Copper alloy wire, copper alloy twisted wire, electric wire, and method for producing copper alloy wire
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Filing Date
- 2025-12-17
- Publication Date
- 2026-06-22
Abstract
Description
Copper alloy wire, copper alloy stranded wire, electric wire, and method for manufacturing copper alloy wire
[0001] The present disclosure relates to a copper alloy wire, a copper alloy stranded wire, an electric wire, and a method for manufacturing a copper alloy wire. This application claims priority based on Japanese Patent Application No. 2023-158331 filed on September 22, 2023, and incorporates by reference all of the contents of said Japanese application.
[0002] Conventionally, copper alloy wires have been used for electric wires such as automotive wiring harnesses. Excellent electrical conductivity and strength are required for the copper alloy wires. For example, the copper alloy wires are formed from a copper alloy containing iron, phosphorus, and tin. Patent Documents 1 and 2 disclose copper alloy wires formed from a copper alloy containing nickel in addition to iron, phosphorus, and tin.
[0003] International Publication No. 2020 / 039712 International Publication No. 2020 / 039711
[0004] The copper alloy wire of the present disclosure is formed from a copper alloy. The copper alloy contains iron, phosphorus, tin, and auxiliary elements, with the balance being copper and inevitable impurities. The auxiliary elements are two or more elements selected from the group consisting of zinc, nickel, and chromium, or zinc alone. The iron content is 0.1% by mass or more and 1.0% by mass or less. The phosphorus content is 0.1% by mass or more and 0.6% by mass or less. The tin content is 0.1% by mass or more and 0.4% by mass or less. If zinc is contained, the zinc content is 0.005% by mass or more and 1.40% by mass or less. If nickel is contained, the nickel content is 0.005% by mass or more and 0.70% by mass or less. If chromium is contained, the chromium content is 0.005% by mass or more and 0.20% by mass or less. The mass ratio of the total content of iron, nickel, and chromium to the phosphorus content is 3.0 to 7.0.
[0005] Fig. 1 is a schematic diagram showing an example of a copper alloy wire according to an embodiment. Fig. 2 is a schematic diagram showing an example of a copper alloy stranded wire and an electric wire according to an embodiment.
[0006] [Problem to be Solved by the Present Disclosure] In view of the risk of depletion of metal resources, the use of used wire harness scraps as raw materials to produce copper alloy wires has been considered. Wire harness scraps have accessories such as terminals attached to both ends of electric wires. When wire harness scraps are mixed with raw materials, elements contained in the accessories, such as zinc, nickel, and chromium, are mixed into the copper alloy wire. If these elements are contained in amounts exceeding a certain level, the properties of the copper alloy wire are affected, such as a decrease in electrical conductivity. As a result, copper alloy wires that do not meet the required properties are produced. It is desirable to mitigate the deterioration of the properties of copper alloy wires even when elements such as zinc, nickel, and chromium are contained.
[0007] An object of the present disclosure is to provide a copper alloy wire having excellent electrical conductivity and strength.
[0008] [Advantages of the Present Disclosure] The copper alloy wire of the present disclosure has excellent electrical conductivity and strength.
[0009] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.
[0010] (1) The copper alloy wire of the present disclosure is formed from a copper alloy. The copper alloy contains iron, phosphorus, tin, and auxiliary elements, with the balance being copper and inevitable impurities. The auxiliary elements are two or more elements selected from the group consisting of zinc, nickel, and chromium, or zinc alone. The iron content is 0.1% by mass or more and 1.0% by mass or less. The phosphorus content is 0.1% by mass or more and 0.6% by mass or less. The tin content is 0.1% by mass or more and 0.4% by mass or less. When zinc is contained, the zinc content is 0.005% by mass or more and 1.40% by mass or less. When nickel is contained, the nickel content is 0.005% by mass or more and 0.70% by mass or less. When chromium is contained, the chromium content is 0.005% by mass or more and 0.20% by mass or less. The mass ratio of the total content of iron, nickel, and chromium to the phosphorus content is 3.0 to 7.0.
[0011] The copper alloy wire of the present disclosure has excellent electrical conductivity and strength. By including iron, phosphorus, and tin, the copper alloy wire of the present disclosure can have excellent electrical conductivity and strength. Generally, as the amount of dissolved additive elements increases, electrical conductivity decreases. When the mass ratio is 3.0 or more and 7.0 or less, iron, nickel, and chromium are likely to precipitate together with phosphorus. As a result, the amounts of elements such as iron, nickel, and chromium dissolved in copper are reduced. Therefore, even if a copper alloy wire contains a subelement, it can have good electrical conductivity and achieve both strength and electrical conductivity as long as the content ratio of each element is within a predetermined range.
[0012] (2) In the copper alloy wire of (1), the total content of zinc, nickel, and chromium may be 0.05 mass % or more.
[0013] The copper alloy wire of (2) above can have good electrical conductivity even if it contains a large proportion of the auxiliary element.
[0014] (3) In the copper alloy wire of (1) or (2) above, the tensile strength of the copper alloy wire may be 400 MPa or more.
[0015] The copper alloy wire of (3) above has high tensile strength and excellent strength.
[0016] (4) In the copper alloy wire according to any one of (1) to (3) above, the breaking elongation of the copper alloy wire may be 5% or more.
