Aluminum alloy wire and method for producing aluminum alloy wire

Abstract

Provided is an aluminum alloy wire which is formed of an aluminum alloy, wherein: the aluminum alloy contains 1.0% by mass to 1.3% by mass of silicon, 0.5% by mass to 1.2% by mass of magnesium, 0.3% by mass to 0.8% by mass of iron, 0.1% by mass to 0.4% by mass of copper, 0.2% by mass to 0.5% by mass of manganese, 0.001% by mass to 0.3% by mass of chromium, 0% by mass to 0.25% by mass of zinc, 0% by mass to 0.075% by mass of titanium, 0% by mass to 0.17% by mass of zirconium, with the balance being made up of aluminum and inevitable impurities; the 0.2% proof stress at compression is 360 MPa or more; the crystal grain size of the aluminum alloy is 200 μm or less; and the compressive deformation degree is 0.6 to 1.0 inclusive.

Description

Aluminum alloy wire and method for manufacturing aluminum alloy wire

[0001] This disclosure relates to an aluminum alloy wire and a method for manufacturing the aluminum alloy wire. This application claims priority to Japanese Patent Application No. 2023-138357 filed on August 28, 2023, and incorporates the entire contents of said Japanese application by reference.

[0002] Aluminum alloys are used as materials for various products that require lightweight construction. In particular, 6000-series aluminum alloys, defined by the International Alloy Symbology System, have high strength and excellent corrosion resistance, making them used in structural components and automotive parts. 6000-series aluminum alloys are Al-Mg-Si alloys in which silicon and magnesium are added to aluminum. Among the 6000-series aluminum alloys, A6061 can have its strength increased by T6 treatment. T6 treatment is a heat treatment that involves solution treatment followed by artificial aging.

[0003] Patent Documents 1 and 2 disclose aluminum alloy wires made of aluminum alloys having specific compositions. Patent Document 1 describes an aluminum alloy containing, by mass%, more than 1.0% and not more than 1.5% Si (silicon), 0.5% to 1.2% Mg (magnesium), 0.3% to 0.8% Fe (iron), 0% to 0.5% Cu (copper), 0% to 0.5% Mn (manganese), and 0% to 0.5% Cr (chromium), with the balance being aluminum (aluminum) and unavoidable impurities. In the aluminum alloy of Patent Document 1, the iron content is equal to or greater than the copper content. Patent Document 2 describes an aluminum alloy containing 1.0 mass% to 1.3 mass% silicon, 0.5 mass% to 1.2 mass% magnesium, 0.3 mass% to 0.8 mass% iron, 0.1 mass% to 0.4 mass% copper, 0.2 mass% to 0.5 mass% manganese, more than 0 mass% to 0.3 mass% chromium, 0.001 mass% to 0.1 mass% titanium, and the balance consisting of aluminum and inevitable impurities. The aluminum alloy of Patent Document 2 may further contain 0.001 mass% to 0.2 mass% zirconium. The aluminum alloy wire is produced, for example, by rolling a cast aluminum alloy material and then wiredrawing the rolled material.

[0004] JP 2015-166480 A International Publication No. 2022 / 249664

[0005] The aluminum alloy wire according to the present disclosure is an aluminum alloy wire formed from an aluminum alloy containing 1.0 to 1.3 mass% silicon, 0.5 to 1.2 mass% magnesium, 0.3 to 0.8 mass% iron, 0.1 to 0.4 mass% copper, 0.2 to 0.5 mass% manganese, 0.001 to 0.3 mass% chromium, 0 to 0.25 mass% zinc, 0 to 0.075 mass% titanium, 0 to 0.17 mass% zirconium, and the balance consisting of aluminum and inevitable impurities. The aluminum alloy wire is subjected to solution treatment and aging treatment, and the measurement results obtained therefrom are that the 0.2% proof stress during compression is 360 MPa or more, the grain size of the aluminum alloy is 200 μm or less, and the compressive deformation degree C when compressed at a compression rate of 50% is 0.6 or more and 1.0 or less. The solution treatment is performed at a heating temperature of 530° C. or more and 580° C. or less, for a holding time of 15 minutes or more and 360 minutes or less, and for a heating rate of 120° C. / min or less. The aging treatment is performed at a heating temperature of 160° C. or more and 190° C. or less, for a holding time of 2 hours or more and 40 hours or less.

[0006] Fig. 1 is a schematic perspective view showing an example of an aluminum alloy wire according to an embodiment. Fig. 2 is a schematic view illustrating a method for measuring the compressive deformation degree of an aluminum alloy wire. Fig. 3 is a diagram showing Cr K absorption edge spectra of Sample No. 2a and Sample No. 10a of Test Example 1.

[0007] [Problem to be Solved by the Present Disclosure] There is a demand for an aluminum alloy wire that has strength equal to or greater than that of A6061 and is excellent in plastic workability.

[0008] Aluminum alloy members are manufactured by plastically processing aluminum alloy wire. Aluminum alloy members are, for example, structural members and automotive parts. Plastic processing includes, for example, forging, rolling, and press processing. Depending on the application, high yield strength is required for the aluminum alloy member. In particular, in the case of aluminum alloy members that are subjected to compressive loads during use, high yield strength against compression is desirable.

[0009] An object of the present disclosure is to provide an aluminum alloy wire that has high strength and excellent workability.

[0010] [Effects of the Present Disclosure] The aluminum alloy wire of the present disclosure has high strength and excellent workability when subjected to a predetermined solution treatment and aging treatment.

[0011] [Description of Embodiments of the Present Disclosure] First, embodiments of the present disclosure will be listed and described.

[0012] (1) An aluminum alloy wire according to the present disclosure is an aluminum alloy wire formed from an aluminum alloy containing 1.0 to 1.3 mass% silicon, 0.5 to 1.2 mass% magnesium, 0.3 to 0.8 mass% iron, 0.1 to 0.4 mass% copper, 0.2 to 0.5 mass% manganese, 0.001 to 0.3 mass% chromium, 0 to 0.25 mass% zinc, 0 to 0.075 mass% titanium, 0 to 0.17 mass% zirconium, and the balance consisting of aluminum and inevitable impurities. The aluminum alloy wire is subjected to solution treatment and aging treatment, and the measurement results obtained therefrom are that the 0.2% proof stress during compression is 360 MPa or more, the grain size of the aluminum alloy is 200 μm or less, and the compressive deformation degree C when compressed at a compression rate of 50% is 0.6 or more and 1.0 or less. The solution treatment is performed at a heating temperature of 530° C. or more and 580° C. or less, for a holding time of 15 minutes or more and 360 minutes or less, and for a heating rate of 120° C. / min or less. The aging treatment is performed at a heating temperature of 160° C. or more and 190° C. or less, for a holding time of 2 hours or more and 40 hours or less.

[0013] The aluminum alloy wire of (1) above has a specific composition, and therefore has high strength and excellent workability when subjected to a predetermined solution treatment and aging treatment. The aluminum alloy wire of (1) above, after solution treatment and aging treatment, has a 0.2% yield strength during compression, an aluminum alloy grain size, and a compressive deformation degree C that each satisfy specific ranges. Since the 0.2% yield strength during compression is 360 MPa or more, the yield strength against compression is high. Since the aluminum alloy grain size is 200 μm or less, the wire has high strength and excellent workability. Furthermore, since the compressive deformation degree C is 0.6 or more and 1.0 or less, the wire has excellent workability. The aluminum alloy wire of (1) above is not subjected to solution treatment and aging treatment, and corresponds to a "normal wire rod" described later.

[0014] (2) In the aluminum alloy wire of (1), a measurement result obtained after the solution treatment and the aging treatment of the aluminum alloy wire is obtained by XAFS analysis, and the apex of a main peak in a chromium K absorption edge spectrum is located in a range of 6012.75 eV or more and 6014.00 eV or less. The apex of the main peak is determined by fitting the main peak with a Gaussian function in a range of 6009 eV to 6017 eV.

