 15.0% by mass. If the Ag content exceeds 15.0% by mass, even if the degree of workability (area reduction) and intermediate heat treatment at the time of wire drawing are adjusted, the predetermined conductivity as described later cannot be obtained, and it is less than 0.5% by mass. And even if it adjusts the workability at the time of wire drawing, and intermediate heat processing, the predetermined intensity | strength which is mentioned later cannot be obtained.

  In the manufacturing method of the present invention, the wire drawing (particularly cold) is performed over a plurality of passes until the final wire diameter is reached. The wire drawing conditions may be adjusted so that a wire having characteristics such as a desired wire diameter and tensile strength can be obtained. In particular, the cold wire drawing performed first is easy to perform the subsequent wire drawing with a predetermined degree of processing when the degree of processing is 70% or more.

  When performing a multipass wire drawing process, if an intermediate heat treatment is performed at an intermediate stage, it is possible to remove the processing distortion introduced into the wire before the intermediate heat treatment and facilitate the subsequent wire drawing. Moreover, the strength of the ultrafine wire can be improved by precipitating Ag by an intermediate heat treatment and making the Ag precipitate into a fibrous form by subsequent wire drawing. The conditions for the intermediate heat treatment include heating temperature: 350 to 500 ° C. (preferably 400 to 450 ° C.) and holding time: 0.5 to 10 hours.

  In the production method of the present invention, at least the removal of the surface layer in the fine wire processing step is preferably performed by chemical treatment or electrochemical treatment. The wire that is subject to removal of the surface layer in the thin wire processing step is thin with a wire diameter φ of 1.0 mm or less, so when using a peeling die that is used for normal skinning, the center of the wire is located at the center of the die hole. It is difficult to match, leading to a decrease in productivity. On the other hand, chemical treatment and electrochemical treatment can be easily applied to wires of any wire diameter, and the surface after treatment is very smooth and hardly causes defects such as wire breakage. For this reason, when the drawn wire is further subjected to wire drawing, it is difficult to break and excellent in wire drawing. Typical processing includes electrolytic polishing. A known process may be used. The wire that removes the surface layer in the thin wire processing step may have a wire diameter of φ1.0 mm or less, but if the wire diameter is too small, the amount of waste removed from the wire increases, resulting in an increase in manufacturing cost. Therefore, the wire diameter is preferably φ0.2 mm or more.

  In the fine wire processing step, the removal rate t / r of the surface layer is 0.02 or more, preferably 0.08 or more. Also, if the surface layer is removed multiple times including the thin wire processing step, the amount of removal of the surface layer increases, so that wrinkles and foreign matters can be sufficiently removed, and the occurrence of disconnection can be reduced. it can. When removing the surface layer a plurality of times, it is preferable to remove the surface layer so that the total removal ratio t / r in each treatment is 0.08 or more, and more preferably 0.12 or more. However, if the removal amount becomes too large, the yield deteriorates, so the upper limit of the total t / r is about 0.20. The surface layer thickness t is a distance along the radial direction of the wire from the surface of the wire. Moreover, the cross-sectional shape of a wire is typically circular.

  The Cu—Ag alloy wire produced by the production method of the present invention may have plating. By performing the plating, the corrosion resistance of the Cu-Ag alloy wire can be improved, and the connectivity between the wires and when connecting the wires to other members can be enhanced. Examples of the plating include one or more selected from Au, Au alloy, Ag, Ag alloy, Sn, Sn alloy, Ni, and Ni alloy. This plating may be performed at any time after the surface layer is removed by the fine wire processing step. That is, the plating process may be performed after the end of the final wire drawing or during the wire drawing (between passes) after the fine wire processing step. The wire after removal of the surface layer is easy to be plated because the surface is smooth and clean.

  The Cu-Ag alloy wire of the present invention obtained by the above-described production method of the present invention contains 0.5% by mass or more and 15.0% by mass or less of Ag, with the balance being Cu and inevitable impurities. Further, the Cu-Ag alloy wire of the present invention has a small amount of Al and Si as in the above-described cast material, and each is 1 ppm by mass or less. Since the Cu-Ag alloy wire of the present invention has a very low content of foreign matter, for example, when further drawing, or when twisting a plurality of Cu-Ag alloy wires into a stranded wire, disconnection may occur. Not likely to occur. Moreover, when a Cu-Ag alloy wire or its stranded wire is used as the central conductor of a coaxial cable, problems such as disconnection are less likely to occur when the coaxial cable is used.