[0017] The copper alloy wire of (4) above has high breaking elongation and excellent elongation.
[0018] (5) In the copper alloy wire according to any one of (1) to (4) above, the electrical conductivity of the copper alloy wire may be 59% IACS or more.
[0019] The copper alloy wire (5) has high electrical conductivity and excellent electrical conductivity. "% IACS" indicates electrical conductivity when the electrical conductivity of international annealed copper standard is taken as 100% IACS. The resistivity of international standard annealed copper is 1.7241 × 10 －８ Ωm.
[0020] (6) In the copper alloy wire according to any one of (1) to (5) above, the tensile strength of the copper alloy wire may be 400 MPa or more, the breaking elongation of the copper alloy wire may be 5% or more, and the electrical conductivity of the copper alloy wire may be 59% IACS or more.
[0021] The copper alloy wire (6) has an excellent balance of tensile strength, elongation at break, and electrical conductivity, and has excellent strength, elongation, and electrical conductivity.
[0022] (7) The copper alloy stranded wire of the present disclosure is formed by twisting together a plurality of the copper alloy wires described in (6) above.
[0023] The copper alloy stranded wire of the present disclosure is formed from the copper alloy wire of (6) above, and therefore has excellent strength, elongation, and electrical conductivity.
[0024] (8) The present disclosure provides an electric wire including a conductor and an insulating layer covering the conductor, the conductor being the copper alloy stranded wire described above in (7).
[0025] The electric wire of the present disclosure includes the copper alloy stranded wire of the present disclosure, and therefore has excellent strength, elongation, and electrical conductivity.
[0026] (9) A method for producing a copper alloy wire according to the present disclosure includes the steps of: preparing a cast material made of a copper alloy; drawing the cast material to prepare a drawn wire material; and heat treating the drawn wire material. The copper alloy contains iron, phosphorus, tin, and auxiliary elements, with the balance consisting of copper and inevitable impurities. The auxiliary elements are two or more elements selected from the group consisting of zinc, nickel, and chromium, or zinc alone. The iron content is 0.1% by mass or more and 1.0% by mass or less. The phosphorus content is 0.1% by mass or more and 0.6% by mass or less. The tin content is 0.1% by mass or more and 0.4% by mass or less. When zinc is contained, the zinc content is 0.005% by mass or more and 1.40% by mass or less. When nickel is contained, the nickel content is 0.005% by mass or more and 0.70% by mass or less. When chromium is contained, the chromium content is 0.005 mass % or more and 0.20 mass % or less. The mass ratio of the total content of iron, nickel, and chromium to the content of phosphorus is 3.0 or more and 7.0 or less.
[0027] The copper alloy wire manufacturing method of the present disclosure can manufacture a copper alloy wire having excellent conductivity and strength. By including iron, phosphorus, and tin in the copper alloy wire, the copper alloy wire can have excellent conductivity and strength. When the mass ratio is 3.0 or more and 7.0 or less, iron, nickel, and chromium are likely to precipitate together with phosphorus. As a result, the amounts of elements such as iron, nickel, and chromium that are solid-solved in copper are reduced. Therefore, even if a copper alloy wire contains a subelement, as long as the content ratio of each element is within a predetermined range, the copper alloy wire can have good conductivity, and both strength and conductivity can be achieved.
[0028] (10) In the method for producing a copper alloy wire according to (9) above, the step of heat treating the drawn wire material may involve holding the drawn wire material at a temperature of 300°C or higher and 700°C or lower for 4 hours or higher and 40 hours or lower.
[0029] In the method for manufacturing a copper alloy wire according to (9), iron, nickel, and chromium are easily precipitated together with phosphorus by the heat treatment under the above conditions. This precipitation can increase the electrical conductivity of the copper alloy wire. Furthermore, the heat treatment under the above conditions can soften the copper alloy wire. This softening can increase the elongation of the copper alloy wire.
[0030] [Details of the embodiment of the present disclosure] Specific examples of the copper alloy wire, copper alloy stranded wire, and electric wire of the present disclosure will be described below. In the drawings, the same reference numerals indicate the same items. For the sake of convenience, some components may be exaggerated or simplified in the drawings. The dimensional ratios of the various parts in the drawings may also differ from the actual ratios.
[0031] <Copper Alloy Wire> The copper alloy wire 1 of the embodiment shown in Fig. 1 is formed from a copper alloy having a specific composition. The copper alloy contains specific additive elements in specific ranges.
[0032] (Composition) The copper alloy has a composition containing iron (Fe), phosphorus (P), tin (Sn), and auxiliary elements, with the balance being copper (Cu) and inevitable impurities. The auxiliary elements are two or more elements selected from the group consisting of zinc (Zn), nickel (Ni), and chromium (Cr), or Zn alone. Of the elements contained in the copper alloy, Fe, P, and Sn are essential elements in the copper alloy. The effects and content ratios of each element contained in the copper alloy are explained below. The content ratios of each element are expressed as mass percentages when the entire copper alloy is taken as 100 mass%.
