Copper alloy wire

Abstract

Provided is a copper alloy wire having excellent balance among strength, conductivity, and drawability. The copper alloy wire 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 and the peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio (the peak intensity I(111) / the peak intensity I(220)) of the peak intensity I(111) to the peak intensity I(220) is 0.50 or more and 1.50 or less.

Description

Technical Field

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

[0002] For machine connection cables, due to the miniaturization of products, space-saving of wires, increase in signal lines, etc., the wire diameter has a tendency to become thinner than in the past. For example, copper alloy wires such as Cu-Sn based, Cu-Cr based, and Cu-Ag based are gradually used instead of pure copper wires with insufficient strength. Among copper alloys, the Cu-Ag alloy has excellent balance of high strength and high electrical conductivity.

[0003] For example, Patent Document 1 describes a method for manufacturing a copper alloy, in which an ingot having a copper alloy composition containing 1 to 10% by weight of Ag and the balance being Cu and inevitable impurities is cold-worked, and during the cold working, heat treatment is carried out at a temperature of 570 to 680°C for 0.5 to 5 hours in a vacuum atmosphere or an inert gas atmosphere, and further cold working is carried out, and during the cold working, heat treatment is carried out at a temperature of 400 to 550°C for 0.5 to 40 hours in a vacuum atmosphere or an inert gas atmosphere.

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

[0005] In the above Patent Documents 1 to 2, the eutectic phase of Cu and Ag is stretched into a long filament shape, and improvement in strength and conductivity is achieved. In addition, in Patent Document 2, in the method for manufacturing a Cu-Ag alloy fine wire, improvement in strength is achieved by heat treatment for developing a recrystallized texture and high processing after the heat treatment.

[0006] However, in Patent Document 1, particularly, the control of the precipitation distribution of the eutectic phase that 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 embrittlement of the material during heat treatment progresses, and it is difficult to make the wire thinner. Therefore, due to poor productivity, it cannot be a cost-competitive product. As such, in Patent Documents 1 to 2, it is difficult to simultaneously improve the drawability as manufacturability while improving the strength and electrical conductivity.

[0007] Prior Art Documents

[0008] Patent Documents

[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 excellent in the balance among strength, electrical conductivity, and drawability.

[0013] Means for Solving the Problems

[0014] [1] A copper alloy wire having an alloy composition containing 1.0 mass% or more and 6.0 mass% or less of Ag, with the balance being Cu and unavoidable impurities. For the peak intensity I(111) of the 111 diffraction and the peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio of the peak intensity I(111) to the peak intensity I(220) (the peak intensity I(111) / the peak intensity I(220)) is 0.50 or more and 1.50 or less.

[0015] [2] The copper alloy wire according to [1] above, wherein for 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 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 1.20 or more and 3.00 or less.

[0016] [3] The copper alloy wire according to [1] or [2] above, wherein the alloy composition further contains one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr in a total amount of 0.05 mass% or more and 0.30 mass% or less.

[0017] [4] The copper alloy wire according to any one of [1] to [3] above, having a tensile strength of 1000 MPa or more, an electrical conductivity of 60% IACS or more, and the content X (mass%) of Ag, the tensile strength Y (MPa), and the electrical conductivity Z (% IACS) satisfying the following formulas (1), (2), and (3).

[0018] Y≥110X + 880... Formula (1)

[0019] Z≥ -4.6X + 82... Formula (2)

[0020] Y≥ -0.040Z + 117... Formula (3)

[0021] [5] The copper alloy wire described in any one of the above [1] to [4] has a circular cross-section with a diameter of 0.02 mm or more and 0.08 mm or less.

[0022] [6] The copper alloy wire described in any one of the above [1] to [4] 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.

[0023] Effects of the Invention

[0024] According to the present invention, it is possible to provide a copper alloy wire excellent in the balance of strength, electrical conductivity, and drawability. Detailed Embodiments

[0025] Hereinafter, the description will be made in detail based on the embodiments.

[0026] 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 ratio of the peak intensities of the specified planes within a specified range, it is possible to make the balance of strength, electrical conductivity, and drawability excellent, and the present invention was completed based on this finding.

[0027] The copper alloy wire of the embodiment has an alloy composition containing 1.0% by mass or more and 6.0% by mass or less of Ag, with the balance being Cu and inevitable impurities. For the peak intensity I(111) of the 111 diffraction and the peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio (the peak intensity I(111) / the peak intensity I(220)) of the former peak intensity I(111) to the latter peak intensity I(220) is 0.50 or more and 1.50 or less.