[0015] It is considered that the aluminum alloy wire of (2) is in a state where chromium is dissolved and precipitated in the aluminum alloy in a balanced manner when the aluminum alloy wire is subjected to solution treatment and aging treatment. The aluminum alloy wire of (2) has a fine crystalline structure of the aluminum alloy, high strength, and excellent workability.

[0016] (3) The present disclosure provides an aluminum alloy wire formed from an aluminum alloy containing 1.0 to 1.3 mass% silicon, 0.5 to 1.2 mass% magnesium, 0.3 to 0.8 mass% iron, 0.1 to 0.4 mass% copper, 0.2 to 0.5 mass% manganese, 0.001 to 0.3 mass% chromium, 0 to 0.25 mass% zinc, 0 to 0.075 mass% titanium, 0 to 0.17 mass% zirconium, and the remainder consisting of aluminum and inevitable impurities. The aluminum alloy wire is subjected to an aging treatment, and the measurement results obtained after the aging treatment are that the 0.2% proof stress during compression is 360 MPa or more, the grain size of the aluminum alloy is 200 μm or less, and the compressive deformation degree C when compressed at a compression rate of 50% is 0.6 or more and 1.0 or less. The aging treatment is performed at a heating temperature of 160° C. or more and 190° C. or less for a holding time of 2 hours or more and 40 hours or less.

[0017] The aluminum alloy wire of (3) above has a specific composition, and therefore has high strength and excellent workability when subjected to a predetermined aging treatment. The aluminum alloy wire of (3) above, after aging treatment, has a 0.2% yield strength during compression, a crystal grain size of the aluminum alloy, and a compressive deformation degree C that each satisfy specific ranges. Since the 0.2% yield strength during compression is 360 MPa or more, the yield strength against compression is high. Since the crystal grain size of the aluminum alloy is 200 μm or less, the wire has high strength and excellent workability. Furthermore, since the compressive deformation degree C is 0.6 or more and 1.0 or less, the wire has excellent workability. The aluminum alloy wire of (3) above is subjected to only a solution treatment, and corresponds to the "solution treated wire rod" described below.

[0018] (4) In the aluminum alloy wire of (3), a measurement result obtained after the aging treatment of the aluminum alloy wire is that a chromium K absorption edge spectrum obtained by XAFS analysis has a main peak apex located in a range of 6012.75 eV or more and 6014.00 eV or less, the main peak apex being determined by fitting the main peak with a Gaussian function in a range of 6009 eV to 6017 eV.

[0019] It is considered that the aluminum alloy wire of (4) is in a state where chromium is dissolved and precipitated in the aluminum alloy in a balanced manner when subjected to aging treatment. The aluminum alloy wire of (4) has a fine crystalline structure of the aluminum alloy, high strength, and excellent workability.

[0020] (5) The present disclosure provides an aluminum alloy wire formed from an aluminum alloy containing 1.0 to 1.3 mass% silicon, 0.5 to 1.2 mass% magnesium, 0.3 to 0.8 mass% iron, 0.1 to 0.4 mass% copper, 0.2 to 0.5 mass% manganese, 0.001 to 0.3 mass% chromium, 0 to 0.25 mass% zinc, 0 to 0.075 mass% titanium, and 0 to 0.17 mass% zirconium, with the balance being aluminum and inevitable impurities. The aluminum alloy wire has a 0.2% yield strength of 360 MPa or more when compressed, a crystal grain size of the aluminum alloy of 200 μm or less, and a compressive deformation degree C of 0.6 to 1.0 when compressed at a compression ratio of 50%.

[0021] The aluminum alloy wire of (5) above has a specific composition, and therefore has high strength and excellent workability. The aluminum alloy wire of (5) above has a 0.2% yield strength of 360 MPa or more when compressed, and therefore has high compressive strength. The aluminum alloy wire has a crystal grain size of 200 μm or less, and therefore has high strength and excellent workability. Furthermore, the compressive deformation degree C is 0.6 or more and 1.0 or less, and therefore has excellent workability. The aluminum alloy wire of (5) above has been subjected to solution treatment and aging treatment, and corresponds to the "aged wire" described below.

[0022] (6) In the aluminum alloy wire of (5), a chromium K-absorption spectrum obtained by XAFS analysis may have a main peak apex located in the range of 6012.75 eV to 6014.00 eV, the main peak apex being determined by fitting the main peak with a Gaussian function in the range of 6009 eV to 6017 eV.

[0023] The aluminum alloy wire of (6) is considered to be in a state in which chromium is dissolved and precipitated in the aluminum alloy in a balanced manner. The aluminum alloy wire of (6) has a fine crystalline structure of the aluminum alloy, high strength, and excellent workability.

[0024] (7) In the aluminum alloy wire according to any one of (1) to (6) above, the aluminum alloy wire may have a wire diameter of 1 mm or more and 30 mm or less.

[0025] The aluminum alloy wire of (7) above has a wire diameter of 1 mm or more and 30 mm or less, and therefore can achieve weight reduction while maintaining the required strength.

[0026] (8) The method for manufacturing an aluminum alloy wire according to the present disclosure includes the steps of: preparing a continuously cast and rolled material made of an aluminum alloy; subjecting the continuously cast and rolled material to a first wire drawing process to prepare a first wire drawn material; subjecting the first wire drawn material to an intermediate heat treatment process to prepare an intermediate heat treated material; and subjecting the intermediate heat treated material to a second wire drawing process to prepare a second wire drawn material. The aluminum alloy contains 1.0 to 1.3 mass% silicon, 0.5 to 1.2 mass% magnesium, 0.3 to 0.8 mass% iron, 0.1 to 0.4 mass% copper, 0.2 to 0.5 mass% manganese, 0.001 to 0.3 mass% chromium, 0 to 0.25 mass% zinc, 0 to 0.075 mass% titanium, and 0 to 0.17 mass% zirconium, with the balance being aluminum and inevitable impurities. The intermediate heat treatment is performed at a heating temperature of 250°C or higher and lower than 350°C for a holding time of 1 hour or higher and lower than 5 hours. The second wiredrawing process has a second working ratio of 20% or lower.

[0027] The manufacturing method of the aluminum alloy wire of the present disclosure allows for control of the balance of the solid solution / precipitation states of chromium in the aluminum alloy when solution treatment and aging treatment are performed, by ensuring that the conditions of the intermediate heat treatment and the second working ratio of the second wiredrawing process satisfy specific ranges in an aluminum alloy wire having a specific composition. An aluminum alloy wire in which chromium is dissolved and precipitated in a balanced manner when solution treatment and aging treatment are performed has a fine crystalline structure of the aluminum alloy. The manufacturing method of the aluminum alloy wire of the present disclosure allows for the production of an aluminum alloy wire that has high strength and excellent workability when solution treatment and aging treatment are performed.

[0028] (9) The method for producing an aluminum alloy wire according to (8) above may include a step of subjecting the second drawn wire material to a solution treatment to produce a solution wire material, wherein the solution treatment is performed at a heating temperature of 530°C to 580°C, a holding time of 15 minutes to 360 minutes, and a heating rate of 120°C / min or less.

[0029] The method for producing an aluminum alloy wire in (9) above can produce an aluminum alloy wire in which chromium is dissolved and precipitated in a balanced manner in the aluminum alloy when subjected to aging treatment.

[0030] (10) The method for producing an aluminum alloy wire according to (9) above may include a step of subjecting the solution-treated wire to an aging treatment to produce an aged wire, wherein the aging treatment is performed at a heating temperature of 160°C or higher and 190°C or lower for a holding time of 2 hours or higher and 40 hours or lower.

[0031] The above-mentioned method (10) for producing an aluminum alloy wire can produce an aluminum alloy wire in which chromium is dissolved and precipitated in the aluminum alloy in a balanced manner.

[0032] (11) In the method for producing an aluminum alloy wire according to any one of (8) to (10), the second drawn wire material may have a wire diameter of 1 mm or more and 30 mm or less.

[0033] The manufacturing method of the aluminum alloy wire in (11) above can manufacture an aluminum alloy wire that has the required strength and can achieve weight reduction.

[0034] [Details of the Embodiments of the Present Disclosure] Specific examples of the embodiments of the present disclosure will be described below with reference to the drawings. The same reference numerals in the drawings indicate the same or equivalent parts. 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.

