Copper alloy wire, plated wire, electrical wire and cable

Abstract

The present invention provides a copper alloy wire, a plated wire, an electric wire and a cable, the problem of which is to improve both the strength and the conductivity of the copper alloy wire. The solution is a copper alloy wire (10), which is composed of a copper alloy (11) containing 0.3% by mass or more and 0.65% by mass of indium, has a 0.2% yield strength of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more.

Description

Technical Field

[0001] The present invention relates to a copper alloy wire, a plated wire, and an electric wire and a cable using the same. Background Art

[0002] Patent document 1 (Japanese Patent Publication No. 5-311285) describes a copper alloy wire containing In and Sn in addition to Cu. Patent document 2 (Japanese Patent Publication No. 2014-159609) describes a copper alloy body containing 0.01 atomic % or more of at least one element selected from the group consisting of Ag, In, Mg and Sn as a copper alloy body before wire drawing. Patent document 3 (International Publication No. 2014 / 007259) describes that in the manufacturing process of a copper alloy material, an intermediate heat treatment is performed between multiple cold workings. Patent document 4 (Japanese Patent Publication No. 2015-4118) describes that in the manufacturing process of a drawn copper wire, annealing is performed after drawing, and then fine drawing is performed.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 5-311285

[0006] Patent Document 2: Japanese Patent Application Publication No. 2014-159609

[0007] Patent Document 3: International Publication No. 2014 / 007259

[0008] Patent Document 4: Japanese Patent Application Publication No. 2015-4118 Summary of the invention

[0009] Problems to be solved by the invention

[0010] Metal wires made of copper alloys are used for various purposes. For example, in wires and cables used as internal wiring components for wiring in electronic equipment, industrial robots, automobiles, etc., metal wires made of copper alloys are used as conductors. In order to improve the bending life of wires and cables and improve transmission characteristics, metal wires used for such purposes are required to have increased strength and increased conductivity.

[0011] An object of the present invention is to provide a technology that achieves both improvement in strength and improvement in electrical conductivity of a metal wire.

[0012] Solutions to Solve Problems

[0013] The copper alloy wire according to one embodiment is a copper alloy wire comprising 0.3 mass % or more and 0.65 mass % or less of indium, having a 0.2% yield strength of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more.

[0014] For example, the copper alloy contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is preferably 0.65 mass % or less.

[0015] The electric wire as another embodiment comprises a conductor composed of a copper alloy wire and an insulator covering the conductor. The copper alloy wire is composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium. The 0.2% yield strength of the copper alloy wire is 300 MPa or more, the electrical conductivity of the copper alloy wire is 80% IACS or more, and the elongation is 7% or more.

[0016] For example, the copper alloy in the electric wire contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is preferably 0.65 mass % or less.

[0017] For example, the conductor is preferably formed by twisting a plurality of the copper alloy wires.

[0018] As another embodiment, the plated wire comprises a copper alloy wire and a plating layer arranged around the copper alloy wire, wherein the copper alloy wire is composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium, has a 0.2% yield strength of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more.

[0019] A cable as another embodiment comprises: a plurality of core wires, each of which has a conductor composed of a copper alloy wire and an insulator covering the conductor; and a sheath covering the plurality of core wires. The copper alloy wire is composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium. The copper alloy wire has a 0.2% yield strength of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more.

[0020] For example, the copper alloy in the cable contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is preferably 0.65 mass % or less.

[0021] Effects of the Invention

[0022] According to the typical embodiment of the present invention, it is possible to achieve both improvement in strength and improvement in electrical conductivity of the metal wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a perspective cross-sectional view of a metal wire as one embodiment.

[0024] Figure 2 Yes means Figure 1 A flowchart of an example of a process for producing a metal wire is shown.

[0025] Figure 3 is included Figure 1 A cross-sectional view of a cable of metal wires is shown.

[0026] Figure 4 yes Figure 3 A cross-sectional view of one of the plurality of electric wires included in the cable shown.

[0027] Explanation of symbols

[0028] 10: Copper alloy wire, 10D: Wire diameter, 11: Copper alloy, 60: Cable, 61, 74: Sheath (insulator), 70: Wire (core wire, coaxial cable), 71: Center conductor, 72: Insulator, 73: Outer conductor. DETAILED DESCRIPTION

[0029] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following description, a metal wire made of a copper alloy having a wire diameter (outer diameter) of 100 μm or less is referred to as a copper alloy wire. In addition, a copper alloy wire before being drawn is referred to as a rough rolled wire. In addition, a wire having a plating layer around a copper alloy wire (metal wire) is referred to as a plated wire.