[0028] First, the alloy composition of the copper alloy wire will be described.

[0029] The copper alloy wire of the above embodiment has the following alloy composition, which contains 1.0% by mass or more and 6.0% by mass or less of Ag, with the balance being Cu and inevitable impurities.

[0030] <Ag: 1.0% by mass or more and 6.0% by mass or less>

[0031] 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 amount of Ag used 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.

[0032] <Sub-components of the copper alloy wire rod: 0.05 mass% or more and 0.30 mass% or less>

[0033] 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 seriously 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.

[0034] <Sn: 0.05 mass% or more and 0.20 mass% or less>

[0035] When the content of Sn (tin) is 0.05 mass% or more, it helps to improve the strength of the copper alloy wire. When the content of Sn is 0.20 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0036] <Mg: 0.05 mass% or more and 0.20 mass% or less>

[0037] When the content of Mg (magnesium) is 0.05 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 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0038] <Zn: 0.05 mass% or more and 0.30 mass% or less>

[0039] When the content of Zn (zinc) is 0.05 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 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly 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, further preferably 0.20 mass% or less, and particularly preferably 0.15 mass% or less.

[0040] <In: 0.05 mass% or more and 0.20 mass% or less>

[0041] When the content of In (indium) is 0.05 mass% or more, it helps to improve the strength of the copper alloy wire. When the content of In is 0.20 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0042] <Ni: 0.05 mass% or more and 0.30 mass% or less>

[0043] When the content of Ni (nickel) is 0.05 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 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly 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, further preferably 0.20 mass% or less, and particularly preferably 0.15 mass% or less.

[0044] <Co: 0.05 mass% or more and 0.20 mass% or less>

[0045] When the content of Co (cobalt) is 0.05 mass% or more, it helps to improve the strength of the copper alloy wire. When the content of Co is 0.20 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 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0046] <Zr: 0.05 mass% or more and 0.20 mass% or less>

[0047] When the content of Zr (zirconium) is 0.05 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 mass% or less, it will not seriously damage the electrical conductivity of the copper alloy wire rod and the manufacturability during casting. Therefore, the content of Zr is preferably 0.05 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0048] <Cr: 0.05 mass% or more and 0.20 mass% or less>

[0049] When the content of Cr (chromium) is 0.05 mass% or more, it helps to improve the strength of the copper alloy wire rod. When the content of Cr is 0.20 mass% or less, it will not seriously damage the electrical conductivity of the copper alloy wire rod. Therefore, the content of Cr is preferably 0.05 mass% or more, more preferably 0.07 mass% or more, further preferably 0.08 mass% or more, and particularly preferably 0.10 mass% or more. On the other hand, it is preferably 0.20 mass% or less, more preferably 0.18 mass% or less, further preferably 0.15 mass% or less, and particularly preferably 0.12 mass% or less.

[0050] <Balance: Cu and unavoidable impurities>

[0051] 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 mass% for each of the above elements, and preferably the total of the above elements is less than 0.0005 mass%.

[0052] Next, the peak intensity ratio obtained by X-ray diffraction analysis of the surface of the copper alloy wire rod will be described.

[0053] When the peak intensities of the 111 and 220 diffractions obtained by X-ray diffraction analysis of the surface of the copper alloy wire rod are set as I(111) and I(220), respectively, the peak intensity ratio of peak intensity I(111) to peak intensity I(220) (peak intensity I(111) / peak intensity I(220)) (hereinafter also referred to as the first peak intensity ratio) is 0.50 or more and 1.50 or less.

[0054] When the intensity ratio of the first peak is 0.50 or more, the strength and drawability of the copper alloy wire can be increased. Specifically, when the intensity ratio of the first peak is less than 0.50, although the drawability is excellent, sufficient strength cannot be obtained. In addition, when the intensity ratio of the first peak is 1.50 or less, the strength and drawability can be increased. Specifically, when the intensity ratio of the first peak is greater than 1.50, although the strength is excellent, sufficient drawability cannot be obtained. Therefore, it becomes difficult to perform wire drawing to reduce the copper alloy wire to a desired wire diameter, or the manufacturing yield of the copper alloy wire is significantly reduced. In order to balance the improvement of the strength and drawability of the copper alloy wire and the electrical conductivity, the lower limit of the intensity ratio of the first peak is preferably 0.60 or more, more preferably 0.70 or more. On the other hand, the upper limit is preferably 1.20 or less, more preferably 1.00 or less.

