High-strength aluminum alloy for electricians and smelting process thereof

Abstract

The invention relates to the technical field of aluminum alloys, in particular to a high-strength aluminum alloy for electricians and a smelting process thereof.The aluminum alloy comprises an aluminum alloy matrix and a grain inhibitor, and the adding amount of the grain inhibitor is 0.08-0.16% of the weight of the aluminum alloy matrix; the aluminum alloy matrix is prepared from the following chemical components in percentage by weight: 0.6 to 0.85 percent of Fe, 0.7 to 0.9 percent of Mg, 0.05 to 0.09 percent of Si, 0.3 to 0.5 percent of Cu, 0.12 to 0.22 percent of Re, 0.02 to 0.06 percent of B and the balance of Al; the grain inhibitor is prepared by the following steps: treating a metal carbide mixture with a cationic surfactant, loading graphene oxide, and reducing the graphene oxide with hydrazine hydrate, the metal carbide mixture is a mixture of titanium carbide, vanadium carbide and tantalum carbide; the method has the advantage that the conductivity and the strength of the aluminum alloy for the electricians are improved.

Description

Technical Field

[0001] The present application relates to the technical field of aluminum alloys, and in particular to a high-strength electrical aluminum alloy and a smelting process thereof. Background Art

[0002] At present, electrical aluminum alloys are widely used in the power industry and electronic products. Electrical aluminum alloys have high requirements for electrical conductivity, corrosion resistance and mechanical strength. For the preparation of electrical aluminum alloys, the traditional smelting process is affected by problems such as raw material costs, energy consumption, environmental pollution, etc., and it is difficult to balance the contradiction between high performance and low cost. Among them, the main problems faced are: the traditional smelting process generally has high energy consumption, uneven distribution of alloy elements, and large fluctuations in material properties. Existing improvement measures are usually focused on optimizing composition design and smelting conditions, such as introducing rare earth metals to improve grain structure, but this increases costs and increases environmental pressure. Although these measures can improve alloy performance to a certain extent, they still cannot meet the strict requirements of the modern electrical industry because they fail to completely solve the problem of alloy element segregation during heat treatment. Summary of the Invention

[0003] In order to improve the electrical conductivity and strength of aluminum alloys for electrical use, the present application provides a high-strength aluminum alloy for electrical use and a smelting process thereof.

[0004] In a first aspect, the present application provides a high-strength aluminum alloy for electrical use, which adopts the following technical solution: A high-strength aluminum alloy for electrical use, comprising an aluminum alloy matrix and a grain inhibitor, wherein the grain inhibitor is added in an amount of 0.08-0.16% of the weight of the aluminum alloy matrix; The weight percentages of the chemical components of the aluminum alloy matrix are as follows: Fe 0.6-0.85%, Mg 0.7-0.9%, Si 0.05-0.09%, Cu 0.3-0.5%, Re 0.12-0.22%, B 0.02-0.06%, and the balance is Al; The grain inhibitor is prepared by loading graphene oxide on a metal carbide mixture treated with a cationic surfactant, and then reducing the graphene oxide with hydrazine hydrate; the metal carbide mixture is a mixture of titanium carbide, vanadium carbide and tantalum carbide.

[0005] By adopting the above technical solution, by the compounding of the grain inhibitor, then on its surface load graphene oxide, graphene oxide is a two-dimensional sheet structure, after hydrazine hydrate reduction, a graphene structure is obtained, and the thermal stability of graphene is higher, and it is not easy to decompose at high temperature. After the grain inhibitor is added to the aluminum alloy, the graphene on its surface can be combined with the metal atoms in the aluminum alloy due to its electron cloud effect, mainly generating an Al-GO interface layer, thereby greatly reducing the interfacial tension formed between the grain inhibitor and the aluminum alloy system, greatly improving the dispersibility and compatibility of the grain inhibitor in the aluminum alloy system, and the grain inhibitor can still play its role in reducing the grain fineness of the aluminum alloy. And the electron cloud effect of graphene can make the electrical conductivity of the aluminum alloy be improved to a certain extent. Therefore, by adding the grain inhibitor prepared by the present application, the aluminum alloy can be improved in terms of electrical conductivity and strength.

[0006] Preferably, the weight ratio of the titanium carbide, vanadium carbide and tantalum carbide is 10:3:(0-1).

