Copper alloy wire

Abstract

Provided is a copper alloy wire rod having an excellent balance among strength, electrical conductivity and wire drawability.　This copper alloy wire material has: an alloy composition that contains 1.0 to 6.0 mass% of Ag and, as the balance, Cu and inevitable impurities; and a peak intensity ratio (peak intensity I (111) / peak intensity I (220)) of the peak intensity I (111) to the peak intensity I (220) of 0.50 to 1.50, when the peak intensity I (111) of the 111 diffraction and the peak intensity I (220) of the 220 diffraction are obtained by surface X-ray diffraction.

Description

Technical Field

[0001] This disclosure relates to copper alloy wires.

Background Art

[0002] In equipment connection cables, due to miniaturization of products, space saving of electric wires, increase in signal lines, etc., the wire diameter tends to be further reduced compared to the past. For example, instead of pure copper wires with insufficient strength, wire materials of copper alloys such as Cu-Sn-based, Cu-Cr-based, and Cu-Ag-based have been used. Among copper alloys, Cu-Ag-based alloys are excellent in the balance of high strength and high conductivity.

[0003] For example, Patent Document 1 describes a method for producing 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 heat-treated at a temperature of 570 to 680°C for 0.5 to 5 hours in a vacuum atmosphere or an inert gas atmosphere during this cold-working, further cold-worked, and heat-treated at a temperature of 400 to 550°C for 0.5 to 40 hours in a vacuum atmosphere or an inert gas atmosphere during this cold-working.

[0004] Further, 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, and a Cu-Ag alloy fine wire in which the entire structure composed of a solid solution of Cu is composed of a recrystallized aggregate structure.

[0005] In the above Patent Documents 1 to 2, the eutectic phase of Cu and Ag is extended in a filamentous form to improve strength and conductivity. Further, in Patent Document 2, in the method for producing a Cu-Ag alloy fine wire, strength is improved by heat treatment for developing a recrystallized aggregate structure and high processing after heat treatment.

[0006] However, in Patent Document 1, the strength characteristics are insufficient, particularly due to the inadequate control of the precipitation distribution of the eutectic phase, which contributes to the strength after wire drawing. Furthermore, in Patent Document 2, appropriate wire drawing conditions are not set before heat treatment, leading to material embrittlement during heat treatment and making it difficult to create thin wires. As a result, the product is not cost-competitive due to poor productivity. Thus, in Patent Documents 1 and 2, it is difficult to simultaneously achieve improvements in strength and conductivity, as well as improvements in manufacturability, such as wire drawability. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 3325639 [Patent Document 2] Patent No. 5051647 [Overview of the project] [Problems that the invention aims to solve]

[0008] The purpose of this disclosure is to provide a copper alloy wire that offers an excellent balance of strength, conductivity, and drawability. [Means for solving the problem]

[0009] [1] A copper alloy wire having an alloy composition containing 1.0% by mass or more and 6.0% by mass or less of Ag, with the remainder being Cu and unavoidable impurities, wherein the peak intensity ratio of peak intensity I(111) to peak intensity I(220) obtained by surface X-ray diffraction analysis (peak intensity I(111) / peak intensity I(220)) is 0.50 or more and 1.50 or less. [2] The copper alloy wire according to [1] above, wherein, with respect to the 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, the peak intensity ratio of the sum of the peak intensities I(111), I(200), and I(311) to the peak intensity I(220) ((I(111) + I(200) + I(311)) / I(220) is 1.20 or more and 3.00 or less. [3] The copper alloy wire according to [1] or [2] above, wherein the alloy composition further contains a total of 0.05% by mass or more and 0.30% by mass or less of one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr. [4] A copper alloy wire as described in any one of [1] to [3] above, wherein the tensile strength is 1000 MPa or more, the conductivity is 60% IACS or more, and the Ag content X (mass%), tensile strength Y (MPa), and conductivity Z (% IACS) satisfy the following formulas (1), (2), and (3). Y≧110X+880...Formula (1) Z≧-4.6X+82...Formula (2) Y≧-0.040Z+117...Equation (3) [5] A copper alloy wire as described in any one of [1] to [4] above, having a circular cross-section with a diameter of 0.02 mm or more and 0.08 mm or less. [6] A copper alloy wire as described in any one of [1] to [4] above, which is ribbon-shaped with a cross-section having 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. [Effects of the Invention]

[0010] According to this disclosure, it is possible to provide a copper alloy wire with an excellent balance of strength, conductivity, and drawability. [Modes for carrying out the invention]

[0011] Hereinafter, a detailed description will be given based on embodiments.