[0035] <Aluminum Alloy Wire> (Overview) The aluminum alloy wire 1 according to this embodiment shown in FIG. 1 is formed from an aluminum alloy having a specific composition. The aluminum alloy contains silicon (Si), magnesium (Mg), iron (Fe), copper (Cu), manganese (Mn), and chromium (Cr), with the balance being aluminum (Al) and unavoidable impurities. The aluminum alloy may further contain one or more elements selected from the group consisting of zinc (Zn), titanium (Ti), and zirconium (Zr). The content of each element will be described later.

[0036] The aluminum alloy wire 1 according to this embodiment has the following properties (a) to (c) when subjected to solution treatment and aging treatment: (a) the 0.2% yield strength during compression is 360 MPa or more; (b) the crystal grain size of the aluminum alloy is 200 μm or less; and (c) the compressive deformation degree C is 0.6 or more and 1.0 or less.

[0037] (Aluminum Alloy) Of the elements contained in the aluminum alloy, Si, Mg, Fe, Cu, Mn, and Cr are essential elements, while Zn, Ti, and Zr are optional elements. The aluminum alloy does not necessarily contain Zn, Ti, and Zr. Each of these elements is in a state of solid solution or precipitated in the aluminum alloy. The precipitated element may precipitate alone, or may precipitate by forming a compound with another element. The properties of the aluminum alloy wire 1 are improved by the solid solution or precipitation of each element in the aluminum alloy. The effect and content of each element will be described below. The content of each element is expressed as a mass percentage when the entire aluminum alloy is taken as 100 mass%.

[0038] Si Si strengthens aluminum alloys by forming Mg-Si compounds with Mg and precipitating them. The remaining Si that does not form compounds strengthens aluminum alloys by dissolving in the aluminum alloy or precipitating. However, excessive Si content increases the segregation of Si at grain boundaries and tends to form coarse compounds.

[0039] The Si content is 1.0% by mass or more and 1.3% by mass or less. When the Si content is 1.0% by mass or more, Si precipitates, improving the strength of the aluminum alloy. When the Si content is 1.3% by mass or less, embrittlement due to Si segregation and the formation of coarse compounds can be reduced. As a result, the strength and workability of the aluminum alloy are less likely to decrease. The Si content may be 1.1% by mass or more and 1.3% by mass or less.

[0040] Mg Mg strengthens aluminum alloys by dissolving in the aluminum alloy or by forming and precipitating Mg-Si compounds. However, excessive Mg content can lead to reduced strength, segregation of Mg, reduced workability, and reduced heat resistance.

[0041] The Mg content is 0.5% by mass or more and 1.2% by mass or less. When the Mg content is 0.5% by mass or more, Mg precipitates, improving the strength of the aluminum alloy. When the Mg content is 1.2% by mass or less, not only is the strength and workability of the aluminum alloy less likely to decrease, but also the heat resistance is less likely to decrease. The Mg content may be 0.6% by mass or more and 1.1% by mass or less, or 0.7% by mass or more and 1.0% by mass or less.

[0042] Fe: Fe strengthens aluminum alloys by dissolving in the aluminum alloy or by forming and precipitating Al-Fe compounds. Fe also refines the crystal grains of the aluminum alloy and makes work hardening more likely to occur. Refining the crystal grains increases the number of grain boundaries, which relatively reduces embrittlement due to Si segregation. As a result, the strength and workability of the aluminum alloy are improved. However, excessive Fe content can lead to excessive compound formation or coarsening, resulting in reduced workability.

[0043] The Fe content is 0.3% by mass or more and 0.8% by mass or less. When the Fe content is within this range, Fe dissolves or precipitates, and crystal grains are refined, thereby improving the strength and workability of the aluminum alloy. The Fe content may be 0.3% by mass or more and 0.7% by mass or less, or 0.3% by mass or more and 0.6% by mass or less. The Fe content is preferably equal to or greater than the Cu content described below. By including Fe equal to or more than Cu, the strength of the aluminum alloy can be further increased.

[0044] Cu: Cu strengthens aluminum alloys by forming and precipitating Al-Cu compounds. Cu also has the effect of reducing embrittlement caused by Si segregation. However, excessive Cu content can lead to a decrease in corrosion resistance and heat resistance.

[0045] The Cu content is 0.1% by mass or more and 0.4% by mass or less. When the Cu content is 0.1% by mass or more, Cu precipitates, improving the strength of the aluminum alloy. When the Cu content is 0.4% by mass or less, the corrosion resistance and heat resistance of the aluminum alloy are less likely to decrease.

[0046] Mn Mn strengthens aluminum alloys by dissolving in the aluminum alloy or by forming and precipitating Al-Mn compounds. Furthermore, by being finely dispersed and precipitated in the aluminum alloy, Mn reduces the coarsening of the aluminum alloy's crystal grains and contributes to the refinement of the crystal grains. Mn also has the effect of improving the heat resistance of the aluminum alloy. However, excessive Mn content tends to form coarse compounds, resulting in a decrease in workability.

[0047] The Mn content is 0.2% by mass or more and 0.5% by mass or less. When the Mn content is within this range, Mn dissolves or precipitates, and crystal grains are refined, thereby improving not only the strength and workability of the aluminum alloy but also the heat resistance. The Mn content may be 0.2% by mass or more and 0.4% by mass or less, or 0.2% by mass or more and 0.3% by mass or less.

[0048] ・Cr Cr strengthens aluminum alloys by dissolving in the aluminum alloy or by forming and precipitating Al-Cr compounds. Furthermore, Cr precipitates finely dispersed in the aluminum alloy, reducing the coarsening of the aluminum alloy's crystal grains and contributing to the refinement of the crystal grains. Cr also has the effect of improving the heat resistance and corrosion resistance of the aluminum alloy. However, excessive Cr content tends to form coarse compounds, resulting in reduced workability.

[0049] The Cr content is 0.001% by mass or more and 0.3% by mass or less. When the Cr content is within this range, Cr dissolves or precipitates, and the crystal grains are refined, thereby improving not only the strength and workability of the aluminum alloy but also the heat resistance and corrosion resistance. The Cr content may be 0.005% by mass or more and 0.2% by mass or less, or 0.01% by mass or more and 0.1% by mass or less.

[0050] Zn strengthens aluminum alloys by forming and precipitating Al-Zn compounds. However, excessive Zn content reduces workability, corrosion resistance, and heat resistance.

[0051] The Zn content is 0% by mass or more and 0.25% by mass or less. When Zn is contained, by setting the Zn content to 0.005% by mass or more and 0.25% by mass or less, not only the strength of the aluminum alloy is improved but also the corrosion resistance and heat resistance are less likely to decrease. The Zn content may be 0.05% by mass or more and 0.2% by mass or less.

[0052] Ti Ti has the effect of refining the crystal grains of an aluminum alloy. However, excessive Ti content leads to a decrease in workability.

[0053] The Ti content is 0% by mass or more and 0.075% by mass or less. When Ti is contained, the strength and workability of the aluminum alloy are improved by the Ti content being 0.001% by mass or more and 0.075% by mass or less. The Ti content may be 0.005% by mass or more and 0.05% by mass or less, or 0.01% by mass or more and 0.05% by mass or less.

[0054] Zr: Zr is finely dispersed and precipitated in the aluminum alloy, reducing the coarsening of the crystal grains of the aluminum alloy and contributing to the refinement of the crystal grains. Zr also has the effect of improving the heat resistance of the aluminum alloy. However, if Zr is contained in excess, coarse compounds are likely to be formed, resulting in a decrease in workability.

[0055] The Zr content is 0% by mass or more and 0.17% by mass or less. When Zr is contained, the Zr content of 0.001% by mass or more and 0.17% by mass or less improves the strength and workability of the aluminum alloy. The Zr content may be 0.001% by mass or more and 0.15% by mass or less, or 0.005% by mass or more and 0.1% by mass or less. The total content of Ti and Zr is, for example, 0.001% by mass or more and 0.2% by mass or less, or 0.005% by mass or more and 0.1% by mass or less.