[0055] In addition, when the peak intensities of 111, 200, 220, and 311 diffraction obtained by X-ray diffraction analysis of the surface of the copper alloy wire are respectively set as I(111), I(200), I(220), and I(311), the peak intensity ratio of the sum 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 intensity ratio of the second peak) is preferably 1.20 or more and 3.00 or less.

[0056] When the intensity ratio of the second peak is 1.20 or more, the drawability of the copper alloy wire can be further improved. In addition, when the intensity ratio of the second peak is 3.00 or less, the strength of the copper alloy wire can be further improved. From the viewpoint of balancing the improvement of the strength and drawability of the copper alloy wire and the improvement of the electrical conductivity, the lower limit of the intensity ratio of the second peak is preferably 1.30 or more, more preferably 1.50 or more. On the other hand, the upper limit is preferably 2.80 or less, more preferably 2.50 or less.

[0057] The peak intensity I(111) of 111 diffraction obtained by X-ray diffraction analysis of the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height in the range of 2θ = 43 ± 1°. For the related {111} plane, it contributes to the improvement of the strength of the copper alloy wire. On the other hand, there is a tendency to reduce the drawability of the copper alloy wire. However, in the case where no heat treatment is performed in the manufacturing process of the copper alloy wire described later, even in a state where the peak intensity I(111) is high, the copper alloy wire sometimes shows a decrease in drawability without an increase in strength.

[0058] The peak intensity I(200) of the 200 diffraction obtained by X-ray diffraction analysis of the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height in the range of 2θ = 50 ± 1°. For the relevant {100} plane, it contributes to the improvement of the drawability of the copper alloy wire. On the other hand, it tends to have a relatively low contribution to the strength improvement.

[0059] The peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height in the range of 2θ = 74 ± 1°. For the relevant {110} plane, when its total amount is large, relatively speaking, the proportions of the {111} plane and the {100} plane decrease and the effects relatively decrease. Therefore, it needs to be below a suitable value. In addition, although the contribution degree is low, it contributes to the strength improvement and drawability improvement of the copper alloy wire.

[0060] The peak intensity I(311) of the 311 diffraction obtained by X-ray diffraction analysis of the surface of the copper alloy wire is the maximum value (highest intensity) of the peak height in the range of 2θ = 90 ± 1°. For the relevant {311} plane, when its total amount is large, relatively speaking, the proportions of the {111} plane and the {100} plane decrease and the effects relatively decrease. Therefore, it needs to be below a suitable value. In addition, although the contribution degree is low, it contributes to the strength improvement and drawability improvement of the copper alloy wire.

[0061] The X-ray diffraction analysis of the surface of the copper alloy wire is measured according to the following method. Using an X-ray diffractometer and 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 plane. In the X-ray diffraction analysis, on the sample holder, a plurality of copper alloy wires are brought into contact and arranged side by side in the same direction.

[0062] In addition, for the copper alloy wire, preferably, when the tensile strength satisfies 1000 MPa or more, the conductivity satisfies 60% IACS or more, and the content of Ag is set as X (mass %), the tensile strength of the copper alloy wire is set as Y (MPa), and the conductivity of the copper alloy wire is set as Z (% IACS), the content of Ag X, the tensile strength Y, and the conductivity Z satisfy the following formulas (1), (2), and (3). The balance of the strength and conductivity of the copper alloy wire with such a structure becomes further good.

[0063] Y ≥ 110X + 880... Formula (1)

[0064] Z ≥ -4.6X + 82... Formula (2)

[0065] Y ≥ -0.040Z + 117… Equation (3)

[0066] The tensile strength of the copper alloy wire is measured by conducting a tensile test in accordance with JIS Z 2241:2011.

[0067] The electrical conductivity of the copper alloy wire is measured in accordance with JISH0505:1975.

[0068] In addition, the cross-section of the copper alloy wire preferably has a circular shape with a diameter of 0.02 mm or more and 0.08 mm or less. Even for a copper alloy wire with a cross-section having a diameter within the above range, that is, an extremely fine wire with a cylindrical shape, the balance between high strength and high electrical conductivity is excellent.

