Copper alloy wire

Abstract

Provided is a copper alloy wire having excellent balance among strength, electrical conductivity and wire drawing properties. The copper alloy wire has an alloy composition containing 1.0 mass % to 6.0 mass % of Ag, with the remainder being Cu and inevitable impurities, wherein a peak intensity ratio ((peak intensity I(111)+peak intensity I(200)+peak intensity I(311)) / peak intensity I(220)) of the total intensity of peak intensity I(111), peak intensity I(200), peak intensity I(220) and peak intensity I(311) of 111 diffraction, obtained by X-ray diffraction analysis of the surface, to the peak intensity I(220) is 1.20 to 3.00.

Description

Technical Field

[0001] The present invention relates to a copper alloy wire. Background Art

[0002] For cables connecting devices, the diameter of wires tends to be thinner than before due to the miniaturization of products, space saving of wires, increase in signal lines, etc. For example, copper alloy wires such as Cu-Sn, Cu-Cr, and Cu-Ag are gradually being used to replace pure copper wires with insufficient strength. Among copper alloys, Cu-Ag alloys have an excellent balance of high strength and high conductivity.

[0003] For example, Patent Document 1 describes a method for manufacturing a copper alloy, wherein a copper alloy ingot having a composition of 1 to 10 wt % Ag, the remainder being Cu and inevitable impurities is cold worked, heat treated in a vacuum atmosphere or in an inert gas atmosphere at a temperature of 570 to 680° C. for 0.5 to 5 hours in the middle of the cold working, and further cold worked, heat treated in a vacuum atmosphere or in an inert gas atmosphere at a temperature of 400 to 550° C. for 0.5 to 40 hours in the middle of the cold working.

[0004] Patent Document 2 describes a Cu-Ag alloy fine wire having an Ag content of 1 to 10 wt % and the balance being Cu and inevitable impurities, wherein the entire structure formed by a solid solution of Cu is formed by a recrystallized texture.

[0005] In the above-mentioned patent documents 1 and 2, the eutectic phase of Cu and Ag is stretched into a filament to achieve an improvement in strength and conductivity. In addition, in patent document 2, in a method for manufacturing Cu-Ag alloy fine wires, the strength is improved by heat treatment to develop a recrystallized texture and high processing after the heat treatment.

[0006] However, in Patent Document 1, the control of the precipitation distribution of the eutectic phase, which contributes to the strength after wire drawing, is inappropriate, so the strength characteristics are insufficient. In addition, in Patent Document 2, appropriate wire drawing conditions are not set before heat treatment, so the material embrittlement during heat treatment proceeds, making it difficult to thin the wire. Therefore, due to poor productivity, it cannot be a cost-competitive product. As such, in Patent Documents 1 and 2, it is difficult to simultaneously improve the wire drawing properties as a manufacturability while improving the strength and electrical conductivity.

[0007] Prior art literature

[0008] Patent Literature

[0009] Patent Document 1: Japanese Patent No. 3325639

[0010] Patent Document 2: Japanese Patent No. 5051647 Summary of the invention

[0011] Problems to be solved by the invention

[0012] An object of the present invention is to provide a copper alloy wire having an excellent balance among strength, electrical conductivity and wire drawing properties.

[0013] Means for solving problems

[0014] [1] A copper alloy wire having an alloy composition containing 1.0 mass % to 6.0 mass % of Ag, the remainder being Cu and inevitable impurities, wherein, with respect to peak intensities I(111) of 111 diffraction, I(200) of 200 diffraction, I(220) of 220 diffraction, and I(311) of 311 diffraction obtained by X-ray diffraction analysis of the surface, a peak intensity ratio of the total intensity of the peak intensity I(111), the peak intensity I(200), and the peak intensity I(311) to the peak intensity I(220) ((the peak intensity I(111)+the peak intensity I(200)+the peak intensity I(311)) / the peak intensity I(220)) of 1.20 to 3.00.