[0056] Sr: The aluminum alloy may also contain strontium (Sr). Sr has the effect of finely precipitating Si. As a result, the workability of the aluminum alloy is improved. The Sr content is, for example, 0.005% by mass to 0.05% by mass, or 0.005% by mass to 0.03% by mass.

[0057] The composition of the aluminum alloy can be measured by a known method, for example, an energy dispersive X-ray analyzer.

[0058] (Form of Aluminum Alloy Wire) The aluminum alloy wire 1 is manufactured through wiredrawing. The aluminum alloy wire 1 may be subjected to solution treatment or aging treatment after solution treatment. The aluminum alloy wire 1 of the present embodiment may be in any of the following forms: a state in which neither solution treatment nor aging treatment has been performed, a state in which aging treatment has not been performed after solution treatment, or a state in which aging treatment has been performed after solution treatment. Hereinafter, the aluminum alloy wire 1 that has not been subjected to solution treatment and aging treatment may be referred to as a "normal wire rod," an aluminum alloy wire 1 that has only been subjected to solution treatment may be referred to as a "solution wire rod," and an aluminum alloy wire 1 that has been subjected to solution treatment and aging treatment may be referred to as an "aged wire rod."

[0059] When the aluminum alloy wire 1 is a normal wire rod, the properties of the aluminum alloy wire 1 are improved by subjecting it to solution treatment and aging treatment. When the aluminum alloy wire 1 is a solution-treated wire rod, the properties of the aluminum alloy wire 1 are improved by subjecting it to aging treatment. When comparing normal wire rods, solution-treated wire rods, and aged wire rods, the relationship between the tensile strength and elongation of each wire rod generally tends to be as follows: The normal wire rod has low tensile strength and elongation. The solution-treated wire rod has low tensile strength but high elongation. The aged wire rod has high tensile strength and elongation.

[0060] <Solution Treatment> The conditions for solution treatment are a heating temperature of 530°C to 580°C, a holding time of 15 minutes to 360 minutes, and a heating rate of 120°C / min or less. A heating temperature of 530°C or higher and a holding time of 15 minutes or longer allow the elements contained in the aluminum alloy to be fully dissolved in the aluminum alloy. The higher the heating temperature, the more the solid solution of elements such as Fe can be promoted. The heating temperature may be 550°C or higher. If the heating temperature is too high, Si segregation occurs and voids are likely to occur in the aluminum alloy. If the heating temperature is 580°C or lower, Si segregation and the occurrence of voids can be sufficiently reduced. A longer holding time promotes solid solution of elements, but if the holding time is too long, Si segregation will progress. Therefore, the holding time may be 30 minutes to 120 minutes, or 50 minutes to 100 minutes.

[0061] If the heating rate is too high, voids are likely to occur in the aluminum alloy. If the heating rate is 120°C / min or less, the occurrence of voids can be reduced. Furthermore, the heating rate is preferably 2°C / min or more. The higher the heating rate, the easier it is to reduce the segregation of Si. The heating rate may be 2°C / min or more and 120°C / min or less, 10°C / min or more and 120°C / min or less, or 25°C / min or more and 120°C / min or less.

[0062] In the solution treatment, the aluminum alloy wire 1 is held at a heating temperature for a certain period of time and then cooled to room temperature. The faster the cooling rate during this cooling, the more the elements can be maintained in a solid solution state in the aluminum alloy. The cooling rate is, for example, 50°C / sec or more. The cooling rate may be 100°C / sec or more, 200°C / sec or more, or 500°C / sec or more. The cooling in the solution treatment can be performed, for example, by water cooling.

[0063] <Aging Treatment> Aging treatment is performed after solution treatment. The conditions for the aging treatment are a heating temperature of 160°C or higher and 190°C or lower, and a holding time of 2 hours or higher and 40 hours or lower. A heating temperature of 160°C or higher and a holding time of 2 hours or higher allow the elements dissolved by the solution treatment to precipitate sufficiently in the aluminum alloy. A heating temperature of 190°C or lower can reduce coarsening of the aluminum alloy crystal grains and precipitates. The higher the heating temperature, the more the precipitation of elements progresses, and therefore a shorter holding time is required. The heating temperature may be 170°C or higher. The holding time may be 4 hours or higher and 20 hours or lower, or 6 hours or higher and 10 hours or lower.

[0064] (Shape of aluminum alloy wire 1) The shape of the aluminum alloy wire 1 may be any shape. The cross-sectional shape of the aluminum alloy wire 1 shown in FIG. 1 is circular. The cross section of the aluminum alloy wire 1 is a cross section perpendicular to the length of the aluminum alloy wire 1. The cross-sectional shape of the aluminum 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.

[0065] (Wire diameter of aluminum alloy wire 1) The wire diameter D of the aluminum alloy wire 1 is, for example, 1 mm or more and 30 mm or less. When the cross-sectional shape of the aluminum alloy wire 1 is circular, the wire diameter D of the aluminum alloy wire 1 is the diameter of the cross section. When the cross-sectional shape of the aluminum alloy wire 1 is non-circular, the wire diameter D of the aluminum alloy wire 1 is regarded as the diameter of a circle having an area equal to the cross-sectional area. The wire diameter D may be 4 mm or more and 10 mm or less.

[0066] (Characteristics of Aluminum Alloy Wire) The aluminum alloy wire 1 of the present embodiment, in a state where it has been subjected to a solution treatment and an aging treatment, i.e., an aged wire, has a 0.2% proof stress during compression of 360 MPa or more, a crystal grain size of the aluminum alloy of 200 μm or less, and a compressive deformation degree C of 0.6 or more and 1.0 or less. Furthermore, the apex of the main peak in the Cr K-absorption edge spectrum obtained by XAFS analysis may be located in the range of 6012.75 eV or more and 6014.00 eV or less. Measurement conditions for these characteristics vary depending on the form of the aluminum alloy wire 1. When the aluminum alloy wire 1 is a normal wire, the aluminum alloy wire 1 is measured after being subjected to a solution treatment and an aging treatment. When the aluminum alloy wire 1 is a solution-treated wire, the aluminum alloy wire 1 is measured after being subjected to only an aging treatment without being subjected to a solution treatment. When the aluminum alloy wire 1 is an aged wire, the aluminum alloy wire 1 is measured as is.

[0067] <0.2% Proof Stress Under Compression> The higher the 0.2% proof stress under compression, the higher the proof stress against compression. When the 0.2% proof stress under compression is 360 MPa or more, the aluminum alloy wire 1 has high proof stress against compression and excellent compression characteristics. The 0.2% proof stress under compression may be 380 MPa or more, or 400 MPa or more. The upper limit of the 0.2% proof stress under compression is, for example, 500 MPa. The 0.2% proof stress under compression may be, for example, 360 MPa or more and 500 MPa or less, 380 MPa or more and 480 MPa or less, or 400 MPa or more and 450 MPa or less.

[0068] The 0.2% yield strength during compression can be determined from the stress-strain curve (SS curve) obtained through a compression test. Specifically, the 0.2% yield strength during compression is determined by reading the stress at which a permanent strain of 0.2% occurs from the stress-strain curve. The compression test is performed in accordance with JIS K 7181:2011.

[0069] <Crystal Grain Size of Aluminum Alloy> The smaller the crystal grain size of the aluminum alloy, the finer the crystalline structure of the aluminum alloy, and therefore the strength and workability of the aluminum alloy wire 1 are improved. When the crystal grain size is 200 μm or less, the aluminum alloy wire 1 has high strength and excellent workability. The crystal grain size may be 150 μm or less, or 100 μm or less. The lower limit of the crystal grain size is, for example, 5 μm. The crystal grain size may be, for example, 5 μm or more and 200 μm or less, 10 μm or more and 150 μm or less, or 20 μm or more and 100 μm or less.