[0033] Fe: Fe strengthens the copper alloy by forming a compound with P and precipitating. The Fe content is 0.1 mass% or more and 1.0 mass% or less. When the Fe content is 0.1 mass% or more, a compound containing Fe and P is formed. This compound precipitates in Cu, improving the strength of the copper alloy. Furthermore, the precipitation of the compound reduces the amount of Fe and P dissolved in Cu, thereby reducing the decrease in the conductivity of the copper alloy. Therefore, the copper alloy wire 1 has excellent conductivity and strength.
[0034] By setting the Fe content to 1.0 mass% or less, the decrease in electrical conductivity of the copper alloy is reduced and the coarsening of the above-mentioned compounds can be made less likely to occur. Therefore, the copper alloy has a structure in which the above-mentioned compounds are finely dispersed. Therefore, the copper alloy wire 1 has excellent elongation. Furthermore, since breakage due to coarse compounds is less likely to occur during the manufacturing process of the copper alloy wire 1, the copper alloy wire 1 also has excellent manufacturability. The Fe content may be 0.11 mass% or more and 0.9 mass% or less, or 0.12 mass% or more and 0.8 mass% or less.
[0035] P strengthens the copper alloy by forming compounds with elements such as Fe, Ni, and Cr and precipitating them. The P content is 0.1 mass% or more and 0.6 mass% or less. When the P content is 0.1 mass% or more, P reacts with elements such as Fe to form compounds containing P. As described above, the precipitation of these compounds on Cu improves the strength of the copper alloy and reduces the decrease in the conductivity of the copper alloy. Therefore, the copper alloy wire 1 has excellent conductivity and strength. Note that a portion of P acts as a deoxidizer and is allowed to be contained in the copper alloy as phosphate.
[0036] By setting the P content to 0.6% by mass or less, the decrease in electrical conductivity of the copper alloy is reduced and the coarsening of the above-mentioned compounds is prevented. Therefore, the copper alloy has a structure in which the above-mentioned compounds are finely dispersed. Furthermore, breakage due to the coarse compounds is less likely to occur during the manufacturing process of the copper alloy wire 1. The P content may be 0.11% by mass or more and 0.5% by mass or less, or 0.12% by mass or more and 0.4% by mass or less.
[0037] Sn Sn strengthens the copper alloy by dissolving. The Sn content is 0.1% by mass or more and 0.4% by mass or less. When the Sn content is 0.1% by mass or more, the strength-improving effect of Sn can be obtained. When the Sn content is 0.4% by mass or less, the decrease in conductivity due to the solid solution of Sn in Cu can be reduced. Therefore, the copper alloy wire 1 has excellent conductivity and strength. When Sn dissolves excessively in Cu, the workability of the copper alloy decreases. When the Sn content is 0.4% by mass or less, the copper alloy wire 1 is likely to have excellent elongation, and wire drawing is easy to perform in the manufacturing process of the copper alloy wire 1. Therefore, the copper alloy wire 1 is also excellent in manufacturability. The Sn content may be 0.2% by mass or more and 0.35% by mass or less, or 0.25% by mass or more and 0.35% by mass or less.
[0038] The copper alloy contains, in addition to Fe, P, and Sn, a secondary element. The secondary element is two or more elements selected from the group consisting of Zn, Ni, and Cr, or Zn alone. The combination of the secondary elements is Zn, Ni, and Cr, Zn and Ni, Zn and Cr, Ni and Cr, or Zn alone. The respective content ratios of Zn, Ni, and Cr are shown below.
[0039] Zn Zn is in a solid solution state in Cu. When the copper alloy contains Zn, the Zn content is 0.005% by mass or more and 1.40% by mass or less. By having a Zn content of 1.40% by mass or less, the decrease in conductivity due to Zn being solid-dissolved in Cu can be reduced. When Ni and Cr are contained, Zn may not be contained. That is, the Zn content may be zero. If the Zn content is less than 0.005% by mass, it is considered that Zn has almost no effect on the properties. If the Zn content is less than 0.005% by mass, Zn is considered an inevitable impurity. The Zn content may further be 0.01% by mass or more, or 0.02% by mass or more. The Zn content may be 0.05% by mass or more and 1.35% by mass or less, or 0.10% by mass or more and 1.30% by mass or less. The Zn content may further be 0.40 mass % or less, 0.35 mass % or less, or 0.30 mass % or less.
[0040] Ni Ni forms a compound with P and precipitates in Cu. When the copper alloy contains Ni, the Ni content is 0.005% by mass or more and 0.70% by mass or less. A Ni content of 0.70% by mass or less can reduce the decrease in conductivity due to the inclusion of Ni. Furthermore, the precipitation of compounds containing Ni and P reduces the amount of Ni and P dissolved in Cu, thereby reducing the decrease in conductivity. When Zn and Cr are included, or when only Zn is included, Ni may not be included. That is, the Ni content may be zero. When the Ni content is less than 0.005% by mass, Ni is considered to have almost no effect on the properties. When the Ni content is less than 0.005% by mass, Ni is considered to be an inevitable impurity. The Ni content may further be 0.01% by mass or more, or 0.02% by mass or more. The Ni content may be 0.10 mass % or more and 0.60 mass % or less, or 0.20 mass % or more and 0.50 mass % or less.
