High-conductivity aluminum alloy conductor and preparation method thereof

Abstract

The invention discloses a high-conductivity aluminum alloy conductor and a preparation method thereof, and belongs to the field of metal material processing and manufacturing, the conductor is a silicon-rich low-magnesium aluminum alloy, the component of the conductor is Al-xSi-yMg-zFe-mCu-n rare earth RE, 0.4 < = x < = 1.2, 0.05 < = y < = 0.3, 0.05 < = z < = 0.15, m < = 0.1, n < = 0.5, and x > = y. According to the preparation method, a smelting-refining-homogenizing-cold deformation-aging process method matched with a new alloy formula is adopted, the high conductivity (larger than or equal to 62% IACS) is obtained while the high mechanical strength (larger than or equal to 110 MPa) of the aluminum alloy wire is obtained, and the elongation is larger than or equal to 15%; the method is short in technological process, easy to operate, low in preparation cost and convenient to industrialize, and the wire is suitable for medium and low voltage cables for power transmission; good application and popularization prospects are realized.

Description

Technical Field

[0001] The invention relates to the field of metal material processing and manufacturing, and in particular to a high-conductivity aluminum alloy wire and a preparation method thereof. Background Art

[0002] my country's copper resources are in short supply and most of them are imported. In recent years, copper prices have fluctuated drastically due to factors such as the international situation, which has seriously affected my country's use of copper. my country is rich in aluminum resources and aluminum industry. In recent years, my country's electrolytic aluminum industry has increased sharply, and some places have experienced overcapacity in electrolytic aluminum. The development of aluminum alloy wires for cables can alleviate the problem of overcapacity in aluminum production on the one hand. On the other hand, as one of the important basic materials in the electrical industry, improving conductivity and reducing line loss has become a major problem that the power industry urgently needs to solve. Expanding the application of aluminum alloy cables is also a response to the country's "saving copper with aluminum", which is of great strategic significance to the development of the power industry.

[0003] At present, aluminum alloy conductors are widely used in long-distance power transmission lines, power cables, communication cables and other fields. In the field of cables, power transmission is accompanied by the problem of power loss. For every 1% IACS increase in the conductivity of the conductor, the country saves more than 7 billion kWh of line loss each year. Improving the conductivity of aluminum alloy conductors, reducing line losses, and reducing the total cost of the project have always been the key research directions of aluminum alloy conductors. The existing aluminum alloy conductors for cables are mainly 8-series aluminum alloy conductors. The 8-series aluminum alloy is an aluminum alloy based on the Al-Fe system. Its second phase is mostly large and AlFe phase segregated at the grain boundary, which greatly affects the improvement of the conductivity of the 8-series aluminum alloy. Since the 8-series aluminum alloy is a non-heat-treated strengthened aluminum alloy, the tensile strength and conductivity are not significantly improved in the cast state and after heat treatment. Its tensile strength and conductivity cannot be taken into account. In terms of performance, most of the 8-series aluminum alloy conductors on the market can only barely reach the lower limit of the national standard. Its development potential is not large, and it is difficult to break the mutual restriction relationship between strength and conductivity through conventional means. The 6-series Al-Mg-Si-based aluminum alloy conductors, with their excellent mechanical properties, are often used in overhead transmission lines. Existing overhead transmission lines require the conductors to have a tensile strength of ≥300MPa and a conductivity of ≥53.0% IACS. However, the national standard for aluminum alloy wires for cables (GB / T 30552-2014) requires a tensile strength between 98MPa and 159MPa and a conductivity of ≥61% IACS. The aluminum alloy used for overhead conductors has too high a tensile strength, resulting in poor bending flexibility of the conductors. In addition, the conductivity of overhead conductors is far lower than the national standard for aluminum alloy conductors for cables. It can be seen that the 6-series aluminum alloys currently developed for overhead conductors are difficult to meet the requirements of aluminum alloy conductors for cables, both from the perspective of mechanical properties and electrical properties.