[0030] In the following description, the International Annealed Copper Standard (IACS) is used as an evaluation index for electrical conductivity. Among the electrical conductivity using IACS, annealed standard soft copper (volume resistivity: 1.7241×10 -2 The electrical conductivity of 100 μΩm) is defined as 100% IACS, and the ratio of the electrical conductivity of the annealed standard soft copper is recorded as "○○% IACS". The electrical conductivity described below is calculated based on the measurement results of the resistance and diameter of the test piece measured according to the test method for electrical copper wire specified in Japanese Industrial Standards (JIS C 3002: 1992).

[0031] In the following description, when the “elongation” of a metal wire or a plated wire is described, a tensile test of a test piece is performed according to the test method for electrical copper wire specified in Japanese Industrial Standards (JIS C 3002: 1992), and the value calculated from the measurement result is referred to as the “elongation”. Furthermore, in the following description, when the “0.2% yield strength” of a metal wire or a plated wire is described, a tensile test of a test piece is performed according to the metal material tensile test method specified in Japanese Industrial Standards (JIS Z 2241: 2011), and the value calculated from the measurement result is referred to as the “0.2% yield strength”.

[0032] <New Findings of the Present Invention>

[0033] For example, electric wires and cables are used as internal wiring components of the internal wiring of industrial robots installed in factories, etc. In the electric wires and cables used for such purposes, it is required to improve the bending life and transmission characteristics. In this regard, the present inventors have found that by improving the 0.2% yield strength, which is one of the indicators of the strength of the metal wires and plated wires used as conductors of electric wires and cables, and improving the conductivity, which has a trade-off relationship with the improvement of the 0.2% yield strength, it is possible to solve the problems of improving the bending life of electric wires and cables and improving the transmission characteristics, thereby completing the present invention.

[0034] <Structure of Metal Wire>

[0035] Figure 1 It is a perspective cross-sectional view of the metal wire according to the present embodiment. Figure 1 The copper alloy wire 10 shown is a copper alloy wire composed of a copper alloy 11, and the copper alloy 11 contains indium (In) of 0.3 mass % or more and 0.65 mass % or less. The copper alloy 11 contains inevitable impurities in the remainder. In addition, the 0.2% yield strength of the copper alloy wire 10 is 300 MPa or more (preferably 300 MPa or more and 350 MPa or less), the electrical conductivity of the copper alloy wire 10 is 80% IACS or more (preferably 80% IACS or more and 90% IACS or less), and the elongation of the copper alloy wire 10 is 7% or more (preferably 7% or more and 18% or less).

[0036] Examples of the inevitable impurities contained in the copper alloy 11 include aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), chromium (Cr), iron (Fe), nickel (Ni), arsenic (As), selenium (Se), silver (Ag), antimony (Sb), lead (Pb), and bismuth (Bi). The inevitable impurities contained in the copper alloy 11 are present in a range of, for example, 20 mass ppm to 30 mass ppm.

[0037] The copper alloy wire 10 having the copper alloy 11 can achieve both 0.2% yield strength and electrical conductivity at high levels. The details will be described later as an example, and the inventors of the present application have confirmed that the copper alloy wire 10 is composed of a copper alloy 11 containing 0.3% by mass or more and 0.65% by mass or less of indium (In) and the balance of copper (Cu) and inevitable impurities, and has an electrical conductivity of 80% IACS or more and a 0.2% yield strength of 300 MPa or more.

[0038] A conductive wire for transmitting electricity (hereinafter, simply referred to as a wire) is a component that constitutes a transmission path for power or a transmission path for electrical signals, and is widely used in various fields. Conductors in wires use conductive materials such as various types of pure metals, alloys, or composite materials. In this embodiment, a copper alloy wire 10 composed of a copper alloy 11 having high conductivity is used as a conductor in a wire for illustration.

[0039] The copper wire used as a conductor in the electric wire is used in various fields as described above, but depending on the field of use, a copper wire with a thin wire diameter is sometimes required. For example, in electronic devices such as portable terminals, electric wires with conductors composed of copper wires are used as their internal wiring components. In this case, the wire diameter of one copper wire is sometimes required to be less than 100 μm. In addition, in the case of probe cables used in the medical field, they are sometimes used for insertion into the patient's body, and copper wires with thin wire diameters are further required. In this embodiment, as an example of an ultra-fine wire, a copper alloy wire 10 with a wire diameter of 10D of 80 μm is cited for illustration.

[0040] The 0.2% yield strength of the copper alloy wire 10 composed of the copper alloy 11 can be improved by applying strain to the copper alloy 11. As a method of applying strain to the copper alloy 11, there are a method of increasing the content of metal elements other than copper contained in the copper alloy 11, and a method of performing wire drawing, etc. However, when the copper alloy wire 10 is strained by these methods, the resistivity of the copper alloy 11 as a conductive member increases, so the conductivity of the copper alloy wire 10 decreases. That is, increasing the 0.2% yield strength of the copper alloy wire 10 and increasing the conductivity of the copper alloy wire 10 are in a trade-off relationship.