[0007] By adopting the above technical solution, the performance of the aluminum alloy obtained when the grain inhibitors are titanium carbide, vanadium carbide and tantalum carbide, which are compounded in this proportion, is better.

[0008] Preferably, the added amount of the grain inhibitor is 0.12% of the weight of the aluminum alloy matrix.

[0009] By adopting the above technical solution and exploring the addition amount of grain inhibitor, it was found that when the addition amount was 0.12% of the weight of the aluminum alloy matrix, the comprehensive cost of the aluminum alloy was better. When the addition amount was further increased, the strength improvement was smaller.

[0010] Preferably, the cationic surfactant is a quaternary ammonium salt cationic surfactant.

[0011] By adopting the above technical solution, the surface of the metal carbide is charged by a surfactant, and the metal carbide is loaded with graphene oxide by electrostatic attraction.

[0012] Preferably, the average particle size of the titanium carbide is 40 nm, the average particle size of the vanadium carbide is 500 nm, and the average particle size of the tantalum carbide is 200 nm.

[0013] Preferably, the aluminum alloy further comprises a compatibilizer, and the added amount of the compatibilizer is 1.2-1.7% of the weight of the aluminum alloy matrix.

[0014] By adopting the above technical solution and adding a compatibilizer, the compatibility between the grain inhibitor and the raw materials can be improved, the overall strength of the aluminum alloy can be further improved, and its uniformity can be improved, and the product qualification rate can reach more than 99%.

[0015] Preferably, the compatibilizer is a mixture of nickel powder and cobalt powder.

[0016] By adopting the above technical solution, when nickel powder and cobalt powder are added as compatibilizers at the same time, the strength of the obtained aluminum alloy is better than that of the aluminum alloy to which only one of them is added.

[0017] Preferably, the weight ratio of the nickel powder to the cobalt powder is 2:1.

[0018] By adopting the above technical solution, this ratio is a better choice.

[0019] In a second aspect, the present application provides a smelting process for high-strength electrical aluminum alloy, which adopts the following technical solution: A smelting process for high-strength electrical aluminum alloy comprises the following steps: S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys containing Re, and aluminum-boron master alloys, and then batch them according to the weight percentage of each chemical component of the aluminum alloy matrix; S2. Set the melting furnace temperature to 800-870°C, add aluminum ingots, and when the aluminum ingots are melted to 70-80%, add covering agent. After the aluminum ingots are completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy and aluminum-boron master alloy in sequence. After the ingredients are prepared, keep the temperature at 740-770°C, blow in refining agent with argon gas for refining and deslagging, and then perform furnace composition analysis; then add raw materials other than the aluminum alloy matrix; S4, after refining and slag removal, ingot casting is carried out, and the ingot casting process parameters are as follows: inlet water temperature 20-25°C, outlet water temperature 30-35°C, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10°C; S5. Homogenize the ingot in a heating furnace at a temperature of 575-595°C for 10-15 hours, and then cool naturally; S6. Tempering the ingot: Continue to uniformly heat the ingot to 380-420° C. in a heating furnace, and then cool it naturally to obtain an aluminum alloy.

[0020] By adopting the above technical solution, through the order of adding raw materials in the smelting process and the setting of process parameters, the grain fineness of the aluminum alloy is reduced, the compatibility of the raw materials inside the aluminum alloy is improved, and the bubble content inside is greatly reduced, thereby producing an aluminum alloy with excellent conductivity and strength.

[0021] In summary, this application includes at least one of the following beneficial technical effects: 1. By compounding the grain inhibitor, graphene oxide is then loaded on its surface. Graphene oxide is a two-dimensional sheet structure. After being reduced with hydrazine hydrate, a graphene structure is obtained. The thermal stability of graphene is high and it is not easy to decompose at high temperatures. After the grain inhibitor is added to the aluminum alloy, the graphene on its surface can combine with the metal atoms in the aluminum alloy due to its electron cloud effect, mainly generating an Al-GO interface layer, thereby greatly reducing the interfacial tension formed between the grain inhibitor and the aluminum alloy system, greatly improving the dispersibility and compatibility of the grain inhibitor in the aluminum alloy system, and the grain inhibitor can still play its role in reducing the grain fineness of the aluminum alloy. And the electron cloud effect of graphene can make the electrical conductivity of the aluminum alloy be improved to a certain extent. Therefore, by adding the grain inhibitor prepared by this application, the aluminum alloy can be improved in terms of both electrical conductivity and strength.