[0004] Chinese patent CN103397226A discloses an aluminum alloy conductor with an elemental composition of Al, Si, Mg, Fe, Cu, Zn, and B. The content of its constituent elements is extremely low, especially the Si content is only 0.08-0.1%, and the corresponding conductivity is only 59.5-60% IACS, and the mechanical properties of the conductor are not mentioned. Chinese patent CN115948684B discloses an aluminum alloy conductor with an elemental composition of Al, Si, Mg, Cu, Mn, and Fe, wherein the Si content is 0.68-0.78%, the Mg content is 0.65-0.75%, the conductivity is ≥55% IACS, and the tensile strength is ≥340MPa. The addition of the Mg element improves the mechanical properties by sacrificing the electrical properties, and its conductivity is too low. Chinese patent CN107326230B discloses an aluminum alloy conductor with an elemental composition of Al, Fe, Si, Mg, Cu, B, Zn, Sc, and Ru, and its main constituent elements are Fe, Si, Mg, and Sc. It adopts a multi-element and small amount strategy for alloying and adds expensive elements such as Ru and Sc. The Fe content is 0.25-0.35%, the Si content is 0.1-0.3%, the Mg content is 0.2-0.4%, the Sc content is 0.2-0.34%, and the Ru content is 0.05-0.14%. The conductivity is ≥61.3% IACS, the tensile strength is ≥231MPa, and the elongation is ≥13.2%. Its mechanical and electrical performance indicators are higher than the national standard GB / T30552-2014, and its conductivity and elongation are lower than the present invention. Chinese patent CN107267820A discloses an aluminum alloy conductor whose element composition contains Al, Si, Mg, Fe, Cu, Sr, and B. The content of its constituent elements is extremely high, the Si content reaches 3.8-4.0%, the conductivity reaches 60% IACS, and the conductivity requirement does not meet the standard. Therefore, there is still a certain gap in the high conductivity aluminum alloy conductors with a tensile strength of 110-180MPa and a conductivity ≥62% IACS for medium and low voltage use, and progress in this area needs to be strengthened urgently.

[0005] At present, in the design of aluminum alloy conductor composition, the alloying design is still carried out according to the principle of "multiple and small amount", and a small amount of alloying elements is added to improve the mechanical properties of the conductor without significantly reducing its conductivity. The present invention adjusts the alloying strategy and adds excess Si elements to the alloy through the "excess Si" theory to form a nano-scale excess silicon phase dispersion phase different from the common 6-series aluminum alloy β phase, thereby reducing the solid solubility of the alloy elements and reducing the alloy lattice distortion, thereby significantly improving the alloy conductivity. In the prior art, in order to improve the strength and conductivity, high-energy consumption and high-cost processes such as hot rolling are often used in the process. The aluminum alloy conductor designed by the present invention only needs to adopt a simple "melting-refining-homogenization-cold deformation-aging" process to improve the strength of the aluminum alloy conductor, reduce the probability of wire breakage during production, and reduce the scrap rate. At the same time, a high-conductivity aluminum alloy conductor is prepared, which provides an important core wire material for the development of a new generation of aluminum alloy cables. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a high conductivity aluminum alloy conductor and a preparation method thereof, which belongs to the field of metal material processing and manufacturing. The conductor is a "silicon-rich and low-magnesium" aluminum alloy, and its composition is Al-xSi-yMg-zFe-mCu-n rare earth RE, wherein 0.4≤x≤1.2, 0.05≤y≤0.3, 0.05≤z≤0.15, m≤0.1, n≤0.5, x≥y. The preparation method adopts a "melting-refining-homogenization-cold deformation-aging" process method that matches the new alloy formula, and obtains a high aluminum alloy conductor mechanical strength (≥110MPa) while obtaining a high conductivity (≥62%IACS); the method has a short process flow, is easy to operate, has a low preparation cost, is easy to industrialize, and the conductor is suitable for medium and low voltage cables for power transmission; it has an excellent application and promotion prospect.

[0007] In order to achieve the above technical effects, the following technical solutions are adopted:

[0008] A high conductivity aluminum alloy wire is an Al-Si-Mg based aluminum alloy, wherein the nominal composition is Al-xSi-yMg-zFe-mCu-n rare earth RE, wherein the coefficients x, y, z, m, and n are respectively the mass percentages of Si, Mg, Fe, Cu, and rare earth RE in the alloy, 0.4≤x≤1.2, 0.05≤y≤0.3, 0.05≤z≤0.15, m≤0.1, n≤0.5, and x≥y.

[0009] A method for preparing a high-conductivity aluminum alloy wire is a "melting-refining-homogenization-cold deformation-aging" processing method adapted to a "silicon-rich, low-magnesium" formula; the method is implemented through weighing, melting, refining, casting, homogenization heat treatment, cold deformation, and aging treatment steps; specifically, the following steps are included:

[0010] Step S1: Weighing

[0011] Pure Al is weighed as aluminum alloy parent material, Si, Mg, Fe, Cu, rare earth RE single substance or its aluminum-based master alloy is weighed as alloying agent, and hexachloroethane is weighed as refining agent according to mass ratio;

[0012] Step S2: Smelting

[0013] The pure Al in step S1 is heated to 730-770°C in a reaction vessel to melt the aluminum completely, and then kept warm for 10 minutes. Then, alloying agents of Si, Mg, Fe, Cu, and rare earth RE are added in sequence. Each time an alloying agent is added, it is stirred for 5 minutes and allowed to stand for 5 minutes.