[0041] Therefore, the inventors of the present invention have focused on the influence of various metal elements on the reduction of the electrical conductivity of the copper alloy 11 and the degree of contribution to the enhancement of the 0.2% yield strength when the metal elements are dissolved in the copper alloy 11 in order to find a structure that can improve the characteristics of the electrical conductivity and the 0.2% yield strength in the solid solution-enhanced copper alloy 11. That is, the degree of contribution to the improvement of the 0.2% yield strength of the copper alloy wire 10 varies depending on the type of metal element, and if the content of the element dissolved in copper increases, the 0.2% yield strength increases in proportion to it. Compared with metals such as aluminum (Al), nickel (Ni) or magnesium (Mg), tin (Sn) and indium (In) have a greater influence on the increase of the 0.2% yield strength when dissolved in copper, and are therefore effective additive elements.

[0042] On the other hand, regarding the influence on the reduction of electrical conductivity, the degree of influence varies greatly depending on the type of metal element. In detail, in the case of silver (Ag), indium (In) or magnesium (Mg), compared with metals such as nickel (Ni), tin (Sn), and aluminum (Al), even if the concentration of the solid solution in copper increases, the reduction of electrical conductivity can be suppressed. For example, when the concentration (mass concentration) of the above-mentioned metal elements solid-dissolved in oxygen-free copper is 900ppm, in the case of tin (Sn), relative to the conductivity of pure copper set to 100% (percentage), it is reduced to about 92%, but in the case of indium (In), it is only reduced to about 98%. In addition, in the case of silver (Ag), relative to the conductivity of pure copper set to 100% (percentage), it is only reduced to about 99%.

[0043] According to the above characteristics, the copper alloy 11 obtained by dissolving indium in copper has high electrical conductivity and 0.2% yield strength. It should be noted that in the case of a copper alloy in which silver (Ag) is dissolved in copper, higher electrical conductivity than the copper alloy wire 10 of the present embodiment can be obtained. However, in the case of the same concentration, silver has a smaller effect of increasing the 0.2% yield strength than indium, so if the silver content is increased, the raw material cost of the copper alloy wire 10 increases, so it is preferable to dissolve indium.

[0044] In addition, in order to improve the 0.2% yield strength of the copper alloy 11, it is preferable that the content of oxygen contained in the copper alloy is low. In the case of this embodiment, the oxygen contained in the copper alloy 11 is 0.002 mass % or less. If the oxygen contained in the copper alloy 11 is 0.002 mass % or less, the decrease in the 0.2% yield strength of the copper alloy 11 due to oxygen can be suppressed.

[0045] As Figure 1In the modification of the copper alloy wire 10 shown, the copper alloy 11 may contain 0.3 mass % or more and less than 0.65 mass % of indium (In) and 0.02 mass % or more and less than 0.1 mass % of tin (Sn), and the balance includes copper (Cu) and inevitable impurities. However, the total content of indium and tin contained in the copper alloy 11 is 0.65 mass % or less.

[0046] In the case of the modification of the copper alloy wire 10, the copper alloy 11 contains tin in solid solution, so the electrical conductivity is relatively low compared to the copper alloy wire 10 not containing the above tin. However, by making the tin content less than 0.1% by mass and containing 0.3% by mass or more of indium, the electrical conductivity of 80% IACS or more can be maintained. Among them, the total content of indium and tin contained in the copper alloy 11 is preferably 0.65% by mass or less. In this way, in the case of the modification of the copper alloy wire 10, by making tin in a predetermined content solid solution, it is possible to maintain an electrical conductivity of 80% IACS or more, while reducing the raw material cost of the copper alloy wire 10.

[0047] <Method for producing metal wire>

[0048] Next, Figure 1 The following will describe a method for producing the copper alloy wire 10 shown in FIG. The copper alloy wire 10 may be produced in a case where the copper alloy contains tin or in a case where the copper alloy does not contain tin, but the production method is the same. Figure 2 Yes means Figure 1 A flowchart of an example of a process for producing a metal wire is shown.

[0049] Hereinafter, as a method for manufacturing a metal wire, a method of manufacturing a metal wire by manufacturing a rough rolled wire having a certain wire diameter (e.g., about 8 mm to 12 mm) by a continuous casting and rolling method and then subjecting the rough rolled wire to a wire drawing process will be described. The continuous casting and rolling method may be, for example, a continuous casting and rolling method called the SCR method (Southwire Continuous Rod system).

[0050] First, as Figure 2 In the raw material preparation step shown in the figure, raw materials are prepared. The raw materials are metals with copper as the main component. In addition to copper, the raw materials may contain impurity elements that are inevitably mixed in as mentioned above. In addition, the raw materials contain additive elements including indium. Figure 1 In the method for producing a metal wire described in the modification of the copper alloy wire 10 shown, the added elements are indium and tin. These added elements are added to the raw material containing copper as the main component within the range satisfying the above-mentioned content conditions.