[0022] 2. The electrical conductivity of the aluminum alloys prepared in this application is between 56.8-57.6% IACS, and their tensile strength is between 246-279 MPa; this indicates that the aluminum alloys prepared in this application have both high strength and high conductivity, and have great application potential in the field of aluminum alloys for electrical engineering. DETAILED DESCRIPTION

[0023] The following is a further detailed description of this application in conjunction with the specific content.

[0024] raw material The raw materials of this application were all purchased from the market. Among them, the covering agent and refining agent were purchased from Jiangxi Century New Materials Co., Ltd.; the brand of aluminum ingot was A199.7E, and the master alloys were purchased from Xuzhou Jinlong Metal Aluminum Co., Ltd.; the chemical composition of the rare earth master alloy is:

[0025] The parameters of the other master alloys are as follows:

[0026] Preparation Example 1 A grain inhibitor, the preparation method of which is as follows: S1. Prepare a surfactant solution with a concentration of 2 g / L, wherein the surfactant is a cationic surfactant, and the cationic surfactant is a quaternary ammonium salt cationic surfactant with a CAS number of 61791-10-4; S2, titanium carbide, vanadium carbide and tantalum carbide are mixed in a weight ratio of 10:3:1, and the mixture is dispersed into 3 times the weight of the surfactant solution prepared in S1, stirred for 20 minutes, filtered, and the precipitate is dried to obtain a surface-modified metal carbide mixture; wherein the average particle size of titanium carbide is 40 nm; the average particle size of vanadium carbide is 500 nm; the average particle size of tantalum carbide is 200 nm, S3. Prepare a 1.5 g / L graphene oxide aqueous dispersion, enhance the dispersion by ultrasound, then add a surface-modified metal carbide mixture in an amount of one-quarter the weight of the graphene oxide aqueous dispersion, stir for 10 minutes, then add hydrazine hydrate to a concentration of 1.2 g / L, then increase the temperature to 90° C., stir the reaction for 2 hours, then filter, and dry the precipitate to obtain a grain inhibitor.

[0027] Example 1 A high-strength aluminum alloy for electrical use includes an aluminum alloy matrix, a grain suppressant, and a compatibilizer. The weight percentages of the chemical components of the aluminum alloy matrix are shown in Table 1. The smelting process of the high-strength aluminum alloy for electrical use is as follows: S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys, and aluminum-boron master alloys, and then batch them according to the weight percentages of the chemical components of the aluminum alloy matrix in Table 1; S2. Before production, perform a furnace cleaning process to remove all debris from the melting furnace. After the furnace cleaning is completed, wash the furnace once with 99.7% E aluminum; S3. Set the melting furnace temperature to 850°C, add aluminum ingots, and add covering agent when the aluminum ingots are melted to 70-80%. After the aluminum ingots are completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy and aluminum-boron master alloy in sequence. The aluminum-boron master alloy and rare earth master alloy are added in the launder, and the remaining raw materials are added in the melting furnace. After the ingredients are prepared, keep the temperature at 760°C, blow in refining agent with high-purity argon gas for refining and slag removal for no less than 15 minutes to ensure uniformity and avoid tumbling of the molten aluminum. After refining for 60 minutes, the furnace temperature was controlled at 725°C. After standing for 15 minutes, the slag was skimmed and a rapid analysis of the composition was performed before the furnace. The composition was adjusted to meet the requirements based on the analysis results. A grain inhibitor and a compatibilizer were then added. The grain inhibitor was added in an amount of 0.12% by weight of the aluminum alloy matrix, and the compatibilizer was added in an amount of 1.5% by weight of the aluminum alloy matrix. The grain inhibitor was obtained from Preparation Example 1. The compatibilizer was a mixture of nickel powder and cobalt powder in a weight ratio of 2:1. The particle size of the nickel powder was 80 nm, and the particle size of the cobalt powder was 50 nm. S4. After refining and slag removal, ingot casting is carried out. The ingot casting process parameters are as follows: inlet water temperature 20-25°C, outlet water temperature 30-35°C, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10°C; during the ingot casting process, the flow trough, flow plate, and crystallizer liquid level are well controlled to prevent fluctuations. At the beginning, the bottom slag is cleaned, first the periphery and then the center. The height of the flow plate is adjusted so that the liquid level is higher than the funnel mouth. The liquid level is controlled to be 70-80 mm from the upper edge of the crystallizer; S5. Homogenize the ingot in a heating furnace at 585°C for 13 hours, and then cool naturally. S6. Tempering the ingot: Continue to uniformly heat the ingot in a heating furnace to 400° C. at a heating rate of 50° C. / h, and then cool it naturally to obtain an aluminum alloy.