[0014] Step S3: Refining

[0015] The hexachloroethane in step S1 is placed in a reaction vessel, stirred for 5 minutes, allowed to stand for 5 minutes, and then slag is discharged, and the mixture is kept at 730-770°C for 10 minutes before casting;

[0016] Step S4: Casting

[0017] The melt obtained in step S3 is poured into a mold preheated to 200-400° C., and naturally cooled to room temperature in air to form an aluminum alloy cylindrical cast rod;

[0018] Step S5: Homogenization heat treatment

[0019] The aluminum alloy cylindrical casting rod obtained in step S4 is heated to 510-560° C., kept at this temperature for 1-6 hours, and then cooled in the furnace;

[0020] Step S6: Cold deformation

[0021] The heat-treated aluminum alloy cylindrical cast rod obtained in step S5 is cold rolled and cold drawn, with the number of cold rolling passes being ≥10 and the total deformation being ≥90%; the number of cold drawing passes being ≥4 and the deformation being ≥30%.

[0022] Step S7: Aging annealing treatment

[0023] The aluminum alloy cylindrical casting rod obtained in step S6 is heated to 200-280° C. and kept at this temperature for 5-15 hours; the sample is cooled to room temperature in the furnace to obtain a high conductivity aluminum alloy wire.

[0024] Furthermore, the rare earth RE is Ce or Er; the pure Al in step S2 is solid metal or aluminum liquid; when the pure Al is aluminum liquid, it does not need to be melted, but still needs to be heated and kept warm.

[0025] Furthermore, the grade of pure Al is industrial pure aluminum or above; when the pure Al is solid metal, it is aluminum ingot, aluminum particles or powder.

[0026] Furthermore, the aluminum-based master alloy in step S1 is any composition of Al-Si, Al-Mg, Al-Fe, Al-Cu, Al-rare earth RE or any composition of aluminum-based ternary alloy.

[0027] Furthermore, the aluminum-based master alloy is in the form of blocks, particles or powder.

[0028] Furthermore, the amount of hexachloroethane added in step S1 is 0.5-1 wt % of the total mass of the alloy.

[0029] Furthermore, the reaction container in step S2 is graphite, silicon carbide or a high temperature resistant and oxidation resistant ceramic crucible.

[0030] Furthermore, in step S4, the mold is a high-strength graphite, ceramic or steel mold.

[0031] Furthermore, the aluminum alloy wire simultaneously meets the requirements of room temperature conductivity ≥ 62% IACS, tensile strength ≥ 110 MPa, and elongation ≥ 15%.

[0032] The beneficial effects of the present invention are:

[0033] (1) The present invention adopts a new formula of "rich in silicon and high in magnesium" and combines it with the process method of "smelting-refining-homogenization-cold deformation-aging". Through the synergistic effect of smelting-refining-homogenization-cold deformation-aging, under suitable process parameter conditions, a uniformly distributed nano-scale excess silicon dispersion phase is formed in the prepared aluminum alloy wire matrix, thereby improving the strength of the aluminum alloy while obtaining a higher electrical conductivity.

[0034] (2) The cold deformation process adopted in the present invention not only produces a significant "work hardening" effect on the aluminum alloy cast rod to improve its strength, but also significantly improves the electrical conductivity of the wire along the stretching direction (axial direction) due to the reduction of axial grain boundary density and deformation aging during the rolling and stretching process.

[0035] (3) The equipment, process method and process parameters adopted by the present invention are not difficult to implement in industrial production, and are convenient for future industrial application. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. The drawings in the following description are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0037] Figure 1 This is a process flow chart of preparing a high conductivity aluminum alloy wire according to an embodiment of the present invention;

[0038] Figure 2 This is a field emission scanning electron microscope image of a cross section of a high-conductivity aluminum alloy wire prepared in Example 1 of the present invention;

[0039] Figure 3 A bar graph showing the tensile strength and elongation of the aluminum alloy wires prepared in Examples 1 to 9 of the present invention and Comparative Examples 1 to 6;

[0040] Figure 4 The electrical conductivity bar graph of the aluminum alloy wires prepared in Examples 1 to 9 of the present invention and Comparative Examples 1 to 6 is shown. DETAILED DESCRIPTION

[0041] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0042] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present invention belongs.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations and / or combinations thereof.