[0069] In addition, the cross-section of the copper alloy wire may also be a strip shape 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. Even for an extremely fine wire with a cross-section having a long side and a short side within the above range, the balance between high strength and high electrical conductivity of the copper alloy wire is excellent.

[0070] The strength and electrical conductivity of the strip-shaped copper alloy wire do not change significantly from those of the cylindrical copper alloy wire (for example, an extremely fine cylindrical 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 values, then the strength and electrical conductivity of the strip-shaped copper alloy wire are above the desired values.

[0071] In this way, the copper alloy wire has high drawability, so even if the copper alloy wire is thinned to an extremely fine wire, an extremely fine wire with an excellent balance between high strength and high electrical conductivity that has never existed before can be obtained. As a result, miniaturization of electrical products, space saving of circuits, increase in the number of circuits, etc. can be achieved at a level that has not been realized so far, thereby contributing to the high added value of the product.

[0072] Next, the manufacturing method of the copper alloy wire of the embodiment will be described.

[0073] In the manufacturing method of the copper alloy wire of the embodiment, during the process of drawing the ingot having the above alloy composition to the final wire diameter of the copper alloy wire, at least one heat treatment is performed. This 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 precipitation amount of Ag, the heat treatment time is preferably 10 hours or more and 100 hours or less.

[0074] In addition, cold wire drawing is performed on the specimens before and after the above heat treatment. Here, the cold wire drawing before heat treatment is referred to as the first wire drawing, and the cold wire drawing after heat treatment is referred to as the second wire drawing. By performing the second wire drawing on the specimens cooled after heat treatment, copper alloy wire rods can be manufactured.

[0075] The ratio of the degree of processing in the second wire drawing to the degree of processing in the first wire drawing (degree of processing in the second wire drawing / degree of processing in the first wire drawing) (hereinafter also simply referred to as the processing degree ratio) is 5.0 or more and 12.0 or less. When the above processing degree ratio is less than 5.0, for the copper alloy wire rod obtained after the second wire drawing, the final wire drawing rate is significantly reduced, so the desired strength cannot be obtained. When the above processing degree ratio is 5.0 or more, recrystallization can start earlier in the heating and holding temperature region from the temperature rise during the above heat treatment, thereby eliminating the accumulated strain, and embrittlement, which is the cause of poor wire drawing in the subsequent process, i.e., the second wire drawing, can be suppressed. When the above processing degree ratio is greater than 12.0, the wire drawing rate of the first wire drawing before heat treatment will decrease, so heat treatment is performed on specimens with a low degree of processing. As a result, since the strain relief during heat treatment becomes slow, embrittlement progresses, and it becomes difficult to make the wire thinner in the subsequent process.

[0076] In addition, the reduction ratio in one pass during each wire drawing is 15% or more and 35% or less for wire diameters thicker than 0.9 mm, and 10% or more and 25% or less for wire diameters of 0.9 mm or less. Other wire drawing conditions can be applied to the wire drawing speed, die size, and capstan diameter under extremely general conditions used in the operation.

[0077] Here, the degree of processing in each wire drawing can be calculated by the following formula.

[0078] Degree of processing: η = 2 × ln (wire diameter before wire drawing / wire diameter after wire drawing)

[0079] ln: natural logarithm

[0080] In addition, the recrystallization orientation during heat treatment and the degree of wire drawing contribute greatly to the above peak strength of the copper alloy wire rod.

[0081] For example, when heat treatment is not performed, since the final degree of processing becomes high and no recrystallized structure is formed, the peak strength I(200) becomes too low and the peak strength I(111) becomes too high, resulting in a decrease in the drawability of the copper alloy wire rod. Moreover, generally, although when the peak strength I(111) increases, it is easy to bring about high strength of the copper alloy wire rod, when heat treatment is not performed, sometimes the degree of increase in the strength of the copper alloy wire rod becomes low.

[0082] In addition, when the above-mentioned degree of working 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 first peak intensity ratio and the second peak intensity ratio. When the above-mentioned degree of working 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 first peak intensity ratio and the second peak intensity ratio.

[0083] In addition, although the peak intensities I(220) and I(311) are not actively controlled, when these ratios become high, there is sometimes an adverse effect that the effects brought by the peak intensities I(200) and I(111) are relatively reduced. By satisfying the above-mentioned manufacturing conditions, it becomes possible to control within a desired range.