[0015] [2] The copper alloy wire according to [1], wherein the alloy composition further contains a total of 0.05 mass % to 0.30 mass % of one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr and Cr.

[0016] [3] The copper alloy wire described in [1] or [2] above, wherein the tensile strength satisfies 1000 MPa or more, the electrical conductivity satisfies 60% IACS or more, and the Ag content X (mass %), the tensile strength Y (MPa) and the electrical conductivity Z (% IACS) satisfy the following formulas (1), (2), and (3).

[0017] Y≥110X+880…Formula (1)

[0018] Z≥-4.6X+82…Formula (2)

[0019] Y≥-0.040Z+117…Formula (3)

[0020] [4] The copper alloy wire according to any one of [1] to [3] above, wherein the cross section is a circle having a diameter of 0.02 mm to 0.08 mm.

[0021] [5] The copper alloy wire described in any one of [1] to [3] above has a strip-shaped cross-section with a long side of 0.060 mm or more and 0.500 mm or less and a short side of 0.005 mm or more and 0.040 mm or less.

[0022] Effects of the Invention

[0023] According to the present invention, a copper alloy wire excellent in the balance of strength, electrical conductivity, and drawability can be provided. Detailed Description of Embodiments

[0024] Hereinafter, description will be made in detail based on embodiments.

[0025] As a result of repeated and in-depth studies by the inventors of the present application, focusing on the peak intensity of a specified plane obtained by X-ray diffraction analysis of the surface of the copper alloy wire, it was found that by controlling the peak intensity ratio of the specified plane within a specified range, the balance of strength, electrical conductivity, and drawability can be made excellent, and the present invention was completed based on this finding.

[0026] The copper alloy wire of the embodiment has an alloy composition containing 1.0 mass% or more and 6.0 mass% or less of Ag, with the balance being Cu and inevitable impurities. Regarding the peak intensity I(111) of the 111 diffraction, the peak intensity I(200) of the 200 diffraction, the peak intensity I(220) of the 220 diffraction, and the peak intensity I(311) of the 311 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio ((the peak intensity I(111)+the peak intensity I(200)+the peak intensity I(311)) / the peak intensity I(220)) of the total intensity of the peak intensity I(111), the peak intensity I(200), and the peak intensity I(311) relative to the peak intensity I(220) is 1.20 or more and 3.00 or less.

[0027] First, the alloy composition of the copper alloy wire will be described.

[0028] The copper alloy wire of the above embodiment has the following alloy composition, which contains 1.0 mass% or more and 6.0 mass% or less of Ag, with the balance being Cu and inevitable impurities.

[0029] <Ag: 1.0 mass% or more and 6.0 mass% or less>

[0030] Ag (silver) is an element required to increase the strength of copper alloy wire rods, and contains 1.0 mass% or more and 6.0 mass% or less of Ag. When the content of Ag is 1.0 mass% or more, the strength of the copper alloy wire rod can be increased through the solid solution and precipitation of Ag. In addition, when the content of Ag is 6.0 mass% or less, the decrease in the electrical conductivity of the copper alloy wire rod can be suppressed, and the high electrical conductivity of the copper alloy wire rod can be maintained. Moreover, when the content of Ag is more than 6.0 mass%, since high strength corresponding to the cost increase of the material cost caused by the increase in the usage amount of Ag cannot be achieved, it is difficult to contribute to the added value of the customer's product. In order to achieve the balance between the increase in the strength and the increase in the electrical conductivity of the copper alloy wire rod, the content of Ag is 1.0 mass% or more, preferably 1.5 mass% or more. On the other hand, the content of Ag is 6.0 mass% or less, preferably 4.0 mass% or less.

