A kind of high conductivity aluminum alloy casting and preparation method thereof

Abstract

The invention discloses a high-conductivity aluminum alloy casting and a preparation method thereof. The aluminum alloy casting comprises, by weight percentage, 2.0-4.3% Si, 0.2-1.0% Mg, 0.1-0.5% Cu, and the rest aluminum, wherein the content of impurity elements is ≤0.1% as a whole, wherein Fe is ≤0.2%, and the content of the other impurity elements is ≤0.01% individually. The aluminum alloy casting prepared by adjusting the composition of alloy elements and a heat treatment process has the advantage of good electrical conductivity. The electrical conductivity of the high-conductivity aluminum alloy casting at room temperature is not less than 50% IACS, and the tensile strength is not less than 275 MPa, thereby solving the problem of low electrical conductivity of the cast aluminum alloy casting.

Description

Technical Field

[0001] The invention belongs to the technical field of alloy casting and relates to a high-conductivity aluminum alloy casting and a preparation method thereof. Background Art

[0002] With the continuous development of the power transmission and distribution industry, while meeting the material strength requirements, higher requirements are put forward for the conductivity of aluminum alloy castings. At present, the conductivity of cast aluminum alloys used in the high-voltage electrical industry is generally 38-41% IACS, and the tensile strength is between 275-315MPa, such as ZL101A-T6. The conductivity is difficult to meet the improvement needs of power transmission and distribution industry products.

[0003] In recent years, the electrical conductivity of aluminum alloys has been studied, and it has been found that the electrical conductivity of aluminum alloys mainly depends on their heat treatment process, alloying elements and organizational morphology, among which the heat treatment process has a particularly significant effect on the electrical conductivity. The heat treatment of aluminum alloys includes solution treatment and aging treatment. As the artificial aging temperature increases, the electrical conductivity gradually increases. This is because when the aging temperature increases, the supersaturated solid solution obtained by quenching will gradually precipitate solute atoms, reduce the degree of distortion of the alloy, reduce internal stress, and thus make the movement of electrons easier, and the electrical conductivity gradually increases. As the temperature increases, the electrical conductivity increases. However, as the temperature further increases, the density of the precipitated transition phase decreases, and thus the changes in strength and electrical conductivity tend to be gentle. Therefore, appropriately increasing the temperature of artificial aging is one of the ways to develop high-conductivity aluminum alloys.

[0004] The patent with application number 201710125313.3 and titled "A high conductivity cast aluminum alloy and its manufacturing method" adds Si element content of 4.5-6.5%, and adds trace special elements boron and lanthanum. The solution treatment temperature is 540±5℃, the solution time is 2-8h; the aging treatment temperature is 223±5℃, the aging time is 3-7 hours, and the conductivity of the alloy at room temperature is 46.5-50.7% IACS. While this technology obtains conductivity, the economic benefits of production and application are reduced due to the addition of high-cost boron and lanthanum elements. The patent named "A high conductivity cast aluminum alloy and its preparation method" includes material preparation, melting, aluminum liquid refining, slag removal and degassing, modification, boronization and rare earth treatment, static treatment, dual rotor online degassing, and finally the filtered aluminum liquid is introduced into the distributor for casting. The temperature of the aluminum liquid entering the distributor is controlled at 660-680℃, and finally the aluminum silicon alloy is obtained. This technology adjusts the alloy element composition and combines boronization and LaCe rare earth treatment to obtain an alloy with good conductivity. However, the addition of boron and rare earth elements makes the process complex and costly.

[0005] In summary, it is urgent to solve the problems of low conductivity, complex process and high cost of aluminum alloy castings in the prior art. Summary of the invention

[0006] In view of the problems existing in the prior art, the purpose of the present invention is to provide a high conductivity aluminum alloy casting and a preparation method thereof, which solves the problems of low conductivity, complex process and high cost of cast aluminum alloy castings.

[0007] The present invention is achieved through the following technical solutions:

[0008] A high-conductivity aluminum alloy casting comprises, in terms of mass percentage, 2.0%-4.3% Si, 0.2%-1.0% Mg, 0.1%-0.5% Cu, and the remainder aluminum.

[0009] Preferably, the impurity elements in the high conductivity aluminum alloy casting include Fe and other impurity elements, wherein Fe≤0.2%, the content of the other impurity elements as a whole is ≤0.1%, and the content of each of the other impurity elements is ≤0.01%.

[0010] Preferably, the electrical conductivity of the high-conductivity aluminum alloy casting at room temperature exceeds 50% IACS, and the tensile strength exceeds 275 MPa.