[0084] In this way, by performing heat treatment, first wire drawing, and second wire drawing, and making the degree of working within the above range, it is possible to control the peak intensity obtained by X-ray diffraction analysis.

[0085] In addition, for the above heat treatment, when the heating rate is 1 °C / min or more, it is possible to efficiently suppress the progress of embrittlement during heating. In addition, the faster the heating rate during heat treatment, the more effective the suppression of the progress of embrittlement, but considering the simplification of the device for performing heat treatment, the upper limit value of the heating rate is preferably 15 °C / min or less.

[0086] In addition, when the degree of working of the first wire drawing before heat treatment is 0.69 or more and 2.31 or less, it is possible to suppress the progress of embrittlement and make it easier to thin the wire in the second wire drawing as a subsequent process.

[0087] In addition, before the above heat treatment, solution heat treatment for promoting the precipitation of Ag in the above heat treatment may be performed. For the solution heat treatment, the heat treatment temperature is preferably 700 °C or more and 900 °C or less, and the heat treatment time is preferably 10 minutes or more and 5 hours or less. The solution heat treatment is used to dissolve Ag, so it is effective for precipitating more homogeneous Ag precipitates.

[0088] In addition, as described above, the strength and conductivity of the cylindrical copper alloy wire before being formed into a strip do not change much from those of the strip-shaped copper alloy wire. Therefore, by rolling the copper alloy wire obtained by the second wire drawing, a strip-shaped copper alloy wire can be manufactured.

[0089] The above copper alloy wire can be suitably used for machine connection cables such as micro speaker wires that require an excellent balance of strength, conductivity, and drawability.

[0090] According to the embodiments described above, focusing on the peak intensity of a specified plane obtained by X-ray diffraction analysis of the surface, by controlling the ratio of the peak intensities of the specified planes within a specified range, a copper alloy wire excellent in the balance of strength, electrical conductivity, and drawability can be obtained.

[0091] The above describes the embodiments, but the present invention is not limited to the above embodiments, but includes any mode included in the concept and claims of the present invention, and various changes can be made within the scope of the present invention.

[0092] Examples

[0093] Next, examples and comparative examples will be described, but the present invention is not limited to these examples.

[0094] (Examples 1 to 34 and Comparative Examples 1 to 12, 14)

[0095] For ingots having the alloy compositions shown in Table 1 and cast into an outer diameter of 6 mm or more and 39 mm or less, the first wire drawing as a cold wire drawing process is performed to a wire diameter of 4 mm or more and 9 mm or less according to the conditions shown in Table 2, heat treatment is performed at a heating rate of 10 °C / min, and after cooling, the second wire drawing as a cold wire drawing process is performed to the final wire diameter, thereby manufacturing a cylindrical copper alloy wire. The degree of work for each wire drawing is calculated by the degree of work η = 2 × ln (wire diameter before wire drawing / wire diameter after wire drawing) (ln is the natural logarithm). In addition, the work ratio is calculated by dividing the degree of work of the first wire drawing by the degree of work of the second wire drawing.

[0096] (Example 35)

[0097] 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 processing to manufacture 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.

[0098] (Examples 36 to 37)

[0099] A copper alloy wire was manufactured in the same manner as in Example 1, except that the ingot was subjected to solution heat treatment at 800 °C for 2 h before the first wire drawing.

[0100] (Comparative Example 13)

[0101] A cylindrical copper alloy wire having the alloy composition shown in Table 1 and having the final wire diameter shown in Table 2 by casting was manufactured. That is, in Comparative Example 13, the heat treatment, the first wire drawing, and the second wire drawing in Example 1 were not performed.

[0102] It should be noted that the copper alloy wire shown in Table 1 contains S, Pb, Sb, and Bi as inevitable impurities, and the content of the inevitable impurities is less than 0.0001% by mass for each element, and the total of the elements is less than 0.0005% by mass.

[0103] [Table 1]

[0104]

[0105] [Table 2]

[0106]

[0107] [Measurement and Evaluation]

[0108] For the copper alloy wires obtained in the above-mentioned examples and comparative examples, the following measurements and evaluations were carried out. The results are shown in Table 3.