[0031] <Sub-components of copper alloy wire rod: 0.05 mass% or more and 0.30 mass% or less>

[0032] The alloy composition of the copper alloy wire rod can also contain one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr, with a total of 0.05 mass% or more and 0.30 mass% or less. That is, in addition to Ag as an essential basic component, the copper alloy wire rod can also contain one or more components selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr, with a total of 0.05 mass% or more and 0.30 mass% or less, as optional sub-components. When the content of the sub-component is 0.05 mass% or more, the strength characteristics of the copper alloy wire rod are improved, and among several elements, the effect of alleviating the brittleness of the copper alloy wire rod can be brought. In addition, when the content of the sub-component is 0.30 mass% or less, the electrical conductivity of the copper alloy wire rod is not severely damaged. Therefore, the content of the sub-component is preferably 0.05 mass% or more, more preferably 0.08 mass% or more, and further preferably 0.10 mass% or more. On the other hand, it is preferably 0.30 mass% or less, more preferably 0.25 mass% or less, and further preferably 0.20 mass% or less.

[0033] <Sn: 0.05 mass% or more and 0.20 mass% or less>

[0034] When the content of Sn (tin) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire. When the content of Sn is 0.20% by mass or less, it will not seriously damage the electrical conductivity of the copper alloy wire. Therefore, the content of Sn is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0035] <Mg: 0.05% by mass or more and 0.20% by mass or less>

[0036] When the content of Mg (magnesium) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire and has the effect of alleviating the brittleness of the copper alloy wire. When the content of Mg is 0.20% by mass or less, it will not seriously damage the electrical conductivity and manufacturability during casting of the copper alloy wire. Therefore, the content of Mg is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0037] <Zn: 0.05% by mass or more and 0.30% by mass or less>

[0038] When the content of Zn (zinc) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire and has the effect of alleviating the brittleness of the copper alloy wire. When the content of Zn is 0.30% by mass or less, it will not seriously damage the electrical conductivity of the copper alloy wire. Therefore, the content of Zn is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.30% by mass or less, more preferably 0.25% by mass or less, further preferably 0.20% by mass or less, and particularly preferably 0.15% by mass or less.

[0039] <In: 0.05% by mass or more and 0.20% by mass or less>

[0040] When the content of In (indium) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire. When the content of In is 0.20% by mass or less, it will not seriously damage the electrical conductivity of the copper alloy wire. Therefore, the content of In is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0041] <Ni: 0.05% by mass or more and 0.30% by mass or less>

[0042] When the content of Ni (nickel) is 0.05% by mass or more, it has the effect of helping to improve the strength of the copper alloy wire. When the content of Ni is 0.30% by mass or less, it will not seriously damage the electrical conductivity of the copper alloy wire. Therefore, the content of Ni is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.30% by mass or less, more preferably 0.25% by mass or less, further preferably 0.20% by mass or less, and particularly preferably 0.15% by mass or less.

[0043] <Co: 0.05% by mass or more and 0.20% by mass or less>

[0044] When the content of Co (cobalt) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire. When the content of Co is 0.20% by mass or less, it will not seriously damage the electrical conductivity of the copper alloy wire. Therefore, the content of Co is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0045] <Zr: 0.05% by mass or more and 0.20% by mass or less>

[0046] When the content of Zr (zirconium) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire rod and has the effect of alleviating the brittleness of the copper alloy wire rod. When the content of Zr is 0.20% by mass or less, it does not seriously damage the electrical conductivity and manufacturability during casting of the copper alloy wire rod. Therefore, the content of Zr is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0047] <Cr: 0.05% by mass or more and 0.20% by mass or less>

[0048] When the content of Cr (chromium) is 0.05% by mass or more, it helps to improve the strength of the copper alloy wire rod. When the content of Cr is 0.20% by mass or less, it does not seriously damage the electrical conductivity of the copper alloy wire rod. Therefore, the content of Cr is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, further preferably 0.08% by mass or more, and particularly preferably 0.10% by mass or more. On the other hand, it is preferably 0.20% by mass or less, more preferably 0.18% by mass or less, further preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0049] <Balance: Cu and unavoidable impurities>

[0050] The balance other than the above components is Cu (copper) and unavoidable impurities. Unavoidable impurities are substances that are inevitably mixed in during the manufacturing process. Depending on the content, they can become factors that reduce any one or more of the strength, electrical conductivity, and drawability of the copper alloy wire rod, and have an impact on the environment or cause embrittlement of the material. Therefore, the content of unavoidable impurities is preferably as low as possible. Examples of unavoidable impurities include elements such as S, Pb, Sb, and Bi. The upper limit of the content of the above unavoidable impurities is preferably less than 0.0001% by mass for each of the above elements, and preferably the total of the above elements is less than 0.0005% by mass.