[0012] As a result of intensive research, the inventor of the present invention focused on the peak intensity of a predetermined plane obtained by X-ray diffraction analysis of the surface of a copper alloy wire, and by controlling the ratio of the peak intensities of the predetermined plane within a predetermined range, it was found that the balance of strength, conductivity, and drawability was excellent, and based on such findings, the present disclosure was completed.

[0013] The copper alloy wire of the embodiment contains 1.0 mass% or more and 6.0 mass% or less of Ag, has an alloy composition in which the balance is Cu and unavoidable impurities, and 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.

[0014] First, the alloy composition of the copper alloy wire will be described.

[0015] The copper alloy wire of the above embodiment contains 1.0 mass% or more and 6.0 mass% or less of Ag, and has an alloy composition in which the balance is Cu and unavoidable impurities.

[0016] <Ag: 1.0 mass% or more and 6.0 mass% or less> Ag (silver) is an element necessary for increasing the strength of the copper alloy wire, and it 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 can be increased due to the solid solution and precipitation of Ag. Also, when the content of Ag is 6.0 mass% or less, the decrease in the conductivity of the copper alloy wire can be suppressed, and the high conductivity of the copper alloy wire can be maintained. Furthermore, when the content of Ag exceeds 6.0 mass%, it is not possible to expect a high strength increase commensurate with the increase in the material cost due to the increase in the amount of Ag used, so it becomes difficult to contribute to the added value of the customer's product. To balance the improvement in the strength and conductivity of the copper alloy wire, the content of Ag is 1.0 mass% or more, preferably 1.5 mass% or more, while on the other hand, it is 6.0 mass% or less, preferably 4.0 mass% or less.

[0017] <Minor components of the copper alloy wire: 0.05 mass% or more and 0.30 mass% or less> The alloy composition of the copper alloy wire can further contain a total of 0.05 mass% or more and 0.30 mass% or less of one or more elements selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr. That is, in addition to Ag which is an essential basic component, the copper alloy wire can further contain a total of 0.05 mass% or more and 0.30 mass% or less of one or more components selected from the group consisting of Sn, Mg, Zn, In, Ni, Co, Zr, and Cr as optional minor components. When the content of the minor components is 0.05 mass% or more, the strength characteristics of the copper alloy wire are improved, and in some elements, it has the effect of alleviating the brittleness of the copper alloy wire. Also, when the content of the minor components is 0.30 mass% or less, the conductivity of the copper alloy wire is not significantly impaired. Therefore, the content of the minor components is preferably 0.05 mass% or more, more preferably 0.08 mass% or more, still more preferably 0.10 mass% or more, while on the other hand, it is preferably 0.30 mass% or less, more preferably 0.25 mass% or less, still more preferably 0.20 mass% or less.

[0018] <Sn: 0.05 mass% or more and 0.20 mass% or less> When the Sn (tin) content is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire. When the Sn content is 0.20% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the Sn content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more 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, still more preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0019] <Mg: 0.05% by mass or more and 0.20% by mass or less> When the Mg (magnesium) content is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire and has the effect of alleviating the brittleness of the copper alloy wire. When the Mg content is 0.20% by mass or less, it does not significantly impair the conductivity of the copper alloy wire and the manufacturability during casting. Therefore, the Mg content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more 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, still more preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0020] <Zn: 0.05% by mass or more and 0.30% by mass or less> When the Zn (zinc) content is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire and has the effect of alleviating the brittleness of the copper alloy wire. When the Zn content is 0.30% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the Zn content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more 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, still more preferably 0.20% by mass or less, and particularly preferably 0.15% by mass or less.

[0021] <In: 0.05% by mass or more and 0.20% by mass or less> When the indium (In) content is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire, and when the In content is 0.20% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the In content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more preferably 0.08% by mass or more, 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, still more preferably 0.15% by mass or less, particularly preferably 0.12% by mass or less.