[0044] Embodiment 1:

[0045] like Figure 1 As shown:

[0046] Al-1.2Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0047] The raw materials are prepared according to the mass percentage of each element in the Al-1.2Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0048] S1: Ingredients: weigh 137.10 g pure aluminum, 9.02 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0049] S2: Melting: melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically and evenly after adding the alloying agent each time, and then heat it for 5 minutes to form an alloy melt.

[0050] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and then keeping the temperature at 750° C. for 10 minutes, and using a special slag removal tool to remove slag on the surface of the melt.

[0051] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 120 mm.

[0052] S5: Homogenization heat treatment. The cast rod obtained in step S4 is placed in a heat treatment furnace for homogenization heat treatment at 520° C. for 4 hours, and then the furnace is cooled to room temperature.

[0053] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0054] S7: Aging annealing: placing the wire obtained in step S6 into a heat treatment furnace and annealing at 260° C. for 12 hours to optimize its mechanical and electrical properties.

[0055] The aluminum alloy wire prepared through the above steps has a tensile strength of 138 MPa, an elongation of 17%, and an electrical conductivity of 62.6% IACS.

[0056] Example 2

[0057] Al-1Si-0.05Mg-0.05Fe-0.025Cu-0.5Ce aluminum alloy wire preparation:

[0058] The raw materials are prepared according to the mass percentage of each element in the Al-1Si-0.05Mg-0.05Fe-0.025Cu-0.5Ce aluminum alloy: This example is used to illustrate the influence of alloy composition and homogenization heat treatment parameters on conductor performance. The preparation steps of the conductor are as follows:

[0059] S1: Ingredients: weigh 133.35 g pure aluminum, 7.49 g Al-20Si master alloy, 0.75 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, 7.50 g Al-10Ce master alloy, and 1.50 g hexachloroethane.

[0060] S2: Melting: melt the prepared pure aluminum and heat it to 770°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy, Al-50Cu master alloy and Al-10Ce master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0061] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, stirring evenly mechanically, keeping the temperature at 770° C. for 10 minutes, and then using a special slag removal tool to remove slag on the surface of the melt.

[0062] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 120 mm.

[0063] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 560° C. for 1 h, and then cooling the furnace to room temperature.

[0064] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0065] S7: Aging annealing: placing the wire obtained in step S6 into a heat treatment furnace at 260° C. for 12 hours for annealing to optimize its mechanical and electrical properties, and finally obtaining a high-conductivity aluminum alloy wire.

[0066] The aluminum alloy prepared by the above steps Gold wire The tensile strength is 130MPa, the elongation is 18%, and the conductivity is 62.8% IACS.

[0067] Example 3

[0068] Al-0.5Si-0.2Mg-0.05Fe-0.5Ce aluminum alloy wire preparation:

[0069] The raw materials are prepared according to the mass percentage of each element in the Al-0.5Si-0.2Mg-0.05Fe-0.5Ce aluminum alloy: This example is used to illustrate the influence of aging annealing parameters on the performance of the conductor. The preparation steps of the conductor are as follows:

[0070] S1: Ingredients: weigh 134.96 g pure aluminum, 3.74 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 7.50 g Al-10Ce master alloy, and 1.50 g hexachloroethane.

[0071] S2: Melting: melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0072] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and evenly maintaining the temperature at 750° C. for 10 minutes, and then using a dedicated slag removal tool to remove slag on the surface of the melt.

[0073] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 130 mm.

[0074] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 510° C. for 6 hours, and then cooling the furnace to room temperature.

[0075] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0076] S7: placing the wire obtained in step S6 into a heat treatment furnace at 280° C. for 5 h for annealing to optimize its mechanical and electrical properties.

[0077] The aluminum alloy wire prepared through the above steps has a tensile strength of 128 MPa, an elongation of 18%, and an electrical conductivity of 62.7% IACS.

[0078] Example 4

[0079] Al-0.8Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0080] The raw materials are prepared according to the mass percentage of each element in the Al-0.8Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0081] S1: Ingredients: weigh 140.13 g pure aluminum, 6.02 g Al-20Si master alloy, 3.01 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0082] S2: Melting: melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0083] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and evenly maintaining the temperature at 750° C. for 10 minutes, and then using a dedicated slag removal tool to remove slag on the surface of the melt.

[0084] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 110 mm.

[0085] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 520° C. for 5 hours, and then cooling the furnace to room temperature.

[0086] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0087] S7: placing the wire obtained in step S6 into a heat treatment furnace for annealing at 260° C. for 12 h to optimize its mechanical and electrical properties.