[0051] Next, the peak intensity ratio obtained by X-ray diffraction analysis of the surface of the copper alloy wire rod will be described.

[0052] When the peak intensities of 111, 200, 220, and 311 diffractions obtained by X-ray diffraction analysis on the surface of the copper alloy wire are respectively represented by I(111), I(200), I(220), and I(311), the peak intensity ratio of the total intensity of the peak intensity I(111), the peak intensity I(200), and the peak intensity I(311) to the peak intensity I(220) ((peak intensity I(111) + peak intensity I(200) + peak intensity I(311)) / peak intensity I(220)) (hereinafter also referred to as the peak intensity ratio) is 1.20 or more and 3.00 or less.

[0053] When the peak intensity ratio is 1.20 or more, the wire drawing property of the copper alloy wire can be improved. In addition, when the peak intensity ratio is 3.00 or less, the strength of the copper alloy wire can be increased. In order to balance the improvement of the strength and wire drawing property of the copper alloy wire and achieve a balance with the electrical conductivity, the peak intensity ratio is 1.20 or more, preferably 1.30 or more, and more preferably 1.50 or more. On the other hand, the peak intensity ratio is 3.00 or less, preferably 2.80 or less, and more preferably 2.50 or less.

[0054] The peak intensity I(111) of 111 diffraction obtained by X-ray diffraction analysis on the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height within the range of 2θ=43±1°. The {111} plane contributes to the improvement of the strength of the copper alloy wire, but on the other hand, there is a tendency to reduce the wire drawing properties of the copper alloy wire. However, when heat treatment is not performed in the manufacturing process of the copper alloy wire described later, the copper alloy wire sometimes shows a decrease in wire drawing properties without increasing strength even in a state where the peak intensity I(111) is high.

[0055] The peak intensity I(200) of the 200 diffraction obtained by X-ray diffraction analysis on the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height within the range of 2θ=50±1°. The {100} plane contributes to the improvement of the wire drawing property of the copper alloy wire, but on the other hand, it tends to contribute less to the improvement of strength.

[0056] The peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis on the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height within the range of 2θ=74±1°. For the relevant {110} plane, when the total amount is large, the proportion of the {111} plane and the {100} plane is relatively reduced, and the effect is relatively reduced, so it needs to be below an appropriate value. In addition, although the contribution is low, it helps to improve the strength and wire drawing properties of the copper alloy wire.

[0057] The peak intensity I(311) of 311 diffraction obtained by X-ray diffraction analysis on the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height within the range of 2θ=90±1°. For the relevant {311} plane, when the total amount is large, the proportion of the {111} plane and the {100} plane is relatively reduced, and the effect is relatively reduced, so it needs to be below an appropriate value. In addition, although the contribution is low, it helps to improve the strength and wire drawing properties of the copper alloy wire.

[0058] The X-ray diffraction analysis of the surface of the copper alloy wire is measured according to the following method. Using an X-ray diffraction device and using the θ-2θ method, the side surface of the copper alloy wire is set as the measurement object, and the X-ray diffraction intensity between 40° and 100° is measured. The background value as noise is subtracted from the confirmed peak intensity to obtain the peak intensity of each surface. In the X-ray diffraction analysis, multiple copper alloy wires are placed in contact and arranged side by side in the same direction on a sample holder.