[0041] Cr Cr precipitates in Cu by forming intermetallic compounds containing Cr or compounds with P. When a copper alloy contains Cr, the Cr content is 0.005% by mass or more and 0.20% by mass or less. A Cr content of 0.20% by mass or less can reduce the decrease in conductivity due to the inclusion of Cr. Furthermore, the precipitation of compounds containing Cr and P reduces the amount of Cr and P dissolved in Cu, thereby reducing the decrease in conductivity. When Zn and Ni are included, or when only Zn is included, Cr may not be included. That is, the Cr content may be zero. When the Cr content is less than 0.005% by mass, it is considered that Cr has almost no effect on the properties. When the Cr content is less than 0.005% by mass, Cr is considered an inevitable impurity. The Cr content may be 0.01% by mass or more and 0.18% by mass or less. The Cr content may further be 0.16 mass % or less, 0.10 mass % or less, or 0.08 mass % or less.
[0042] Other Additive Elements The copper alloy may contain aluminum (Al) or silicon (Si). Al has the effect of reducing the segregation of P to grain boundaries. The Al content is, for example, 0.005% by mass or more and 1.0% by mass or less. The Al content may further be 0.01% by mass or more. Si acts as a deoxidizer for Fe, P, Sn, etc., and has the effect of reducing the oxidation of these elements. The Si content is, for example, 0.005% by mass or more and 1.0% by mass or less. The Si content may further be 0.01% by mass or more.
[0043] (Fe + Ni + Cr) / P The mass ratio X of the total content of Fe, Ni, and Cr to the content of P is 3.0 or more and 7.0 or less. When the mass ratio X is within the above range, Fe, Ni, and Cr are likely to precipitate together with P. As a result of reducing the amount of these elements dissolved in Cu, the strength of the copper alloy is improved and the decrease in the conductivity of the copper alloy is reduced. Therefore, the copper alloy wire 1 has excellent conductivity and strength. The mass ratio X may be 3.2 or more and 6.9 or less, or 3.5 or more and 6.8 or less.
[0044] The copper alloy wire 1 can have excellent electrical conductivity and strength by containing Fe, P, and Sn. However, if an auxiliary element selected from Zn, Ni, and Cr is contained in addition to the basic composition containing only Fe, P, and Sn, the electrical conductivity decreases. If the mass ratio X is 3.0 or more and 7.0 or less, Fe, Ni, and Cr are likely to precipitate sufficiently together with P. Therefore, when the mass ratio X satisfies the range of 3.0 or more and 7.0 or less, even if an auxiliary element is contained, good electrical conductivity can be obtained as long as the content ratio of each element is within a predetermined range, and both strength and electrical conductivity can be achieved.
[0045] <Total Content of Additional Elements> The total content of additional elements contained in the copper alloy, i.e., the total content of Fe, P, and Sn and auxiliary elements, is, for example, 1.00 mass% or more and 3.00 mass% or less. The total content of additional elements may be 1.04 mass% or more and 2.90 mass% or less, 1.14 mass% or more and 2.80 mass% or less, or 1.20 mass% or more and 2.70 mass% or less. The total content of additional elements may further be 2.50 mass% or less, 2.40 mass% or less, 2.30 mass% or less, or 2.20 mass% or less.
[0046] <Sub-element content> The sub-element content, i.e., the total content of Zn, Ni, and Cr, is, for example, 0.05 mass% or more. The upper limit of the sub-element content is, for example, 1.70 mass%. The sub-element content may further be 0.20 mass% or more, or 0.30 mass% or more. The sub-element content may be 0.05 mass% or more and 1.70 mass% or less, 0.10 mass% or more and 1.60 mass% or less, 0.15 mass% or more and 1.50 mass% or less, or 0.20 mass% or more and 1.40 mass% or less. The sub-element content may further be 1.10 mass% or less, 1.00 mass% or less, or 0.90 mass% or less.
[0047] The composition of the copper alloy wire 1 can be determined by a known analytical method, such as inductively coupled plasma (ICP) emission spectroscopy or X-ray fluorescence analysis.
[0048] (Structure) <Grain size> Copper alloys have a fine crystal structure. Copper alloy wires having a fine crystal structure have high strength. The average crystal grain size of the copper alloy is, for example, 0.1 μm or more and 10 μm or less. The smaller the crystal grain size, the higher the strength of the copper alloy wire. The average crystal grain size of the copper alloy may further be 7 μm or less, or 5 μm or less.
[0049] The average crystal grain size of a copper alloy is measured as follows: The cross section of a copper alloy wire is observed using a microscope. The cross section is perpendicular to the length of the copper alloy wire. The microscope may be an optical microscope or a scanning electron microscope (SEM). A predetermined observation range is taken from the observation image, and the individual areas of all crystal grains within the observation range are measured. The diameter of a circle having an area equal to the area of each crystal grain is calculated as the crystal grain size, and the average value is taken as the average crystal grain size. This crystal grain size can be calculated using a commercially available image processing device. The observation range can be an area containing 50 or more crystal grains, or the entire cross section. By making the observation range sufficiently wide in this way, errors caused by particles such as precipitates can be sufficiently reduced.