[0088] The aluminum alloy wire prepared through the above steps has a tensile strength of 130 MPa, an elongation of 16%, and an electrical conductivity of 62.5% IACS.

[0089] Example 5

[0090] Al-0.6Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0091] The raw materials are prepared according to the mass percentage of each element in the Al-0.6Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0092] S1: Ingredients: weigh 141.66 g pure aluminum, 4.50 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0093] S2: Melting: Melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0094] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and evenly maintaining the temperature at 750° C. for 10 minutes, and then using a dedicated slag removal tool to remove slag on the surface of the melt.

[0095] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 135 mm.

[0096] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 520° C. for 4 hours, and then cooling the furnace to room temperature.

[0097] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0098] S7: Aging annealing: placing the wire obtained in step S6 into a heat treatment furnace at 240° C. for 12 hours for annealing to optimize its mechanical and electrical properties.

[0099] The aluminum alloy wire prepared through the above steps has a tensile strength of 118 MPa, an elongation of 18%, and an electrical conductivity of 62.9% IACS.

[0100] Example 6

[0101] Al-0.5Si-0.2Mg-0.05Fe-0.1Cu aluminum alloy wire preparation:

[0102] The raw materials are prepared according to the mass percentage of each element in the Al-0.5Si-0.2Mg-0.05Fe-0.1Cu aluminum alloy: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0103] S1: Ingredients: weigh 142.15 g pure aluminum, 3.75 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0104] S2: Melting: Melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0105] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and evenly maintaining the temperature at 750° C. for 10 minutes, and then using a dedicated slag removal tool to remove slag on the surface of the melt.

[0106] S4: Casting: pour the melt obtained in S3 into a preheated mold, and obtain a cylindrical cast rod with a diameter of 12 mm and a height of 100 mm after natural cooling.

[0107] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 520° C. for 4 hours, and then cooling the furnace to room temperature.

[0108] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0109] S7: placing the wire obtained in step S6 into a heat treatment furnace at 220° C. for 12 h for annealing to optimize its mechanical and electrical properties.

[0110] The aluminum alloy wire prepared through the above steps has a tensile strength of 114 MPa, an elongation of 18%, and an electrical conductivity of 63.2% IACS.

[0111] Example 7

[0112] Al-0.4Si-0.2Mg-0.05Fe-0.5Er aluminum alloy wire preparation:

[0113] According to the mass percentage of each element in Al-0.4Si-0.2Mg-0.05Fe-0.5Er, the raw materials are prepared: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0114] S1: Ingredients: weigh 135.76 g pure aluminum, 3.00 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 7.50 g Al-10Er master alloy, and 1.50 g hexachloroethane.

[0115] S2: Melting: melt the prepared pure aluminum and heat it to 730°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0116] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and then keeping the temperature at 730° C. for 10 minutes, and using a special slag removal tool to remove slag on the surface of the melt.

[0117] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 125 mm.

[0118] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 530° C. for 4 hours, and then cooling the furnace to room temperature.

[0119] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0120] S7: placing the wire obtained in step S6 into a heat treatment furnace for annealing at 220° C. for 10 h to optimize its mechanical and electrical properties.

[0121] The aluminum alloy wire prepared through the above steps has a tensile strength of 112 MPa, an elongation of 17%, and an electrical conductivity of 62.8% IACS.

[0122] Example 8

[0123] Al-0.5Si-0.2Mg-0.15Fe-0.05Cu aluminum alloy wire preparation:

[0124] The raw materials are prepared according to the mass percentage of each element in the Al-0.5Si-0.2Mg-0.15Fe-0.05Cu aluminum alloy: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0125] S1: Ingredients: weigh 140.75 g pure aluminum, 3.75 g Al-20Si master alloy, 3.00 g Al-10Mg master alloy, 2.25 g Al-10Fe master alloy, 0.15 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0126] S2: Melting: Melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence according to the composition ratio, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0127] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and then keeping warm for 10 minutes, and using a special slag removal tool to remove slag on the surface of the melt.

[0128] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 118 mm.

[0129] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 520° C. for 5 hours, and then cooling the furnace to room temperature.

[0130] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0131] S7: Aging annealing: placing the wire obtained in step S6 into a heat treatment furnace at 220° C. for 12 h for annealing to optimize its mechanical and electrical properties.

[0132] The aluminum alloy wire prepared through the above steps has a tensile strength of 110 MPa, an elongation of 18%, and an electrical conductivity of 63.0% IACS.