  In the above-mentioned production method of the present invention, it is difficult for wire breakage to occur at the time of wire drawing, so that an ultrafine Cu-Ag alloy wire of the present invention can be obtained. Specifically, the wire diameter can be 0.05 mm or less. By further drawing, the wire diameter can be set to 0.01 mm (10 μm) to 0.03 mm (30 μm).

  In the production method of the present invention, the Cu-Ag alloy wire of the present invention having high strength can be obtained by work hardening by wire drawing, the effect of making the above Ag precipitate into a fiber, or the like. In particular, the tensile strength is preferably 800 MPa or more and 1600 MPa or less. The Cu—Ag alloy wire of the present invention having such a tensile strength is difficult to break when wound into a coil or when a plurality of Cu—Ag alloy wires are twisted together. It is advisable to adjust the Ag content, the workability during wire drawing (area reduction ratio), the intermediate heat treatment conditions, etc. so that the tensile strength and the electrical conductivity described later have desired values.

  The Cu—Ag alloy wire of the present invention preferably has a conductivity of 65% IACS or more, particularly 70% IACS or more, more preferably 80% IACS or more. Such an ultrafine, high strength and high conductivity Cu-Ag alloy wire of the present invention is expected to be suitably used as a conductor material for various electrical devices.

  According to the method for producing a Cu-Ag alloy wire of the present invention, an ultrafine Cu-Ag alloy wire having a wire diameter of 0.05 mm or less can be continuously produced, and the productivity of the Cu-Ag alloy wire is excellent. Moreover, the Cu-Ag alloy wire obtained by this manufacturing method and the stranded wire of this Cu-Ag alloy wire have high strength and high conductivity, and can be suitably used for conductors such as coaxial cables.

  Several ultra-fine wires made of Cu-Ag alloy were manufactured and the drawability was investigated.

<Production of casting material>
Electrolytic copper having a purity of 99.99% or more was prepared as a raw material Cu, and silver grains (Ag) having a purity of 99.99% or more were prepared as a raw material Ag. After the prepared electrolytic copper is pickled and foreign matter adhering to the surface of the electrolytic copper is removed, the pickled electrolytic copper and the silver particles are put into a high-purity carbon crucible and vacuumed in a continuous casting apparatus. A mixed molten metal was prepared by melting and dissolving Cu and Ag. In addition, the addition amount of the silver grain was adjusted so that Ag content with respect to mixed molten metal might be 0.6 mass%.

  After the silver melt was added, the mixed molten metal was held at a temperature higher than the liquidus temperature of the mixture of Cu and Ag for 30 minutes to separate impurities including foreign matters on the surface of the mixed molten metal in the crucible.

  After separating the impurities, a round wire (cast material) having a wire diameter of 8.0 mm was manufactured using a high purity carbon mold. The amount of Al and the amount of Si in the obtained cast material were measured. Here, 200 g of the cast material was separated and dissolved in an aqueous solution containing 6.4 mol or more of nitric acid. This solution was filtered with a filter having a pore size of 0.2 μm, and the residue was collected with a filter. The collected residue was dried in a platinum crucible to incinerate the filter, and then melted by adding a flux to give a glassy substance. The obtained glassy substance was dissolved in an aqueous solution containing hydrochloric acid. The work from the melting of the cast material to the melting of the glassy substance was carried out in a clean booth. The amount of Si and Al was quantified by inductively coupled plasma (ICP) emission spectroscopic analysis of the solution in which the glassy substance was dissolved. As a result, the Si content was 0.1 mass ppm and the Al was 0.3 mass ppm, both of which were 1 mass ppm or less. In addition, about 100-200g is sufficient for the quantity of the casting material utilized for the measurement of Si amount and Al amount.

  The obtained cast material was subjected to multiple passes of cold drawing to obtain a wire material having a final wire diameter of 0.021 mm. For wire drawing, an American Wire Gage standard (AWG standard) die was used. In each sample, intermediate heat treatment (400 ° C. × 8 hours) was performed on a wire rod having a wire diameter of 2.6 mm, which is an intermediate stage of wire drawing. Further, in any sample, Ag plating was applied to a wire material having a wire diameter of 0.3 mm, which is an intermediate stage of wire drawing.