[0059] In addition, for the copper alloy wire, when the tensile strength satisfies 1000 MPa or more and the electrical conductivity satisfies 60% IACS or more, and when the Ag content is X (mass %), the tensile strength of the copper alloy wire is Y (MPa), and the electrical conductivity of the copper alloy wire is Z (% IACS), the Ag content X, the tensile strength Y, and the electrical conductivity Z preferably satisfy the following formula (1), formula (2), and formula (3). The copper alloy wire satisfying such a configuration has a better balance between strength and electrical conductivity.

[0060] Y≥110X+880…Formula (1)

[0061] Z≥-4.6X+82…Formula (2)

[0062] Y≥-0.040Z+117…Formula (3)

[0063] The tensile strength of the copper alloy wire was measured by a tensile test in accordance with JIS Z 2241:2011.

[0064] The electrical conductivity of the copper alloy wire was measured in accordance with JIS H0505:1975.

[0065] In addition, the cross section of the copper alloy wire is preferably a circular shape having a diameter of 0.02 mm or more and 0.08 mm or less. Even a copper alloy wire having a circular cross section having a diameter within the above range, that is, a copper alloy wire having a cylindrical ultrafine wire, has an excellent balance between high strength and high conductivity.

[0066] In addition, the cross section of the copper alloy wire may be in the shape of a strip having a long side of 0.060 mm to 0.500 mm and a short side of 0.005 mm to 0.040 mm. Even if the cross section is an ultra-fine wire in the shape of a strip having a long side and a short side within the above range, the copper alloy wire has an excellent balance between high strength and high conductivity.

[0067] The strength and electrical conductivity of the strip-shaped copper alloy wire are not much different from the strength and electrical conductivity of the cylindrical copper alloy wire (for example, a cylindrical ultrafine wire) before being formed into a strip shape. That is, if the strength and electrical conductivity of the cylindrical copper alloy wire before being formed into a strip shape are above the desired value, the strength and electrical conductivity of the strip-shaped copper alloy wire are above the desired value.

[0068] As described above, copper alloy wires have high wire drawing properties, so even if the copper alloy wires are thinned to ultra-fine wires, ultra-fine wires with excellent balance of high strength and high conductivity that have never been achieved before can be obtained. This makes it possible to miniaturize electrical products, save circuit space, increase the number of circuits, etc. at a level that has not been achieved so far, thereby contributing to the high added value of products.

[0069] Next, a method for producing a copper alloy wire according to an embodiment will be described.

[0070] In the method for manufacturing a copper alloy wire of the embodiment, at least one heat treatment is performed during the drawing of the ingot having the above alloy composition to the final wire diameter of the copper alloy wire. The heat treatment is an aging treatment for the purpose of precipitation and recrystallization of Ag. The heat treatment temperature is preferably 400°C or more and 500°C or less. In addition, in order to obtain a sufficient amount of precipitation of Ag, the heat treatment time is preferably 10 hours or more and 100 hours or less.

[0071] In addition, cold wire drawing is performed on the samples before and after the heat treatment. Here, the cold wire drawing before the heat treatment is referred to as the first wire drawing, and the cold wire drawing after the heat treatment is referred to as the second wire drawing. By performing the second wire drawing on the sample cooled after the heat treatment, a copper alloy wire can be manufactured.

[0072] The ratio of the processing degree of the second wire drawing process to the processing degree of the first wire drawing process (processing degree of the second wire drawing process / processing degree of the first wire drawing process) (hereinafter also referred to as the processing degree ratio) is greater than 5.0 and less than 12.0. When the processing degree ratio is less than 5.0, the final drawing rate of the copper alloy wire obtained after the second wire drawing process is greatly reduced, so the desired strength cannot be obtained. When the processing degree ratio is greater than 5.0, it is possible to recrystallize earlier in the heating and holding temperature range from the temperature rise during the heat treatment, thereby eliminating the accumulated strain, and suppressing the embrittlement that causes poor wire drawing in the subsequent process, i.e., the second wire drawing process. When the processing degree ratio is greater than 12.0, the drawing rate of the first wire drawing process before the heat treatment will be reduced, so that a sample with a low processing degree is heat treated. As a result, due to the slow strain relief during the heat treatment, embrittlement proceeds, and wire thinning in the subsequent process becomes difficult.