[0028] Table 1 Weight percentage of each chemical component of the aluminum alloy matrix of Example 1 (%)

[0029] Example 2 A high-strength aluminum alloy for electrical use, which differs from Example 1 in that the nickel powder in its compatibilizer is replaced by cobalt powder of equal mass, and the remaining raw materials are the same as those in Example 1.

[0030] Example 3 A high-strength aluminum alloy for electrical use, which differs from Example 1 in that the cobalt powder in its compatibilizer is replaced by nickel powder of equal mass, and the remaining raw materials are the same as those in Example 1.

[0031] Example 4 A high-strength aluminum alloy for electrical use, which differs from Example 1 in that its compatibilizer is replaced by aluminum ingots of equal mass, and the remaining raw materials are the same as those in Example 1.

[0032] Example 5 A high-strength aluminum alloy for electrical use is different from Example 1 in that the added amount of the grain inhibitor is 0.08% of the weight of the aluminum alloy matrix, and the other raw materials are the same as those in Example 1.

[0033] Example 6 A high-strength aluminum alloy for electrical use is different from Example 1 in that the added amount of the grain inhibitor is 0.16% of the weight of the aluminum alloy matrix, and the other raw materials are the same as those in Example 1.

[0034] Example 7 A high-strength aluminum alloy for electrical use is different from Example 1 in that no tantalum carbide is added during the preparation of the grain inhibitor, and the remaining raw materials are the same as those in Example 1.

[0035] Comparative Example 1 A high-strength aluminum alloy for electrical use, which differs from Example 1 in that its grain inhibitor is replaced by an aluminum ingot of equal mass, and the remaining raw materials are the same as those in Example 1.

[0036] Comparative Example 2 A high-strength aluminum alloy for electrical use, which differs from Example 1 in that the surface of its grain inhibitor is not loaded with graphene oxide, that is, the grain inhibitor is replaced by a mixture of equal masses of titanium carbide, vanadium carbide, and tantalum carbide, with the weight ratio of titanium carbide, vanadium carbide, and tantalum carbide being 10:3:1. The remaining raw materials are the same as those in Example 1.

[0037] Performance testing Detection method / test method High-strength electrical aluminum alloys were prepared according to Examples 1-7 and Comparative Examples 1-2, and then tested according to the following test method. The test results are shown in Table 2.

[0038] Conductivity and tensile strength: Test according to the test method in GB / T 31840. Each sample is tested three times and the average value is taken. The conductivity is calculated from the measured resistivity.

[0039] Table 2 Test results of Examples 1-7 and Comparative Examples 1-2

[0040] It can be seen from Examples 1-7 and Comparative Examples 1-2, as well as the test data in Table 2, that the electrical conductivity of the aluminum alloys prepared in the present application is between 56.8% and 57.6% IACS, and their tensile strength is between 246 MPa and 279 MPa, indicating that the aluminum alloys prepared in the present application have both high strength and high conductivity, and have great application potential in the field of aluminum alloys for electrical engineering.

[0041] By compounding the grain inhibitor, graphene oxide is then loaded on its surface. Graphene oxide is a two-dimensional sheet structure. After being reduced with hydrazine hydrate, a graphene structure is obtained. The thermal stability of graphene is high and it is not easy to decompose at high temperatures. After the grain inhibitor is added to the aluminum alloy, the graphene on its surface can combine with the metal atoms in the aluminum alloy due to its electron cloud effect, mainly generating an Al-GO interface layer, thereby greatly reducing the interfacial tension formed between the grain inhibitor and the aluminum alloy system, greatly improving the dispersibility and compatibility of the grain inhibitor in the aluminum alloy system, and the grain inhibitor can still play its role in reducing the grain fineness of the aluminum alloy. And the electron cloud effect of graphene can make the electrical conductivity of the aluminum alloy be improved to a certain extent. Therefore, by adding the grain inhibitor prepared by the present application, the aluminum alloy can be improved in terms of both electrical conductivity and strength. This can be verified by Example 1 and Comparative Examples 1-2. On this basis, combined with Examples 5-6, an investigation into the addition of grain suppressants revealed that an addition of 0.12% of the aluminum alloy matrix resulted in a favorable overall cost performance. However, increasing the addition yielded a smaller increase in strength. Furthermore, a composite of three metal carbides—titanium carbide, vanadium carbide, and tantalum carbide—produced an aluminum alloy with even better performance.

