Production process of high-strength and high-conductivity aluminum rod

Abstract

The invention discloses a production process of a high-strength and high-conductivity aluminum rod. The production process comprises alloy component design, casting process optimization and rolling cooling control. According to the method, Zr is added into matrix aluminum, the Zr element achieves fine grain strengthening by forming a nanoscale Al3Zr precipitated phase, meanwhile, grain boundary scattering is reduced to maintain high conductivity, gradient water cooling is adopted in the continuous casting cooling stage, rapid solidification of refined grains can be achieved, atomization water cooling is adopted in the second stage of the hot rolling stage, and therefore Al3Zr coarsening is restrained, and the conductivity of the aluminum alloy is improved. Through low-cost process adjustment, the comprehensive performance of the aluminum rod is remarkably superior to that of a conventional product, the tensile strength of the aluminum rod is improved by 30% or above, the conductivity loss is smaller than 1.5% IACS, and the aluminum rod is suitable for the fields of high-voltage transmission wires and new energy automobile cables.

Description

Technical Field

[0001] The present invention belongs to the technical field of non-ferrous metal processing, and particularly relates to a production process for high-strength and high-conductivity aluminum rods. Background Art

[0002] As the core material of power transmission conductors, aluminum rods need to meet the requirements of both high strength and high conductivity. Traditional aluminum rods mostly adopt pure aluminum or low-alloy design. Although the conductivity is relatively high (≥63% IACS), the tensile strength is usually lower than 100 MPa, making it difficult to meet the requirements of long-span power transmission. In the prior art, by adding trace alloying elements (such as Mg, Si, Fe), the strength can be improved, but the conductivity will be significantly reduced. In addition, although complex heat treatment or cold deformation processes can improve the performance, they require additional equipment investment and high costs. Summary of the Invention

[0003] The purpose of the present invention is to provide a production process for high-strength and high-conductivity aluminum rods to solve the problems of high process cost and poor process compatibility.

[0004] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A production process for high-strength and high-conductivity aluminum rods includes the following steps: S1. Alloy composition design: Using Al≥99.7% matrix aluminum, adding Zr to the matrix aluminum, the content of Zr is 0.10 - 0.15 wt%, the content of Fe ≤ 0.15%, the content of Si ≤ 0.10%, and the sum of the contents of other impurities ≤ 0.05%; S2. Foundry process optimization: Melting each alloy component designed in S1, the melting temperature is 720 - 750 °C, and argon protection is used to prevent oxidation. After standing for 30 min, continuous casting is carried out. The continuous casting cooling adopts gradient water cooling: the water temperature in the first cooling zone, that is, the outlet water temperature of the mold, is 25 - 35 °C, and the flow rate is controlled at 8 - 12 m³ / h; the water temperature in the second cooling zone, that is, at a distance of 0.5 m from the outlet, is 40 - 45 °C, and the flow rate is controlled at 5 - 8 m³ / h; S3. Rolling cooling control: Hot-rolling the blank obtained in S2 at a temperature of 450 - 480 °C, controlling the final rolling diameter at 8 - 10 mm, and immediately performing two-stage cooling after rolling: The first stage, that is, 0 - 3 s after rolling: air cooling to 300 - 350 °C, and the wind speed is controlled at 10 - 15 m / s; The second stage, that is, 3 - 10 s after rolling: atomized water cooling to below 80 °C; Obtaining high-strength and high-conductivity aluminum rods.

[0005] To further implement the present invention, the water-gas ratio of the atomized water cooling in S3 is 1:3.

[0006] The beneficial effects of the present invention compared with the prior art are as follows: In the present invention, Zr is added to the matrix aluminum, and the Zr element realizes fine grain strengthening through the formation of nano-scale Al 3 Zr precipitation phase, while reducing grain boundary scattering to maintain high electrical conductivity.

[0007] In the continuous casting cooling stage of the present invention, gradient water cooling is adopted, which can achieve rapid solidification of refined grains.

[0008] In the second stage of the hot rolling stage of the present invention, atomized water cooling is adopted to inhibit the coarsening of Al3Zr.

