JP2022109209A - Copper alloy wire, plated wire, electric wire, and cable - Google Patents

Abstract

To provide a copper alloy wire improved in both strength and electrical conductivity.SOLUTION: A copper alloy wire 10 comprises a copper alloy 11 containing indium of 0.3 mass% to 0.65 mass% inclusive, and has 0.2% proof stress of 300 MPa or more, electrical conductivity of 80% IACS or more, and elongation of 7% or more.SELECTED DRAWING: Figure 1

Description

TECHNICAL FIELD The present invention relates to a copper alloy wire, a plated wire, an electric wire using the same, and a cable.

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

JP-A-5-311285 JP 2014-159609 A WO2014/007259 JP 2015-4118 A

Metal wires made of copper alloys are used for various purposes. For example, in electric wires and cables as internal wiring parts wired inside electronic devices, industrial robots, automobiles, etc., metal wires made of a copper alloy are used as conductors. Metal wires used for such applications are required to have improved strength and conductivity in order to improve the flex life of electric wires and cables and to improve transmission characteristics.

SUMMARY OF THE INVENTION An object of the present invention is to provide a technique for achieving both strength improvement and conductivity improvement of a metal wire.

A copper alloy wire according to one embodiment is a copper alloy wire made of a copper alloy, and the copper alloy contains 0.3% by mass or more and 0.65% by mass or less of indium. The copper alloy wire has a 0.2% yield strength of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more.

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

An electric wire according to another embodiment includes a conductor made of a copper alloy wire and an insulator covering the circumference of the conductor. The copper alloy wire is made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium. The copper alloy wire has a 0.2% proof stress of 300 MPa or more, a conductivity of 80% IACS or more, and an elongation of 7% or more.

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

For example, it is preferable that the conductor is formed by twisting a plurality of the copper alloy wires.

A plated wire according to another embodiment includes a copper alloy wire and a plated layer provided around the copper alloy wire, and the copper alloy wire contains 0.3% by mass or more and 0.65% by mass It is composed of a copper alloy containing the following indium, and has a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more.

A cable according to another embodiment includes a conductor made of a copper alloy wire, a plurality of core wires provided with an insulator covering the circumference of the conductor, and a sheath collectively covering the circumference of the plurality of core wires. and have The copper alloy wire is made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium. The copper alloy wire has a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more.

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

According to the representative embodiment of the present invention, both strength improvement and conductivity improvement of the metal wire can be achieved.

It is a perspective sectional view of the metal wire which is one embodiment. FIG. 2 is a flowchart showing an example of a manufacturing process of the metal wire shown in FIG. 1; 2 is a cross-sectional view of a cable including the metal wire shown in FIG. 1; FIG. FIG. 4 is a cross-sectional view of one of a plurality of electric wires included in the cable shown in FIG. 3;

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In the following description, a metal wire made of a copper alloy and having a wire diameter (outer diameter) of 100 μm or less is referred to as a copper alloy wire. A wire before being drawn into a copper alloy wire is called a rough drawn wire. A copper alloy wire (metal wire) having a plating layer around it is called a plated wire.

Further, in the following description, an index called "IACS (International Annealed Copper Standard)" is used as an evaluation index of conductivity. The conductivity using IACS defines the conductivity of annealed standard annealed copper (volume resistivity: 1.7241 × 10 ^-2 μΩm) as 100% IACS, and the ratio to the conductivity of this annealed standard annealed copper is “○○ %IACS”. The conductivity described below is calculated based on the measurement results of measuring the electrical resistance and diameter of a test piece according to the test method for electrical copper wires specified in Japanese Industrial Standards (JIS C 3002: 1992). be.

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

<Knowledge newly discovered by the present inventors>
For example, electric wires and cables are used as internal wiring components wired inside industrial robots installed in factories and the like. Wires and cables used for such applications are required to have improved flex life and improved transmission characteristics. On the other hand, the present inventors have improved the 0.2% proof stress, which is one of the indicators of the strength of metal wires and plated wires used as conductors of electric wires and cables, and improved the 0.2% proof stress. The inventors have found that the problems of improving the flex life of electric wires and cables and improving the transmission characteristics can be solved by improving the conductivity, which was a trade-off relationship with improvement, and have completed the present invention.

