Aluminum alloy wire, electric wire, and wire harness

Abstract

The problem to be solved by the present invention is to provide an aluminum alloy wire rod, an electric wire, and a wire harness, the aluminum alloy wire rod having high tensile strength and high conductivity, and also having excellent elongation characteristics, whereby these balance characteristics are excellent, and variations in tensile strength and elongation characteristics along the length are small. In order to solve the problem, the aluminum alloy wire rod has an alloy composition containing 0.30 mass% or more and 0.70 mass% or less of Mg and 0.30 mass% or more and 1.00 mass% or less of Si, with the balance made up of Al and unavoidable impurities; in a crystal orientation analysis using an electron backscatter diffraction (EBSD) method in an observation region of a cross section perpendicular to the longitudinal direction, the abundance ratio of a measurement point having a crystal orientation difference of 5 DEG or less from an adjacent measurement point with respect to all measurement points is 85% or less.

Description

Technical Field

[0001] The present invention relates to an aluminum alloy wire, an electric wire, and a wire harness. Background Art

[0002] In recent years, automobiles have been trending towards electrification, and the usage amount of wire harnesses for transmitting automotive electrical signals has correspondingly increased. Along with this, the weight of the electric wires that make up the wire harness has become larger. As a result, the problem is that the total weight of the wire harness for each automobile reaches several tens of kg.

[0003] In order to lighten the wire harness, research has been conducted on making the electric wire thinner, etc., but the effect of reducing the weight of the wire harness is not sufficient. On the other hand, as one of the methods for lightening the wire harness, copper electric wires are replaced with aluminum electric wires, but mainly the centers of thick electric wires are replaced in this way. In particular, in recent years, the practice of replacing copper electric wires with high-strength aluminum alloy wires for thin electric wires has also been spreading.

[0004] As the material for such high-strength aluminum alloy wires, mostly aluminum alloys of the 6000 series are selected.

[0005] For example, Patent Document 1 describes an aluminum alloy wire used for a conductor. The aluminum alloy wire contains 0.2% or more and 1.5% or less of Mg, 0.1% or more and 2.0% or less of Si, 0.1% or more and 1.0% or less of Fe, or contains at least one element selected from Cu, Cr, Mn, and Zr in a total amount of 0.1% or more and 1.0% or less together with Fe, 0.08% or less of Ti, and 0.016% or less of B, with the balance being composed of Al and impurities, has a conductivity of 40% IACS or more, a tensile strength of 150 MPa or more, an elongation of 5% or more, a wire diameter of 0.5 mm or less, and a maximum crystal grain size of 50 μm or less.

[0006] In addition, Patent Document 2 describes the following aluminum alloy conductor. The aluminum alloy conductor contains 0.01 to 0.4% by mass of Fe, 0.01% by mass or more and less than 0.3% by mass of Mg, 0.01% by mass or more and less than 0.3% by mass of Si, 0.01 to 0.5% by mass of Cu, and the balance is composed of Al and inevitable impurities. Regarding the area ratio of crystal grains having a plane inclined at an angle within the range of the standard triangle of the stereoscopic projection diagram by 25° or more with respect to the (111) plane located at a position parallel to the cross section perpendicular to the wire drawing direction of the wire, when the radius of the wire is R, it is 50% or more within a circle having a radius of (3 / 10)R from the center of the wire. And, regarding the area ratio of crystal grains having a plane inclined within the range of 0° or more and less than 25° with respect to the normal direction with respect to the (111) plane located at a position parallel to the cross section perpendicular to the wire drawing direction of the wire, it is 50% or more in the range obtained by removing the range within a circle having a radius of (7 / 10)R from the center of the wire from the entire wire.

[0007] In addition, Patent Document 3 describes the following aluminum alloy wire. The aluminum alloy wire has the following composition: containing 0.1 to 1.0% by mass of Mg, 0.1 to 1.0% by mass of Si, 0.01 to 1.40% by mass of Fe, 0.000 to 0.100% by mass of Ti, 0.000 to 0.030% by mass of B, 0.00 to 1.00% by mass of Cu, 0.00 to 0.50% by mass of Ag, 0.00 to 0.50% by mass of Au, 0.00 to 1.00% by mass of Mn, 0.00 to 1.00% by mass of Cr, 0.00 to 0.50% by mass of Zr, 0.00 to 0.50% by mass of Hf, 0.00 to 0.50% by mass of V, 0.00 to 0.50% by mass of Sc, 0.00 to 0.50% by mass of Sn, 0.00 to 0.50% by mass of Co, 0.01 to 0.50% by mass of Ni, and the total content of Fe, Ti, B, Cu, Ag, Au, Mn, Cr, Zr, Hf, V, Sc, Sn, Co and Ni is 2.00% by mass or less, and the balance is Al and inevitable impurities; the area ratio of the region where the angle formed by the longitudinal direction and the <111> direction of the crystal is within 20° is 20% or more and 65% or less.

[0008] [Prior Art Documents]

[0009] (Patent Document)

[0010] Patent Document 1: Japanese Patent No. 5155464 Gazette

[0011] Patent Document 2: Japanese Patent No. 5846360 Gazette

[0012] Patent Document 3: Japanese Patent No. 6499190 Gazette Summary of the Invention

[0013] [Problems to be Solved by the Invention]

[0014] Patent Document 1 describes an aluminum wire in which Mg, Si, etc. are added to an aluminum alloy and the maximum crystal grain size is controlled. In addition, in Patent Documents 2 and 3, the crystal plane and crystal orientation of the aluminum alloy wire are controlled in terms of microstructure, and it has a high tensile strength, high conductivity, and excellent elongation characteristics. In addition to these features, it also has the following features, etc., that is, it has fracture resistance and high tolerance to repeated movement, and has excellent elongation characteristics.

[0015] These alloys have common features at least in terms of having a high tensile strength, high conductivity, and excellent elongation characteristics, but there is still room for further improvement in reducing the deviation of the tensile strength and elongation characteristics along the length.

[0016] An object of the present invention is to provide an aluminum alloy wire, wire, and wire harness that have a high tensile strength, high conductivity, and excellent elongation characteristics, whereby these balanced characteristics are excellent and the deviation of the tensile strength and elongation characteristics along the length is small.

[0017] [Technical Means for Solving the Problem]

[0018] In response to the above-mentioned prior problems, intensive research and development have been carried out. As a result, the inventors of the present invention have found that by setting the composition of the aluminum alloy wire within a specified range, further controlling the temperature and time in the heat treatment process when manufacturing the aluminum alloy wire, and controlling the crystal orientation difference from an adjacent measurement point when performing crystal orientation analysis, it is possible to provide an aluminum alloy wire, wire, and wire harness in which the tensile strength, conductivity, and elongation characteristics are evenly improved. The present invention has been completed based on the above knowledge and insights.

[0019] In order to achieve the above object, the gist of the present invention is configured as follows.