[0009] Through low-cost process adjustment, the comprehensive performance of the aluminum rod in the present invention is significantly better than that of conventional products. Its tensile strength is increased by more than 30%, and the loss of electrical conductivity is <1.5% IACS, which is applicable to the fields of high-voltage transmission wires and new energy vehicle cables. Specific embodiments

[0010] The present invention will be further described below in conjunction with specific embodiments.

[0011] A production process of a high-strength and high-conductivity aluminum rod includes the following steps: S1. Alloy composition design: Using Al≥99.7% matrix aluminum, adding Zr to the matrix aluminum, the content of Zr is 0.10-0.15wt%, the content of Fe is ≤0.15%, the content of Si is ≤0.10%, and the sum of the contents of other impurities is ≤0.05%; S2. Optimization of casting process: Melting the alloy components designed in S1, the melting temperature is 720-750°C, and argon protection is used to prevent oxidation. After standing for 30 minutes, continuous casting is carried out. Gradient water cooling is adopted for continuous casting cooling: the water temperature at the outlet of the mold in the first cooling zone is 25-35°C, and the flow rate is controlled at 8-12m³ / h; the water temperature at 0.5m from the outlet in the second cooling zone is 40-45°C, and the flow rate is controlled at 5-8m³ / h; S3. Rolling cooling control: Hot rolling the billet obtained in S2 at a temperature of 450-480°C, controlling the final rolling diameter at 8-10mm, and immediately performing two-stage cooling after rolling: The first stage, that is, 0-3s after rolling: air cooling to 300-350°C, and the wind speed is controlled at 10-15m / s; The second stage, that is, 3-10s after rolling: atomized water cooling to below 80°C, and the water-gas ratio of atomized water cooling is 1:3; A high-strength and high-conductivity aluminum rod is obtained.

[0012] Example 1: S1. Alloy composition design: Al matrix (base aluminum) - 0.13Zr - 0.12Fe - 0.08Si (wt%); S2. Foundry process optimization: Melt each alloy composition designed in S1 at a melting temperature of 740°C, protect from oxidation with argon, let stand for 30 min and then continuously cast. The continuous casting cooling uses gradient water cooling: in the first cooling zone, i.e., the water temperature at the mold outlet is 31°C and the flow rate is controlled at 10 m³ / h; in the second cooling zone, i.e., the water temperature at 0.5 m from the outlet is 42°C and the flow rate is controlled at 6 m³ / h. Detect that the crystal grain size of the cast billet is ≤50 μm; S3. Rolling cooling control: Hot-roll the cast billet obtained in S2 at a temperature of 460°C, control the final rolling diameter at 8 - 10 mm, and immediately perform two-stage cooling after rolling: The first stage, i.e., 2 s after rolling: cool down to 320°C by air cooling, and control the wind speed at 13 m / s; The second stage, i.e., 6 s after rolling: cool down to below 80°C by atomized water cooling, and the water-gas ratio of the atomized water cooling is 1:3; Obtain a high-strength and high-conductivity aluminum rod.

[0013] Detect the aluminum rod obtained by rolling. The tensile strength is 125 MPa and the conductivity is 62.5% IACS.

[0014] Example 2: S1. Alloy composition design: Al matrix (base aluminum) - 0.13Zr - 0.10Fe - 0.05Si (wt%); S2. Foundry process optimization: Melt each alloy composition designed in S1 at a melting temperature of 740°C, protect from oxidation with argon, let stand for 30 min and then continuously cast. The continuous casting cooling uses gradient water cooling: in the first cooling zone, i.e., the water temperature at the mold outlet is 32°C and the flow rate is controlled at 11 m³ / h; in the second cooling zone, i.e., the water temperature at 0.5 m from the outlet is 45°C and the flow rate is controlled at 7 m³ / h; S3. Rolling cooling control: Hot-roll the billet obtained in S2 at a temperature of 470°C, control the final rolling diameter at 8 - 10 mm, and immediately perform two-stage cooling after rolling: The first stage, i.e., 2 s after rolling: cool down to 330°C by air cooling, and control the wind speed at 12 m / s; The second stage, i.e., 8 s after rolling: cool down to below 80°C by atomized water cooling, and the water-gas ratio of the atomized water cooling is 1:3; Obtain a high-strength and high-conductivity aluminum rod.