<Structure of Metal Wire>
FIG. 1 is a perspective cross-sectional view of a metal wire according to this embodiment. The copper alloy wire 10 shown in FIG. 1 is a copper alloy wire composed of a copper alloy 11, and the copper alloy 11 contains 0.3% by mass or more and 0.65% by mass or less of indium (In). contains. The copper alloy 11 contains unavoidable impurities in its balance. 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), and the electrical conductivity of the copper alloy wire 10 is 80% IACS or more (preferably 80% IACS or more 90 %IACS), and the elongation of the copper alloy wire 10 is 7% or more (preferably 7% or more and 18% or less).

Examples of unavoidable 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), or bismuth (Bi). The unavoidable impurities contained in the copper alloy 11 are contained, for example, in the range of 20 mass ppm or more and 30 mass ppm or less.

Copper alloy wire 10 having copper alloy 11 described above can achieve both 0.2% proof stress and electrical conductivity at high levels. Details will be described later as an example, but as a result of confirmation by the inventor of the present application, it contains 0.3% by mass or more and 0.65% by mass or less of indium (In), and the balance is copper (Cu) and unavoidable The copper alloy wire 10 having the copper alloy 11 containing impurities has a conductivity of 80% IACS or more and a 0.2% proof stress of 300 MPa or more.

Conductive wires for transmitting electricity (hereinafter simply referred to as electric wires) are members constituting power transmission paths or electrical signal transmission paths, and are widely used in various fields. Electrically conductive materials such as various types of pure metals, alloys, or composites are used for conductors in electrical wires. In this embodiment, a copper alloy wire 10 made of a copper alloy 11 having high electrical conductivity will be described as a conductor of an electric wire.

Copper wires, which are used as conductors in electric wires, are used in various fields as described above, and depending on the fields of use, there are cases where copper wires with a small wire diameter are required. For example, in electronic devices such as portable terminals, electric wires having conductors made of copper wires are used as internal wiring components. In this case, the wire diameter of one copper wire may be required to be 100 μm or less. Moreover, in the case of probe cables used in the medical field, there are cases where they are used for applications where they are inserted into the body of a patient, and copper wires with a smaller wire diameter are required. In the present embodiment, a copper alloy wire 10 having a wire diameter 10D of 80 μm will be described as an example of an ultrafine wire.

The 0.2% yield strength of the copper alloy wire 10 made of the copper alloy 11 can be improved by straining the copper alloy 11 . Methods for causing strain in the copper alloy 11 include a method of increasing the content of metal elements other than copper contained in the copper alloy 11, and a method of wire drawing. However, when the copper alloy wire 10 is strained by these methods, the electrical conductivity of the copper alloy wire 10 is lowered because the resistivity of the copper alloy 11 as the conductive member is increased. That is, increasing the 0.2% proof stress of the copper alloy wire 10 and increasing the electrical conductivity of the copper alloy wire 10 are in a trade-off relationship.

Therefore, in order to find a configuration that improves the properties of electrical conductivity and 0.2% proof stress in the solid-solution-strengthened copper alloy 11, the present inventors have made a plurality of types of metal elements into a solid solution in the copper alloy 11. Attention was paid to the influence on the decrease in electrical conductivity of the copper alloy 11 and the extent to which it contributes to the enhancement of the 0.2% yield strength when the temperature is increased. 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 the higher the content of the element dissolved in copper, the more proportional it is. As a result, the 0.2% yield strength increases. Tin (Sn) and indium (In) have the effect of increasing the 0.2% proof stress when dissolved in copper compared to metals such as aluminum (Al), nickel (Ni), or magnesium (Mg). is an effective additive element because of its large

On the other hand, the degree of influence on the decrease in electrical conductivity varies greatly depending on the type of metal element. Specifically, in the case of silver (Ag), indium (In), or magnesium (Mg), the concentration of solid solution in copper compared to metals such as nickel (Ni), tin (Sn), and aluminum (Al) Even if is increased, the decrease in conductivity can be suppressed. For example, when the concentration (mass concentration) of the metal element dissolved in oxygen-free copper is 900 ppm, in the case of tin (Sn), when the conductivity of pure copper is 100% (percentage) On the other hand, it decreases to about 92%, but in the case of indium (In), it can be reduced to about 98%. In addition, in the case of silver (Ag), the electrical conductivity can be lowered to about 99% when the electrical conductivity of pure copper is 100% (percentage).