[0020] (1) An aluminum alloy wire having the following alloy composition: containing 0.30% by mass or more and 0.70% by mass or less of Mg, and 0.30% by mass or more and 1.00% by mass or less of Si, and the balance being composed of Al and inevitable impurities;

[0021] In the crystal orientation analysis performed by the electron backscatter diffraction (EBSD) method in the observation region of the cross section perpendicular to the length direction of the aforementioned aluminum alloy wire, the occupancy ratio of the measurement points with a crystal orientation difference of 5° or less from an adjacent measurement point with respect to all measurement points is 85% or less.

[0022] (2) An aluminum alloy wire has the following alloy composition: containing Mg in an amount of 0.30% by mass or more and 0.70% by mass or less, and Si in an amount of 0.30% by mass or more and 1.00% by mass or less, further containing one or more components selected from the group consisting of Mn, Fe, Ni, Ti, Cr, and Zr in a total amount of 0.001% by mass or more and 0.55% by mass or less, and the balance being composed of Al and inevitable impurities.

[0023] In the crystallographic orientation analysis performed by the electron backscatter diffraction (EBSD) method in the observation region of the cross-section perpendicular to the length direction of the aforementioned aluminum alloy wire, the ratio of the measurement points with a crystallographic orientation difference of 5° or less from the adjacent measurement points to all the measurement points is 85% or less.

[0024] (3) The aluminum alloy wire according to the above (1) or (2), wherein, in the aforementioned crystallographic orientation analysis performed in the aforementioned observation region, when the crystallographic orientation within ±5° of the <100> orientation is set as the <100> orientation group, the crystallographic orientation within ±5° of the <110> orientation is set as the <110> orientation group, and the crystallographic orientation within ±5° of the <111> orientation is set as the <111> orientation group, the ratio of the number of crystal grains having the <111> orientation group to the total ratio of the number of crystal grains having the <100> orientation group and the number of crystal grains having the <110> orientation group (<111> orientation group / (<100> orientation group + <110> orientation group)) is in the range of 5 or more and 30 or less.

[0025] (4) The aluminum alloy wire according to any one of the above (1) to (3), wherein the average crystal grain size of the crystal grains obtained from the aforementioned crystallographic orientation analysis in the aforementioned observation region is in the range of 5 μm or more and 9 μm or less.

[0026] (5) A wire having the aluminum alloy wire according to any one of the above (1) to (4).

[0027] (6) A wire harness having the wire according to the above (5).

[0028] (Effects of the Invention)

[0029] According to the present invention, an aluminum alloy wire, a wire, and a wire harness can be provided. The aluminum alloy wire has a high tensile strength and a high conductivity, and also has excellent elongation characteristics. Therefore, these balanced characteristics are excellent, and the deviation of the tensile strength and elongation characteristics along the length is small. Description of the Drawings

[0030] None Detailed Description of the Invention

[0031] Hereinafter, preferred embodiments of the aluminum alloy wire, wire, and wire harness of the present invention will be described in detail. In addition, in the compositional components of the alloy of the present invention, "mass%" may sometimes be shown simply as "%".

[0032] The aluminum alloy wire of the present invention has the following alloy composition: containing 0.30% by mass or more and 0.70% by mass or less of Mg, and 0.30% by mass or more and 1.00% by mass or less of Si, and the balance being composed of Al and inevitable impurities; and in the crystal orientation analysis using the electron backscatter diffraction (EBSD) method in the observation region of the cross-section perpendicular to the length direction, the ratio of the measurement points with a crystal orientation difference of 5° or less from the adjacent measurement points to all the measurement points is 85% or less.

[0033] In the aluminum alloy wire of the present invention, by setting the alloy composition within a specified range and further controlling the temperature and time in the heat treatment process when manufacturing the aluminum alloy wire to control the crystal orientation difference from the adjacent measurement points, the tensile strength, conductivity, and elongation characteristics can be improved in a balanced manner. More specifically, the aluminum alloy wire has the following alloy composition: containing 0.30% by mass or more of Mg and containing 0.30% by mass or more of Si; and the ratio of the measurement points with a crystal orientation difference of 5° or less from the adjacent measurement points to all the measurement points is 85% or less, whereby the tensile strength of the aluminum alloy wire can be improved. On the other hand, having the following alloy composition: the content of Mg is 0.70% by mass or less, and the content of Si is 1.00% by mass or less; and the ratio of the measurement points with a crystal orientation difference of 5° or less from the adjacent measurement points to all the measurement points is 85% or less, whereby the conductivity and elongation characteristics of the aluminum alloy wire can be improved.

[0034] Therefore, the aluminum alloy wire according to the present invention has a high tensile strength and a high conductivity, and also has excellent elongation characteristics. Thus, an aluminum alloy wire, a wire, and a wire harness can be provided, in which these balanced characteristics are excellent and the deviation of the tensile strength and elongation characteristics along the length is small.

[0035] [1] Alloy composition of aluminum alloy wire

[0036] <Essential components to be contained>

[0037] The alloy composition of the aluminum alloy wire of the present invention contains, as essential components, 0.30% by mass or more and 0.70% by mass or less of Mg, and 0.30% by mass or more and 1.00% by mass or less of Si.

[0038] (Mg: 0.30% by mass or more and 0.70% by mass or less)

[0039] Mg (Magnesium) is an element that, when finely precipitated in an aluminum alloy together with other additive elements such as Si, improves the tensile strength and electrical conductivity of the aluminum alloy. To exert these effects, it contains 0.30 mass% or more of Mg. Here, if the content of Mg is less than 0.30 mass%, most of the Mg remains in a solid solution state, so it is difficult to precipitate Mg in the aluminum alloy. In addition, if the Mg content exceeds 0.70 mass%, an amount of Mg far exceeding the solid solubility limit exists in the form of coarse compounds. Thus, it not only does not contribute to the improvement of tensile strength and electrical conductivity but also becomes a cause of wire breakage during wire drawing, thereby causing an adverse effect of reduced elongation characteristics. Therefore, the content of Mg is 0.70 mass% or less. Thus, the content of Mg is in the range of 0.30 mass% or more and 0.70 mass% or less.

[0040] (Si: 0.30 mass% or more to 1.00 mass%)

[0041] Si (Silicon) is an element that, when finely precipitated in an aluminum alloy together with other additive elements, improves the tensile strength and electrical conductivity of the aluminum alloy. To exert these effects, it contains 0.30 mass% or more of Si. Here, if the content of Si is less than 0.30 mass%, most of the Si remains in a solid solution state, so it is difficult to precipitate Si in the aluminum alloy. In addition, if the Si content exceeds 1.00 mass%, an amount of Si far exceeding the solid solubility limit exists in the form of coarse compounds. Thus, it not only does not contribute to the improvement of tensile strength and electrical conductivity but also becomes a cause of wire breakage during wire drawing, thereby causing an adverse effect of reduced elongation characteristics. Therefore, the content of Si is 1.00 mass% or less. Thus, the content of Si is in the range of 0.30 mass% or more to 1.00 mass%.