[0070] The crystal grain size of an aluminum alloy can be determined by a cutting method. Measurement of the crystal grain size by the cutting method is performed as follows: A cross section of an aluminum alloy wire is observed using a microscope. The cross section is a cross section perpendicular to the length of the aluminum alloy wire. The microscope may be an optical microscope or a scanning electron microscope (SEM). The magnification of the microscope is appropriately adjusted according to the crystal grain size. The magnification of the microscope is, for example, 50 times or more and 1000 times or less. A straight line is drawn on a photograph of the observed cross section. The number n of crystal grains crossed by this line is determined. If the end of the line is inside a crystal grain, that is, if the line does not completely cross a crystal grain, it is counted as 1 / 2. The value obtained by dividing the length L of the line by the number n of crystal grains and multiplying this value by 1.5 is considered to be the crystal grain size. There may be multiple lines. The number of lines is, for example, 4 to 10. If multiple lines are drawn, the crystal grain size is determined from each line, and the average value is taken as the crystal grain size.

[0071] <Compressive Deformation Degree> The compressive deformation degree C represents the uniformity of deformation when the aluminum alloy wire 1 is compressed at a compression rate of 50%. A method for measuring the compressive deformation degree C will be described with reference to FIG. 2 . An aluminum alloy wire test piece 1s is prepared. The test piece 1s is cut out from the aluminum alloy wire 1. The test piece 1s has a cylindrical shape. The end face shape of the test piece 1s is circular, with a diameter d of 1 mm or more and 30 mm or less. The length h of the test piece 1s is 10 mm. The end face shape of the test piece 1s does not have to be a perfect circle. If the circularity of the end face of the test piece 1s before compression is 0.9 or more and 1 or less, the end face shape is considered to be circular. The circularity is calculated by using the area Ss and the perimeter Ls of the end face of the test piece 1s, as follows: 4×π×Ss / Ls２ The closer the circularity is to 1, the closer the end face shape is to a perfect circle. When the cross-sectional shape of the aluminum alloy wire 1 is non-circular, a test piece 1s cut out from the aluminum alloy wire 1 is machined into a cylindrical shape.

[0072] As shown in FIG. 2 , the test piece 1 s is sandwiched between two plates 21 and 22, and a compressive load F is applied to the test piece 1 s. The two plates 21 and 22 are arranged parallel to each other. The end faces 11 and 12 of the test piece 1 s are in contact with the plates 21 and 22, respectively. The test piece 1 s is compressed by moving the plates 21 and 22 toward each other along the axis of the test piece 1 s. The test piece 1 s, which has a length h before compression, is compressed at a compression rate of 50%, to obtain a compressed test piece 1 a. A compression rate of 50% means that the length of the compressed test piece 1 a is half the length h of the test piece 1 s before compression. In other words, the length of the compressed test piece 1 a is h / 2. The compressive deformation degree C is calculated using the cross-sectional area Sa and circumferential length La of the compressed test piece 1 a as follows: C = 4 × π × Sa / La ２ The cross-sectional area Sa is calculated by multiplying the cross-sectional area of ​​the test piece 1s before compression by 2. That is, the cross-sectional area Sa is equal to the above-mentioned area Ss multiplied by 2. In other words, Sa = Ss ２ The perimeter La is measured at the center position of the length of the test piece 1a after compression, that is, at the position h / 4.

[0073] When the compressive deformation degree C is 0.6 or more and 1.0 or less, it can be said that the end face shape of the compressed test piece 1a is almost maintained as a circle compared to the end face shape of the test piece 1s before compression, and is uniformly deformed. Such an aluminum alloy wire is excellent in workability because it is uniformly deformed during processing. In other words, the compressive deformation degree C can be used as an index indicating workability. When the compressive deformation degree C is less than 0.6, the end face shape is not sufficiently maintained before and after compression, and it is deformed unevenly. Such an aluminum alloy wire is poor in workability because it is deformed unevenly during processing. It can be said that the closer the compressive deformation degree C is to 1, the better the workability. The compressive deformation degree C may be 0.7 or more, or even 0.8 or more.

[0074] <Position of the main peak in the Cr K-edge absorption spectrum> XAFS stands for X-ray absorption fine structure, and is a method of analyzing the absorption spectrum obtained by irradiating a material with X-rays. XAFS analysis can be used to evaluate the state of elements in an aluminum alloy.

[0075] The reason why the aluminum alloy wire 1 of this embodiment has the above-mentioned characteristics after being subjected to solution treatment and aging treatment is not clear, but it is thought to be due to an optimized balance between solid solution and precipitation of the above elements contained in the aluminum alloy. The Cr K-absorption edge spectrum represents the solid solution / precipitation state of Cr. When the apex of the main peak in the Cr K-absorption edge spectrum is located in the range of 6012.75 eV or more and 6014.00 eV or less, Cr is in a well-balanced solid solution and precipitation state in the aluminum alloy. Such an aluminum alloy wire 1 has a fine crystalline structure of the aluminum alloy, high strength, and excellent workability. The apex of the main peak was determined by fitting the main peak in the range of 6009 eV to 6017 eV in the Cr K-absorption edge spectrum with a Gaussian function.

[0076] (Applications of Aluminum Alloy Wire) The aluminum alloy wire 1 of the present embodiment can be suitably used as a material for aluminum alloy members such as structural members and automobile parts. Since the aluminum alloy wire 1 has high compressive strength, it is particularly suitable as a material for aluminum alloy members that are subjected to compressive loads during use.

[0077] <Method for manufacturing aluminum alloy wire> The present inventors have investigated a method for manufacturing an aluminum alloy wire having the above-mentioned specific composition, which has high strength and excellent workability after being subjected to solution treatment and aging treatment. As a result, the present inventors have found that it is preferable to adjust the conditions of the intermediate heat treatment performed during wiredrawing and the conditions of the wiredrawing performed immediately before solution treatment to specific ranges.

[0078] The aluminum alloy wire 1 of this embodiment can be manufactured by the aluminum alloy wire manufacturing method according to the embodiment. The aluminum alloy wire manufacturing method of this embodiment includes, in order, a first step, a second step, a third step, and a fourth step. Each step is as follows.

[0079] The first step is a step of producing a continuously cast and rolled material made of an aluminum alloy. This aluminum alloy has the specific composition described above. The second step is a step of subjecting the continuously cast and rolled material to a first wire drawing process to produce a first drawn wire material. The third step is a step of subjecting the first drawn wire material to an intermediate heat treatment to produce an intermediate heat treated material. The conditions for this intermediate heat treatment are a heating temperature of 250°C or higher and lower than 350°C, and a holding time of 1 hour or higher and lower than 5 hours. The fourth step is a step of subjecting the intermediate heat treated material to a second wire drawing process to produce a second drawn wire material. The second working ratio in the second wire drawing process is 20% or lower.

[0080] The aluminum alloy wire manufacturing method of this embodiment produces an aluminum alloy wire by drawing a continuously cast and rolled material. In the aluminum alloy wire manufacturing method of this embodiment, intermediate heat treatment is performed during the wiredrawing process. One of the features of the aluminum alloy wire manufacturing method of this embodiment is that the heating temperature in the intermediate heat treatment is relatively low, the holding time is short, and the second wiredrawing process after the intermediate heat treatment has a second working ratio of 20% or less. The aluminum alloy wire manufacturing method of this embodiment controls the balance between the solid solution and precipitation states of Cr in the aluminum alloy when solution treatment and aging treatment are performed by setting the intermediate heat treatment conditions and the second working ratio in the second wiredrawing process to satisfy specific ranges. This aluminum alloy wire manufacturing method of this embodiment can produce the aluminum alloy wire 1 of this embodiment. Each step will be described in detail below.

[0081] (First step) Continuously cast and rolled material can be produced by a continuous casting and rolling method. The continuous casting and rolling method is a method in which a molten aluminum alloy is cast and then continuously rolled. The continuously cast and rolled material is used as a raw material for aluminum alloy wire. If the raw material is a continuously cast and rolled material, a continuous, long aluminum alloy wire can be produced. In particular, the Properti continuous casting and rolling method has a fast solidification rate, which makes it easy for elements contained in the aluminum alloy to form a solid solution, and also makes it easy for crystallized particles generated during casting to become finely dispersed. Therefore, the continuously cast and rolled material produced by the Properti continuous casting and rolling method has excellent plastic workability and is easy to draw.