[0073] In addition, the cross-sectional reduction ratio of each wire drawing process is 15% to 35% for a wire diameter thicker than 0.9 mm, and 10% to 25% for a wire diameter less than 0.9 mm. Other wire drawing conditions can be the wire drawing speed, die size, and capstan diameter under the most general conditions used in the operation.

[0074] Here, the degree of processing of each wire drawing process can be calculated by the following formula.

[0075] Processing degree: η = 2 × ln (wire diameter before drawing / wire diameter after drawing)

[0076] ln: natural logarithm

[0077] In addition, the recrystallization orientation and the degree of wire drawing during heat treatment greatly contribute to the above-mentioned peak strength of the copper alloy wire.

[0078] For example, when heat treatment is not performed, the final processing degree becomes high and the recrystallized structure is not formed, resulting in the peak strength I(200) becoming too low and the peak strength I(111) becoming too high, thereby reducing the wire drawing property of the copper alloy wire. In addition, although it is generally easy to increase the strength of the copper alloy wire when the peak strength I(111) increases, when heat treatment is not performed, the increase in the strength of the copper alloy wire sometimes becomes low.

[0079] In addition, when the processing ratio is less than 5.0, the peak intensity I(200) becomes too high and the peak intensity I(111) becomes too low, thereby affecting the peak intensity ratio. When the processing ratio is greater than 12.0, the peak intensity I(200) becomes too low and the peak intensity I(111) becomes too high, thereby affecting the peak intensity ratio.

[0080] In addition, although the peak intensity I(220) and the peak intensity I(311) are not actively controlled, when these ratios become high, there may be an adverse effect that the effects of the peak intensity I(200) and the peak intensity I(111) are relatively reduced. By satisfying the above manufacturing conditions, it is possible to control within the desired range.

[0081] By performing the heat treatment, the first wire drawing, and the second wire drawing and adjusting the processing ratio to be within the above range, the peak intensity obtained by the X-ray diffraction analysis can be controlled.

[0082] In addition, for the above-mentioned heat treatment, when the heating rate is set to 1°C / min or more, the embrittlement during the heating process can be effectively suppressed. In addition, the faster the heating rate during the heat treatment, the more effective the suppression of embrittlement, but from the perspective of simplifying the device for heat treatment, the upper limit of the heating rate is preferably 15°C / min or less.

[0083] In addition, when the working degree of the first wire drawing process before the heat treatment is 0.69 or more and 2.31 or less, the progress of embrittlement can be suppressed, and wire thinning in the second wire drawing process as a subsequent process can be facilitated.

[0084] In addition, before the above-mentioned heat treatment, a solution heat treatment may be performed to promote the precipitation of Ag in the above-mentioned heat treatment. For the solution heat treatment, the heat treatment temperature is preferably 700°C to 900°C, and the heat treatment time is preferably 10 minutes to 5 hours. The solution heat treatment is used to dissolve Ag, so it is effective for precipitating more homogeneous Ag precipitates.

[0085] As described above, the strength and electrical conductivity of the cylindrical copper alloy wire before being formed into a strip shape are not much different from those of the strip-shaped copper alloy wire. Therefore, by rolling the copper alloy wire obtained by the second wire drawing process, a strip-shaped copper alloy wire can be produced.

[0086] The copper alloy wire material can be suitably used for device connection cables such as micro speaker wires that require an excellent balance of strength, electrical conductivity, and wire drawing properties.

[0087] According to the above-described embodiment, by focusing on the peak intensity of a predetermined surface obtained by X-ray diffraction analysis of the surface and controlling the ratio of the peak intensity of the predetermined surface within a predetermined range, a copper alloy wire having excellent balance among strength, electrical conductivity and wire drawing properties can be obtained.