[0050] <Precipitates> The copper alloy also contains precipitates made of the above-mentioned compounds. The precipitates are finely dispersed in the copper alloy. The smaller the particle size of the precipitates, the less likely they are to become the starting point of fracture. This improves the strength of the copper alloy wire. The average particle size of the precipitates is, for example, 1 nm or more and 2 μm or less.
[0051] The average particle size of the precipitates is measured by observing the cross section of the copper alloy wire with a microscope, similar to the measurement of the average crystal grain size of the copper alloy described above. In the observation image, the areas of all precipitates within the observation range are measured. The diameters of circles having an area equal to the area of each precipitate are calculated as the particle size of the precipitates, and the average value is taken as the average particle size of the precipitates. A commercially available image processing device can be used to calculate the particle size. In measuring the average particle size of the precipitates, the average value of the particle diameters in three observation ranges is obtained. Each observation range is a rectangular region of the cross section having a size of 5 μm × 3 μm. The magnification of the microscope is, for example, 400 times or more and 20,000 times or less.
[0052] Specific examples of compounds that constitute the precipitates are as follows. The precipitate is, for example, a compound containing Fe and P. When Ni is contained as a secondary element, a compound containing Ni and P, and a compound containing Fe, Ni, and P may be generated as the precipitate. When Cr is contained as a secondary element, a compound containing Cr and P, and a compound containing Fe, Cr, and P may be generated as the precipitate. When Ni and Cr are contained as secondary elements, a compound containing Ni, Cr, and P, and a compound containing Fe, Ni, Cr, and P may be generated as the precipitate.
[0053] The composition of the compound constituting the precipitate will be described. The content ratio of each element contained in the compound constituting the precipitate is as follows. The content ratio of each element constituting the compound shown below is the mass ratio when the compound is taken as 100 mass%. The composition of the compound can be analyzed, for example, by energy dispersive X-ray spectroscopy. When the compound contains all four elements, Fe, Ni, Cr, and P, for example, the Fe content is 30 mass% to 65 mass% inclusive, the Ni content is 2 mass% to 40 mass% inclusive, the Cr content is 10 mass% to 25 mass% inclusive, and the P content is 15 mass% to 25 mass% inclusive. When the compound contains only Fe and P among the above four elements, for example, the Fe content is 70 mass% to 85 mass% inclusive, and the P content is 15 mass% to 30 mass% inclusive. When the compound contains Fe, Ni, and P among the four elements, the Fe content is, for example, 40% by mass to 80% by mass, the Ni content is 4% by mass to 40% by mass, and the P content is 15% by mass to 25% by mass. When the compound contains Fe, Cr, and P among the four elements, the Fe content is, for example, 45% by mass to 65% by mass, the Cr content is 15% by mass to 45% by mass, and the P content is 5% by mass to 30% by mass.
[0054] (Shape) The cross-sectional shape of the copper alloy wire 1 may be any shape. The copper alloy wire 1 shown in FIG. 1 is a round wire whose cross-sectional shape is circular. The cross-section of the copper alloy wire 1 is a cross section perpendicular to the length of the copper alloy wire 1. The cross-sectional shape of the copper alloy wire 1 may be non-circular. Examples of non-circular shapes include polygonal and oval shapes. Examples of polygonal shapes include quadrilaterals and hexagons. Quadrilaterals include rectangles and squares. Oval shapes include ellipses.
[0055] (Wire Diameter) The wire diameter D of the copper alloy wire 1 is, for example, 0.025 mm or more and 0.5 mm or less. When the cross section of the copper alloy wire 1 has a circular shape, the wire diameter D is equal to the diameter of the cross section. When the cross section of the copper alloy wire 1 has a non-circular shape, the wire diameter D is regarded as the diameter of a circle having an area equal to the area of the cross section. The smaller the wire diameter D, the thinner and lighter the copper alloy wire 1 is. The wire diameter D of the copper alloy wire 1 may be 0.05 mm or more and 0.35 mm or less, or 0.1 mm or more and 0.3 mm or less.
[0056] (Characteristics) The copper alloy wire 1 has at least one of the following characteristics: Tensile strength of 400 MPa or more. Breaking elongation of 5% or more. Electrical conductivity of 59% IACS or more. The copper alloy wire 1 can have all of the above three characteristics. The copper alloy wire 1 having all of the above three characteristics has an excellent balance of tensile strength, breaking elongation, and electrical conductivity, and has excellent strength, elongation, and electrical conductivity.
[0057] <Tensile Strength> A copper alloy wire 1 having a tensile strength of 400 MPa or more has excellent strength. The tensile strength may be 420 MPa or more, or 440 MPa or more. The upper limit of the tensile strength is, for example, 640 MPa. The higher the tensile strength, the smaller the elongation at break and electrical conductivity tend to be. From the viewpoint of obtaining good electrical conductivity while achieving both strength and elongation of the copper alloy wire 1, the tensile strength may be 600 MPa or less, or 580 MPa or less. The tensile strength may be 400 MPa or more and 640 MPa or less, 420 MPa or more and 600 MPa or less, or 440 MPa or more and 580 MPa or less.