[0011] A method for preparing a high-conductivity aluminum alloy casting comprises the following steps:

[0012] S1, melting the aluminum-silicon alloy to obtain an aluminum alloy melt A, and keeping it still at a temperature;

[0013] S2, adding aluminum-strontium alloy to aluminum alloy melt A for furnace pre-modification treatment, and then adding magnesium block and Al-Cu alloy block, and after they are completely melted, obtaining aluminum alloy melt B;

[0014] S3, evenly sprinkle a layer of slag removal agent on the surface of aluminum alloy melt B, rub for 2-5 minutes and then scrape off the surface slag; evenly sprinkle another layer of slag removal agent on the liquid surface, scrape the slag removal agent in the middle part of the liquid surface to the periphery, insert a rotating air blowing refining rotor to perform degassing refining; after refining, scrape off the slag on the surface of the aluminum alloy melt, and obtain aluminum alloy melt C after degassing and deslagging refining treatment;

[0015] S4, making the refined aluminum alloy melt C into an aluminum alloy casting, and heat-treating the aluminum alloy casting to obtain a high conductivity aluminum alloy casting.

[0016] Preferably, before use, the tools in contact with the aluminum liquid of the aluminum-silicon alloy need to be preheated to 150-250°C, then coated with zinc oxide paint, and then dried at 300°C-600°C.

[0017] Preferably, the specific process of the furnace-front deterioration treatment in S2 is:

[0018] The aluminum alloy melt is transferred into a refining and metamorphic furnace, the aluminum strontium alloy is preheated, and then placed in a crucible, and then the aluminum alloy melt A is poured in, and the crucible is placed in the refining and metamorphic furnace, the temperature of the aluminum alloy melt is maintained at 690-720°C, and stirred with a bell jar for 3-5 minutes, so that the aluminum alloy melt A is metamorphosed before the furnace, and the outlet temperature of the refining and metamorphic furnace is 700-720°C.

[0019] Preferably, the amount of the slag cleaning agent added in S3 is 0.15%-0.2% of the weight of the aluminum alloy melt; and the amount of the aluminum strontium alloy added in S2 is 0.05%-0.15% of the weight of the aluminum silicon alloy.

[0020] Preferably, the treatment temperature of the degassing and deslagging refining treatment in S3 is 690-720° C., and the treatment time is 15-60 min.

[0021] Preferably, the aluminum-silicon alloy is melted in a natural gas melting furnace, the outlet temperature of the natural gas melting furnace is 720-740° C., and the insulation temperature of the aluminum alloy melt A is 690-720° C.;

[0022] Preferably, the heat treatment process is:

[0023] The aluminum alloy casting is placed in a solution furnace at a temperature of 525-545°C, kept warm for 4-10 hours, and then water quenched; after water quenching, the aluminum alloy casting is transferred to an aging furnace at a temperature of 200-250°C, kept warm for 1-4 hours, and then air-cooled to obtain a high conductivity aluminum alloy casting; wherein, the time for the aluminum alloy casting to be transferred from the solution furnace to the aging furnace does not exceed 24 hours, and the process time from taking out of the solution furnace to water quenching does not exceed 1 minute.

[0024] Compared with the prior art, the present invention has the following beneficial technical effects:

[0025] The object of the present invention is to provide a high-conductivity aluminum alloy casting and a preparation method thereof. The aluminum alloy casting prepared by adjusting the composition of alloy elements and heat treatment process has the advantage of good conductivity. The conductivity of the high-conductivity aluminum alloy casting at room temperature is not less than 50% IACS, and the tensile strength is not less than 275Mpa, which solves the problem of low conductivity of cast aluminum alloy castings.

[0026] In addition, the preparation method of the present invention is to subject the aluminum alloy melt to furnace pre-modification treatment, degassing and deslagging refining treatment and heat treatment; in the aluminum silicon alloy smelting process, after furnace pre-modification treatment, by adding a proper amount of modifier aluminum strontium alloy to adjust the organizational structure of the aluminum alloy and improve its performance, the addition of aluminum strontium alloy modifier can change the solidification behavior of the aluminum silicon alloy, promote the precipitation of fine silicon phase, thereby refining the grains of the alloy; the aluminum silicon alloy can obtain higher strength, hardness and wear resistance, and improve its tensile strength. After degassing and deslagging refining treatment, it is used to remove impurities and impure substances in the metal smelting process; after further heat treatment of the aluminum alloy, the supersaturated solid solution obtained by quenching will gradually precipitate solute atoms, so that the lattice distortion of the alloy is reduced, the internal stress is reduced, so that the movement of electrons becomes easy, and the conductivity gradually increases. As the aging temperature increases, the strengthening phase precipitates more fully, and the conductivity of the aluminum alloy casting alloy increases, meeting the material performance requirements of the power industry. The process is simple, the cycle is short, the production efficiency is high, and the cost is low, so large-scale industrial preparation is easy and batch production is convenient.