[0051] Then, as Figure 2In the melting step shown, the raw material is melted in a melting furnace (not shown). The melting furnace is a heating furnace capable of continuously melting the raw material, and the molten copper melted in the melting furnace is sequentially moved to a holding furnace (not shown).

[0052] Then, as Figure 2 In the casting process shown, the molten copper in the holding furnace is poured into a casting mold (not shown) and then solidified by cooling. The solidified casting is removed from the casting mold and sent to a rolling device in sequence. Figure 2 The melting step to the casting step are performed in an inert gas atmosphere (e.g., a nitrogen atmosphere). Oxygen is almost absent in the inert gas atmosphere, and at least the oxygen concentration (volume concentration) is 10 ppm or less. Thus, by manufacturing the rough rolling wire in an inert gas atmosphere with an extremely low oxygen concentration, it is possible to suppress the inclusion of oxygen in copper in the casting step.

[0053] Then, as Figure 2 In the rolling process shown, the casting is rolled to form a rough rolled wire with a wire diameter of about 8 mm to 12 mm. In the rolling process, the rolling process is sometimes divided into multiple times. It should be noted that when the casting obtained in the casting process is directly used as a rough rolled wire, the rolling process can be omitted. In addition, the rough rolled wire can also be subjected to surface cleaning treatment such as oxide removal after the rolling process.

[0054] Then, as Figure 2 The coiling step shown is performed by a coiling device (not shown) to obtain a coil of the rough rolled wire. The rough rolled wire coiled by the coiling device has a 0.2% yield strength of 50 MPa to about 150 MPa and an electrical conductivity of more than 85% IACS to about 95% IACS.

[0055] Then, as Figure 2 In the wire drawing process shown, the rough rolled wire is stretched to a wire diameter of less than 100 μm (for example, about 50 μm to 80 μm) to obtain a wire drawing material of a hard material. The wire drawing process is implemented as a so-called cold working performed at room temperature (for example, 25°C). In the wire drawing process, the rough rolled wire is stretched in the extension direction, and the wire drawing process is divided into a plurality of (a first wire drawing process and a second wire drawing process), and between the wire drawing processes, a heat treatment process (sometimes also referred to as an annealing process) is performed on the wire drawing material in the wire drawing process. It should be noted that in the first wire drawing process, it is preferred to draw the rough rolled wire (for example, a wire diameter of about 8 mm to 12 mm) into a desired wire diameter (for example, a wire diameter of more than 0.5 mm and less than 3.0 mm) through one wire drawing process.

[0056] During the wire drawing process, strain is generated in the metal wire, thereby increasing the 0.2% yield strength of the metal wire, but the electrical conductivity of the metal wire will decrease. If heat treatment is performed in the middle of the wire drawing process, the strain in the metal wire will decrease. Therefore, the 0.2% yield strength of the metal wire after the heat treatment decreases, but the electrical conductivity increases. According to the research of the inventors of the present application, by implementing a heat treatment process in the middle of the wire drawing process (between the first wire drawing process and the second wire drawing process) in a manner that satisfies the following conditions, the 0.2% yield strength and electrical conductivity of the final semi-hard metal wire (copper alloy wire 10) can be maintained at a high state. It should be noted that the semi-hard copper alloy wire mentioned here is a metal wire with an elongation of more than 7% and less than 18%.

[0057] When the 0.2% yield strength of the metal wire before heat treatment (i.e., after the wire drawing process before heat treatment) is set to A, the 0.2% yield strength of the metal wire after heat treatment (just after heat treatment) is set to B, and C=B / A, the heat treatment is performed in such a way that the value of the 0.2% yield strength ratio C becomes greater than 0.5 and less than 0.8. In addition, when the elongation of the metal wire before heat treatment (i.e., after the wire drawing process before heat treatment) is set to D, the elongation of the metal wire after heat treatment (just after heat treatment) is set to E, and F=E / D, the heat treatment is performed in such a way that the value of the elongation ratio F becomes greater than 10 and less than 50. It should be noted that, if Figure 2 As shown, since wire drawing is further performed after the heat treatment process, in the heat treatment process, it is preferred to perform heat treatment in such a manner that the electrical conductivity of the metal wire immediately after the heat treatment process is 86% IACS or more (preferably 88% IACS or more). In addition, the 0.2% yield strength of the metal wire immediately after the heat treatment process is between 60 MPa and 200 MPa, and the elongation of the metal wire immediately after the heat treatment process is preferably between 20% and 40%. Thus, the electrical conductivity after the wire drawing process (second wire drawing process) performed after the heat treatment process can be made to be 80% IACS or more. In addition, in the above-mentioned heat treatment process, the heat treatment can be performed at a temperature of, for example, between 400°C and 900°C.