[0042] <Optional Additive Components>

[0043] In the alloy composition of the aluminum alloy wire of the present invention, as optional additive components, one or more components selected from the group consisting of Mn, Fe, Ni, Ti, Cr, and Zr can be further contained in a total range of 0.001 mass% or more and 0.55 mass% or less.

[0044] (Mn: 0.001 mass% or more and 0.50 mass% or less)

[0045] Mn (Manganese) is an element that helps further refine the crystal grains, thereby bringing about further strengthening of the aluminum alloy wire. In addition, it is an element that is less likely to cause grain growth during the heat treatment process accompanied by recrystallization, thus bringing about the effect of preventing wire breakage. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more. On the other hand, even if the Mn content is excessive, the effect will reach saturation and the effect will not change, or precipitation will be promoted, resulting in a relatively reduced precipitation amount of the MgSi-based compound that is particularly effective in the present invention. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0046] (Fe: 0.001% by mass or more and 0.50% by mass or less)

[0047] Fe (Iron) is an element that helps further strengthen the aluminum alloy wire. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more of Ti. On the other hand, even if the Fe content is excessive, the effect will reach saturation and the effect will not change. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0048] (Ni: 0.001% by mass or more and 0.50% by mass or less)

[0049] Ni (Nickel) is an element that has the effect of improving the impact resistance characteristics of the aluminum alloy wire. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more of Ni. On the other hand, even if the Ni content is excessive, the effect will reach saturation and the effect will not change. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0050] (Ti: 0.001% by mass or more and 0.50% by mass or less)

[0051] Ti (Titanium) is an element that has the effect of making the solidification structure fine during casting when added in the form of TiB, and helps improve the manufacturability of the rolling process after casting. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more of Ti. On the other hand, the Ti content may cause drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0052] (Cr: 0.001% by mass or more and 0.50% by mass or less)

[0053] Cr (chromium) is the same as Mn and is a component that has the effect of refining crystal grains and is not prone to grain growth at high temperatures, thus not prone to wire breakage. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more. On the other hand, even if the Cr content is excessive, the effect will reach saturation and the effect will not change. In addition, precipitation is promoted, and as a result, the precipitation amount of the MgSi-based compound may relatively decrease. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0054] (Zr: 0.001% by mass or more and 0.50% by mass or less)

[0055] Zr (zirconium) is a component that can improve the heat resistance of aluminum alloy wire. To exert this effect, it is preferably contained in an amount of 0.001% by mass or more. On the other hand, even if the Zr content is excessive, the effect will reach saturation and the effect will not change. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.50% by mass or less.

[0056] (Total amount of optional addition components: 0.001% by mass or more and 0.55% by mass or less)

[0057] The optional addition components composed of one or more components selected from the group consisting of Mn, Fe, Ni, Ti, Cr, and Zr, in order to obtain the effects brought by these optional addition components, are preferably contained in a total amount of 0.001% by mass or more. These optional addition components can also be in a solid solution or precipitated form in the aluminum alloy wire. In addition, solid solution strengthening can be brought about by increasing their content, strengthening can be brought about by refining the crystal grains of the matrix phase, and precipitation strengthening can be brought about by promoting the reaction with the optional addition components. On the other hand, even if the content of these optional addition components is excessive, the effect will reach saturation and the effect will not change. In addition, there may be drawbacks such as a decrease in conductivity and an adverse impact on manufacturability. Therefore, it is preferably set to 0.55% by mass or less in total.

[0058] (Remaining part: Al and inevitable impurities)

[0059] In the alloy composition of the aluminum alloy wire of the present invention, the remaining portion other than the above elements consists of Al and inevitable impurities. Additionally, the "inevitable impurities" mentioned here are roughly the following impurities, which are substances present in the raw materials of the aluminum alloy wire, substances inevitably mixed in during the manufacturing process, and substances that are originally useless. However, since the amount of these impurities is tiny and will not affect the properties of the aluminum alloy wire, their existence is allowed. Examples of the components listed as inevitable impurities include non-metallic elements such as sulfur (S), carbon (C), and oxygen (O), and metallic elements such as vanadium (V), gallium (Ga), and antimony (Sb). Regarding the upper limit of the content of these components, since they will be the main reasons for reducing the conductivity and tensile strength, it is preferably less. Each of the above components can be set to 0.05% by mass, or the total amount of the above components can be set to 0.05% by mass. More preferably, each of the above components is 0.01% by mass, or the total amount of the above components is 0.01% by mass.

[0060] [2] Metallographic structure of the aluminum alloy wire

[0061] Next, the metallographic structure of the aluminum alloy wire will be described.

[0062] In the aluminum alloy wire of the present invention, in the crystallographic orientation analysis using the electron backscatter diffraction (EBSD) method in the observation area of the cross-section perpendicular to its length direction, the ratio of the measurement points with a crystallographic orientation difference of 5° or less from the adjacent measurement points to all the measurement points is 85% or less. Most of the crystallographic orientation differences of such low angles of 5° or less are formed due to dislocation defects. When the existence ratio exceeds 85%, it is generally considered that the plastic working strain imparted during the manufacturing process of the aluminum alloy wire cannot be sufficiently removed. For the reason, it can be cited that the heating in the following third heat treatment process (solution heat treatment process) is insufficient, and it can be cited that recrystallization cannot be sufficiently carried out due to insufficient heating, so that the strain remains. In addition, due to insufficient heating in the third heat treatment process (solution heat treatment process), the solid solubility of Mg and Si cannot be sufficiently increased, so that the recovery of the elongation property and the precipitation strengthening carried out by the subsequent aging treatment process are insufficient. That is, by setting the ratio of the measurement points with a crystallographic orientation difference of 5° or less from the adjacent measurement points to all the measurement points in the measurement area to 85% or less, the plastic working strain can be sufficiently removed, and the recovery of the elongation property and the precipitation strengthening can be pursued, so that the tensile strength and elongation property of the aluminum alloy wire can be improved. In addition, the length direction of the aluminum alloy wire means the wire drawing direction of the wire during the manufacturing process.

[0063] Here, the crystal orientation analysis using the electron backscatter diffraction (EBSD) method can be performed, for example, by the following method: Continuously measure the crystal orientation using an EBSD detector (manufactured by TSL Corporation, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope JSM-7001FA (manufactured by JEOL Ltd.), and use analytical software (manufactured by TSL Solutions Corporation, OIM-Analysis) to calculate (process) the crystal orientation data obtained by the measurement, thereby obtaining crystal orientation analysis data. "EBSD" is an abbreviation for Electron Back Scatter Diffraction, and is a crystal orientation analysis technique that utilizes Kikuchi lines generated when an electron beam is irradiated onto an aluminum alloy wire as a measurement specimen in a scanning electron microscope (SEM). The measurement object is a surface that has been mirror-polished in advance by grinding the cross-section perpendicular to the length direction of one aluminum alloy wire. In addition to grinding using a cross-section polisher (registered trademark) device for the cross-section grinding, wet grinding, focused ion beam (FIB), a microtome, or other methods capable of mirror polishing can also be used, and the specific grinding method is not limited. The measurement area can be set to the range where one aluminum alloy wire is cut out, for example, a square of 50 μm to 300 μm. The measurement of the crystal orientation when obtaining the crystal orientation data can be performed, for example, at a step size of 0.5 μm to 2 μm. In particular, by using analytical software in the analysis of the crystal orientation data, when allowing a specific angular range as the crystal orientation difference from an adjacent measurement point, it is possible to easily determine whether the crystal orientation difference from an adjacent measurement point is within the allowable range for each measurement point.