[0027] Furthermore, the alloy system involved in the present invention is simple and easy to prepare and operate, the alloy system elements used are low-cost, the addition amount is easy to control, no pollutants are discharged, the production efficiency is high, the cost is low, and it is suitable for large-scale industrial production.

[0028] Furthermore, the aluminum alloy casting prepared by adjusting the composition of alloy elements and the heat treatment process in the present invention has the advantage of good electrical conductivity, meeting the improvement needs of products in the power transmission and distribution industry. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below in conjunction with specific embodiments, which are intended to explain the present invention rather than to limit it.

[0030] The material composition used in the present invention is as follows: Si: 2.0-4.3%, Mg: 0.2-1.0%, Cu: 0.1-0.5%, and the rest is aluminum. The content of impurity Fe element is controlled, Fe≤0.2%, and the content of other impurity elements is individually ≤0.01%, and the total is ≤0.1%.

[0031] The furnace charge must be dry and clean, and the parts of the tools that come into contact with the aluminum liquid must be cleaned to remove the rust, residual flux and other adhesions on the surface. Preheat to 150-250℃, apply a certain thickness of zinc oxide paint, and then fully dry at above 300℃. Add the weighed 356Z.2 alloy into the natural gas melting furnace for melting, and the melting temperature is 720-740℃. After the alloy is completely melted, it needs to be transferred to the refining and metamorphic furnace according to production needs. The outlet temperature of the refining and metamorphic furnace is 700-720℃. Before transferring, weigh the aluminum-strontium alloy (the amount of aluminum-strontium alloy added is 0.05%-0.15%, and the Sr content is 0.003%-0.006% after chemical composition detection) and preheat it, then put it into an empty crucible, and then put the aluminum liquid into the crucible from the natural gas melting furnace, put the crucible into the furnace, keep the aluminum liquid temperature at 690-720℃, and stir it with a bell jar for 3-5min. Press the weighed and prepared magnesium block and Al-Cu alloy block into the aluminum liquid with a bell jar, wait for it to be completely melted, stir it evenly, let it stand and keep it warm, and keep the temperature at 690-720℃. Sprinkle a layer of slag remover evenly on the liquid surface, the amount added is 0.15%-0.2% of the aluminum liquid, rub it for 2-5min, and then scrape off the surface scum. Sprinkle another layer of slag remover evenly on the liquid surface (the amount added is the same as above), spread the slag remover in the middle part of the liquid surface to the periphery, and insert the rotating air blowing refining rotor for degassing and refining. Maintain the aluminum temperature at 690-720℃, let it stand for 5-10 minutes, check the gas content of the aluminum liquid, and if it meets the requirements, transfer it to a low-pressure casting insulation furnace with a crucible to make aluminum alloy castings. Place the prepared aluminum alloy castings in a solid solution furnace at a temperature of 525-545℃, keep it warm for 4-10 hours, and then quench it with water; then transfer the castings to an aging furnace at a temperature of 200-250℃, keep it warm for 1-4 hours, and then air cool it. The time for the aluminum alloy castings to be transferred from the first-level heat treatment furnace to the second-level heat treatment furnace shall not exceed 24 hours, and the process time from the solid solution furnace to the water quenching shall not exceed 1 minute.

[0032] Embodiment 1:

[0033] Before use, the charge must be dry and clean. The parts of the tools that come into contact with the aluminum liquid must be cleaned to remove rust, residual flux and other adhesions on the surface. Preheat to 150℃, apply a certain thickness of zinc oxide paint, and then fully dry at 300℃.

[0034] Melting aluminum alloy: adding weighed 356Z.2 aluminum-silicon alloy into a natural gas melting furnace for melting at a melting temperature of 720° C., and obtaining aluminum-silicon alloy melt A after the aluminum-silicon alloy is completely melted.

[0035] Pre-furnace metamorphic treatment: According to production requirements, it needs to be transferred to a refining metamorphic furnace, and the outlet temperature of the refining metamorphic furnace is 700℃.