[0058] It should be noted that in Figure 2In the embodiment, after the rough rolled wire is drawn to the desired wire diameter (for example, a wire diameter of 0.5 mm or more and 3.0 mm or less) by the wire drawing process (first wire drawing process), a heat treatment process is performed on the wire drawing material according to the above-mentioned conditions, and then the wire drawing is performed to the desired wire diameter (for example, a wire diameter of 0.1 mm or less) by the wire drawing process (second wire drawing process), but various modifications can be applied. For example, the second wire drawing process can also be divided into multiple wire drawing processes, and the wire drawing material is drawn to the desired wire diameter in stages through each process in the multiple wire drawing processes. With regard to the second wire drawing process, by drawing the wire drawing material in stages using multiple wire drawing processes, the above-mentioned hard wire drawing material can be stably obtained compared with the case where the second wire drawing process is composed of a single wire drawing process. In addition, in the case where the second wire drawing process is composed of multiple wire drawing processes, the above-mentioned heat treatment process can also be provided between the multiple wire drawing processes as needed. The hard wire drawing material referred to here refers to a metal wire having an elongation of 0.5% to 3% and a wire diameter of 100 μm or less.

[0059] Next, the hard wire drawing material with a wire diameter of less than 100 μm obtained in the wire drawing process is semi-hardened. By semi-hardening the hard wire drawing material, a metal wire (copper alloy wire 10) in a semi-hard state can be obtained. As a semi-hardening treatment, for example, the hard wire drawing material obtained by the wire drawing process can be heated under heating conditions such as a heating temperature of 520°C to 580°C and a heating time of 0.3 seconds to 0.8 seconds. Thus, a copper alloy wire 10 having a 0.2% yield strength of 300 MPa to 350 MPa, a conductivity of 80% IACS to 90% IACS, an elongation of 7% to 18%, and a wire diameter of 100 μm or less can be obtained.

[0060] <Evaluation of alloy composition and characteristics>

[0061] Next, explain Figure 1 The results of experiments on the relationship between the composition and properties of the alloy of the copper alloy wire 10 are shown in Table 1. Table 1 is a table showing the relationship between the composition and properties of the alloy of the metal wire.

[0062] [Table 1]

[0063]

[0064] In Table 1, Samples No. 1 to 3 are examples that meet the conditions of the copper alloy wire 10, and Samples No. 4 to 7 are comparative examples that do not meet the conditions of the copper alloy wire 10. Samples No. 1 to 7 were respectively subjected to Figure 2 The sample is manufactured by the manufacturing process described in the description. In addition, in Table 1, the sample used for the test of 0.2% yield strength and the test of elongation is a metal wire processed into a wire diameter of about 80μm. In addition, the tensile speed when measuring the elongation is set to 50mm / minute, and the mark distance is set to 250mm. The 0.2% yield strength was measured by performing a tensile test in accordance with JIS Z2241. More specifically, the above-mentioned tensile test (offset method, distance between marks: 250mm, tensile speed: 50m / minute) was carried out to measure the 0.2% yield strength. Regarding the cross-sectional area of ​​the sample, the wire diameter was measured to 1 / 1000mm using a micrometer, and the area of ​​the perfect circle was calculated based on the measured wire diameter. The value of elongation is the total elongation at break (the value of the elastic elongation and plastic elongation of the tensiometer combined), expressed as a percentage relative to the tensiometer mark distance. Although not described in Table 1, each of Samples No. 1 to 7 was prepared in an environment where oxygen is difficult to mix into, and the oxygen contained in the copper alloy of each sample was 0.002 mass % or less.

[0065] In Table 1, the bending life is measured by hanging a 20g weight on the sample, bending it 90 degrees to the left and right with a jig of 5mm bending radius as a fulcrum, and measuring the number of times until it breaks. In addition, the number of bending times is counted as 1 time.

[0066] In Table 1, it can be seen from Samples No. 1 to 2 that when only indium is added to the copper alloy, the indium content is 0.30 mass % or more, and a good bending life (bending times of 3000 or more) can be obtained by making the 0.2% yield strength of the sample 300 MPa or more and the elongation 7% or more.

[0067] In addition, in Table 1, by comparing Samples No. 3 to 7, it can be seen that when indium and tin are added to the copper alloy, the indium content is greater than 0.30 mass % and less than 0.65 mass %, and the tin content is greater than 0.02 mass % and less than 0.1 mass %, and by making the 0.2% yield strength of the sample greater than 300 MPa and the elongation greater than 7%, a good bending life (for example, a bending number of more than 3000 times) can be obtained.

[0068] <Application examples of copper alloy wire>

[0069] Next, Figure 1 An application example of the copper alloy wire 10 shown will be described. Figure 3 is included Figure 1 A cross-sectional view of a cable of copper alloy wire 10 is shown. Figure 4 yes Figure 3 A cross-sectional view of one of the plurality of electric wires included in the cable shown.