[0042] On this basis, by adding a compatibilizer, the compatibility between the grain inhibitor and the raw materials can be improved, further improving the overall strength of the aluminum alloy and its uniformity, and the product qualification rate can reach over 99%. This can be verified by the test results of Examples 1-4.

[0043] This specific embodiment is merely an explanation of the present invention and is not intended to limit the present invention. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed. However, as long as such modifications are within the scope of the claims of the present invention, they are protected by patent law.

Claims

1. A high-strength aluminum alloy for electrical use, characterized by: It includes an aluminum alloy matrix and a grain inhibitor, wherein the addition amount of the grain inhibitor is 0.08-0.16% of the weight of the aluminum alloy matrix; The weight percentages of the chemical components of the aluminum alloy matrix are as follows: Fe 0.6-0.85%, Mg 0.7-0.9%, Si 0.05-0.09%, Cu 0.3-0.5%, Re 0.12-0.22%, B 0.02-0.06%, and the balance is Al; The grain inhibitor is prepared by loading graphene oxide on a metal carbide mixture treated with a cationic surfactant, and then reducing the graphene oxide with hydrazine hydrate; the metal carbide mixture is a mixture of titanium carbide, vanadium carbide and tantalum carbide.

2. The high-strength electrical aluminum alloy according to claim 1, characterized in that: The weight ratio of the titanium carbide, vanadium carbide and tantalum carbide is 10:3:(0-1).

3. The high-strength electrical aluminum alloy according to claim 1, characterized in that: The addition amount of the grain inhibitor is 0.12% of the weight of the aluminum alloy matrix.

4. The high-strength aluminum alloy for electrical use according to claim 1, characterized in that: The cationic surfactant is a quaternary ammonium salt cationic surfactant.

5. The high-strength aluminum alloy for electrical use according to claim 1, characterized in that: The average particle size of the titanium carbide is 40 nm, the average particle size of the vanadium carbide is 500 nm, and the average particle size of the tantalum carbide is 200 nm.

6. The high-strength aluminum alloy for electrical use according to claim 1, characterized in that: The aluminum alloy further includes a compatibilizer, and the added amount of the compatibilizer is 1.2-1.7% of the weight of the aluminum alloy matrix.

7. The high-strength aluminum alloy for electrical use according to claim 1, characterized in that: The compatibilizer is a mixture of nickel powder and cobalt powder.

8. The high-strength aluminum alloy for electrical use according to claim 1, characterized in that: The weight ratio of the nickel powder to the cobalt powder is 2:

1.

9. A smelting process for the high-strength electrical aluminum alloy according to any one of claims 1 to 8, characterized in that: It includes the following steps: S1. Prepare aluminum ingots, aluminum-iron master alloys, aluminum-magnesium master alloys, aluminum-silicon master alloys, aluminum-copper master alloys, rare earth master alloys containing Re, and aluminum-boron master alloys, and then batch them according to the weight percentage of each chemical component of the aluminum alloy matrix; S2. Set the melting furnace temperature to 800-870°C, add aluminum ingots, and when the aluminum ingots are melted to 70-80%, add covering agent. After the aluminum ingots are completely melted, add aluminum-magnesium master alloy, aluminum-iron master alloy, aluminum-copper master alloy, rare earth master alloy, aluminum-silicon master alloy and aluminum-boron master alloy in sequence. After the ingredients are prepared, keep the temperature at 740-770°C, blow in refining agent with argon gas for refining and deslagging, and then perform furnace composition analysis; then add raw materials other than the aluminum alloy matrix; S4, after refining and slag removal, ingot casting is carried out, and the ingot casting process parameters are as follows: inlet water temperature 20-25°C, outlet water temperature 30-35°C, water pressure 0.15-0.2Mpa, casting speed 50-55mm / min, casting temperature 715±10°C; S5. Homogenize the ingot in a heating furnace at a temperature of 575-595°C for 10-15 hours, and then cool naturally; S6. Tempering the ingot: Continue to uniformly heat the ingot to 380-420° C. in a heating furnace, and then cool it naturally to obtain an aluminum alloy.

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