[0058] <Elongation at break> A copper alloy wire 1 having an elongation at break of 5% or more has excellent elongation. The elongation at break may be 6% or more, or 7% or more. The upper limit of the elongation at break is, for example, 20%. The larger the elongation at break, the smaller the tensile strength tends to be. From the viewpoint of achieving both strength and elongation of the copper alloy wire 1, the elongation at break may be 15% or less, or 13% or less. The elongation at break may be 5% or more and 20% or less, 6% or more and 15% or less, or 7% or more and 13% or less. A copper alloy wire 1 having a tensile strength of 400 MPa or more and an elongation at break of 5% or more has an excellent balance between tensile strength and elongation, and has excellent strength and elongation.
[0059] The tensile strength and elongation at break can be measured by a tensile test, which is performed in accordance with "JIS Z 2241:2011 Tensile test method for metallic materials."
[0060] <Conductivity> A copper alloy wire 1 having a conductivity of 59% IACS or more has excellent conductivity. The conductivity may be 60% IACS or more, or 61% IACS or more. The upper limit of the conductivity is, for example, 75% IACS. The higher the conductivity, the lower the tensile strength tends to be. From the viewpoint of achieving both strength and conductivity of the copper alloy wire 1, the conductivity may be 70% IACS or less, or 66% IACS or less. The conductivity may be 59% IACS or more and 75% IACS or less, 60% IACS or more and 70% IACS or less, or 61% IACS or more and 66% IACS or less. A copper alloy wire 1 having a tensile strength of 400 MPa or more and a conductivity of 59% IACS or more has an excellent balance between tensile strength and conductivity, and has excellent strength and conductivity.
[0061] The electrical conductivity can be measured by a four-terminal method. Specifically, the electrical conductivity is calculated from the resistance value measured for the copper alloy wire 1 having a length of 1 m.
[0062] <Copper alloy stranded wire> The copper alloy stranded wire 2 shown in Fig. 2 is a stranded wire having the above-mentioned copper alloy wire 1 as a strand, and is formed by stranding a plurality of copper alloy wires 1. The copper alloy stranded wire 2 can withstand a larger tensile load and can carry a larger current than a single copper alloy wire 1 as a strand. The copper alloy stranded wire 2 is easy to bend and twist, and has excellent flexibility and twistability. Fig. 2 shows an example of a copper alloy stranded wire 2 in which seven copper alloy wires 1 are concentrically stranded. The number of copper alloy wires 1 twisted and the twisting method can be changed as appropriate.
[0063] The copper alloy stranded wires 2 may be compressed stranded wires (not shown) that are formed by compressing after twisting. The compressed stranded wires have a smaller outer diameter than the simply twisted stranded wires.
[0064] 2 includes a conductor 31 and an insulating layer 32 coated around the conductor 31. The conductor 31 is the copper alloy stranded wire 2 described above. The insulating layer 32 is made of a known insulating material. The insulating material is a resin such as polyvinyl chloride (PVC) or polypropylene (PP).
[0065] The electric wire 3 may be a terminal-attached electric wire having a terminal (not shown) attached to an end of the conductor 31. The terminal is, for example, a crimp terminal. The crimp terminal is attached to the end of the conductor 31 exposed by removing the insulating layer 32.
[0066] <Method for manufacturing copper alloy wire> The copper alloy wire 1 of the embodiment can be manufactured by the method for manufacturing a copper alloy wire of the embodiment. The method for manufacturing a copper alloy wire of the embodiment includes, in order, a first step, a second step, and a third step. Each step is as follows.
[0067] The first step is to produce a cast material made of a copper alloy, the second step is to draw the cast material to produce a drawn wire material, and the third step is to heat treat the drawn wire material.
[0068] (First Step) The casting material is produced by casting a molten copper alloy having the above-described composition containing Fe, P, Sn, and auxiliary elements. Used wire harness scraps or the like can be used as the raw material for the casting material. The wire harness scraps contain Fe, P, and Sn, as well as one or more auxiliary elements selected from Zn, Ni, and Cr. The raw material may be mixed with a Cu—Fe alloy, a Cu—P alloy, Sn, or the like to adjust the composition of the copper alloy to fall within the above-described range.
[0069] The cast material can be produced by a known casting method. Examples of the casting method include the belt and wheel method, the twin belt method, and the up-cast method. The cast material is, for example, a round wire having a circular cross-sectional shape. The wire diameter of the cast material is, for example, 5 mm or more and 40 mm or less. The wire diameter of the cast material is the diameter of a circle having the same area as the cross-sectional area of the cast material.
[0070] (Second step) The cast material is subjected to wire drawing to produce a drawn wire material having a predetermined wire diameter. The wire drawing is performed in a cold state. The wire drawing may be repeated until the drawn wire material reaches the predetermined wire diameter. The wire diameter of the drawn wire material is, for example, 0.025 mm to 0.5 mm, 0.05 mm to 0.35 mm, or 0.1 mm to 0.3 mm.
[0071] Intermediate heat treatment may be performed during the wire drawing process. Intermediate heat treatment is a heat treatment that improves workability by removing processing strain. The temperature of the intermediate heat treatment is, for example, 350°C or higher and 1000°C or lower, 380°C or higher and 950°C or lower, or 400°C or higher and 900°C or lower. The time of the intermediate heat treatment is, for example, 10 minutes or higher and 16 hours or lower, 20 minutes or higher and 12 hours or lower, or 30 minutes or higher and 8 hours or lower. The time of the intermediate heat treatment means the time for which the temperature is maintained. Intermediate heat treatment may be performed two or more times.