[0070] Figure 3 The cable 60 shown has a plurality of electric wires (core wires) 70 and a sheath 61 covering the periphery of the plurality of electric wires 70. An interposer (not shown) is arranged around each of the plurality of electric wires 70, and the plurality of electric wires 70 are separated from each other by the interposer. The interposer is formed, for example, of a linear member composed of fibers or resins. The sheath 61 is formed, for example, of a resin composition having a resin such as chlorinated polyethylene or polyvinyl chloride as a main component (matrix resin), a fluororesin composition, or the like. The plurality of electric wires 70 may be in contact with each other. The cable 60 is used, for example, as an internal wiring material for portable electronic devices such as smartphones, industrial robots installed in factories, or automobiles. The cable 60 has a plurality of electric wires 70, and the outer diameter of each of the plurality of electric wires 70 is relatively small. For example, in Figure 3 and Figure 4 In the example shown, the outer diameter of the electric wire 70 is, for example, approximately 0.86 mm (860 μm).

[0071] like Figure 4 As shown, the electric wire 70 includes a central conductor 71 composed of a plurality of copper alloy wires 10 twisted together and an insulator 72 covering the central conductor 71. The plurality of copper alloy wires 10 constituting the central conductor 71 are respectively made of Figure 1 The copper alloy 11 described above is formed. That is, the copper alloy 11 constituting the copper alloy wire 10 contains 0.3 mass % or more and 0.65 mass % or less of indium. The wire diameter of each of the plurality of copper alloy wires 10 is, for example, 0.08 mm (80 μm). The insulator 72 is formed of, for example, a resin such as polyethylene, polypropylene, or a fluororesin.

[0072] Thus, the electric wire 70 using a plurality of copper alloy wires 10 and the cable 60 using the electric wire 70 can improve the transmission characteristics of electric signals or power in a portable electronic device. Alternatively, the electric wire 70 using a plurality of copper alloy wires 10 as ultra-fine wires and the cable 60 using the electric wire 70 can reduce the wire diameter, thereby miniaturizing the size of the housing of a portable electronic device and miniaturizing an industrial robot, etc.

[0073] It should be noted that in Figure 4 In the example, the wire 70 is shown, but in the application Figure 1 There are various modifications of the copper alloy wire 10 shown in the figure. For example, it can be applied to an electric wire composed of a conductor formed by one copper alloy wire 10 and an insulator covering the surrounding of the conductor. Figure 3 as well as Figure 4 In the figure, an example of a conductor formed by twisting a plurality of copper alloy wires 10 is illustrated as the central conductor 71 of the electric wire 70, but the invention is not limited thereto, and the central conductor 71 may be a plated wire described later.

[0074] <Plating Wire>

[0075] The plating line is composed of Figure 1 The copper alloy wire 10 shown has a plated wire around its periphery (outer surface). The plated wire has a 0.2% yield strength of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more. Figure 1 In the state where the copper alloy wire shown is provided with a plating layer around it, the 0.2% yield strength is 300 MPa or more (preferably 300 MPa or more and 340 MPa or less), the conductivity is 80% IACS or more (preferably 80% IACS or more and 89% IACS or less), and the elongation is 7% or more (preferably 7% or more and 18% or less). In addition, the plated wire is a semi-hard wire.

[0076] As described above, the copper alloy wire is composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium (In). In particular, the copper alloy wire may be composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium (In), the balance of which includes copper (Cu) and inevitable impurities. In addition, the copper alloy wire may also be composed of a copper alloy containing 0.3 mass % or more and less than 0.65 mass % of indium (In) and 0.02 mass % or more and less than 0.1 mass % of tin (Sn), the balance of which includes copper (Cu) and inevitable impurities. In this case, the total content of indium and tin contained in the copper alloy is 0.65 mass % or less.

[0077] The plating layer is provided so as to be in contact with the periphery of the copper alloy wire, that is, the surface of the copper alloy wire. The thickness of the plating layer is, for example, 0.1 μm or more and 1.5 μm or less. The plating layer is formed of, for example, tin (Sn), silver (Ag), nickel (Ni), or the like.

[0078] <Method for manufacturing plated wire>

[0079] The plated wire can be Figure 2The copper alloy wire obtained by the manufacturing method of the copper alloy wire shown in the figure is obtained by forming a plating layer. The copper alloy wire before the plating layer is formed is a semi-hard metal wire with a 0.2% yield strength of 300 MPa or more and a conductivity of 80% IACS or more. The copper alloy wire is immersed in a plating tank storing a molten plating material (such as Sn) at a predetermined temperature (for example, 250°C or more and 300°C or less). Thus, the molten plating material is applied to the entire circumference of the outer surface of the copper alloy wire. Thereafter, the copper alloy wire in a state coated with the molten plating material is passed through a plating die to adjust the thickness of the molten plating material applied to the surface of the copper alloy wire, thereby forming a plating layer with a predetermined thickness. In particular, as a condition for applying the molten plating material on the surface of the copper alloy wire, it is better to carry out under the conditions of a line speed of 100 m / min or more and an immersion time in the molten plating material of 0.1 second or more and 1.0 second or less. The copper alloy wire with the plating layer formed in this way maintains a semi-hard state, and the elongation as a plated wire is 7% or more and 18% or less.