From the above properties, the copper alloy 11 obtained by dissolving indium in copper has high levels of electrical conductivity and 0.2% yield strength. In the case of a copper alloy in which silver (Ag) is dissolved in copper, a higher electrical conductivity than that of the copper alloy wire 10 of the present embodiment can be obtained. However, at the same concentration, silver has a smaller effect in increasing the 0.2% proof stress than indium. Dissolution is preferred.

Moreover, in order to improve the 0.2% proof stress of the copper alloy 11, it is preferable that the oxygen content in the copper alloy is small. In this embodiment, the oxygen content in copper alloy 11 is 0.002% by mass or less. If the oxygen contained in the copper alloy 11 is 0.002% by mass or less, it is possible to suppress the decrease in the 0.2% proof stress of the copper alloy 11 due to oxygen.

As a modification of copper alloy wire 10 shown in FIG. 1, copper alloy 11 contains 0.3% by mass or more and less than 0.65% by mass of indium (In), less than .1 mass % tin (Sn), with the balance consisting of copper (Cu) and unavoidable impurities. However, the total content of indium and tin contained in copper alloy 11 is 0.65% by mass or less.

In the case of the modification of the copper alloy wire 10, since the copper alloy 11 contains solutionized tin, the electrical conductivity is relatively low compared to the copper alloy wire 10 containing no tin. However, if the tin content is less than 0.1% by mass and the indium content is 0.3% by mass or more, the electrical conductivity of 80%IACS or more can be maintained. However, the total content of indium and tin contained in copper alloy 11 is preferably 0.65% by mass or less. In this way, in the case of the modified example of the copper alloy wire 10, by making a solid solution of tin at a predetermined content, while maintaining the conductivity of 80% IACS or more, the raw material cost of the copper alloy wire 10 is reduced. can be made

<Manufacturing method of metal wire>
Next, a method for manufacturing the copper alloy wire 10 shown in FIG. 1 will be described. The copper alloy wire 10 described above may or may not contain tin in the copper alloy, but the manufacturing method is the same. FIG. 2 is a flowchart showing an example of the manufacturing process of the metal wire shown in FIG.

In the following, as a method for manufacturing a metal wire, after manufacturing a wire with a certain thickness (for example, about 8 mm to 12 mm) by a continuous casting and rolling method, the wire is drawn. A method of manufacturing a metal wire is taken up and described. For the continuous casting and rolling method, for example, a continuous casting and rolling method called SCR (Southwire Continuous Rod system) can be used.

First, as a raw material preparation step shown in FIG. 2, raw materials are prepared. The raw material is a metal whose main component is copper. In addition to copper, the raw material may contain impurity elements that are inevitably mixed as described above. In addition, the raw material contains an additive element including indium. Further, in the metal wire manufacturing method described as a modification of the copper alloy wire 10 shown in FIG. 1, the additive elements are indium and tin. These additive elements are added to the raw material containing copper as the main component within a range that satisfies the above-described content ratio conditions.

Next, as the melting step shown in FIG. 2, the raw material is melted in a melting furnace (not shown). A melting furnace is a heating furnace capable of continuously melting raw materials, and molten copper melted in the melting furnace is sequentially transferred to a heat retaining furnace (not shown).

Next, as a casting process shown in FIG. 2, the molten copper in the heat insulating furnace is poured into a mold (not shown) and then cooled to solidify. The solidified castings are removed from the molds and sequentially delivered to the rolling mill. The steps from the melting step to the casting step shown in FIG. 2 are performed in an inert gas atmosphere (for example, in a nitrogen atmosphere). Almost no oxygen exists in the inert gas atmosphere, and at least the oxygen concentration (volume concentration) is 10 ppm or less. In this way, by manufacturing the wire rod in an inert gas atmosphere with an extremely low oxygen concentration, it is possible to suppress the inclusion of oxygen in the copper during the casting process.