[0072] (Third Step) A copper alloy wire is produced by subjecting the drawn wire material to heat treatment. This heat treatment precipitates elements such as Fe, P, Ni, and Cr that are solid-solved in the copper alloy, and softens the drawn wire material that has been work-hardened by the wiredrawing process. Hereinafter, this heat treatment will be referred to as aging treatment. The temperature of the aging treatment is, for example, 300°C or higher and 700°C or lower, or 350°C or higher and 650°C or lower. The temperature of the aging treatment may further be 400°C or higher, or 420°C or higher. The time of the aging treatment is, for example, 4 hours or higher and 40 hours or lower, 5 hours or higher and 20 hours or lower, or 6 hours or higher and 10 hours or lower. The time of the aging treatment refers to the time during which the above temperature is maintained.
[0073] The precipitation of the above elements by the aging treatment improves the strength of the copper alloy wire and reduces the decrease in the electrical conductivity of the copper alloy wire. In addition, the softening of the copper alloy wire by the aging treatment improves the elongation of the copper alloy wire. The wire diameter of the copper alloy wire is equal to the wire diameter of the drawn wire material.
[0074] Test Example 1 Copper alloy wire samples having the compositions shown in Table 1 were manufactured. The compositions of Sample No. 1-1 to Sample No. 1-22 are within the composition range of this embodiment and contain Fe, P, and Sn, as well as a sub-element selected from Zn, Ni, and Cr, in specific ranges. The compositions of Sample No. 1-1 to Sample No. 1-10, Sample No. 1-17 to Sample No. 1-19, Sample No. 1-21, and Sample No. 1-22 contain Zn, Ni, and Cr as sub-elements. The compositions of Sample No. 1-11 to Sample No. 1-13 contain two of Zn, Ni, and Cr as sub-elements. The sub-elements of Sample No. 1-11 are Zn and Cr. The sub-elements of Sample No. 1-12 are Ni and Cr. The secondary elements of Sample No. 1-13 are Zn and Ni. The compositions of Sample No. 1-14 to Sample No. 1-16 and Sample No. 1-20 contain only Zn as a secondary element. The mass ratio X in Sample No. 1-1 to Sample No. 1-22 is 3.0 or more and 7.0 or less.
[0075] In Table 1, the "Total Amount of Added Elements" column indicates the total content of added elements, i.e., the total content of Fe, P, and Sn and auxiliary elements, rounded to two decimal places. The "Zn + Ni + Cr" column indicates the total content of auxiliary elements, i.e., the total content of Zn, Ni, and Cr, rounded to two decimal places. The "(Fe + Ni + Cr) / P" column indicates the mass ratio X of the total content of Fe, Ni, and Cr to the P content.
[0076] The compositions of Sample No. 1-100 to Sample No. 1-110 and Sample No. 1-121 to Sample No. 1-124 are outside the composition range of this embodiment. The composition of Sample No. 1-100 is a basic composition containing only Fe, P, and Sn, and does not substantially contain any secondary elements. The compositions of Sample No. 1-101 to Sample No. 1-110 contain secondary elements. The compositions of Sample No. 1-101 to Sample No. 1-108 contain Zn, Ni, and Cr as secondary elements. The mass ratio X in Sample No. 1-101 to Sample No. 1-107 is greater than 7.0. The composition of Sample No. 1-108 contains an excess of Ni. The composition of Sample No. 1-109 contains only Cr as a sub-element and has a mass ratio X of less than 3.0. The composition of Sample No. 1-110 contains only Ni as a sub-element and has a mass ratio X of more than 7.0. The compositions of Sample No. 1-121 to Sample No. 1-124 contain only Ni as a sub-element and have a mass ratio X of 3.0 or more and 7.0 or less.
[0077] Cast materials of copper alloys having the compositions shown in Table 1 were prepared. The wire diameters of the cast materials for each sample were as shown in Table 2. The prepared cast materials were subjected to wire drawing to prepare drawn wire materials. The wire diameters of the drawn wire materials for each sample were as shown in Table 2. The prepared drawn wire materials were subjected to aging treatment. The aging treatment conditions were the temperature and time shown in Table 2.
[0078] [Composition Analysis] The composition of the copper alloy wire of each sample was examined by ICP emission spectroscopy. As a result, the composition of the copper alloy wire of each sample was as shown in Table 1.
[0079] [Characteristics] The tensile strength, breaking elongation, and electrical conductivity of each sample copper alloy wire were measured. The results of these characteristics are shown in Table 2. The methods for measuring these characteristics are as described above. Each characteristic was measured at room temperature.
[0080]
[0081]
[0082] As shown in Table 2, the copper alloy wires of Sample No. 1-1 to Sample No. 1-22 have a tensile strength of 400 MPa or more, a breaking elongation of 5% or more, and an electrical conductivity of 59% IACS or more. The copper alloy wires of Sample No. 1-1 to Sample No. 1-22 have excellent strength, elongation, and electrical conductivity.