[0064] In the aluminum alloy wire of the present invention, in the crystal orientation analysis using the electron backscatter diffraction (EBSD) method in the observation region of the cross-section perpendicular to the length direction, when the crystal orientation within ±5° of the <100> orientation is set as the <100> orientation group, the crystal orientation within ±5° of the <110> orientation is set as the <110> orientation group, and the crystal orientation within ±5° of the <111> orientation is set as the <111> orientation group, the ratio of the number of crystal grains having the <111> orientation group to the total ratio of the number of crystal grains having the <100> orientation group and the number of crystal grains having the <110> orientation group (<111> orientation group / (<100> orientation group + <110> orientation group)) is preferably in the range of 5 or more and 30 or less.

[0065] Here, the crystal grains with the <111> orientation group have the following properties: they contribute to an increase in the tensile strength of the aluminum alloy wire, but reduce the elongation characteristics. In addition, when the crystal grains with the <111> orientation group do not undergo sufficient recrystallization, they sometimes exist in the form of a worked aggregate structure. In this case, in addition to the reduction in elongation characteristics, it also becomes a cause of insufficient precipitation strengthening due to insufficient solid solution of Mg and Si. Thus, the crystal grains with the <111> orientation group have the drawback of reducing the tensile strength and elongation characteristics of the aluminum alloy wire, and the higher their ratio, the stronger the tendency to exhibit this drawback.

[0066] In addition, the crystal grains with the <100> orientation group and the <110> orientation group, although not as helpful in increasing the tensile strength as the crystal grains with the <111> orientation group, can improve the elongation characteristics. Moreover, the crystal grains with the <100> orientation group and the <110> orientation group aggregate during sufficient recrystallization. Therefore, when the ratio of the crystal grains with these orientation groups is high, the solid solubility of Mg and Si becomes high, and thus the tensile strength of the aluminum alloy wire can be increased. In particular, by increasing both the recrystallization rate and the solid solubility of the aluminum alloy wire, there is the advantage of stably obtaining high tensile strength and elongation characteristics. Therefore, it is preferable to increase the ratio of such crystal grains.

[0067] In particular, when the ratio of (<111> orientation group / (<100> orientation group + <110> orientation group)) is 1 or less, the ratio of the crystal grains with the <111> orientation group becomes small, and thus the tensile strength of the aluminum alloy wire decreases. On the other hand, when the ratio of (<111> orientation group / (<100> orientation group + <110> orientation group)) is 100 or more, the ratio of (<100> orientation group + <110> orientation group) becomes small, and thereby the elongation characteristics of the aluminum alloy wire deteriorate. In particular, when Mg and Si are not sufficiently solid-solved and recrystallized, it is also difficult to stably obtain a high tensile strength. Therefore, the ratio of (<111> orientation group / (<100> orientation group + <110> orientation group)) is preferably in the range of 5 or more and 30 or less.

[0068] Regarding the number ratio of the crystal grains with the <100> orientation group, the <110> orientation group, and the <111> orientation group, in the analysis of the crystal orientation data obtained in the cross-section by the above EBSD detector, when the boundary with an orientation difference of 15° or more from the adjacent measurement points is set as the interface (grain boundary) of the crystal grains, the set of continuous measurement points within the range surrounded by the grain boundary is regarded as a crystal grain, and the ratio of the number of crystal grains with the <100> orientation group, the <110> orientation group, and the <111> orientation group to the total number of crystal grains in the measurement area can be obtained.

[0069] In the aluminum alloy wire of the present invention, the average crystal grain size obtained from the crystal orientation analysis using the electron backscatter diffraction (EBSD) method in the observation region of the cross-section perpendicular to the length direction may be, for example, in the range of 5 μm or more and 20 μm or less, but preferably in the range of 5 μm or more and 9 μm or less. In particular, by setting the average crystal grain size of the crystals contained in the metal structure of the aluminum alloy wire to be in the range of 5 μm or more and 9 μm or less, the average value and standard deviation of one or both of the tensile strength and elongation characteristics of the aluminum alloy wire can be further improved. On the other hand, if the average crystal grain size is less than 5 μm, Mg and Si are not sufficiently solid-solved, resulting in insufficient precipitation strengthening. In addition, due to insufficient heating for crystallization, the plastic working strain imparted in the manufacturing process of the aluminum alloy wire remains, and the elongation characteristics are also likely to decrease. On the other hand, if the average crystal grain size is greater than 9 μm, especially greater than 20 μm, it is easy to break the wire when annealing is performed for recrystallization.

[0070] Here, the average crystal grain size of the crystal grains of the aluminum alloy wire, in the analysis of the crystal orientation data of the above electron backscatter diffraction (EBSD) method, when the boundary with an azimuth difference of 15° or more from the adjacent measurement points is set as the interface (grain boundary) of the crystal grains, it can be set as the circular equivalent average diameter of the crystal grains when calculating the cross-sectional area of the crystal grains using the number of continuous measurement points within the range surrounded by the grain boundaries and the above step size.

[0071] The aluminum alloy wire of the present invention has high tensile strength and high elongation characteristics. Therefore, even if the wire diameter (diameter) is in the range of 0.1 mm or more and 0.5 mm or less, high toughness can be achieved. Here, toughness is a characteristic that becomes higher when both the tensile strength and elongation characteristics are high. Due to the high toughness of the aluminum alloy wire, even when a force in the tensile direction is applied, it is not easy to break the wire and it is easy to maintain the original shape.

[0072] In addition, the aluminum alloy wires of the present invention can be stranded in multiple strands to form an aluminum alloy stranded wire. In this case, high conductivity, improved tensile strength, and elongation characteristics can be achieved. Here, the number of strands of the aluminum alloy stranded wire and the total cross-sectional area of the stranded wire are not limited. By stranding the aluminum alloy wires with the above wire diameter in the range of 5 strands or more and 16 strands or less, it is also possible to form an aluminum alloy stranded wire with a fine wire diameter in the range of 0.1 mm 2 or more and 3.0 mm 2 or less.

[0073] Furthermore, the aluminum alloy wire of the present invention is preferably used for an electric wire, and preferably constitutes an electric wire having the above aluminum alloy wire. More specifically, it can constitute an electric wire having the above aluminum alloy wire or aluminum alloy stranded wire and an insulating coating covering the outer periphery of the aluminum alloy wire or aluminum alloy stranded wire. Such an electric wire can improve the tensile strength, conductivity, and elongation characteristics in a balanced manner. Therefore, in particular, a thin-diameter electric wire can be lightened to reduce the weight of the wire harness. That is, it is also preferable to constitute a wire harness having an electric wire having the above aluminum alloy wire.