[0022] <Ni: 0.05% by mass or more and 0.30% by mass or less> When the nickel (Ni) content is at least <0.05%> by mass, it contributes to the improvement of the strength of the copper alloy wire. When the Ni content is 0.30% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the Ni content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more preferably 0.08% by mass or more, 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, still more preferably 0.20% by mass or less, particularly preferably 0.15% by mass or less.

[0023] <Co: 0.05% by mass or more and 0.20% by mass or less> When the cobalt (Co) content is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire, and when the Co content is 0.20% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the Co content is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more preferably 0.08% by mass or more, 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, still more preferably 0.15% by mass or less, particularly preferably 0.12% by mass or less.

[0024] <Zr: 0.05% by mass or more and 0.20% by mass or less> When the content of Zr (zirconium) is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire and has the effect of alleviating the brittleness of the copper alloy wire. When the content of Zr is 0.20% by mass or less, it does not significantly impair the conductivity and manufacturability during casting of the copper alloy wire. Therefore, the content of Zr is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more 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, still more preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0025] <Cr: 0.05% by mass or more and 0.20% by mass or less> When the content of Cr (chromium) is 0.05% by mass or more, it contributes to the improvement of the strength of the copper alloy wire. When the content of Cr is 0.20% by mass or less, it does not significantly impair the conductivity of the copper alloy wire. Therefore, the content of Cr is preferably 0.05% by mass or more, more preferably 0.07% by mass or more, still more 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, still more preferably 0.15% by mass or less, and particularly preferably 0.12% by mass or less.

[0026] <Remainder: Cu and inevitable impurities> The remainder other than the components described above is Cu (copper) and inevitable impurities. Inevitable impurities are those that inevitably混入 during the manufacturing process, and depending on the content, they can also be a factor in reducing one or more of the properties such as the strength, conductivity, and drawability of the copper alloy wire, affecting the environment, or causing material embrittlement. Therefore, the lower the content of inevitable impurities, the better. Examples of inevitable impurities include elements such as S, Pb, Sb, and Bi. The upper limit of the content of the above inevitable impurities is preferably less than 0.0001% by mass for each of the above elements, and preferably less than 0.0005% by mass in total for the above elements.

[0027] Next, the peak intensity ratio obtained by X-ray diffraction analysis of the surface of the copper alloy wire will be described.

[0028] When the peak intensities of the 111 and 220 diffractions obtained by X-ray diffraction analysis of the surface of a copper alloy wire are denoted as I(111) and I(220), 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 between 0.50 and 1.50.

[0029] When the first peak intensity ratio is 0.50 or higher, the strength and drawability of the copper alloy wire can be increased. Specifically, when the first peak intensity ratio is less than 0.50, although the wire has excellent drawability, sufficient strength cannot be obtained. Also, when the first peak intensity ratio is 1.50 or lower, both strength and drawability can be increased. Specifically, when the first peak intensity ratio is greater than 1.50, although the wire has excellent strength, sufficient drawability cannot be obtained. As a result, it becomes difficult to draw the copper alloy wire to the desired diameter, or the manufacturing yield of the copper alloy wire decreases significantly. In order to achieve both improved strength and drawability of the copper alloy wire, and to balance it with conductivity, the lower limit of the first peak intensity ratio is preferably 0.60 or higher, more preferably 0.70 or higher, while the upper limit is preferably 1.20 or lower, more preferably 1.00 or lower.

[0030] Furthermore, when the peak intensities of the 111, 200, 220, and 311 diffractions obtained by X-ray diffraction analysis of the surface of a copper alloy wire are denoted as I(111), I(200), I(220), and I(311), respectively, the peak intensity ratio of the sum of the peak intensities I(111), I(200), and 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 second peak intensity ratio) is preferably 1.20 or more and 3.00 or less.

[0031] If the second peak intensity ratio is 1.20 or higher, the drawability of the copper alloy wire can be further improved. Also, if the second peak intensity ratio is 3.00 or lower, the strength of the copper alloy wire can be further improved. From the viewpoint of achieving both improved strength and drawability of the copper alloy wire, as well as improving the balance with conductivity, the lower limit of the second peak intensity ratio is preferably 1.30 or higher, more preferably 1.50 or higher, while the upper limit is preferably 2.80 or lower, more preferably 2.50 or lower.