Next, as a rolling step shown in FIG. 2, the casting is rolled to form a rough drawn wire having a wire diameter of about 8 mm to 12 mm. In the rolling process, the rolling process may be performed in multiple steps. In addition, when the casting obtained in the casting process is used as it is as the rough drawing wire, this rolling process can be omitted. Also, the rough drawn wire may be subjected to surface cleaning treatment such as removal of oxides after the rolling process.

Next, as a winding step shown in FIG. 2, the wire is wound by a winding device (not shown) to obtain a roll of rough drawn wire. The rough drawn wire wound by the winding device has a 0.2% yield strength of about 50 MPa or more and about 150 MPa, and an electrical conductivity of more than 85% IACS and about 95% IACS or less.

Next, in the wire drawing process shown in FIG. 2, the rough drawn wire is drawn until the wire diameter becomes 100 μm or less (for example, about 50 μm to 80 μm) to obtain a hard drawn wire material. The wire drawing process is carried out as so-called cold working performed at room temperature (for example, 25° C.). In the wire drawing process, the rough drawn wire is elongated in the extending direction. As a heat treatment step (sometimes referred to as an annealing step), heat treatment is applied to the drawn wire during wire drawing. In the first wire drawing process, a rough drawn wire (for example, a wire diameter of about 8 mm to 12 mm) is drawn to a desired wire diameter (for example, 0.5 mm or more and 3.0 mm or less) by one wire drawing process. wire diameter).

The 0.2% proof stress of the metal wire can be increased by straining the metal wire during wire drawing, but the electrical conductivity of the metal wire decreases. Heat treatment during wire drawing reduces strain in the metal wire. Therefore, the 0.2% yield strength of the heat-treated metal wire is lowered, but the electrical conductivity is increased. According to the studies of the inventors of the present application, the heat treatment process performed during the wire drawing process (between the first wire drawing process and the second wire drawing process) should be performed so as to satisfy the following conditions. , the 0.2% proof stress and electrical conductivity of the finally obtained semi-rigid metal wire (copper alloy wire 10) can be maintained at high levels. The semi-rigid copper alloy wire referred to here is a metal wire having an elongation of 7% or more and 18% or less.

Let A be the 0.2% proof stress of the metal wire before the heat treatment (after the wire drawing process immediately before the heat treatment), B be the 0.2% proof stress of the metal wire after the heat treatment (immediately after the heat treatment), and C=B/A. , the heat treatment is performed so that the value of the ratio C of 0.2% proof stress is 0.5 or more and 0.8 or less. In addition, if the elongation of the metal wire before the heat treatment (after the wire drawing process immediately before the heat treatment) is D, the elongation of the metal wire after the heat treatment (immediately after the heat treatment) is E, and F=E/D, the elongation ratio F Heat treatment is performed so that the value becomes 10 or more and 50 or less. As shown in FIG. 2, since the wire drawing process is further performed after the heat treatment process, the conductivity of the metal wire immediately after the heat treatment process becomes 86% IACS or more (preferably 88% IACS or more) in the heat treatment process. It is preferable to perform heat treatment as follows. In addition, the 0.2% yield strength of the metal wire immediately after the heat treatment step is preferably 60 MPa or more and 200 MPa, and the elongation of the metal wire immediately after the heat treatment step is preferably 20% or more and 40% or less. As a result, the electrical conductivity after the wire drawing step (second wire drawing step) performed subsequent to the heat treatment step can be made 80% IACS or higher. In addition, in the heat treatment step described above, the heat treatment is preferably performed at a temperature of, for example, 400° C. or more and 900° C. or less.