[0074] [3] An example of a manufacturing method of an aluminum alloy wire

[0075] The above aluminum alloy wire can be realized by combining the control of the alloy composition and the manufacturing process, and the manufacturing process is not particularly limited. Among them, as an example of the manufacturing process capable of obtaining the above aluminum alloy wire, the following method can be cited.

[0076] As an example of the manufacturing method of the aluminum alloy wire of the present invention, it can be cited that an aluminum alloy material having an alloy composition substantially the same as the alloy composition of the above aluminum alloy wire is at least sequentially subjected to a continuous casting and rolling process, a first heat treatment process, a first wire drawing process, a second heat treatment process, a second wire drawing process, and a third heat treatment process.

[0077] [Continuous casting and rolling process]

[0078] In the manufacturing method of the aluminum alloy wire of the present invention, first, an aluminum raw material and additive elements are selected so as to have a desired component composition, and a continuous casting and rolling process for obtaining a rough aluminum wire is performed. The casting method in the continuous casting and rolling process is not limited. From the viewpoint of manufacturing efficiency, it is preferable to use a Properzi type continuous casting and rolling machine. In such a continuous casting and rolling machine, a casting wheel and a belt are combined, and molten aluminum can be continuously poured into an annular groove die for casting, and a rough wire can be continuously obtained by rolling.

[0079] In the continuous casting and rolling process, for example, a continuous casting and rolling machine is used, and after casting, rolling is performed with a two-way roll or a three-way roll. Thus, a rolled material having a cross-sectional area with a wire diameter equivalent of 9 mm or more and 10 mm or less can be obtained.

[0080] The rolling material is subjected to continuous wire drawing until the wire diameter is in the range of 0.1 mm or more and 0.5 mm or less. However, since the heat treatment performed during wire drawing affects the crystal orientation distribution of the aluminum alloy wire, it is important to perform the heat treatment under appropriate heat treatment conditions. Moreover, if the total processing rate of wire drawing is increased without heat treatment, the deformation resistance increases, and as a result, the aluminum alloy wire is likely to break, and in addition, the wear of the die used for wire drawing becomes severe. Therefore, performing heat treatment at an appropriate time to soften it is useful not only from the viewpoint of improving mechanical properties but also from the viewpoint of improving mass productivity. More specifically, it is preferable to perform heat treatment processes two or more times except for the heat treatment (heat treatment of the third heat treatment process) performed after the following second wire drawing process. In this case, the heat treatment conditions are preferably in the temperature range of 300°C or more and 400°C or less for 1 hour or more and 8 hours or less respectively.

[0081] The following description explains the following aspect: after performing the continuous casting and rolling process, the first wire drawing process and the second wire drawing process are performed as wire drawing processes, and before these wire drawing processes, the first heat treatment process and the second heat treatment process are performed respectively; however, this aspect is not limited. By performing the first heat treatment process, the first wire drawing process, the second heat treatment process, and the second wire drawing process in sequence after performing the continuous casting and rolling process, the aluminum wire can be heat-treated at the time of cold wire drawing at a specific processing rate or more, and when using continuous processing equipment, the wire drawing process and the heat treatment process can be easily performed.

[0082] [First Heat Treatment Process]

[0083] The first heat treatment process is as follows: the rolling material, that is, the aluminum rough wire rod, having a cross-sectional area with a wire diameter equivalent of 9 mm or more and 10 mm or less is heat-treated in the temperature range of 300°C or more and 400°C or less for 1 hour or more and 8 hours or less. The first heat treatment process is a process for softening the aluminum rough wire rod and intentionally precipitating pinning particles that prevent crystal coarsening.

[0084] The crystallization direction during the first heat treatment process also affects the crystallization orientation after the following third heat treatment process. Therefore, the first heat treatment process needs to be carried out at a temperature range of 300°C or higher and 400°C or lower for 1 hour or longer and 8 hours or shorter. Here, when the heat treatment temperature is lower than 300°C or the heat treatment time is shorter than 1 hour, the aluminum rough wire cannot be sufficiently softened, making it difficult to carry out the following first wire drawing process and second wire drawing process. In addition, when the heat treatment temperature exceeds 400°C or the heat treatment time exceeds 8 hours, the metal structure coarsens, and the crystallization orientation distribution of the obtained aluminum alloy wire is likely to change. In addition, the size of the precipitates generated during the heat treatment increases, so that they cannot play the role of grain boundary pinning in the following third heat treatment process, and the crystal grain size of the obtained aluminum alloy wire coarsens. Therefore, the aluminum alloy wire is prone to wire breakage and becomes the cause of reduced tensile strength and elongation characteristics.

[0085] The first heat treatment process can be carried out by a well-known method such as a bell-type furnace.

[0086] [First wire drawing process]

[0087] The first wire drawing process is a process of cold wire drawing the aluminum rough wire after the first heat treatment process. Thus, it is preferable to obtain a rolled material having a cross-sectional area with a wire diameter equivalent of 1 mm or more and 3 mm or less.

[0088] The first wire drawing process can be carried out by a well-known method such as drawing wire drawing using a die. More specifically, for the die material and size, wire drawing oil, path reduction, etc. that are wire drawing conditions, general conditions in the mass production of aluminum wire can be used. The first wire drawing process can be carried out by one path or by multiple paths until the target wire diameter is obtained.

[0089] [Second heat treatment process]

[0090] The second heat treatment process is as follows: The aluminum wire after the first wire drawing process is heat treated at a temperature range of 300°C or higher and 400°C or lower for 1 hour or longer and 8 hours or shorter. The second heat treatment process is also the same as the first heat treatment process and is a process for softening the aluminum wire and precipitating pinning particles that intentionally prevent crystal coarsening.

[0091] For the same reason as the first heat treatment process, the heat treatment conditions of the second heat treatment process need to be carried out at a temperature range of 300°C or higher and 400°C or lower for 1 hour or longer and 8 hours or shorter.

[0092] The second heat treatment process is the same as the first heat treatment process and can be carried out by a well-known method such as a bell-type furnace.

[0093] [Second wire drawing process]

[0094] The second wire drawing process is a process of cold wire drawing the aluminum wire after the first heat treatment process. Thus, an aluminum wire having a desired cross-sectional area can be obtained. Here, the cross-sectional area of the aluminum wire after the second wire drawing process is not particularly limited. For example, it can be set to a cross-sectional area equivalent to a wire diameter of 0.1 mm or more and 0.5 mm or less.

[0095] The second wire drawing process is the same as the first wire drawing process and can be performed by a well-known method such as drawing wire using a die. The second wire drawing process can be performed by one path or by multiple paths until the target wire diameter is obtained.