[0032] The peak intensity I(111) of the 111 diffraction obtained by X-ray diffraction analysis of the surface of a copper alloy wire is the maximum peak height (highest intensity) within the range of 2θ = 43 ± 1°. While the correlated {111} plane contributes to improving the strength of the copper alloy wire, it tends to decrease its drawability. However, if heat treatment is not performed in the copper alloy wire manufacturing process described later, even with a high peak intensity I(111), the copper alloy wire may show a decrease in drawability without an increase in strength.

[0033] The peak intensity I(200) of the 200 diffraction obtained from X-ray diffraction analysis of the surface of a copper alloy wire is the maximum peak height (highest intensity) within the range of 2θ = 50 ± 1°. For the correlated {100} plane, it tends to contribute to improving the drawability of the copper alloy wire, while its contribution to improving strength is relatively low.

[0034] The peak intensity I(220) of the 220 diffraction obtained by X-ray diffraction analysis of the surface of a copper alloy wire is the maximum peak height (highest intensity) within the range of 2θ = 74 ± 1°. For the correlated {110} plane, if its total amount is large, the proportion of {111} and {100} planes decreases relatively, and the relative effect decreases, so it is necessary that it be below an appropriate value. Although its contribution is relatively small, it contributes to improving the strength and drawability of the copper alloy wire.

[0035] The peak intensity I(311) of the 311 diffraction obtained by X-ray diffraction analysis of the surface of a copper alloy wire is the maximum peak height (highest intensity) within the range of 2θ = 90 ± 1°. Regarding the correlated {311} plane, if its total amount is large, the proportion of {111} and {100} planes decreases relatively, thus reducing its relative effect. Therefore, it is necessary for the total amount to be below an appropriate value. Although its contribution is relatively small, it contributes to improving the strength and drawability of the copper alloy wire.

[0036] X-ray diffraction analysis of the surface of copper alloy wire is performed as follows: Using an X-ray diffractometer, the side surface of the copper alloy wire is measured using the θ-2θ method, and the X-ray diffraction intensity between 40° and 100° is measured. The peak intensity for each surface is obtained by subtracting the background value (noise) from the confirmed peak intensity. In X-ray diffraction analysis, multiple copper alloy wires are placed in parallel on a sample holder in the same direction.

[0037] Furthermore, for copper alloy wires, it is preferable that the tensile strength is 1000 MPa or more, the conductivity is 60% IACS or more, and the Ag content is X (mass%), the tensile strength of the copper alloy wire is Y (MPa), and the conductivity of the copper alloy wire is Z (% IACS), so that the Ag content X, tensile strength Y, and conductivity Z satisfy the following equations (1), (2), and (3). Copper alloy wires that satisfy such a configuration have an even better balance of strength and conductivity.

[0038] Y≧110X+880...Formula (1) Z≧-4.6X+82...Formula (2) Y≧-0.040Z+117...Equation (3)

[0039] The tensile strength of copper alloy wire is measured by performing a tensile test in accordance with JIS Z 2241:2011.

[0040] The conductivity of copper alloy wire is measured in accordance with JIS H0505:1975.

[0041] Furthermore, it is preferable that the cross-section of the copper alloy wire is circular in shape with a diameter of 0.02 mm to 0.08 mm. Even if the copper alloy wire has a circular cross-section with a diameter within the above range, i.e., even if the copper alloy wire is an extremely thin cylindrical wire, it will have an excellent balance of high strength and high conductivity.

[0042] Furthermore, the cross-section of the copper alloy wire may be ribbon-shaped, with 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 of the ultra-fine wire is ribbon-shaped with long and short sides within the above ranges, the copper alloy wire offers an excellent balance of high strength and high conductivity.

[0043] The strength and conductivity of ribbon-shaped copper alloy wire are not significantly different from those of cylindrical copper alloy wire before it is formed into a ribbon, such as a thin cylindrical wire. In other words, if the strength and conductivity of the cylindrical copper alloy wire before it is formed into a ribbon are above the desired values, then the strength and conductivity of the ribbon-shaped copper alloy wire will also be above the desired values.