In FIG. 2, after the rough wire is drawn to a desired wire diameter (for example, a wire diameter of 0.5 mm or more and 3.0 mm or less) by a wire drawing process (first wire drawing process), A heat treatment step of heat-treating the drawn wire material under the conditions described above is performed, and a wire drawing step (second wire drawing step) is performed to draw a wire to a desired wire diameter (for example, a wire diameter of 0.1 mm or less). Although described, various variations are applicable. For example, the second wire drawing process is divided into a plurality of wire drawing processes, and the wire drawing material can be drawn step by step to a desired wire diameter by each process in the multiple wire drawing processes. good. In the second wire drawing process, the wire drawing material is drawn step by step through a plurality of wire drawing processes, so that when the second wire drawing process is composed of one wire drawing process, In comparison, it is possible to stably obtain the above-described hard drawn wire material. When the second wire drawing process is composed of a plurality of wire drawing processes, the heat treatment process described above may be provided between the plurality of wire drawing processes, if necessary. The hard drawn wire material referred to here is a metal wire having an elongation of 0.5% or more and 3% or less and a wire diameter of 100 μm or less.

Next, the hard drawn wire material having a wire diameter of 100 μm or less obtained in the wire drawing process is subjected to a semi-hardening treatment. A semi-rigid metal wire (copper alloy wire 10) is obtained by subjecting a hard drawn wire material to a semi-hardening treatment. As the semi-hardening treatment, for example, a hard drawn wire obtained by the wire drawing process is heated under heating conditions such as a heating temperature of 520 ° C. or higher and 580 ° C. or lower and a heating time of 0.3 seconds or more and 0.8 seconds or less. It should be heated. As a result, a copper alloy having a 0.2% proof stress of 300 MPa or more and 350 MPa or less, a conductivity of 80% IACS or more and 90% IACS or less, an elongation of 7% or more and 18% or less, and a wire diameter of 100 μm or less A line 10 is obtained.

<Evaluation of alloy composition and characteristics>
Next, the results of an experiment on the relationship between the alloy composition of the copper alloy wire 10 shown in FIG. 1 and the characteristics will be described. Table 1 is a table showing the relationship between the alloy composition and properties of metal wires.

In Table 1, sample no. 1 to 3 are examples, sample Nos., which meet the conditions of the copper alloy wire 10 described above. 4 to 7 are comparative examples that do not meet the conditions of the copper alloy wire 10 described above. Sample no. 1 to 7 were manufactured through the manufacturing process described with reference to FIG. In Table 1, the samples subjected to the 0.2% yield strength test and the elongation test were metal wires processed to have a wire diameter of about 80 µm. Further, the tensile speed when measuring the elongation was set to 50 mm/min, and the gauge length was set to 250 mm. The 0.2% yield strength was measured by performing a tensile test according to JIS Z2241. More specifically, the above tensile test (offset method, distance between gauge lines: 250 mm, tensile speed: 50 m/min) was performed to measure the 0.2% yield strength. The cross-sectional area of the sample was calculated as the area of a perfect circle from the wire diameter measured to 1/1000 mm with a micrometer. The elongation value is the total elongation at break (combining the elastic elongation and the plastic elongation of the extensometer) expressed as a percentage of the extensometer gauge length. Although not shown in Table 1, Sample No. Each of 1 to 7 was prepared in an environment in which oxygen is difficult to mix, and the oxygen contained in the copper alloy of each sample is 0.002% by mass or less.

In Table 1, the flexing life was determined by suspending a weight of 20 g from the sample, bending the sample 90 degrees left and right around a jig with a bending radius of 5 mm, and measuring the number of times until the sample broke. In addition, the number of times of bending was counted as one bending of 90 degrees to the left and right.

In Table 1, sample no. As can be seen from 1 and 2, when only indium is added to the copper alloy, the indium content is 0.30 mass% or more, the 0.2% proof stress of the sample is 300 MPa or more, and the elongation is 7%. A good flexing life (3000 times or more of flexing) can be obtained by setting the above.

Also, in Table 1, sample No. 3 to 7, when indium and tin are added to the copper alloy, the indium content is 0.30% by mass or more and less than 0.65% by mass, and the tin content is 0.30% by mass or more and less than 0.65% by mass. 02% by mass or more and less than 0.1% by mass, the 0.2% yield strength of the sample is 300 MPa or more, and the elongation is 7% or more, so that a good bending life (for example, the number of times of bending is 3000 times or more) is obtained.

<Application example of copper alloy wire>
Next, application examples of the copper alloy wire 10 shown in FIG. 1 will be described. FIG. 3 is a cross-sectional view of a cable including copper alloy wire 10 shown in FIG. 4 is a cross-sectional view of one of a plurality of electric wires included in the cable shown in FIG. 3. FIG.