[0096] [Third Heat Treatment Process]

[0097] The third heat treatment process is solution heat treatment and is the following process: The aluminum wire after the second wire drawing process is heat treated in a temperature range of 500 °C or more and 580 °C or less for 3 seconds or more and 60 seconds or less. Thus, the elements in the precipitated state are dissolved, and the crystal orientation of recrystallization precipitation is determined in the aluminum alloy wire. Here, when the heat treatment temperature is lower than 500 °C or the heat treatment time is shorter than 3 seconds, in the crystal orientation analysis using the above-mentioned electron backscatter diffraction (EBSD) method, the ratio of the measurement points with a crystal orientation difference of 5° or less from the adjacent measurement points to all the measurement points exceeds 85%. In addition, when the heat treatment temperature exceeds 580 °C or the heat treatment time exceeds 60 seconds, grain growth occurs in the metal structure of the obtained aluminum alloy wire, which causes a decrease in tensile strength and elongation characteristics. In addition, the aluminum alloy wire is prone to wire breakage.

[0098] In addition, the heat treatment conditions of the third heat treatment process also affect the number ratio of crystal grains having a <111> orientation group to the total number ratio of crystal grains having a <100> orientation group and crystal grains having a <110> orientation group. When the heat treatment temperature is low and the heat treatment time is short, the crystal grains having a <111> orientation group increase, so the number ratio of (<111> orientation group / (<100> orientation group + <110> orientation group)) also tends to increase. At this time, solid solution is not sufficiently performed, and thus the generation of crystal grains having a desired crystal orientation by recrystallization is not sufficiently performed. Therefore, it becomes a cause of a decrease in the tensile strength and elongation characteristics of the aluminum alloy wire. In addition, when the heat treatment temperature is high and the heat treatment time is long, the crystal grains having a <100> orientation group and the crystal grains having a <110> orientation group increase, so there is a tendency for the tensile strength of the aluminum alloy wire to decrease. In addition, in these cases, crystal grain coarsening occurs, which causes a decrease in tensile strength and elongation characteristics. In addition, the aluminum alloy wire is prone to wire breakage.

[0099] The third heat treatment process can be carried out by well-known methods such as a ring furnace, etc. However, due to the short heating time, it is preferred to rapidly heat while confirming the arrival temperature of the aluminum wire rod. In addition, the aluminum wire rod after the third heat treatment process is preferably rapidly cooled by water cooling or the like.

[0100] Here, before or after the third heat treatment process, a stranding process of stranding multiple aluminum wire rods with a stranding machine and a compression process of compressing the stranded wire can also be carried out. Thus, the metal structure is hardly affected by the stranding process and the compression process, and an aluminum alloy stranded wire formed by stranding multiple aluminum alloy wire rods can be produced.

[0101] [Aging treatment process]

[0102] The aging treatment process is as follows: The aluminum wire rod after the third heat treatment process is held at a temperature lower than that of the third heat treatment process or heat-treated. Thus, in the metal structure of the aluminum wire rod, crystal grains can be precipitated evenly in the desired crystal orientation by recrystallization. Therefore, it has a high tensile strength and a high conductivity, and also has excellent elongation characteristics. Thus, an aluminum alloy wire rod and an aluminum alloy stranded wire with excellent balance of these characteristics and small deviations in tensile strength and elongation characteristics along the length can be obtained.

[0103] In the aging treatment process, at least artificial aging treatment for heat-treating the aluminum wire rod is carried out. Before the artificial aging treatment, natural aging treatment of holding at a temperature close to room temperature can also be further carried out. Here, the heat treatment in the artificial aging treatment can be carried out in a temperature range of 100°C or higher and 200°C or lower for 2 hours or more and 10 hours or less. In addition, the natural aging treatment can be carried out by holding in a temperature range of 20°C or higher and 50°C or lower for 24 hours or more.

[0104] Using the obtained aluminum alloy wire rod or aluminum alloy stranded wire, a coating extrusion process is carried out, whereby an electric wire can be manufactured. The coating extrusion process is carried out by coating extrusion along the outer circumference of the aluminum alloy stranded wire for insulation coating.

[0105] Above, the embodiments have been described, but the present invention is not limited to the above embodiments, and includes all aspects included in the concept disclosed herein and the claims, and various changes can be made within the scope of the disclosure.

[0106] Examples

[0107] Next, the present invention examples and comparative examples will be described, but the present invention is not limited to these present invention examples.

[0108] Select the aluminum raw material and additive elements in such a way that they become the components shown in Table 1, and use a continuous casting and rolling press (manufactured by Propez Co., Ltd.) to perform the continuous casting and rolling process to manufacture a rolled material, that is, an aluminum rough drawing wire, with a cross-section perpendicular to the length direction equivalent to a circular shape with a diameter of 9.5 mm. After the first heat treatment process on this aluminum rough drawing wire under the temperature and time conditions shown in Table 1, perform the first wire drawing process to make the cross-section size equivalent to a circular shape with a diameter of 2.6 mm. Next, after the second heat treatment process under the temperature and time conditions shown in Table 1, perform the second wire drawing process to make the cross-section size equivalent to a circular shape with a diameter of 0.3 mm. Here, the first heat treatment process and the second heat treatment process are carried out in an inert gas environment of a bell-type furnace.

[0109] For the aluminum wire after the second wire drawing process, perform a solution heat treatment, that is, the third heat treatment process, under the temperature and time conditions shown in Table 1, and then cool it rapidly by water cooling. Here, the third heat treatment process heats the aluminum wire in a protective tube in a ring furnace and heats it while confirming the target temperature reached with a thermocouple.

[0110] After the third heat treatment process, as an aging treatment process, perform natural aging treatment on the aluminum wire in the atmosphere by maintaining it in a temperature range of 25 °C or more and 40 °C or less for 24 hours or more, and artificial aging treatment by heat treatment in a temperature range of 120 °C or more and 170 °C or less for 5 hours, thereby obtaining the aluminum alloy wires of the present invention examples and comparative examples. In addition, in the actual manufacturing process of aluminum electric wires, sometimes the stranding process and the compression process are carried out after these aging treatments, but the influence of these processes on the characteristics is very small, so they are omitted in the present invention examples and comparative examples.

[0111] [Various measurement and evaluation methods]

[0112] Use the aluminum alloy wires obtained in the above-mentioned present invention examples and comparative examples to perform the following characteristic evaluations. The evaluation conditions for each characteristic are as follows.