[0088] Although the embodiments have been described above, the present invention is not limited to the above embodiments, but includes any aspects included in the concept of the present invention and the claims, and various modifications can be made within the scope of the present invention.

[0089] Example

[0090] Next, examples and comparative examples will be described, but the present invention is not limited to these examples.

[0091] (Examples 1 to 34 and Comparative Examples 1 to 12, 14)

[0092] For an ingot having an alloy composition shown in Table 1 and cast into an outer diameter of 6 mm or more and 39 mm or less, a first wire drawing as a cold wire drawing process is performed according to the conditions shown in Table 2 to a wire diameter of 4 mm or more and 9 mm or less, and a heat treatment is performed at a heating rate of 10°C / min. After cooling, a second wire drawing process as a cold wire drawing process is performed to the final wire diameter, thereby manufacturing a cylindrical copper alloy wire. The processing degree of each wire drawing process is calculated by the processing degree η=2×ln (wire diameter before wire drawing / wire diameter after wire drawing) (ln is a natural logarithm). In addition, the processing degree ratio is calculated by dividing the processing degree of the first wire drawing process by the processing degree of the second wire drawing process.

[0093] (Example 35)

[0094] A cylindrical copper alloy wire was obtained in the same manner as in Example 1. Then, the cylindrical copper alloy wire was subjected to rolling to produce a strip-shaped copper alloy wire having a long side of 0.080 mm and a short side of 0.007 mm in cross section.

[0095] (Examples 36-37)

[0096] A copper alloy wire was produced in the same manner as in Example 1, except that the ingot was subjected to a solution heat treatment at 800° C. for 2 hours before the first wire drawing process.

[0097] (Comparative Example 13)

[0098] A cylindrical copper alloy wire material having the alloy composition shown in Table 1 and having the final wire diameter shown in Table 2 by casting was produced. That is, in Comparative Example 13, the heat treatment, the first wire drawing, and the second wire drawing in Example 1 were not performed.

[0099] The copper alloy wires shown in Table 1 contain S, Pb, Sb, and Bi as inevitable impurities, and the content of the inevitable impurities is less than 0.0001 mass % for each element and less than 0.0005 mass % for the total of the elements.

[0100] [Table 1]

[0101]

[0102] [Table 2]

[0103]

[0104] [Measurement and evaluation]

[0105] The copper alloy wires obtained in the above-described Examples and Comparative Examples were subjected to the following measurements and evaluations.

[0106] [1] X-ray diffraction analysis

[0107] For the copper alloy wire obtained in the above-mentioned examples and comparative examples, an X-ray diffraction device (Spectris Co., Ltd., X'Pert PRO MRD) was used, and the θ-2θ method was used to measure the surface of the copper alloy wire. Since the wire diameter is small, the X-ray diffraction intensity between 40° and 100° was measured in a state where the wires were arranged horizontally in a filling manner to ensure a minimum area of ​​20 mm × 40 mm. The background value as noise was subtracted from the confirmed peak intensity to obtain the peak intensity of each surface. In the X-ray diffraction analysis, a plurality of copper alloy wires were placed in contact on the sample holder and arranged side by side in the same direction.

[0108] [2] Tensile strength

[0109] Two copper alloy wires (n=2) obtained in the above-mentioned Examples and Comparative Examples were used to perform a tensile test in accordance with JIS Z 2241:2011, and the tensile strength was calculated by averaging the two measured values.

[0110] [3] Conductivity

[0111] The electrical conductivity was calculated by using two copper alloy wires (n=2) obtained in the above-mentioned Examples and Comparative Examples and measuring them in accordance with JIS H0505:1975, and averaging the two measured values.

[0112] [4] Formula (1) (Y ≥ 110X + 880)

[0113] The following classification was performed by calculating the formula (1) with the content of Ag being X (mass %) and the tensile strength of the copper alloy wire being Y (MPa).