[0080] <Characteristics of Plated Wire>

[0081] Next, the results of experiments on the characteristics of plated wires are described. Tables 2 and 3 are tables showing the relationship between the alloy composition of the copper alloy wire constituting the plated wire and the characteristics of the plated wire.

[0082] [Table 2]

[0083]

[0084] [Table 3]

[0085]

[0086] In Table 2 and Table 3, Sample No. 8, 13-14 are examples that meet the above-mentioned conditions for plating wire, and Sample No. 9-12, 15-16 are comparative examples that do not meet the above-mentioned conditions for plating wire. Sample No. 8-12 shown in Table 2 and Sample No. 13-16 shown in Table 3 are respectively Figure 2 A sample in which a plating layer is formed around the copper alloy wire manufactured by the manufacturing process described above. Figure 2The copper alloy wire manufactured by the manufacturing process described above is immersed in a plating tank storing molten Sn (temperature: 250°C or more and 300°C or less), and then the copper alloy wire coated with the molten plating material is passed through a plating die, thereby adjusting the thickness of the molten plating material coated on the surface of the copper alloy wire to form a plating layer with a predetermined thickness. In addition, in Tables 2 and 3, the samples used for the test of 0.2% yield strength and the test of elongation of the plated wire are samples in which a plating layer (thickness: about 0.5μm) is provided around the copper alloy wire processed into a wire diameter of about 80μm. The copper alloy wire used in Samples No. 8 to 16 is composed of a copper alloy containing indium (In) and tin (Sn) in the amounts shown in Tables 2 and 3, and the balance containing copper (Cu) and inevitable impurities. In addition, the tensile speed when measuring the elongation is set to 50mm / min, and the mark distance is set to 250mm. The 0.2% yield strength was measured by performing a tensile test in accordance with JIS Z2241. More specifically, the above-mentioned tensile test (offset method, distance between markings: 250 mm, tensile speed: 50 m / min) was carried out to measure the 0.2% yield strength. Regarding the cross-sectional area of ​​the sample, the wire diameter was measured to 1 / 1000 mm using a micrometer, and the area of ​​a perfect circle was calculated based on the measured wire diameter. The elongation value is the total elongation at break (the value of the elastic elongation and plastic elongation of the tensiometer combined), expressed as a percentage relative to the distance between the markings of the tensiometer. In addition, although the records are omitted in Tables 2 and 3, Samples No. 8 to 16 were adjusted in an environment where oxygen is difficult to mix, and the oxygen contained in the copper alloy of each sample was less than 0.002 mass%.

[0087] In Tables 2 and 3, the bending life is measured by hanging a 20g weight on the sample, bending it 90 degrees to the left and right with a fixture of a bending radius of 5mm as a fulcrum, and measuring the number of times until it breaks. In addition, the number of bending times is counted as 1 bending of 90 degrees to the left and right.

[0088] In Table 2 and Table 3, it can be seen from Sample Nos. 8, 13 and 14 that the plated wire is provided with a plating layer around the copper alloy wire composed of a copper alloy having an indium content of 0.30 mass % or more, and has a 0.2% yield strength of 300 MPa or more and an elongation of 7% or more, thereby obtaining a good bending life (the number of bendings is 3000 times or more). In particular, in the plated wire, a copper alloy wire composed of a copper alloy having an indium content of 0.30 mass % or more and less than 0.65 mass %, and the balance consisting of copper and inevitable impurities, or a copper alloy wire composed of a copper alloy having an indium content of 0.30 mass % or more and less than 0.65 mass %, a tin content of 0.02 mass % or more and less than 0.1 mass %, and the balance consisting of copper and inevitable impurities, is provided with a plating layer around the copper alloy wire, and has a 0.2% yield strength of 300 MPa or more and an elongation of 7% or more, thereby obtaining a good bending life (for example, the number of bendings is 3000 times or more).

[0089] <Application examples of plated wire>

[0090] As mentioned above, plated wire can be used to form Figure 3 and Figure 4 The central conductor of the wire or cable shown in the figure. Specifically, it is a wire having a central conductor formed by a plurality of plated wires twisted together and an insulator covering the central conductor. In addition, it can also be a cable having a shielding layer or a sheath arranged around the wire.

[0091] The present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the gist of the invention.

[0092] The above-mentioned embodiment includes the following aspects.

[0093] [Note 1]

[0094] A method for manufacturing a copper alloy wire, comprising:

[0095] (a) a step of preparing a raw material containing copper and an additive element other than copper,

[0096] (b) a step of melting the raw materials and then forming a rough rolling line by casting,

[0097] (c) a step of drawing the rough rolled wire to form a metal wire,

[0098] (d) after the step (c), a step of heat treating the metal wire after the wire drawing process;

[0099] (e) after the step (d), further drawing the metal wire subjected to the heat treatment to form a copper alloy wire having an outer diameter of 0.1 mm or less, and

[0100] (f) after the step (e), a step of subjecting the copper alloy wire to a semi-hardening treatment,

[0101] The rough rolled wire is made of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium.