[0113] [1] Measurement of the ratio of the number of measurement points with a crystallographic orientation difference of 5° or less from adjacent measurement points to all measurement points

[0114] The ratio of the measurement points with a crystallographic orientation difference of 5° or less from adjacent measurement points to all measurement points can be obtained from the crystallographic orientation analysis data calculated using the electron backscatter diffraction (EBSD) method. Here, for the crystallographic orientation analysis data calculated using the EBSD method, the crystallographic orientation is continuously measured using an EBSD detector (manufactured by TSL Corporation, OIM5.0 HIKARI) attached to a high-resolution scanning analytical electron microscope JSM-7001FA (manufactured by JEOL Ltd.), and the measured crystallographic orientation data is calculated (processed) using analysis software (manufactured by TSL Solutions Corporation, OIM-Analysis), thereby obtaining the ratio to all measurement points within the measurement region. The measurement object is the surface obtained by mirror polishing a cross-section perpendicular to the length direction of an aluminum alloy wire in advance by grinding. The cross-section is ground using a cross-section polishing machine (registered trademark) device. The measurement region is set to the range where one aluminum alloy wire is cut out. More specifically, it is set to an area range equivalent to a circle with a diameter of 0.3 mm. The measurement of the crystallographic orientation when obtaining the crystallographic orientation data is performed with a step size of 0.5 μm. At this time, the measurement result of the orientation difference from an adjacent measurement point is set to a value with a 1° scale. In addition, in the determination of whether the crystallographic orientation difference from an adjacent measurement point is 5° or less, the measurement result of the crystallographic orientation difference is also set to a value with a 1° scale. When the measurement result is in the range of 1° or more and 5° or less, the crystallographic orientation difference from the adjacent measurement point is set to 5° or less. The results are shown in Table 2.

[0115] [2] Measurement of the ratio of the number of crystallites with the <111> orientation group to the total ratio of the number of crystallites with the <100> orientation group and the number of crystallites with the <110> orientation group

[0116] For the ratio of the number of crystallites with the <100> orientation group, <110> orientation group, and <111> orientation group, in the analysis of the crystallographic orientation data obtained in the cross-section by the EBSD detector as described above, when the boundary with an orientation difference of 15° or more from an adjacent measurement point is set as the interface (grain boundary) of the crystallite, the set of continuous measurement points within the range surrounded by the grain boundary is set as a crystallite, and the number of crystallites with a crystallographic orientation within ±5° of the <100> orientation, that is, the <100> orientation group, the number of crystallites with a crystallographic orientation within ±5° of the <110> orientation, that is, the <110> orientation group, and the number of crystallites with a crystallographic orientation within ±5° of the <111> orientation, that is, the <111> orientation group, are respectively obtained as the number of crystallites within the total number of crystallites in the measurement region. From the number of crystallites with these orientation groups, the ratio of (<111> orientation group / (<100> orientation group + <110> orientation group)) is obtained. The results are shown in Table 2.

[0117] [3]Measurement of the average crystal grain size

[0118] Regarding the average crystal grain size of the crystal grains of the aluminum alloy wire, in the analysis of the crystal orientation data by the above-mentioned electron backscatter diffraction (EBSD) method, when the boundary with an azimuth difference of 15° or more from the adjacent measurement points is set as the interface (grain boundary) of the crystal grains, the number of continuous measurement points within the range surrounded by the grain boundary and the above-mentioned step size are used to calculate the cross-sectional area of the crystal grains, and the circular equivalent average diameter of the crystal grains thus obtained is set as the average crystal grain size. The results are shown in Table 2.

[0119] [4]Measurement and evaluation of the tensile strength

[0120] Regarding the tensile strength of the aluminum alloy wire, test pieces with a length of 200 mm are cut out from an aluminum alloy wire with a length of 2000 m, including positions at 0 m, 500 m, 1000 m, 1500 m, and 2000 m from one end. For these test pieces, the tensile strength Rm is obtained based on Japanese Industrial Standards (JIS) Z2241, and the average value and standard deviation of the tensile strength Rm at these 5 positions are set as the average value [MPa] and standard deviation [MPa] of the tensile strength, respectively.

[0121] Regarding the obtained average value of the tensile strength, when it is 250 MPa or more, the value of the average value of the tensile strength is large enough, and it is excellent in terms of being able to be used alone without being installed in a connector. This case is evaluated as "◎ (excellent)". In addition, when the average value of the tensile strength is in the range of 230 MPa or more and less than 250 MPa, the average value of the tensile strength is relatively large, and it is good in terms of being able to be used in a state where it can be accommodated in a general connector. This case is evaluated as "○ (good)". On the other hand, when the average value of the tensile strength is less than 230 Mpa, the average value of the tensile strength is small, and it is poor as an aluminum alloy wire in terms of the aluminum alloy wire breaking even when accommodated in a connector. This case is evaluated as "× (poor)". In the present invention examples and comparative examples, "◎" and "○" are evaluated as the qualified level. The results are shown in Table 2.

[0122] In addition, regarding the standard deviation of the obtained tensile strength, when the standard deviation of the tensile strength is 5.00 MPa or less, the standard deviation of the tensile strength is small enough, and it is excellent in terms of stably obtaining the tensile strength of the aluminum alloy wire. This case is evaluated as "◎ (excellent)". In addition, when the standard deviation of the tensile strength is in the range exceeding 5.00 MPa and 10.00 MPa or less, the standard deviation of the tensile strength is small, and it is good in terms of stably obtaining the tensile strength of the aluminum alloy wire based on the evaluation of "◎". This case is evaluated as "○ (good)". On the other hand, when the standard deviation of the tensile strength exceeds 10.00 MPa, it is poor in terms of stably obtaining the tensile strength of the aluminum alloy wire, and this case is evaluated as "× (poor)". In the present invention examples and comparative examples, "◎" and "○" are evaluated as the qualified level. The results are shown in Table 2.

[0123] [5] Measurement and evaluation of elongation characteristics

[0124] Regarding the elongation characteristics of the aluminum alloy wire, test pieces with a length of 200 mm are cut from an aluminum alloy wire with a length of 2000 m, including positions at 0 m, 500 m, 1000 m, 1500 m, and 2000 m from one end. For these test pieces, the elongation at break A is obtained based on JIS Z2241, and the average value and standard deviation of the elongation at break A at these 5 positions are respectively set as the average value [%] and standard deviation [%] of the elongation characteristics.

[0125] Regarding the obtained average value of the elongation characteristics, when the average value of the elongation characteristics is 14.0% or more, the value of the average value of the elongation characteristics is large enough, and it is excellent in terms of being usable alone without being installed in a connector. This case is evaluated as "◎ (excellent)". In addition, when the average value of the elongation characteristics is in the range of 12.0% or more and less than 14.0%, the average value of the elongation characteristics is large, and it is good in terms of being usable in a state where it can be accommodated in a general connector. This case is evaluated as "○ (good)". On the other hand, when the average value of the elongation characteristics is less than 12.0%, the average value of the elongation characteristics is small, and it is poor as an aluminum alloy wire in terms of the aluminum alloy wire breaking even when accommodated in a connector. This case is evaluated as "× (poor)". In the present invention examples and comparative examples, "◎" and "○" are evaluated as the qualified level. The results are shown in Table 2.