[0044] Thus, because copper alloy wires have high drawability, even when copper alloy wires are made extremely thin, it is possible to obtain ultra-fine wires with an excellent balance of high strength and high conductivity that was not possible with conventional wires. This makes it possible to miniaturize electrical products to a level that was previously unattainable, reduce the space required for circuits, and increase the number of circuits, thereby contributing to the creation of higher added value for products.

[0045] Next, the method for manufacturing the copper alloy wire according to the embodiment will be described.

[0046] In the method for manufacturing copper alloy wire according to the embodiment, at least one heat treatment is performed while drawing the ingot having the above alloy composition to the final wire diameter of the copper alloy wire. This heat treatment is an aging heat treatment aimed at the precipitation and recrystallization of Ag. The heat treatment temperature is preferably 400°C to 500°C. The heat treatment time is preferably 10 hours to 100 hours in order to obtain a sufficient amount of Ag precipitated.

[0047] Furthermore, cold drawing is performed on the samples before and after the heat treatment described above. Here, cold drawing before heat treatment is called the first drawing process, and cold drawing after heat treatment is called the second drawing process. By performing the second drawing process on the samples cooled after heat treatment, copper alloy wire can be manufactured.

[0048] The 1 The degree of processing in wire drawing 2 Ratio of the degree of processing in wire drawing (No. 2 Degree of processing in wire drawing / No. 1 The degree of processing in wire drawing (hereinafter also simply referred to as the degree of processing ratio) is between 5.0 and 12.0. If the degree of processing ratio is less than 5.0, the final wire drawing rate of the copper alloy wire obtained after the second wire drawing process will decrease significantly, making it impossible to obtain the desired strength. If the degree of processing ratio is 5.0 or higher, recrystallization can be performed early in the heating and holding temperature range from the heating rise during the heat treatment, eliminating accumulated strain, and embrittlement, which causes wire drawing defects in the subsequent second wire drawing process, can be suppressed. If the degree of processing ratio is greater than 12.0, the wire drawing rate of the first wire drawing process before heat treatment will be reduced, resulting in heat treatment of a low degree of processing sample. As a result, the release of strain during heat treatment will be delayed, leading to embrittlement and making it difficult to thin the wire in the subsequent process.

[0049] Furthermore, the single-pass reduction ratio in each wire drawing process is 15% to 35% for wire diameters greater than 0.9 mm, and 10% to 25% for wire diameters of 0.9 mm or less. Other wire drawing conditions are the very common conditions used in operation, such as wire drawing speed, die dimensions, and capstan diameter.

[0050] Here, the degree of processing for each wire drawing process can be calculated using the following formula.

[0051] Degree of processing: η = 2 × ln (wire diameter before drawing / wire diameter after drawing) ln: natural logarithm

[0052] Furthermore, the recrystallization orientation and the degree of wire drawing during heat treatment significantly contribute to the peak intensity of the copper alloy wire.

[0053] For example, if heat treatment is not performed, the final degree of processing will be high and a recrystallized structure will not be formed, resulting in a low peak intensity I(200) and an excessively high peak intensity I(111), which reduces the drawability of the copper alloy wire. Furthermore, while an increase in peak intensity I(111) usually leads to increased strength of copper alloy wire, the lack of heat treatment may result in a lower degree of increase in strength.

[0054] Furthermore, if the above processing ratio is less than 5.0, the peak intensity I(200) becomes too high and the peak intensity I(111) becomes too low, affecting the first and second peak intensity ratios. If the above processing ratio is greater than 12.0, the peak intensity I(200) becomes too low and the peak intensity I(111) becomes too high, affecting the first and second peak intensity ratios.

[0055] Furthermore, while peak intensities I(220) and I(311) are not actively controlled, an increase in their ratio has the adverse effect of relatively reducing the effects of peak intensities I(200) and I(111). By satisfying the above manufacturing conditions, it is possible to keep the values ​​within the desired range.

[0056] In this way, by performing heat treatment, first wire drawing, and second wire drawing, and by keeping the degree of processing ratio within the above range, the peak intensity obtained by X-ray diffraction analysis can be controlled.