A cable 60 shown in FIG. 3 has a plurality of electric wires (core wires) 70 and a sheath 61 that collectively covers the circumference of the plurality of electric wires 70 . An interposition (not shown) is arranged around each of the plurality of electric wires 70, and the plural electric wires 70 are separated from each other by this interposition. The intervention is composed of, for example, a linear member made of fiber or resin. The sheath 61 is made of, for example, a resin composition containing a resin such as chlorinated polyethylene or polyvinyl chloride as a main component (base resin), a fluororesin composition, or the like. A plurality of electric wires 70 may be in contact with each other. The cable 60 is, for example, a cable used as an internal wiring material for portable electronic devices such as smartphones, industrial robots installed in factories, or automobiles. The cable 60 includes a plurality of electric wires 70, and each of the plurality of electric wires 70 has a small outer diameter. For example, in the example shown in FIGS. 3 and 4, the wire 70 has an outer diameter of, for example, approximately 0.86 mm (860 μm).

As shown in FIG. 4 , the electric wire 70 has a central conductor 71 made of a plurality of copper alloy wires 10 twisted together, and an insulator 72 covering the central conductor 71 . Each of the plurality of copper alloy wires 10 forming the central conductor 71 is made of the copper alloy 11 described with reference to FIG. That is, the copper alloy 11 forming this copper alloy wire 10 contains 0.3% by mass or more and 0.65% by mass or less of indium. A wire diameter of each of the plurality of copper alloy wires 10 is, for example, 0.08 mm (80 μm). The insulator 72 is made of, for example, a resin such as polyethylene or polypropylene, or a fluorine resin.

Thus, the electric wire 70 using a plurality of copper alloy wires 10 and the cable 60 using the same can improve the transmission characteristics of electric signals or power in portable electronic devices. Alternatively, the electric wire 70 using a large number of copper alloy wires 10 that are ultrafine wires and the cable 60 using the same can have a small wire diameter, so that the size of the housing of the portable electronic device can be reduced. and industrial robots can be downsized.

Although FIG. 4 shows the electric wire 70 as an example, there are various modifications of the electric wire to which the copper alloy wire 10 shown in FIG. 1 is applied. For example, it can be applied to an electric wire including a conductor made of one copper alloy wire 10 and an insulator covering the periphery of the conductor. 3 and 4, the central conductor 71 of the electric wire 70 is exemplified by twisting a plurality of copper alloy wires 10, but the present invention is not limited to this, and the central conductor 71 may be made of a plated wire described later. .

<Plating wire>
The plated wire is configured by having a plated layer around (outer surface) the copper alloy wire 10 shown in FIG. The plated wire has a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more. That is, the plated wire has a 0.2% yield strength of 300 MPa or more (preferably 300 MPa or more and 340 MPa or less) and a conductivity of 80% IACS or more in a state where a plated layer is provided around the copper alloy wire shown in FIG. (preferably 80% IACS or more and 89% IACS or less) and an elongation of 7% or more (preferably 7% or more and 18% or less). The plated wire is a semi-rigid wire.

The copper alloy wire is made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium (In), as described above. In particular, the copper alloy wire is composed of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium (In), with the balance being copper (Cu) and unavoidable impurities. is good. In addition, the copper alloy wire contains 0.3% by mass or more and less than 0.65% by mass of indium (In) and 0.02% by mass or more and less than 0.1% by mass of tin (Sn). , with the balance being copper (Cu) and unavoidable impurities. In this case, the total content of indium and tin contained in the copper alloy is 0.65% by mass or less.

The plating layer is provided around the copper alloy wire and in contact with 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 made of, for example, tin (Sn), silver (Ag), nickel (Ni), or the like.