[0126] In addition, for the standard deviation of the elongation property obtained, when the standard deviation of the elongation property is 0.30% or less, the standard deviation of the elongation property is small enough, and it is excellent in terms of stably obtaining the elongation property of the aluminum alloy wire rod, and this case is evaluated as "◎ (excellent)". In addition, when the standard deviation of the tensile strength is in the range of more than 0.30% and 0.80% or less, the standard deviation of the elongation property is small, and it is good in terms of stably obtaining the elongation property of the aluminum alloy wire rod when evaluated as "◎", and this case is evaluated as "○ (good)". On the other hand, when the standard deviation of the elongation property exceeds 0.80%, it is poor in terms of not being able to stably obtain the elongation property of the aluminum alloy wire rod, and this case is evaluated as "× (poor)". In the present invention examples and comparative examples, "◎" and "○" are evaluated as the qualified level. The results are shown in Table 2.

[0127] [6] Measurement and evaluation of conductivity

[0128] For the conductivity of the aluminum alloy wire rod, it is measured twice in accordance with JIS H0505(-1975), and the average value of the conductivity obtained from the two measurements is set as the measured value of the conductivity [%IACS].

[0129] For the obtained measured value of the conductivity, when the measured value of the conductivity exceeds 50.0%IACS, the value of the conductivity is large enough, and it is excellent in terms of predicting that the aluminum alloy wire rod can also meet the requirements of further thinning of wires in the future, and this case is evaluated as "◎ (excellent)". In addition, when the measured value of the conductivity is in the range of 48.0%IACS or more and 50.0%IACS or less, the value of the conductivity is large, and it is good as the aluminum alloy wire rod constituting the current thinning wire, and this case is evaluated as "○ (good)". On the other hand, when the measured value of the conductivity is less than 48.0%IACS, the value of the conductivity is small, and it is poor as the aluminum alloy wire rod constituting the thinning wire, and this case is evaluated as "× (poor)". In the present invention examples and comparative examples, "◎" and "○" are evaluated as the qualified level. The results are shown in Table 2.

[0130] In addition, the above-mentioned "%IACS" is the unit of conductivity when the resistivity of the International Annealed Copper Standard is set to 100%IACS with a value of 1.7241×10 -8 Ωm.

[0131] [7] Comprehensive evaluation

[0132] Regarding the five evaluation results related to the average tensile strength, standard deviation of tensile strength, average elongation property, standard deviation of elongation property, and conductivity among these evaluation results, when all five are evaluated as "◎", it is particularly excellent in terms of having a high tensile strength and a high conductivity, having excellent elongation properties, and having a small deviation in tensile strength and elongation properties along the length, and this case is evaluated as "◎". In addition, regarding these five evaluation results, when all five are evaluated as "◎" or "○" (however, excluding the case where all five are evaluated as "◎"), it is excellent in terms of having a high tensile strength and a high conductivity, having excellent elongation properties, and having a small deviation in tensile strength and elongation properties along the length, and this case is evaluated as "○". On the other hand, regarding these five evaluation results, when at least one of the evaluation results is "×", at least one of the tensile strength, conductivity, and elongation properties fails, or it fails in terms of having a large deviation in tensile strength and elongation properties along the length, and this case is evaluated as "×". The results are shown in Table 2.

[0133] [Table 1]

[0134]

[0135] (Note) The underlined boldface notations shown in the table indicate outside the preferred range of the present invention.

[0136] [Table 2]

[0137]

[0138] (Note) The underlined boldface notations shown in the table indicate outside the preferred range of the present invention.

[0139] As shown in Table 1 and Table 2, in Examples 1 to 22 of the present invention, as a result of having a specific alloy composition and manufacturing by managing the first heat treatment process, second heat treatment process, and third heat treatment process of the manufacturing process as specific conditions, the following aluminum alloy wire rods are obtained: In the crystallographic orientation analysis by the electron backscatter diffraction (EBSD) method of the cross-section of the aluminum alloy wire rod, the ratio of the measurement points with a crystallographic orientation difference of 5° or less from adjacent measurement points to all measurement points is 85% or less. The evaluation results confirmed that Examples 1 to 22 of the present invention all have a high tensile strength and a high conductivity, and also have excellent elongation properties. Therefore, these have excellent balanced properties, and the deviation of tensile strength and elongation properties along the length is small.

[0140] On the other hand, for Comparative Example 1 where the contents of Mg and Si in the alloy composition are both outside the appropriate range on the side with relatively small contents, the average value of the tensile strength is not at the qualified level and is poor. In addition, for Comparative Example 2 where the contents of Mg and Si in the alloy composition are both outside the appropriate range on the side with relatively large contents, the average values of the elongation characteristics and the conductivity are not at the qualified level and are poor. Further, for Comparative Examples 3 to 14 where the ratio of the measurement points with a crystallographic orientation difference of 5° or less from the adjacent measurement points to all the measurement points exceeds 85%, at least the average values and the standard deviations of the tensile strength and the elongation characteristics are not at the qualified level and are poor.

Claims

1. An aluminum alloy wire having an alloy composition comprising 0.30 mass % or more and 0.70 mass % or less of Mg and 0.30 mass % or more and 1.00 mass % or less of Si, with the remainder consisting of Al and unavoidable impurities; In the crystal orientation analysis performed using the electron backscatter diffraction (EBSD) method in the observation area of ​​the cross section perpendicular to the length direction of the aforementioned aluminum alloy wire, the existence ratio of measurement points having a crystal orientation difference of 5° or less with adjacent measurement points relative to all measurement points is less than 85%.

2. An aluminum alloy wire having an alloy composition comprising 0.30 mass % to 0.70 mass % of Mg and 0.30 mass % to 1.00 mass % of Si, further comprising at least one component selected from the group consisting of Mn, Fe, Ni, Ti, Cr and Zr in a total amount of 0.001 mass % to 0.55 mass %, and the remainder consisting of Al and unavoidable impurities, In the crystal orientation analysis performed using the electron backscatter diffraction (EBSD) method in the observation area of ​​the cross section perpendicular to the length direction of the aforementioned aluminum alloy wire, the existence ratio of measurement points having a crystal orientation difference of 5° or less with adjacent measurement points relative to all measurement points is less than 85%.

3. The aluminum alloy wire according to claim 1 or 2, wherein: In the crystal orientation analysis performed in the aforementioned observation area, When the general <100> The crystal orientation within ±5° is set as <100> Position group, Will <110> The crystal orientation within ±5° is set as <110> Orientation group, and Will <111> The crystal orientation within ±5° is set as <111> When the orientation group have <111> The ratio of the number of grains in the orientation group is <100> The grains of the orientation group are <110> The total number ratio of crystal grains in the orientation group ( <111> Direction group / ( <100> Direction Group+ <110> The direction group) is in the range of greater than 5 and less than 30.

4. The aluminum alloy wire according to claim 1 or 2, wherein: The average grain size of the crystal grains obtained from the crystal orientation analysis performed in the observation region is in the range of 5 μm or more and 9 μm or less. 5 . An electric wire comprising the aluminum alloy wire material according to claim 1 .

6. A wiring harness comprising the electric wires according to claim 5.

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