[0114] Satisfying formula (1):

[0115] Does not satisfy formula (1): None

[0116] [5] Formula (2) (Z ≥ -4.6X + 82)

[0117] The Ag content is X (mass %), and the electrical conductivity of the copper alloy wire is Z (% IACS), and the following classification is performed by calculating the formula (2).

[0118] Satisfying formula (2):

[0119] Does not satisfy formula (2): None

[0120] [6] Formula (3) (Y ≥ -0.040Z + 117)

[0121] The tensile strength of the copper alloy wire is represented by Y (MPa), and the electrical conductivity of the copper alloy wire is represented by Z (% IACS), and the following classification is performed by calculating the formula (3).

[0122] Satisfying formula (3):

[0123] Does not satisfy formula (3): None

[0124] [7] Wire drawing

[0125] For the copper alloy wires obtained in the above-mentioned examples and comparative examples, the total length after drawing to a wire diameter of 0.02 mm and the number of wire breaks that occurred during the entire wire drawing process were measured, and the following classification was performed. It should be noted that in Example 35, the cylindrical copper alloy wire (wire diameter 0.02 mm) before rolling into a strip shape was measured. When the number of wire breaks relative to the drawn length is 1 time / 100 km or less, the wire drawing property is good.

[0126] The number of wire breakages relative to the drawing length is less than 1 time / 100 km: ○

[0127] The number of wire breaks relative to the drawing length is greater than 1 time / 100km: ×

[0128] [Table 3]

[0129]

[0130] As shown in Tables 1 to 3, in Examples 1 to 37, the Ag content and the peak intensity ratio were controlled within the prescribed ranges, respectively, so the tensile strength, electrical conductivity and wire drawing properties were good. On the other hand, in Comparative Examples 1 to 14, at least one of the Ag content and the peak intensity ratio was not controlled within the prescribed range, so at least one of the tensile strength, electrical conductivity and wire drawing properties was poor.

Claims

1. A copper alloy wire having an alloy composition containing 1.0 mass % or more and 6.0 mass % or less of Ag, the remainder being Cu and unavoidable impurities, With respect to the peak intensity I(111) of 111 diffraction, the peak intensity I(200) of 200 diffraction, the peak intensity I(220) of 220 diffraction and the peak intensity I(311) of 311 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio of the total intensity of the peak intensity I(111), the peak intensity I(200) and the peak intensity I(311) to the peak intensity I(220) ((the peak intensity I(111)+the peak intensity I(200)+the peak intensity I(311)) / the peak intensity I(220)) is greater than 1.20 and less than 3.

00.

2. The copper alloy wire according to claim 1, in, The alloy composition further contains 0.05 mass % to 0.30 mass % in total of one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr.

3. The copper alloy wire according to claim 1 or 2, wherein the tensile strength satisfies 1000 MPa or more, the electrical conductivity satisfies 60% IACS or more, and the Ag content X, the tensile strength Y and the electrical conductivity Z satisfy the following formula (1), formula (2), and formula (3), in, The unit of the Ag content X is mass %, the unit of the tensile strength Y is MPa, and the unit of the electrical conductivity Z is %IACS. Y≥110X+880…Formula (1) Z≥-4.6X+82…Formula (2) Y≥-0.040Z+117…Formula (3). 4 . The copper alloy wire according to claim 1 , wherein the cross section thereof is a circle having a diameter of 0.02 mm to 0.08 mm. 5 . The copper alloy wire according to claim 3 , wherein the cross section thereof is a circle having a diameter of 0.02 mm to 0.08 mm. 6 . The copper alloy wire according to claim 1 , wherein the cross section is in the shape of a strip having a long side of 0.060 mm to 0.500 mm and a short side of 0.005 mm to 0.040 mm. 7 . The copper alloy wire according to claim 3 , wherein the cross section is in the shape of a strip having a long side of 0.060 mm to 0.500 mm and a short side of 0.005 mm to 0.040 mm.

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