[0082] The shape of the continuously cast and rolled material may be any shape. The cross-sectional shape of the continuously cast and rolled material may be circular or rectangular. The cross section of the continuously cast and rolled material is a cross section perpendicular to the length of the continuously cast and rolled material. The wire diameter of the continuously cast and rolled material is, for example, 5 mm or more and 40 mm or less. The wire diameter of the continuously cast and rolled material may be 10 mm or more and 30 mm or less. When the cross-sectional shape of the continuously cast and rolled material is circular, the wire diameter of the continuously cast and rolled material is the diameter of that cross section. When the cross-sectional shape of the continuously cast and rolled material is rectangular, the wire diameter of the continuously cast and rolled material is considered to be the diameter of a circle having an area equal to the cross-sectional area.

[0083] (Second Step) The first wiredrawing is performed cold. The first drawing ratio of the first wiredrawing is not particularly limited. The first drawing ratio is selected so that the final wire diameter of the second drawn wire material in the fourth step falls within a predetermined range. The first drawing ratio is, for example, 1% to 99.9%. The first drawing ratio may be 5% to 80% or 5% to 50%. The first drawing ratio is the difference between the cross-sectional area before the first wiredrawing and the cross-sectional area after the first wiredrawing, divided by the cross-sectional area before the first wiredrawing, expressed as a percentage (%). The cross-sectional area before the first wiredrawing corresponds to the cross-sectional area of ​​the continuously cast and rolled material. The cross-sectional area after the first wiredrawing corresponds to the cross-sectional area of ​​the first drawn wire material. The wire diameter of the first drawn wire material is, for example, 1.01 mm to 33.5 mm. The wire diameter of the first drawn wire material may be 4.5 mm or more, or 11.2 mm or less.

[0084] (Third Step) The first drawn wire material in the second step undergoes work hardening due to the first wire drawing process. The intermediate heat treatment softens the first drawn wire material, thereby improving the workability of the intermediate heat treated material. This makes it easier to perform the second wire drawing process on the intermediate heat treated material in the fourth step. The intermediate heat treatment does not substantially change the wire diameter of the first drawn wire material. In other words, the wire diameter of the intermediate heat treated material is substantially equal to the wire diameter of the first drawn wire material.

[0085] By setting the heating temperature of the intermediate heat treatment to 250°C or higher and the holding time to 1 hour or longer, the first drawn wire material can be sufficiently softened. The higher the heating temperature or the longer the holding time, the more the intermediate heat-treated material softens. On the other hand, if the heating temperature is too high or the holding time is too long, the crystal grains of the aluminum alloy will become coarse, resulting in a decrease in workability. By setting the heating temperature to less than 350°C and the holding time to less than 5 hours, the coarsening of the crystal grains of the aluminum alloy can be reduced, and workability is less likely to decrease. The heating temperature of the intermediate heat treatment may be 280°C or higher and 330°C or lower. The holding time may be 2 hours or higher and 4 hours or lower.

[0086] (Fourth Step) The second wiredrawing is performed in a cold state. The second drawing ratio of the second wiredrawing is 20% or less. The second drawing ratio is selected from a range of 20% or less so that the wire diameter of the second drawn wire material falls within a predetermined range. The second drawing ratio may be 15% or less, or 10% or less. The second drawing ratio may be, for example, 1% to 20%, 2% to 15%, or 5% to 10%. The second drawing ratio is the difference between the cross-sectional area before the second wiredrawing and the cross-sectional area after the second wiredrawing, divided by the cross-sectional area before the second wiredrawing, expressed as a percentage (%). The cross-sectional area before the second wiredrawing corresponds to the cross-sectional area of ​​the intermediate heat-treated material. The cross-sectional area after the second wiredrawing corresponds to the cross-sectional area of ​​the second drawn wire material. The wire diameter of the second drawn wire material is, for example, 1 mm to 30 mm. The wire diameter of the second drawn wire material may be 4 mm or more, or 10 mm or less. The wire diameter of the second drawn wire material is substantially equal to the wire diameter of the aluminum alloy wire 1 to be produced.

[0087] The manufacturing method of the aluminum alloy wire of this embodiment can manufacture the aluminum alloy wire 1 of this embodiment, which has high strength and excellent workability in a state where it has been solution treated and aging treated. The second drawn wire in the fourth step is an aluminum alloy wire that has not been solution treated and aging treated. That is, the second drawn wire corresponds to the normal wire described above. When this aluminum alloy wire, i.e., the normal wire, is subjected to solution treatment and aging treatment and then measured, the aluminum alloy wire that has been solution treated and aging treated, i.e., the aged wire, has the above-mentioned properties. Specifically, the 0.2% proof stress during compression is 360 MPa or more, the grain size of the aluminum alloy is 200 μm or less, and the compressive deformation degree C is 0.6 to 1.0. Furthermore, the aluminum alloy wire that has been solution treated and aging treated has the apex of the main peak in the Cr K-absorption edge spectrum in XAFS analysis located in a specific range.

[0088] (Fifth Step) The method for producing an aluminum alloy wire according to the present embodiment may further include a fifth step after the fourth step. The fifth step is a step of subjecting the second drawn wire material to a solution treatment to produce a solution-treated wire material. The conditions for this solution treatment are as described above.

[0089] The solution-treated wire is an aluminum alloy wire in which elements contained in the aluminum alloy are in a solid solution state due to solution treatment. The solution-treated wire is an aluminum alloy wire that has been subjected to only solution treatment. When this aluminum alloy wire, i.e., the solution-treated wire, is subjected to aging treatment and then measured, the aging-treated aluminum alloy wire, i.e., the aged wire, has the above-mentioned properties.

[0090] (Sixth Step) The method for producing an aluminum alloy wire according to the present embodiment may further include a sixth step after the fifth step. The sixth step is a step of subjecting the solution-treated wire to an aged wire. The conditions for this aging treatment are as described above.

[0091] The aged wire is an aluminum alloy wire that has undergone solution treatment and aging treatment, and the elements dissolved in the aluminum alloy are precipitated by the aging treatment. The aged wire has the above-mentioned properties as it is.

[0092] Test Example 1 Samples of aluminum alloy wires were manufactured having the compositions shown in Table 1. Composition I shown in Table 1 is within the range of the composition of the aluminum alloy in this embodiment. Composition II shown in Table 1 is outside the range of the composition of the aluminum alloy in this embodiment. Composition II corresponds to the composition of the aluminum alloy defined by International Alloy Number A6061.

[0093]

[0094] (Preparation of Samples) Aluminum alloy wire samples were produced by cold drawing continuously cast and rolled materials. Table 2 shows the production conditions for the aluminum alloy wire. Continuously cast and rolled materials were produced using a known Properti-type continuous casting and rolling mill. Continuously cast and rolled materials were produced using molten metal whose components were adjusted to have composition I or composition II shown in Table 1. When the composition item in Table 2 is "I", it means that it is composition I shown in Table 1. When the composition item in Table 2 is "II", it means that it is composition II shown in Table 1.

[0095] When the continuously cast and rolled material was wiredrawn, an intermediate heat treatment was performed midway through the wiredrawing process. That is, the first wiredrawing process, the intermediate heat treatment, and the second wiredrawing process were performed in that order. The first working ratio of the first wiredrawing process, the conditions of the intermediate heat treatment, and the second working ratio of the second wiredrawing process are shown in Table 2. The intermediate heat treatment item in Table 2 indicates the heating temperature and holding time. For example, "300°C x 3h" means that the heating temperature was 300°C and the holding time was 3 hours.

[0096] After the second wiredrawing, the aluminum alloy wire, which was a normal wire rod, was subjected to solution treatment and aging treatment to produce an aluminum alloy wire, which was an aged wire rod. The conditions for the solution treatment and the aging treatment are shown in Table 2. The conditions for the solution treatment were a heating temperature of 550°C and a holding time of 60 minutes. The conditions for the aging treatment were a heating temperature of 175°C and a holding time of 8 hours. The temperature rise rate for the solution treatment was 2.3°C / min or 110°C / min. In the solution treatment, the aluminum alloy wire was held at the heating temperature for a certain period of time and then water-cooled to room temperature. The temperature drop rate for the solution treatment was 1000°C / sec. The cross-sectional shape of the produced aluminum alloy wire was circular. The wire diameter of the aluminum alloy wire was in the range of 1 mm to 30 mm.