[0133] Example 9

[0134] Al-0.5Si-0.3Mg-0.1Fe-0.05Cu aluminum alloy wire preparation:

[0135] The raw materials are prepared according to the mass percentage of each element in the Al-0.5Si-0.3Mg-0.1Fe-0.05Cu aluminum alloy: This example is used to illustrate the influence of alloy composition on conductor performance. The preparation steps of the conductor are as follows:

[0136] S1: Ingredients: weigh 140.30 g pure aluminum, 3.75 g Al-20Si master alloy, 4.50 g Al-10Mg master alloy, 1.50 g Al-10Fe master alloy, 0.14 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0137] S2: Melting: Melt the prepared pure aluminum and heat it to 750°C for 10 minutes, then add Al-20Si master alloy, Al-10Mg master alloy, Al-10Fe master alloy and Al-50Cu master alloy to the melt in sequence according to the composition ratio, stir mechanically after each addition and keep the mixture warm for 5 minutes to form an alloy melt.

[0138] S3: Refining, adding hexachloroethane to the alloy melt obtained in step S2, mechanically stirring and then keeping warm for 10 minutes, and using a special slag removal tool to remove slag on the surface of the melt.

[0139] S4: Casting: pour the melt obtained in S3 into a preheated mold, and after natural cooling, obtain a cylindrical cast rod with a diameter of 12 mm and a height of 115 mm.

[0140] S5: homogenization heat treatment, placing the cast rod obtained in step S4 into a heat treatment furnace for homogenization heat treatment at a constant temperature of 520° C. for 6 hours, and then cooling the furnace to room temperature.

[0141] S6: cold deformation, cold rolling the cast rod obtained after the heat treatment in step S5 on a rolling mill to obtain a rough conductor with a diameter of about 3 mm, and then cold drawing on a wire drawing machine to obtain a round conductor with a diameter of 2 mm.

[0142] S7: Aging annealing: placing the wire obtained in step S6 into a heat treatment furnace at 200° C. for 15 hours for annealing to optimize its mechanical and electrical properties.

[0143] The aluminum alloy wire prepared through the above steps has a tensile strength of 125 MPa, an elongation of 16%, and an electrical conductivity of 62.7% IACS.

[0144] Comparative Example 1

[0145] Al-1.2Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0146] This comparative example is intended to examine the effect of melting temperature on alloy properties. Under the same alloy formulation as in Example 1, the melting temperature used is 850° C. Compared with Example 1, except for the different melting temperature in step S2, the rest of the preparation process is exactly the same.

[0147] The aluminum alloy wire prepared through the above steps has a tensile strength of 95 MPa, an elongation of 12%, and an electrical conductivity of 60.5% IACS.

[0148] Comparative Example 2

[0149] Al-0.8Si-0.2Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0150] This comparative example is intended to examine the effect of aging annealing temperature on alloy properties. Under the same alloy formulation as in Example 4, the annealing temperature used is 160°C. Compared with Example 4, except for the aging annealing temperature in step S7, the other preparation process conditions are exactly the same.

[0151] The aluminum alloy wire prepared through the above steps has a tensile strength of 165 MPa, an elongation of 11%, and an electrical conductivity of 59.2% IACS.

[0152] Comparative Example 3

[0153] Al-0.2Si-0.8Mg-0.05Fe-0.025Cu aluminum alloy wire preparation:

[0154] This comparative example is intended to examine the influence of the relative content of Mg and Si elements on the mechanical and electrical properties of aluminum alloy wires. Under the same alloy formula as in Example 4, the Mg content is 0.8wt% and the Si content is 0.2wt%. Compared with Example 4, except for the different Mg and Si content in step S1, the other preparation process conditions are exactly the same.

[0155] S1: Ingredients: weigh 135.66 g pure aluminum, 1.50 g Al-20Si master alloy, 11.99 g Al-10Mg master alloy, 0.75 g Al-10Fe master alloy, 0.075 g Al-50Cu master alloy, and 1.50 g hexachloroethane.

[0156] The aluminum alloy wire prepared through the above steps has a tensile strength of 162 MPa, an elongation of 8%, and an electrical conductivity of 57.1% IACS.

[0157] Comparative Example 4

[0158] Al-0.5Si-0.2Mg-0.05Fe-0.5Ce aluminum alloy wire preparation:

[0159] This comparative example is intended to examine the effect of refining agents on alloy properties. Under the same alloy formulation as in Example 3, no refining agent is added. Compared with Example 3, except for eliminating the refining step S3, the other preparation process conditions are exactly the same.

[0160] The aluminum alloy wire prepared through the above steps has a tensile strength of 145 MPa, an elongation of 8%, and an electrical conductivity of 59.3% IACS.