(Sample 1)
In Sample 1, when the wire diameter φ became 0.9 mm (≦ 1.0 mm), which was an intermediate stage of wire drawing, the wire was subjected to electropolishing and the surface layer was removed. The electropolishing was performed using an aqueous phosphoric acid solution as the electrolytic solution, with a current density of 40 A / dm ² , an immersion time of 6.8 min, and a temperature of 30 ° C. The thickness t of the removed surface layer was t = 0.06 mm. When r is 1/2 of the wire diameter φ, r = φ × (1/2) = 0.9 × (1/2) = 0.45, t / r≈0.133 (≧ 0.02).

(Sample 2)
For sample 2, when the wire diameter φ ₁ reached 2.6 mm (> 1.0 mm), which was in the middle of wire drawing, the wire was subjected to the above intermediate heat treatment and then subjected to chemical polishing to remove the surface layer. Chemical polishing was performed using an aqueous hydrogen sulfate solution as the polishing liquid, with an immersion time of 150 min and a temperature of 30 ° C. The thickness t ₁ of the removed surface layer was t ₁ = 0.15 mm. If 1/2 of the wire diameter φ ₁ is r ₁ , r ₁ = 1.30 and t ₁ / r ₁ ≈0.115. Further, in this sample 2, when the wire diameter φ ₂ , which is an intermediate stage of wire drawing, became 0.9 mm (≦ 1.0 mm), the wire was subjected to chemical polishing similar to the above to remove the surface layer. The thickness t ₂ of the removed surface layer was changed by varying the immersion time, and t ₂ = 0.01 mm. When 1/2 of the wire diameter φ ₂ is r ₂ , r ₂ = 0.45, t ₂ / r ₂ ≈0.022 (≧ 0.02). Total r ₁ / t ₁ and t ₂ / r ₂ in the removal of the two surface layers is 0.115 + 0.022 = 0.137 (≧ 0.08 ).

(Sample 3)
Sample 3 was subjected to the same electrolytic polishing as that of Sample 1 on the wire when the wire diameter φ was 0.9 mm as in Sample 1, and the surface layer was removed. The thickness t ₃ of the removed surface layer was changed by changing the immersion time to t ₃ = 0.04 mm. When r is 1/2 of the wire diameter φ, r = 0.45 and t / r ₃ ≈0.089 (≧ 0.02).

(Sample 4)
For sample 4, the surface layer was not removed when the wire diameter φ was 2.6 mm, and when the wire diameter φ became 0.9 mm, the wire was subjected to chemical polishing similar to that of sample 2 to remove the surface layer. The thickness t ₄ of the removed surface layer was changed by changing the immersion time to t ₄ = 0.02 mm. When r is 1/2 of the wire diameter φ, r = 0.45 and t / r ₄ ≈0.044 (≧ 0.02).

Comparative example: (Sample I)
Sample I was in the middle of wire drawing, and when the wire diameter φ _I was 2.6 mm (> 1.0 mm), the wire was subjected to the above intermediate heat treatment and then subjected to the same chemical polishing as Sample 2, The layer was removed. The thickness t _I of the removed surface layer was t _I = 0.15 mm. When r _I is 1/2 of the wire diameter φ, r _I = 1.30 and t _I / r _I ≈0.115. In Sample I, the surface layer was not removed when the wire diameter φ was 0.9 mm.

Comparative example: (Sample II)
Sample II is a sample in which the surface layer is not removed in the middle of wire drawing, and only the above-described intermediate heat treatment and plating are applied to the wire.

<Evaluation of wire drawing>
For each sample, the drawability when a cast material having a wire diameter of 8 mm was drawn to a final wire diameter of 0.021 mm was examined. The results are shown in Table 1. The wire drawing property was evaluated by a value (kg / time) obtained by dividing the above-mentioned cast material by 20 kg, measuring the number of breaks that occurred until the entire 20 kg was drawn, and dividing 20 kg by the number of breaks. .

<Characteristics of Cu-Ag alloy wire>
Further, the obtained samples 1 to 4 were measured for tensile strength (MPa) and electrical conductivity (% IACS). The results are also shown in Table 1.