[0097] As shown in Table 2, Sample No. 1a and Sample No. 1b have the same composition and manufacturing conditions except for the heating rate of the solution treatment. In the following description, Sample No. 1a and Sample No. 1b may be collectively referred to as "Sample No. 1." Similarly, Sample No. 2a and Sample No. 2b may be collectively referred to as "Sample No. 2," and Sample No. 10a and Sample No. 10b may be collectively referred to as "Sample No. 10."

[0098]

[0099] (Sample Characteristics) The properties of the aluminum alloy wire samples that had been subjected to solution treatment and aging treatment were examined. The properties examined were 0.2% proof stress during compression, the grain size of the aluminum alloy, the degree of compressive deformation, and the position of the main peak in the Cr K-absorption edge spectrum. The measurement methods for each property are described below. The results of the examined properties are shown in Table 3.

[0100] <0.2% yield strength during compression> The 0.2% yield strength during compression is determined from the stress-strain curve (SS curve) obtained by a compression test. The compression test is performed in accordance with JIS K 7181:2011. The test specimens used in the compression test were cut from the aluminum alloy wire of each sample. The length of the test specimen was 10 mm. The compression test was performed at room temperature.

[0101] <Crystalline Grain Size of Aluminum Alloy> The crystalline grain size of the aluminum alloy is determined by observing the cross section of the aluminum alloy wire under a microscope and by the intercept method. The crystalline grain size measurement by the intercept method was performed by drawing five straight lines on a photograph of the observed cross section and calculating the average value of the crystalline grain size determined from each of the straight lines.

[0102] <Compressive Deformation Degree> As shown in FIG. 2, the test piece 1s is compressed at a compression rate of 50%, and the compressive deformation degree is determined from the shape of the test piece 1a after compression. The test piece 1s is cut out from the aluminum alloy wire of each sample. The length h of the test piece 1s before compression is 10 mm. As described above, the compressive deformation degree C is calculated from the cross-sectional area Sa and the circumferential length La of the test piece 1a after compression by 4×π×Sa / La. ２ The cross-sectional area Sa is the cross-sectional area of ​​the test piece 1s before compression multiplied by 2. The circumferential length La was determined by measuring the circumferential length at the center position of the length of the test piece 1a after compression. When the compressive deformation degree C is 0.6 or more and 1.0 or less, it can be said that the deformation is uniform. In this case, the evaluation of the compressive deformation degree in Table 3 is "A". When the compressive deformation degree C is less than 0.6, it can be said that the deformation is non-uniform. In this case, the evaluation of the compressive deformation degree in Table 3 is "B".

[0103] <Position of the Main Peak in the Cr K-Absorption Edge Spectrum> The Cr K-absorption edge spectrum is measured using an XAFS analyzer installed at Beamline (BL) 16 of the Kyushu Synchrotron Light Research Center. XAFS analysis may be performed using equivalent BLs capable of XAFS analysis, such as BL01B1 or BL14B2 at SPring-8, a large-scale synchrotron radiation facility, or BL5S1 or BL11S2 at the Aichi Synchrotron Light Center. The analytical samples were cut from the aluminum alloy wires of each sample, and the surfaces of the aluminum alloy wires were polished. The position of the apex of the main peak in the obtained Cr K-absorption edge spectrum is determined. The apex of the main peak is determined by fitting the main peak with a Gaussian function in the range from 6009 eV to 6017 eV. If the apex of the main peak is between 6012.75 eV and 6014.00 eV, the position of the main peak in Table 3 is determined as "A." When the position of the apex of the main peak is outside the range of 6012.75 eV or more and 6014.00 eV or less, the position of the main peak in Table 3 is judged as "B".

[0104]

[0105] As shown in Table 3, both Sample No. 1 and Sample No. 2 have a 0.2% yield strength of 360 MPa or more during compression, demonstrating high compressive strength. The 0.2% yield strength during compression of Sample No. 1 and Sample No. 2 is 400 MPa or more. The aluminum alloy grain size of Sample No. 1 and Sample No. 2 is 200 μm or less, and the compressive deformation rating is also "A." Therefore, it can be seen that both Sample No. 1 and Sample No. 2 have high strength and excellent workability. Furthermore, the position of the main peak in the Cr K-absorption edge spectrum of Sample No. 1 and Sample No. 2 is rated "A," and the apex of the main peak is in the range of 6012.75 eV or more and 6014.00 eV or less. The compressive deformation rating C of Sample No. 1a is 0.63, and Sample No. 1b is 0.63. The compressive deformation degree C of sample No. 1b was 0.65, the compressive deformation degree C of sample No. 2a was 0.69, and the compressive deformation degree C of sample No. 2b was 0.90. From these results, it can be seen that the smaller the crystal grain size of the aluminum alloy, the closer the compressive deformation degree C becomes to 1. It is considered preferable that the crystal grain size of the aluminum alloy is 75 μm or less, particularly 70 μm or less.

[0106] In contrast, Sample No. 10 had a low 0.2% yield strength during compression and a large aluminum alloy crystal grain size. Sample No. 10 was evaluated as "B" for the degree of compressive deformation, indicating poor workability. Sample No. 10 was also evaluated as "B" for the position of the main peak in the Cr K-absorption edge spectrum, and the position of the apex of the main peak was outside the range of 6012.75 eV or more and 6014.00 eV or less. Sample No. 11 had a high 0.2% yield strength during compression, but the aluminum alloy crystal grain size was large. Sample No. 11 was evaluated as "B" for the degree of compressive deformation, indicating poor workability. Sample No. 11 was also evaluated as "A" for the position of the main peak in the Cr K-absorption edge spectrum.

[0107] Figure 3 shows the Cr K-absorption edge spectra of Sample No. 2a and Sample No. 10a superimposed on each other. In Figure 3, the Cr K-absorption edge spectrum of Sample No. 2a is shown by a thick solid line, and the Cr K-absorption edge spectrum of Sample No. 10a is shown by a thin solid line. The horizontal axis of the Cr K-absorption edge spectrum shown in Figure 3 represents X-ray energy (eV), and the vertical axis represents X-ray absorption (arbitrary units a.u.). In Figure 3, the thick dashed line indicates the position of the main peak in the Cr K-absorption edge spectrum of Sample No. 2a, and the thin dashed line indicates the position of the main peak in the Cr K-absorption edge spectrum of Sample No. 10a. The position of the main peak in the Cr K-absorption edge spectrum of Sample No. 2a is 6013.1 eV. The position of the main peak in the Cr K-absorption edge spectrum of Sample No. 10a is 6011.9 eV.

[0108] [Test Example 2] Aluminum alloy wire samples were produced with different heating rates in the solution treatment, and the properties of each sample were investigated. The heating rates in the solution treatment and the results of the investigated properties are shown in Table 4.

[0109] The aluminum alloy wires of Sample No. 2-1 to Sample No. 2-5 shown in Table 4 had the same composition and were manufactured under the same conditions as Sample No. 2 of Test Example 1, except that the heating rate of the solution treatment was set as shown in Table 4. Sample No. 2-1 corresponds to Sample No. 2a of Test Example 1, and Sample No. 2-5 corresponds to Sample No. 2b of Test Example 1. The aluminum alloy wires of Sample No. 2-11 to Sample No. 2-15 had the same composition and were manufactured under the same conditions as Sample No. 10 of Test Example 1, except that the heating rate of the solution treatment was set as shown in Table 4. Sample No. 2-11 corresponds to Sample No. 10a of Test Example 1, and Sample No. 2-15 corresponds to Sample No. 10b of Test Example 1.

[0110] The properties of each sample were measured in the same manner as in Test Example 1.