[0161] Comparative Example 5

[0162] Al-0.5Si-0.2Mg-0.05Fe-0.5Ce aluminum alloy wire preparation:

[0163] This comparative example is intended to examine the effect of cold deformation parameters on alloy properties. Under the same alloy formula as in Example 3, the sample was cold rolled to a rough wire with a diameter of about 6.5 mm, and then cold drawn on a wire drawing machine to obtain a round wire with a diameter of 5.0 mm. Compared with Example 3, except for the different degree of deformation in the cold deformation in step S6, the rest of the preparation process is exactly the same.

[0164] The aluminum alloy wire prepared through the above steps has a tensile strength of 110 MPa, an elongation of 6%, and an electrical conductivity of 60.1% IACS.

[0165] Comparative Example 6

[0166] Al-0.5Si-0.2Mg-0.05Fe-0.5Ce aluminum alloy wire preparation:

[0167] This comparative example is intended to examine the effect of the homogenization heat treatment temperature on the performance of the wire. Under the same alloy formulation as in Example 3, the homogenization temperature is 450°C. Compared with Example 3, except for the different temperature in the homogenization treatment in step S5, the other preparation process conditions are exactly the same.

[0168] The aluminum alloy wire prepared through the above steps has a tensile strength of 126 MPa, an elongation of 9%, and an electrical conductivity of 59.8% IACS.

[0169] The data of the embodiments and comparative examples are summarized in Table 1:

[0170] Table 1 Example and Comparative Example Preparation Ingredients (g)

[0171]

[0172]

[0173] For the convenience of comparison, the main mechanical properties and conductivity indicators obtained in the above embodiments and comparative examples are listed in Table 2, as follows:

[0174] Table 2 Performance test data of high-conductivity aluminum alloy wire at room temperature (20°C)

[0175]

[0176] Figure 2 : is a field emission scanning electron microscope image of a cross section of a high-conductivity aluminum alloy wire prepared in Example 1 of the present invention; Figure 3 , Figure 4 As shown, under the scientific formula and matching preparation process conditions, the mechanical properties and electrical properties of the high-conductivity aluminum alloy wires in Examples 1-9 can simultaneously meet the following requirements: 110MPa≤room temperature ultimate tensile strength≤140MPa, elongation≥15%, and electrical conductivity≥62.0% IACS. In addition, the performance of the aluminum alloy wire is significantly higher than the lower limit of the national standard (simultaneously meeting: room temperature ultimate tensile strength≥98MPa, elongation≥10%, and electrical conductivity≥61.0% IACS) (Note: From a technical point of view, the closer the electrical conductivity of the aluminum alloy is to pure aluminum, the more difficult it is to improve). Comparative Example 1 may have a room temperature ultimate tensile strength of the wire lower than the national standard due to overburning; Comparative Example 2 has a low aging annealing temperature and high alloy solid solubility, which makes the tensile strength too high and the conductivity low, and does not meet the national standard requirements; Comparative Example 3 has a high Mg content, which makes the tensile strength too high (beyond the standard tensile strength range), and the conductivity is low, which does not meet the national standard requirements; Comparative Example 4 has a large number of impurities in the alloy due to the cancellation of refining and slag removal, which makes the tensile strength too high, and the conductivity is low, which does not meet the national standard requirements; Comparative Example 5 has a low cold drawing deformation, and the alloy grains are not elongated, so that the tensile strength and conductivity are both low, which does not meet the national standard requirements; Comparative Example 6 has a low homogenization temperature, and the coarse second phase of the alloy casting is not completely dissolved, so that the overall performance does not meet the national standard requirements. In addition, the elongation of Comparative Examples 3-6 does not meet the national standard requirements. In short, the three indicators of tensile strength, elongation and conductivity of the alloy wires prepared in all comparative examples cannot simultaneously meet the national standard requirements for aluminum alloy wires for cables.

[0177] Comprehensive analysis shows that the Al-xSi-yMg-zFe-mCu-n rare earth RE high-conductivity aluminum alloy conductor prepared by the present invention has excellent electrical properties and good mechanical properties within the scope of rights protection, and is expected to become a new type of practical high-conductivity aluminum alloy conductor, and has a good application prospect in aluminum alloy core wires for cables.