[0083] The copper alloy wires of Sample No. 1-1 to Sample No. 1-22 have properties equivalent to or better than the copper alloy wire of Sample No. 1-100 having the basic composition. Although the copper alloy wires of Sample No. 1-1 to Sample No. 1-22 contain auxiliary elements, the reason why they were able to have properties equivalent to the copper alloy wire of Sample No. 1-100 is thought to be as follows. In the copper alloy wires of Sample No. 1-1 to Sample No. 1-22, the P content is adjusted so that the mass ratio X is 3.0 or more and 7.0 or less. By precipitating Fe, Ni, and Cr together with P, the amounts of these elements solid-solubilized in Cu are reduced. As a result, it is thought that good electrical conductivity can be obtained, and both strength and electrical conductivity can be achieved.
[0084] The copper alloy wires of Sample No. 1-101 to Sample No. 1-110 contain auxiliary elements. The reason why the conductivity of the copper alloy wires of Sample No. 1-101 to Sample No. 1-107 and the conductivity of the copper alloy wire of Sample No. 1-110 are low is thought to be because the mass ratio X exceeds 7.0. In Sample No. 1-101 to Sample No. 1-107 and Sample No. 1-110, due to a lack of P, Fe, Ni, and Cr cannot be sufficiently precipitated together with P. Therefore, it is thought that the copper alloy wires of Sample No. 1-101 to Sample No. 1-107 and Sample No. 1-110 resulted in poor conductivity. The reason why the copper alloy wire of Sample No. 1-108 has low conductivity is thought to be because it contains excessive Ni. The reason why the electrical conductivity of the 1-109 copper alloy wire is low is thought to be that the mass ratio X is less than 3.0, so that part of the P does not precipitate but remains in solid solution.
[0085] The copper alloy wires of Sample No. 1-121 to Sample No. 1-124 are reference examples containing only Ni as a subelement. The copper alloy wires of Sample No. 1-121 to Sample No. 1-124 have a mass ratio X of 3.0 or more and 7.0 or less, and have properties equivalent to those of the copper alloy wire of Sample No. 1-100.
[0086] The present invention is not limited to these examples, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.
[0087] REFERENCE SIGNS LIST 1 Copper alloy wire 2 Copper alloy stranded wire 3 Electric wire 31 Conductor 32 Insulation layer D Wire diameter
Claims
1. It is made of a copper alloy, The aforementioned copper alloy contains iron, phosphorus, tin, and minor elements, with the remainder being copper and unavoidable impurities. The aforementioned sub-elements are two or more elements selected from the group of elements consisting of zinc, nickel, and chromium, or zinc alone. The iron content is between 0.1% by mass and 1.0% by mass. The phosphorus content is 0.1% by mass or more and 0.6% by mass or less. The tin content is 0.1% by mass or more and 0.4% by mass or less. If zinc is included, the zinc content is between 0.005% by mass and 1.40% by mass. If nickel is included, the nickel content is 0.005% by mass or more and 0.70% by mass or less. If chromium is present, the chromium content is between 0.005% by mass and 0.20% by mass. The mass ratio of the total content of iron, nickel, and chromium to the phosphorus content is between 3.0 and 7.
0. Copper alloy wire.
2. The copper alloy wire according to claim 1, wherein the total content of zinc, nickel, and chromium is 0.05% by mass or more.
3. The copper alloy wire according to claim 1 or claim 2, wherein the tensile strength of the copper alloy wire is 400 MPa or more.
4. The copper alloy wire according to claim 1 or claim 2, wherein the elongation at break of the copper alloy wire is 5% or more.
5. The copper alloy wire according to claim 1 or claim 2, wherein the conductivity of the copper alloy wire is 59% IACS or higher.
6. The tensile strength of the copper alloy wire is 400 MPa or more. The elongation at break of the copper alloy wire is 5% or more. The copper alloy wire according to claim 1 or claim 2, wherein the conductivity of the copper alloy wire is 59% IACS or higher.
7. A plurality of copper alloy wires as described in claim 6 are twisted together, Copper alloy stranded wire.
8. It comprises a conductor and an insulating layer covering the conductor, The conductor is the copper alloy stranded wire described in claim 7. Electric wire.
9. The process of producing a cast material made of copper alloy, A process of producing a drawn wire by drawing the aforementioned cast material, The process includes a step of heat-treating the drawn wire, The aforementioned copper alloy contains iron, phosphorus, tin, and minor elements, with the remainder being copper and unavoidable impurities. The aforementioned sub-elements are two or more elements selected from the group of elements consisting of zinc, nickel, and chromium, or zinc alone. The iron content is between 0.1% by mass and 1.0% by mass. The phosphorus content is 0.1% by mass or more and 0.6% by mass or less. The tin content is 0.1% by mass or more and 0.4% by mass or less. If zinc is included, the zinc content is between 0.005% by mass and 1.40% by mass. If nickel is included, the nickel content is 0.005% by mass or more and 0.70% by mass or less. If chromium is present, the chromium content is between 0.005% by mass and 0.20% by mass. The mass ratio of the total content of iron, nickel, and chromium to the phosphorus content is between 3.0 and 7.
0. A method for manufacturing copper alloy wire.
10. The method for manufacturing a copper alloy wire according to claim 9, wherein the step of heat-treating the drawn wire is to hold the drawn wire at a temperature of 300°C to 700°C for 4 hours to 40 hours.