<Manufacturing method of plated wire>
The plated wire is obtained by forming a plated layer on the copper alloy wire obtained by the copper alloy wire manufacturing method shown in FIG. The copper alloy wire before forming the plating layer is a metal wire in a semi-rigid state with a 0.2% proof stress of 300 MPa or more and an electrical conductivity of 80% IACS or more. This copper alloy wire is immersed in a plating bath in which a molten plating material (for example, Sn) at a predetermined temperature (for example, 250° C. or higher and 300° C. or lower) is stored. Thus, hot dip plating is applied over the entire circumference of the outer surface of the copper alloy wire. After that, by passing the copper alloy wire coated with the hot-dip plating through a plating die, the thickness of the hot-dip plating applied to the surface of the copper alloy wire is adjusted to form a plating layer having a predetermined thickness. . In particular, as conditions for applying the hot-dip plating to the surface of the copper alloy wire, it is preferable to apply the hot-dip plating at a line speed of 100 m/min or more and for an immersion time in the hot-dip plating of 0.1 to 1.0 seconds. The copper alloy wire on which the plated layer is formed in this manner maintains a semi-rigid state, and the elongation as the plated wire is 7% or more and 18% or less.

<Characteristics of plated wire>
Next, the results of experiments on the characteristics of the plated wire will be described. Tables 2 and 3 are tables showing the relationship between the alloy composition of the copper alloy wire forming the plated wire and the properties of the plated wire.

In Tables 2 and 3, sample no. Nos. 8, 13 to 14 are examples suitable for the above-described plated wire conditions, and sample nos. 9 to 12 and 15 to 16 are comparative examples that do not meet the above conditions for plated wires. Sample No. shown in Table 2. 8 to 12 and sample nos. Each of 13 to 16 has a plating layer formed around a copper alloy wire manufactured through the manufacturing process described with reference to FIG. Specifically, the copper alloy wire manufactured through the manufacturing process described with reference to FIG. By passing the coated copper alloy wire through a plating die, the thickness of the hot dip coating applied to the surface of the copper alloy wire was adjusted to form a plating layer having a predetermined thickness. In Tables 2 and 3, the samples subjected to the 0.2% yield strength test and the elongation test of the plated wire were coated around the copper alloy wire processed to have a wire diameter of about 80 μm (thickness thickness: about 0.5 μm). Sample no. The copper alloy wires used in 8 to 16 are copper alloys containing indium (In) and tin (Sn) having the contents shown in Tables 2 and 3, and the balance being copper (Cu) and unavoidable impurities. Configured. Further, the tensile speed when measuring the elongation was set to 50 mm/min, and the gauge length was set to 250 mm. The 0.2% yield strength was measured by performing a tensile test according to JIS Z2241. More specifically, the above tensile test (offset method, distance between gauge lines: 250 mm, tensile speed: 50 m/min) was performed to measure the 0.2% yield strength. The cross-sectional area of the sample was calculated as the area of a perfect circle from the wire diameter measured to 1/1000 mm with a micrometer. The elongation value is the total elongation at break (combining the elastic elongation and the plastic elongation of the extensometer) expressed as a percentage of the extensometer gauge length. Also, although omitted from Tables 2 and 3, Sample No. Each of Nos. 8 to 16 was prepared in an environment in which oxygen is difficult to mix, and the oxygen contained in the copper alloy of each sample is 0.002% by mass or less.

In Tables 2 and 3, the flexing life was determined by suspending a weight of 20 g from the sample, bending the sample 90 degrees left and right around a jig with a bending radius of 5 mm, and measuring the number of times until the sample broke. In addition, the number of times of bending was counted as one bending of 90 degrees to the left and right.

In Tables 2 and 3, sample no. As can be seen from 8, 13 to 14, the plated wire is provided with a plated layer around the copper alloy wire composed of a copper alloy having an indium content of 0.30% by mass or more. When the % proof stress is 300 MPa or more and the elongation is 7% or more, a good bending life (3000 times or more of bending) can be obtained. In particular, the plated wire is a copper alloy wire composed of a copper alloy having an indium content of 0.30% by mass or more and less than 0.65% by mass, the balance being copper and unavoidable impurities, or an indium content is 0.30% by mass or more and less than 0.65% by mass, the tin content is 0.02% by mass or more and less than 0.1% by mass, and the balance is copper and unavoidable impurities. A plating layer is provided around the copper alloy wire, and the 0.2% yield strength is 300 MPa or more and the elongation is 7% or more, resulting in a good bending life (for example, the number of times of bending is 3000 times or more). is obtained.