[0178] In summary, the present invention discloses a high conductivity aluminum alloy conductor and a preparation method thereof, which belongs to the field of metal material processing and manufacturing. The conductor is a "silicon-rich and low-magnesium" aluminum alloy, and its composition is Al-xSi-yMg-zFe-mCu-n rare earth RE, wherein 0.4≤x≤1.2, 0.05≤y≤0.3, 0.05≤z≤0.15, m≤0.1, n≤0.5, x≥y. The preparation method adopts a "melting-refining-homogenization-cold deformation-aging" process method that matches the new alloy formula, and obtains high conductivity (≥62% IACS) while obtaining a higher mechanical strength (≥110MPa) of the aluminum alloy conductor; the method has a short process flow, is easy to operate, has a low preparation cost, is easy to industrialize, and the conductor is suitable for medium and low voltage cables for power transmission; it has an excellent application and promotion prospect.

[0179] At this point, those skilled in the art recognize that, although the embodiments of the present invention have been shown and described in detail herein, many other variations or modifications that conform to the principles of the present invention can still be directly determined or derived based on the contents disclosed in the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.

Claims

1. A high conductivity aluminum alloy wire, characterized in that: The aluminum alloy wire is an Al-Si-Mg based aluminum alloy, and its nominal composition is Al-xSi-yMg-zFe-mCu-n rare earth RE, wherein coefficients x, y, z, m, and n are respectively the mass percentages of Si, Mg, Fe, Cu, and rare earth RE in the alloy, 0.4≤x≤1.2, 0.05≤y≤0.3, 0.05≤z≤0.15, m≤0.1, n≤0.5, and x≥y.

2. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 1, characterized in that: The preparation method is a "melting-refining-homogenization-cold deformation-aging" processing method adapted to the "silicon-rich and low-magnesium" formula; it is achieved through weighing, melting, refining, casting, homogenization heat treatment, cold deformation, and aging treatment steps; specifically includes the following steps: Step S1: Weighing Pure Al is weighed as aluminum alloy parent material, Si, Mg, Fe, Cu, rare earth RE single substance or its aluminum-based master alloy is weighed as alloying agent, and hexachloroethane is weighed as refining agent according to mass ratio; Step S2: Smelting The pure Al in step S1 is heated to 730-770°C in a reaction vessel to melt the aluminum completely, and then kept warm for 10 minutes. Then, alloying agents of Si, Mg, Fe, Cu, and rare earth RE are added in sequence. Each time an alloying agent is added, it is stirred for 5 minutes and allowed to stand for 5 minutes. Step S3: Refining The hexachloroethane in step S1 is placed in a reaction vessel, stirred for 5 minutes, allowed to stand for 5 minutes, and then slag is discharged, and the mixture is kept at 730-770°C for 10 minutes before casting; Step S4: Casting The melt obtained in step S3 is poured into a mold preheated to 200-400° C., and naturally cooled to room temperature in air to form an aluminum alloy cylindrical cast rod; Step S5: Homogenization heat treatment The aluminum alloy cylindrical casting rod obtained in step S4 is heated to 510-560° C., kept at this temperature for 1-6 hours, and then cooled in the furnace; Step S6: Cold deformation The heat-treated aluminum alloy cylindrical cast rod obtained in step S5 is cold rolled and cold drawn, with the number of cold rolling passes being ≥10 and the total deformation being ≥90%; the number of cold drawing passes being ≥4 and the deformation being ≥30%. Step S7: Aging annealing treatment The aluminum alloy cylindrical casting rod obtained in step S6 is heated to 200-280° C. and kept at this temperature for 5-15 hours; the sample is cooled to room temperature in the furnace to obtain a high conductivity aluminum alloy wire.

3. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The rare earth RE is Ce or Er; the pure Al in step S2 is solid metal or aluminum liquid; when the pure Al is aluminum liquid, it does not need to be melted, but still needs to be heated and kept warm.

4. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 3, characterized in that: The pure Al grade is industrial pure aluminum or above; when the pure Al is solid metal, it is aluminum ingot, aluminum particles or powder.

5. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The aluminum-based master alloy in step S1 is any composition of Al-Si, Al-Mg, Al-Fe, Al-Cu, Al-rare earth RE or any composition of aluminum-based ternary alloy.

6. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 5, characterized in that: The aluminum-based master alloy is in the form of blocks, particles or powder.

7. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The amount of hexachloroethane added in step S1 is 0.5-1 wt % of the total mass of the alloy.

8. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The reaction container in step S2 is graphite, silicon carbide or a high temperature resistant and oxidation resistant ceramic crucible.

9. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The mold in step S4 is a high-strength graphite, ceramic or steel mold.

10. A method for preparing a high conductivity aluminum alloy wire as claimed in claim 2, characterized in that: The aluminum alloy wire simultaneously meets the requirements of room temperature conductivity ≥ 62% IACS, tensile strength ≥ 110 MPa, and elongation ≥ 15%.

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