[0102] [Note 2]

[0103] The method for producing a copper alloy wire according to Supplementary Note 1, wherein the copper alloy contains 0.02 mass % or more and less than 0.1 mass % of tin.

[0104] [Note 3]

[0105] The method for producing a copper alloy wire according to Appendix 1 or 2,

[0106] In the above step (d),

[0107] When the 0.2% yield strength of the metal wire after the wire drawing after the step (c) is defined as A, the 0.2% yield strength of the metal wire after the heat treatment after the step (d) is defined as B, and the ratio of the 0.2% yield strength is defined as C=B / A, the heat treatment is performed so that the value of C becomes 0.5 or more and 0.8 or less,

[0108] When the elongation of the metal wire after wire drawing after the (c) step is set to D, the 0.2% yield strength of the metal wire subjected to heat treatment after the (d) step is set to E, and the elongation ratio is set to F=E / D, the heat treatment is performed in such a way that the value of F becomes greater than 10 and less than 50.

[0109] [Note 4]

[0110] In the method for producing a copper alloy wire according to Supplementary Note 3, in the step (d), the heat treatment is performed so that the electrical conductivity of the metal wire immediately after the heat treatment in the step (d) is 86% IACS or more.

[0111] Possibility of Industrial Application

[0112] The present invention can be used for copper alloy wires used in conductors such as cables (e.g., ultra-fine coaxial cables, etc.) used in internal wiring components of small electronic devices (e.g., digital cameras, surveillance cameras, personal computers, smartphones, etc.), cables with bending resistance (e.g., endoscope cables, probe cables, etc.) used in industrial robots and medical equipment (e.g., gastroscopes, ultrasonic diagnostic equipment, etc.), and cables for automobiles.

Claims

1. A copper alloy wire, comprising a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium, 0.2% yield strength is above 300MPa, conductivity is above 83%IACS, elongation is above 7%, The copper alloy is obtained by at least two wire drawing processes and heat treatments performed between the wire drawing processes, and semi-hardening treatment of the wire drawing material obtained in the final wire drawing process. The semi-hardening treatment is: heating at a temperature of 520° C. to 580° C. for 0.3 seconds to 0.8 seconds.

2. The copper alloy wire according to claim 1, wherein The copper alloy contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is 0.65 mass % or less.

3. A plated wire having: A copper alloy wire composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium, and A plating layer is provided around the copper alloy wire, The plated wire has a 0.2% yield strength of 300 MPa or more, a conductivity of 82% IACS or more, and an elongation of 7% or more. The copper alloy is obtained by at least two wire drawing processes and heat treatments performed between the wire drawing processes, and semi-hardening treatment of the wire drawing material obtained in the final wire drawing process. The semi-hardening treatment is: heating at a temperature of 520° C. to 580° C. for 0.3 seconds to 0.8 seconds.

4. An electric wire comprising a conductor and an insulator covering the periphery of the conductor, The conductor is composed of a copper alloy wire composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium, The copper alloy wire has a 0.2% yield strength of 300 MPa or more, a conductivity of 83% IACS or more, and an elongation of 7% or more. The copper alloy is obtained by at least two wire drawing processes and heat treatments performed between the wire drawing processes, and semi-hardening treatment of the wire drawing material obtained in the final wire drawing process. The semi-hardening treatment is: heating at a temperature of 520° C. to 580° C. for 0.3 seconds to 0.8 seconds.

5. The electric wire according to claim 4, wherein The copper alloy contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is less than 0.65 mass %.

6. The electric wire according to claim 4 or 5, wherein: The conductor is formed by twisting a plurality of the copper alloy wires.

7. A cable comprising: A plurality of core wires, each of which is composed of an electric wire in which a conductor is covered with an insulator; and A sheath covers the plurality of core wires. The conductor is composed of a copper alloy wire composed of a copper alloy containing 0.3 mass % or more and 0.65 mass % or less of indium, The copper alloy wire has a 0.2% yield strength of 300 MPa or more, a conductivity of 83% IACS or more, and an elongation of 7% or more. The copper alloy is obtained by at least two wire drawing processes and heat treatments performed between the wire drawing processes, and semi-hardening treatment of the wire drawing material obtained in the final wire drawing process. The semi-hardening treatment is: heating at a temperature of 520° C. to 580° C. for 0.3 seconds to 0.8 seconds.

8. The cable according to claim 7, wherein The copper alloy contains 0.02 mass % or more and less than 0.1 mass % of tin, and the total content of the indium and the tin is 0.65 mass % or less.

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