<Application example of plated wire>
As described above, the plated wire can be applied as the central conductor constituting the electric wire or cable shown in FIGS. Specifically, it is an electric wire having a central conductor composed of a plurality of mutually twisted plated wires and an insulator covering the central conductor. Moreover, it is good also as a cable which provided the shield layer and the sheath around this electric wire.

The present invention is not limited to the above embodiments and examples, and can be modified in various ways without departing from the scope of the invention.

The embodiment includes the following modes.

[Appendix 1]
(a) preparing a raw material containing copper and an additive element other than copper;
(b) a step of forming a rough drawing wire by casting after melting the raw material;
(c) a step of drawing the rough wire into a metal wire;
(d) after the step (c), heat-treating the drawn metal wire;
(e) a step of further drawing the heat-treated metal wire after the step (d) to form a copper alloy wire having an outer diameter of 0.1 mm or less;
(f) a step of subjecting the copper alloy wire to a semi-hardening treatment after the step (e);
including
A method for producing a copper alloy wire, wherein the rough wire is made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium.

[Appendix 2]
In Appendix 1,
A method for producing a copper alloy wire, wherein the copper alloy contains tin in an amount of 0.02% by mass or more and less than 0.1% by mass.

[Appendix 3]
In Appendix 1 or 2,
In the step (d),
A is the 0.2% proof stress of the drawn metal wire after the step (c), B is the 0.2% proof stress of the heat-treated metal wire after the step (d), 0. If the 2% proof stress ratio is C = B / A, heat treatment is performed so that the value of C is 0.5 or more and 0.8 or less,
D is the elongation of the drawn metal wire after the step (c), E is the 0.2% proof stress of the heat-treated metal wire after the step (d), and the elongation ratio F = E /D, a method for producing a copper alloy wire, wherein the heat treatment is performed so that the value of F is 10 or more and 50 or less.

[Appendix 4]
In addition 3, the method for producing a copper alloy wire, wherein in the step (d), heat treatment is performed so that the conductivity of the metal wire immediately after the heat treatment in the step (d) is 86%IACS or higher.

The present invention is applicable to cables (e.g., microcoaxial cables), industrial robots and medical devices (e.g., gastrocameras, It can be used for cables with bending resistance used in ultrasound diagnostic equipment, etc.) (for example, endoscope cables, probe cables, etc.), copper alloy wires applied to conductors such as automobile cables.

10 copper alloy wire 10D wire diameter 11 copper alloy 60 cable 61, 74 sheath (insulator)
70 electric wire (core wire, coaxial cable)
71 center conductor 72 insulator 73 outer conductor

Claims (8)

Consists of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium,
A copper alloy wire having a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more. In the copper alloy wire according to claim 1,
The copper alloy wire, wherein the copper alloy contains 0.02% by mass or more and less than 0.1% by mass of tin, and the total content of the indium and the tin is 0.65% by mass or less. A copper alloy wire made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium;
a plating layer provided around the copper alloy wire,
A plated wire having a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more. comprising a conductor and an insulator covering the periphery of the conductor,
The conductor is made of a copper alloy wire made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium,
The copper alloy wire has a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more.
Electrical wire. In the electric wire according to claim 4,
The electric wire, wherein the copper alloy contains 0.02% by mass or more and less than 0.1% by mass of tin, and the total content of the indium and the tin is 0.45% by mass or less. In the electric wire according to claim 4 or 5,
The electric wire, wherein the conductor is formed by twisting a plurality of the copper alloy wires. a plurality of core wires made of electric wires in which the circumference of the conductor is covered with an insulator, and a sheath that collectively covers the circumference of the plurality of core wires,
The conductor is made of a copper alloy wire made of a copper alloy containing 0.3% by mass or more and 0.65% by mass or less of indium,
The copper alloy wire has a 0.2% proof stress of 300 MPa or more, an electrical conductivity of 80% IACS or more, and an elongation of 7% or more. A cable according to claim 7, wherein
The cable, wherein the copper alloy contains 0.02% by mass or more and less than 0.1% by mass of tin, and the total content of the indium and the tin is 0.65% by mass or less.

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