[0109] [1] X-ray Diffraction Analysis

[0110] For the copper alloy wires obtained in the above-mentioned examples and comparative examples, an X-ray diffractometer (manufactured by Spectris Co., Ltd., X’Pert PRO MRD) was used, and the θ-2θ method was used. The surface of the copper alloy wire was set as the measurement object. Since the wire diameter was thin, the X-ray diffraction intensity between 40° and 100° was measured in a state where the wires were arranged horizontally in a filled manner to ensure a minimum area of 20 mm × 40 mm. The peak intensity of each plane was obtained by subtracting the background value as noise from the confirmed peak intensity. In the X-ray diffraction analysis, on the sample holder, a plurality of copper alloy wires were brought into contact and arranged side by side in the same direction.

[0111] [2] Tensile Strength

[0112] Two copper alloy wires (n = 2) obtained in the above-mentioned examples and comparative examples were used, and a tensile test was carried out based on JIS Z 2241:2011. The tensile strength was calculated by averaging the two measured values.

[0113] [3] Electrical Conductivity

[0114] Two copper alloy wires (n = 2) obtained in the above-mentioned examples and comparative examples were used, and the measurement was carried out based on JIS H 0505:1975. The electrical conductivity was calculated by averaging the two measured values.

[0115] [4] Equation (1) (Y ≥ 110X + 880)

[0116] Let the content of Ag be X (% by mass) and the tensile strength of the copper alloy wire be Y (MPa), calculate Equation (1) and perform the following grading.

[0117] Satisfy formula (1): There is

[0118] Do not satisfy formula (1): There is no

[0119] [5] Formula (2) (Z ≥ -4.6X + 82)

[0120] Set the content of Ag as X (mass %), and the conductivity of the copper alloy wire as Z (%IACS), calculate formula (2) and perform the following grading.

[0121] Satisfy formula (2): There is

[0122] Do not satisfy formula (2): There is no

[0123] [6] Formula (3) (Y ≥ -0.040Z + 117)

[0124] Set the tensile strength of the copper alloy wire as Y (MPa), and the conductivity of the copper alloy wire as Z (%IACS), calculate formula (3) and perform the following grading.

[0125] Satisfy formula (3): There is

[0126] Do not satisfy formula (3): There is no

[0127] [7] Drawability

[0128] For the copper alloy wires obtained in the above-mentioned examples and comparative examples, measure the total length after drawing to a wire diameter of 0.02 mm and the number of wire breaks occurring during the entire drawing process, and perform the following grading. It should be noted that in Example 35, the measurement was performed on the cylindrical copper alloy wire (wire diameter 0.02 mm) before being rolled into a strip. When the number of wire breaks per 100 km relative to the drawing length is 1 time or less, the drawability is good.

[0129] The number of wire breaks per 100 km relative to the drawing length is 1 time or less: ○

[0130] The number of wire breaks per 100 km relative to the drawing length is greater than 1 time: ×

[0131] [Table 3]

[0132]

[0133] As shown in Tables 1 to 3, in Examples 1 to 37, the content of Ag and the first peak intensity ratio are respectively controlled within the specified ranges, so the tensile strength, conductivity, and drawability are all good. On the other hand, in Comparative Examples 1 to 14, at least one of the content of Ag and the first peak intensity ratio is not controlled within the specified range, so at least one of the tensile strength, conductivity, and drawability is 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, with the balance being Cu and inevitable impurities, Regarding the peak intensity I(111) of the 111 diffraction and the peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface, the peak intensity ratio of the peak intensity I(111) to the peak intensity I(220) (the peak intensity I(111) / the peak intensity I(220)) is 0.50 or more and 1.50 or less, 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 of the combined 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 1.20 or more and 3.00 or less.

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

3. The copper alloy wire according to claim 1 or 2, having a tensile strength of 1000 MPa or more, a conductivity of 60% IACS or more, and the content X of Ag, the tensile strength Y, and the conductivity Z satisfying the following formulas (1), (2), and (3), wherein, the unit of the content X of Ag is mass%, the unit of the tensile strength Y is MPa, and the unit of the 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 or 2, having a circular cross-section with a diameter of 0.02 mm or more and 0.08 mm or less.

5. The copper alloy wire according to claim 3, having a circular cross-section with a diameter of 0.02 mm or more and 0.08 mm or less.

6. The copper alloy wire according to claim 1 or 2, having 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.

7. The copper alloy wire according to claim 3, having 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.

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