[0057] Furthermore, regarding the heat treatment described above, if the heating rate is set to 1°C / min or higher, the progression of embrittlement during the heating process can be efficiently suppressed. Also, the faster the heating rate during heat treatment, the more effective it is in suppressing the progression of embrittlement, but for the sake of simplifying the heat treatment apparatus, it is preferable that the upper limit of the heating rate be 15°C / min or lower.

[0058] Furthermore, if the degree of processing in the first wire drawing process before heat treatment is between 0.69 and 2.31, the progression of embrittlement can be suppressed, and thinning of the wire in the subsequent second wire drawing process becomes easier.

[0059] Furthermore, prior to the above heat treatment, a solution heat treatment may be performed to promote the precipitation of Ag in the above 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 purpose of the solution heat treatment is to solid-solve Ag, and it is effective in precipitating a larger amount of more homogeneous Ag precipitates.

[0060] Furthermore, as described above, the strength and conductivity of the cylindrical copper alloy wire before it is formed into a ribbon shape are not significantly different from those of the ribbon-shaped copper alloy wire. Therefore, ribbon-shaped copper alloy wire can be manufactured by rolling the copper alloy wire obtained in the second wire drawing process.

[0061] The above-mentioned copper alloy wire is suitable for use in equipment connection cables such as micro speaker lead wires, where an excellent balance of strength, conductivity, and drawability is required.

[0062] According to the embodiments described above, by focusing on the peak intensity of a predetermined surface obtained by surface X-ray diffraction analysis and controlling the ratio of the peak intensities of the predetermined surface within a predetermined range, a copper alloy wire with an excellent balance of strength, conductivity, and drawability can be obtained.

[0063] Although embodiments have been described above, the present invention is not limited to the embodiments described above, and includes all aspects included in the concepts and claims of this disclosure, and can be modified in various ways within the scope of this disclosure. [Examples]

[0064] Examples and comparative examples will be described next, but this disclosure is not limited to these examples.

[0065] (Examples 1-34 and Comparative Examples 1-12, 14) For ingots having the alloy composition shown in Table 1 and cast to an outer diameter of 6 mm to 39 mm, a first cold drawing process was performed to a wire diameter of 4 mm to 9 mm under the conditions shown in Table 2. Heat treatment was then performed at a heating rate of 10°C / min, and after cooling, a second cold drawing process was performed to the final wire diameter to produce cylindrical copper alloy wires. The degree of processing for each drawing process was calculated using the formula: degree of processing η = 2 × ln (wire diameter before drawing / wire diameter after drawing) (ln is the natural logarithm). The degree of processing ratio was calculated as follows: 2 The degree of processing in wire drawing is 1 It was calculated by dividing by the degree of processing in the wire drawing process.

[0066] (Example 35) A cylindrical copper alloy wire was obtained in the same manner as in Example 1. Subsequently, the cylindrical copper alloy wire was rolled to produce a ribbon-shaped copper alloy wire having a cross-section with a long side of 0.080 mm and a short side of 0.007 mm.

[0067] (Examples 36-37) A copper alloy wire was manufactured 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.

[0068] (Comparative Example 13) Cylindrical copper alloy wires having the alloy composition shown in Table 1 and the final wire diameter shown in Table 2 were manufactured by casting. In other words, in Comparative Example 13, the heat treatment, first wire drawing, and second wire drawing processes used in Example 1 were omitted.

[0069] The copper alloy wires shown in Table 1 contain S, Pb, Sb, and Bi as unavoidable impurities. The content of each unavoidable impurity was less than 0.0001% by mass, and the total content of all elements was less than 0.0005% by mass.

[0070] [Table 1]

[0071] [Table 2]

[0072] [Measurement and Evaluation] The copper alloy wires obtained in the above examples and comparative examples were subjected to the following measurements and evaluations. The results are shown in Table 3.

[0073] [1] X-ray diffraction analysis For the copper alloy wires obtained in the above examples and comparative examples, the surface of the copper alloy wires was measured using the θ-2θ method with an X-ray diffractometer (Spectris Co., Ltd., X'Pert PRO MRD). Due to the thin diameter of the wires, they were arranged side by side to fill the area, ensuring a minimum area of ​​20 mm × 40 mm. The X-ray diffraction intensity between 40° and 100° was measured, and the peak intensity of each surface was obtained by subtracting the background value (noise) from the confirmed peak intensity. In the X-ray diffraction analysis, multiple copper alloy wires were placed in parallel in the same direction on a sample holder.