[0015] Detect the aluminum rod obtained by rolling. The tensile strength is 127 MPa and the conductivity is 62.2% IACS.

[0016] Example 3: S1. Alloy composition design: Al matrix (base aluminum) - 0.12Zr - 0.08Fe - 0.05Si (wt%); S2. Foundry process optimization: Melt each alloy component designed in S1 at a melting temperature of 720°C, protect it from oxidation with argon, let it stand for 30 min and then perform continuous casting. The continuous casting cooling adopts gradient water cooling: the water temperature at the outlet of the mold in the first cooling zone is 25°C, and the flow rate is controlled at 8 m³ / h; the water temperature at a distance of 0.5 m from the outlet in the second cooling zone is 40°C, and the flow rate is controlled at 5 m³ / h. S3. Rolling cooling control: Hot-roll the billet obtained in S2 at a temperature of 450°C, control the final rolling diameter at 8 - 10 mm, and immediately perform two-stage cooling after rolling: The first stage, i.e., 0 s after rolling: Cool it to 300°C by air cooling, and control the wind speed at 10 m / s; The second stage, i.e., 3 s after rolling: Cool it to below 80°C by atomized water cooling, and the water-gas ratio of the atomized water cooling is 1:3; Obtain a high-strength and high-conductivity aluminum rod.

[0017] Detect the aluminum rod obtained by rolling. The tensile strength is 135 MPa, and the conductivity is 61.3% IACS.

[0018] Example 4: S1. Alloy composition design: Al matrix (base aluminum) - 0.15Zr - 0.15Fe - 0.10Si (wt%); S2. Foundry process optimization: Melt each alloy component designed in S1 at a melting temperature of 750°C, protect it from oxidation with argon, let it stand for 30 min and then perform continuous casting. The continuous casting cooling adopts gradient water cooling: the water temperature at the outlet of the mold in the first cooling zone is 30°C, and the flow rate is controlled at 12 m³ / h; the water temperature at a distance of 0.5 m from the outlet in the second cooling zone is 45°C, and the flow rate is controlled at 8 m³ / h. S3. Rolling cooling control: Hot-roll the billet obtained in S2 at a temperature of 480°C, control the final rolling diameter at 8 - 10 mm, and immediately perform two-stage cooling after rolling: The first stage, i.e., 3 s after rolling: Cool it to 350°C by air cooling, and control the wind speed at 15 m / s; The second stage, i.e., 10 s after rolling: Cool it to below 80°C by atomized water cooling, and the water-gas ratio of the atomized water cooling is 1:3; Obtain a high-strength and high-conductivity aluminum rod.

[0019] The aluminum rod obtained by rolling is tested, with a tensile strength of 130 MPa and an electrical conductivity of 61.8% IACS.

Claims

1. A production process for high-strength and high-conductivity aluminum rods, characterized in that The steps include: S1. Alloy composition design: Adopt Al≥99.7% matrix aluminum, add Zr to the matrix aluminum, the Zr content is 0.10-0.15wt%, the Fe content is ≤0.15%, the Si content is ≤0.10%, and the sum of the contents of other impurities is ≤0.05%; S2. Casting process optimization: The alloy components designed by S1 are melted at a melting temperature of 720-750℃, with argon protection to prevent oxidation. After standing for 30 minutes, continuous casting is performed. Gradient water cooling is used for continuous casting cooling: the water temperature in the first cooling zone, i.e. the outlet of the mold, is 25-35℃, and the flow rate is controlled at 8-12m³ / h; the water temperature in the second cooling zone, i.e. the point 0.5m away from the outlet, is 40-45℃, and the flow rate is controlled at 5-8m³ / h; S3, rolling cooling control: The billet obtained from S2 is hot rolled at a temperature of 450-480°C, the final rolling diameter is controlled at 8-10mm, and two-stage cooling is performed immediately after rolling: The first stage is 0-3s after rolling: air cooling to 300-350℃, with wind speed controlled at 10-15m / s; The second stage is 3-10s after rolling: atomized water cooling to below 80℃; A high-strength and high-conductivity aluminum rod is obtained.

2. The production process of the high-strength and high-conductivity aluminum rod according to claim 1, characterized in that: The water-to-gas ratio of the atomized water cooling in S3 is 1:3.