  As shown in Table 1, while using a cast material prepared by holding the mixed molten metal for 30 minutes or more above the liquidus temperature of the mixture of Cu and Ag, a specific amount is used for the wire material whose wire diameter is 1.0 mm or less. It can be seen that Samples 1 to 4 from which the surface layer was removed are highly wire-drawable and difficult to break even in the production of ultrafine wires having a wire diameter of less than 0.025 mm. In particular, it can be seen that if the surface layer is removed a plurality of times, it becomes more difficult to disconnect. Also, even if a casting material with few foreign objects is used, if the surface layer is not removed from the wire material with a specific wire diameter, disconnection will frequently occur when producing extremely fine wire materials of less than 0.025 mm. I understand.

  Further, it can be seen that all of the obtained samples 1 to 4 have high tensile strength and high electrical conductivity. Seven of each of the samples 1 to 4 were prepared, and a 7-stranded strand was manufactured. As a result, a strand could be produced without disconnection or the like. Further, when a coaxial cable was manufactured using the obtained stranded wire as a central conductor, it could be produced without any problem. Therefore, the Cu-Ag alloy wire of the present invention has sufficient characteristics required for conductors such as wirings used in various electric devices, and is expected to be suitably used for the conductors.

  The above-described embodiment can be appropriately changed without departing from the gist of the present invention, and is not limited to the above-described configuration. For example, the content of Ag, the removal rate of the surface layer, the wire diameter for removing the surface layer, the final wire diameter, and the like can be appropriately changed.

  The method for producing a Cu-Ag alloy wire of the present invention can be suitably used for producing an ultrafine wire having a wire diameter of 0.05 mm or less. The Cu-Ag alloy wire and the stranded wire of the present invention can be suitably used for the conductor of the coaxial cable of the present invention used for automobiles, electronic parts, industrial robots and the like.

Claims (8)

A method for producing a Cu-Ag alloy wire, in which an ultrafine wire having a final wire diameter of 0.05 mm or less is produced by performing wire drawing on a cast material containing 0.5 mass% or more and 15.0 mass% or less of Ag,
The prepared raw material Cu and raw material Ag are melted in a crucible made of high-purity carbon, and this mixed molten metal is kept at a temperature higher than the liquidus temperature of the mixture of Cu and Ag for 30 minutes or more, so that impurities are introduced into the surface of the mixed molten metal After separating, a casting process for producing the cast material using a mold made of high purity carbon,
In the wire in the middle of the drawing until reaching the final wire diameter, comprising a surface layer removal step of removing the surface layer of the wire,
The surface layer removing step includes a thin wire processing step of removing a surface layer of a thin wire having a wire diameter φ of 1.0 mm or less,
In the fine wire processing step, the surface layer is removed so that the thickness t of the surface layer to be removed satisfies t / r ≧ 0.02 when r is 1/2 of the wire diameter φ of the wire before the surface layer is removed. A method for producing a Cu-Ag alloy wire, which is characterized in that it is performed.   2. The Cu-Ag alloy wire according to claim 1, wherein the surface layer removal step is provided a plurality of times, and the surface layer is removed so that the total t / r in each step is 0.08 or more. Production method.   3. The method for producing a Cu—Ag alloy wire according to claim 1, further comprising a plating step of plating the surface of the wire rod that has undergone the thin wire processing step. Produced by the method for producing a Cu-Ag alloy wire according to any one of claims 1 to 3,
Containing 0.5 mass% or more and 15.0 mass% or less of Ag, with the balance consisting of Cu and inevitable impurities,
A Cu-Ag alloy wire characterized by a wire diameter of 0.05 mm or less.   5. The Cu—Ag alloy wire according to claim 4, wherein the tensile strength is 800 MPa or more and 1600 MPa or less. The surface is plated,
6. The Cu—Ag alloy wire according to claim 4, wherein the plating is made of at least one selected from Au, Au alloy, Ag, Ag alloy, Sn, Sn alloy, Ni and Ni alloy. .   A Cu-Ag alloy stranded wire obtained by twisting the Cu-Ag alloy wire according to any one of claims 4 to 6 as a strand.   Coaxial, characterized in that the Cu-Ag alloy wire according to any one of claims 4 to 6, or a Cu-Ag alloy stranded wire obtained by twisting the Cu-Ag alloy wire as a strand is used as a central conductor. cable.