[0074] [2] Tensile strength Using two copper alloy wires (n=2) obtained in the above examples and comparative examples, tensile tests were performed according to JIS Z 2241:2011, and the tensile strength was calculated by averaging the two measured values.

[0075] [3] Conductivity Using two copper alloy wires (n=2) obtained in the above examples and comparative examples, measurements were performed according to JIS H0505:1975, and the conductivity was calculated by averaging the two measured values.

[0076] [4] Formula (1) (Y≧110X+880) Using X (mass%) as the Ag content and Y (MPa) as the tensile strength of the copper alloy wire, equation (1) was calculated, and the following rankings were assigned.

[0077] Satisfying equation (1): Yes Does not satisfy equation (1): None

[0078] [5] Formula (2) (Z≧-4.6X+82) Using X (mass%) as the Ag content and Z (%IACS) as the conductivity of the copper alloy wire, equation (2) was calculated, and the following rankings were assigned.

[0079] Satisfying equation (2): Yes If equation (2) is not satisfied: None

[0080] [6] Formula (3) (Y≧-0.040Z+117) Using Y (MPa) as the tensile strength of the copper alloy wire and Z (%IACS) as the electrical conductivity of the copper alloy wire, equation (3) was calculated, and the following rankings were assigned.

[0081] Equation (3) is satisfied: Yes If equation (3) is not satisfied: None

[0082] [7] Wire drawability For the copper alloy wires obtained in the above examples and comparative examples, the total length after drawing to a wire diameter of 0.02 mm and the number of breaks that occurred during the entire drawing process were measured and ranked as follows. In Example 35, the measurement was taken for a cylindrical copper alloy wire (wire diameter 0.02 mm) before being rolled into a ribbon shape. If the number of breaks relative to the drawn length is 1 or less per 100 km, the drawability is good.

[0083] Number of breaks per 100km of length: 1 or less: ○ Number of breaks relative to the length of the drawn wire exceeds 1 per 100km: ×

[0084] [Table 3]

[0085] As shown in Tables 1-3, in Examples 1-37, the Ag content and the first peak intensity ratio were controlled within predetermined ranges, resulting in good tensile strength, conductivity, and drawability. On the other hand, in Comparative Examples 1-14, at least one of the Ag content and the first peak intensity ratio was not controlled within predetermined ranges, resulting in poor tensile strength, conductivity, and drawability.

Claims

1. The alloy has a composition containing 1.0% to 6.0% by mass of Ag, with the remainder being Cu and unavoidable impurities. A copper alloy wire in which, with respect to the peak intensity I(111) of 111 diffraction and the peak intensity I(220) of 220 diffraction obtained by surface X-ray diffraction analysis, the peak intensity ratio of peak intensity I(111) to peak intensity I(220) (peak intensity I(111) / peak intensity I(220)) is 0.50 or more and 1.50 or less.

2. The copper alloy wire according to claim 1, wherein, with respect to the 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, the peak intensity ratio of the sum of the peak intensities I(111), I(200), and I(311) to the peak intensity I(220) ((I(111) + I(200) + I(311)) / I(220)) is 1.20 or more and 3.00 or less.

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

4. A copper alloy wire according to any one of claims 1 to 3, wherein the tensile strength is 1000 MPa or more, the electrical conductivity is 60% IACS or more, and the Ag content X (mass%), tensile strength Y (MPa), and electrical conductivity Z (% IACS) satisfy the following formulas (1), (2), and (3). Y≧110X+880...Formula (1) Z≧-4.6X+82 ...Formula (2) Y≧-0.040Z+117...Formula (3)

5. A copper alloy wire according to any one of claims 1 to 4, wherein the cross-section is circular in shape and has a diameter of 0.02 mm or more and 0.08 mm or less.

6. A copper alloy wire according to any one of claims 1 to 4, wherein the cross-section is ribbon-shaped, having 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.

Images