[0111]

[0112] As shown in Table 4, Samples No. 2-1 to No. 2-5 all have a 0.2% yield strength during compression of 360 MPa or more, and the aluminum alloy grain size is 200 μm or less. Samples No. 2-1 to No. 2-5 also received an "A" rating for the degree of compressive deformation. Therefore, it can be seen that Samples No. 2-1 to No. 2-5 all have high strength and excellent workability. Furthermore, Samples No. 2-1 to No. 2-5 also received an "A" rating for the position of the main peak in the Cr K-absorption edge spectrum, and the position of the apex of the main peak is within the range of 6012.75 eV or more and 6014.00 eV or less.

[0113] In contrast, Samples No. 2-11 to No. 2-15 have low 0.2% yield strength during compression and large aluminum alloy crystal grain sizes. Samples No. 2-11 to No. 2-15 were evaluated as "B" for the degree of compressive deformation, indicating poor workability. Furthermore, Samples No. 2-11 to No. 2-15 were evaluated as "B" for the position of the main peak in the Cr K-absorption edge spectrum, and the position of the apex of the main peak was outside the range of 6012.75 eV or more and 6014.00 eV or less.

[0114] It should be noted that 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.

[0115] 1 Aluminum alloy wire 1s Test piece 1a Test piece after compression 11, 12 End faces 21, 22 Plate D Wire diameter h Length d Diameter

Claims

1. An aluminum alloy wire formed of an aluminum alloy, the aluminum alloy containing 1.0 mass% or more and 1.3 mass% or less of silicon, 0.5 mass% or more and 1.2 mass% or less of magnesium, 0.3 mass% or more and 0.8 mass% or less of iron, 0.1 mass% or more and 0.4 mass% or less of copper, 0.2 mass% or more and 0.5 mass% or less of manganese, 0.001 mass% or more and 0.3 mass% or less of chromium, 0 mass% or more and 0.25 mass% or less of zinc, 0 mass% or more and 0.075 mass% or less of titanium, and 0 mass% or more and 0.17 mass% or less of zirconium, with the balance being aluminum and unavoidable impurities, and measurement results obtained after subjecting the aluminum alloy wire to solution treatment and aging treatment show that the 0.2% proof stress during compression is 360 MPa or more, and the grain size of the aluminum alloy is 200 μm or less, an aluminum alloy wire having a compressive deformation degree C of 0.6 or more and 1.0 or less when compressed at a compression rate of 50%, wherein the solution treatment is performed at a heating temperature of 530° C. or more and 580° C. or less, with a holding time of 15 minutes or more and 360 minutes or less, and a heating rate of 120° C. / min or less, and wherein the aging treatment is performed at a heating temperature of 160° C. or more and 190° C. or less, with a holding time of 2 hours or more and 40 hours or less.

2. The aluminum alloy wire according to claim 1, wherein a measurement result obtained after subjecting the aluminum alloy wire to the solution treatment and the aging treatment shows that an apex of a main peak in a chromium K absorption edge spectrum obtained by XAFS analysis is located in a range of 6012.75 eV or more and 6014.00 eV or less, and the apex of the main peak is determined by fitting the main peak with a Gaussian function in a range of 6009 eV to 6017 eV.

3. An aluminum alloy wire formed of an aluminum alloy, the aluminum alloy containing 1.0 mass% or more and 1.3 mass% or less of silicon, 0.5 mass% or more and 1.2 mass% or less of magnesium, 0.3 mass% or more and 0.8 mass% or less of iron, 0.1 mass% or more and 0.4 mass% or less of copper, 0.2 mass% or more and 0.5 mass% or less of manganese, 0.001 mass% or more and 0.3 mass% or less of chromium, 0 mass% or more and 0.25 mass% or less of zinc, 0 mass% or more and 0.075 mass% or less of titanium, and 0 mass% or more and 0.17 mass% or less of zirconium, with the remainder being aluminum and unavoidable impurities, and a measurement result obtained after subjecting the aluminum alloy wire to aging treatment shows that the 0.2% yield strength during compression is 360 MPa or more, and the crystal grain size of the aluminum alloy is 200 μm or less, An aluminum alloy wire, wherein a compressive deformation degree C when compressed at a compression rate of 50% is 0.6 or more and 1.0 or less, and the aging treatment is performed at a heating temperature of 160°C or more and 190°C or less for a holding time of 2 hours or more and 40 hours or less.

4. The aluminum alloy wire according to claim 3, wherein a measurement result obtained after subjecting the aluminum alloy wire to the aging treatment shows that an apex of a main peak in a chromium K absorption edge spectrum obtained by XAFS analysis is located in a range of 6012.75 eV or more and 6014.00 eV or less, and the apex of the main peak is determined by fitting the main peak with a Gaussian function in a range of 6009 eV to 6017 eV.

5. An aluminum alloy wire formed from an aluminum alloy, the aluminum alloy containing 1.0 mass% or more and 1.3 mass% or less of silicon, 0.5 mass% or more and 1.2 mass% or less of magnesium, 0.3 mass% or more and 0.8 mass% or less of iron, 0.1 mass% or more and 0.4 mass% or less of copper, 0.2 mass% or more and 0.5 mass% or less of manganese, 0.001 mass% or more and 0.3 mass% or less of chromium, 0 mass% or more and 0.25 mass% or less of zinc, 0 mass% or more and 0.075 mass% or less of titanium, and 0 mass% or more and 0.17 mass% or less of zirconium, with the remainder being aluminum and unavoidable impurities, the aluminum alloy wire having a 0.2% yield strength during compression of 360 MPa or more, a crystal grain size of the aluminum alloy being 200 μm or less, and a compressive deformation degree C when compressed at a compression rate of 50% being 0.6 to 1.0, Aluminum alloy wire.

6. The aluminum alloy wire according to claim 5, wherein an apex of a main peak in a chromium K absorption edge spectrum obtained by XAFS analysis is located in a range of 6012.75 eV or more and 6014.00 eV or less, and the apex of the main peak is determined by fitting the main peak with a Gaussian function in a range of 6009 eV to 6017 eV.

7. The aluminum alloy wire according to any one of claims 1 to 6, wherein the aluminum alloy wire has a wire diameter of 1 mm or more and 30 mm or less.

8. A method for producing a continuous cast and rolled material made of an aluminum alloy, comprising: a step of subjecting the continuously cast and rolled material to a first wire drawing process to produce a first wire drawn material; a step of subjecting the first wire drawn material to an intermediate heat treatment to produce an intermediate heat treated material; and a step of subjecting the intermediate heat treatment material to a second wire drawing process to produce a second wire drawn material, wherein the aluminum alloy contains: 1.0% by mass or more and 1.3% by mass or less of silicon; 0.5% by mass or more and 1.2% by mass or less of magnesium; 0.3% by mass or more and 0.8% by mass or less of iron; 0.1% by mass or more and 0.4% by mass or less of copper; 0.2% by mass or more and 0.5% by mass or less of manganese; 0.001% by mass or more and 0.3% by mass or less of chromium; 0% by mass or more and 0.25% by mass or less of zinc; 0% by mass or more and 0.075% by mass or less of titanium; and 0% by mass or more and 0.17% by mass or less of zirconium, the balance consisting of aluminum and unavoidable impurities, the intermediate heat treatment has a heating temperature of 250°C or higher and lower than 350°C and a holding time of 1 hour or higher and lower than 5 hours, and a second working degree in the second wiredrawing process is 20% or lower.

9. A method for producing an aluminum alloy wire according to claim 8, further comprising a step of subjecting the second drawn wire material to a solution treatment to produce a solution wire material, wherein the solution treatment is performed at a heating temperature of 530°C or more and 580°C or less, for a holding time of 15 minutes or more and 360 minutes or less, and at a heating rate of 120°C / min or less.

10. A method for producing an aluminum alloy wire according to claim 9, further comprising a step of subjecting the solution wire to an aging treatment to produce an aged wire, the aging treatment being performed at a heating temperature of 160°C or higher and 190°C or lower for a holding time of 2 hours or higher and 40 hours or lower.

11. The method for producing an aluminum alloy wire according to any one of claims 8 to 10, wherein the wire diameter of the second drawn wire material is 1 mm or more and 30 mm or less.

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