[0036] Before transferring, the aluminum strontium alloy is weighed (the amount of aluminum strontium alloy added is 0.05% of the weight of the aluminum silicon alloy, and the Sr content is 0.003% after chemical composition detection) and preheated, and then placed in an empty crucible, and then the aluminum alloy melt A in the natural gas melting furnace is placed in the crucible, and the crucible is placed in the furnace of the refining and metamorphic furnace, the aluminum liquid temperature of the aluminum alloy melt is maintained at 690°C, and stirred for 3 minutes with a bell jar;

[0037] The weighed and prepared magnesium block and Al-Cu alloy block are pressed into the above aluminum alloy melt by using a bell jar, the addition amount of magnesium accounts for 0.2% of the total addition amount, and the addition amount of copper accounts for 0.1% of the total addition amount. After they are completely melted, they are stirred evenly, and allowed to stand and heat-insulated. The temperature is maintained at 690° C. to obtain aluminum alloy melt B;

[0038] Melt degassing and slag refining: a layer of slag removal agent is evenly sprinkled on the liquid surface of the aluminum alloy melt B after standing and heat preservation for 10 minutes, and the surface scum is scraped off after rubbing for 2 minutes; another layer of slag removal agent is evenly sprinkled on the liquid surface (the amount added is the same as above), wherein the total amount of slag removal agent added is 0.15% of the weight of the aluminum silicon alloy; the slag removal agent in the middle part of the liquid surface is scraped to the periphery, and a rotating air blowing refining rotor is inserted for degassing and refining; the aluminum liquid temperature is maintained at 690°C, and the aluminum melt is kept standing and heat-insulated for 5 minutes to obtain aluminum alloy melt C;

[0039] The gas content of the aluminum liquid is checked. If it meets the requirements, it is transferred into a low-pressure casting holding furnace using a crucible to make aluminum alloy castings.

[0040] Heat treatment: The prepared aluminum alloy castings are placed in a solution furnace at 535°C, kept warm for 4 hours and then water quenched; the aluminum alloy castings are then transferred to an aging furnace at 215°C, kept warm for 1 hour and then air-cooled. The time for the aluminum alloy castings to be transferred from the solution furnace to the aging furnace is 0.5 hours, and the process time from taking out of the solution furnace to water quenching is 1 minute.

[0041] After machining, the aluminum alloy casting of this embodiment was sampled and tested, and the conductivity at room temperature was 51% IACS and the tensile strength was 295 MPa.

[0042] The high-conductivity aluminum alloy casting comprises the following components in percentage by mass: Si: 3.5%, Mg: 0.2%, Cu: 0.1%, and the rest is aluminum, and the content of impurity Fe element is controlled, Fe≤0.2%, and the content of other impurity elements individually ≤0.01%, and the total content ≤0.1%.

[0043] Embodiment 2:

[0044] Before use, the charge must be dry and clean. The parts of the tools that come into contact with the aluminum liquid must be cleaned to remove rust, residual flux and other adhesions on the surface. Preheat to 250℃, apply a certain thickness of zinc oxide paint, and then fully dry at 600℃.

[0045] Melting aluminum alloy: adding weighed 356Z.2 aluminum-silicon alloy into a natural gas melting furnace for melting at a melting temperature of 740°C. After the aluminum-silicon alloy is completely melted, an aluminum-silicon alloy melt A is obtained;

[0046] Pre-furnace metamorphic treatment: According to production requirements, it needs to be transferred to a refining metamorphic furnace, and the outlet temperature of the refining metamorphic furnace is 720℃.

[0047] Before transferring, the aluminum strontium alloy is weighed (the amount of aluminum strontium alloy added is 0.08% of the weight of the aluminum silicon alloy, and the Sr content is 0.006% after chemical composition detection) and preheated, and then placed in an empty crucible, and then the aluminum alloy melt A in the natural gas melting furnace is placed in the crucible, and the crucible is placed in the furnace of the refining and metamorphic furnace, the aluminum liquid temperature of the aluminum alloy melt is maintained at 720°C, and stirred for 5 minutes with a bell jar;

[0048] The weighed and prepared magnesium block and Al-Cu alloy block are pressed into the above aluminum alloy melt by using a bell jar, the addition amount of magnesium accounts for 1.0% of the total addition amount, and the addition amount of copper accounts for 0.5% of the total addition amount. After they are completely melted, they are stirred evenly, and allowed to stand and heat-insulated. The temperature is maintained at 720° C. to obtain aluminum alloy melt B;

[0049] Melt degassing and slag refining: a layer of slag removal agent is evenly sprinkled on the liquid surface of the aluminum alloy melt B after standing and heat preservation for 10 minutes, and the surface scum is scraped off after rubbing for 2 minutes; another layer of slag removal agent is evenly sprinkled on the liquid surface (the amount added is the same as above), wherein the total amount of slag removal agent added is 0.2% of the weight of the aluminum silicon alloy; the slag removal agent in the middle part of the liquid surface is scraped to the periphery, and a rotating air blowing refining rotor is inserted for degassing and refining; the aluminum liquid temperature is maintained at 720°C, and the aluminum melt is kept standing and heat preserved for 10 minutes to obtain aluminum alloy melt C;

[0050] The gas content of the aluminum liquid is checked. If it meets the requirements, it is transferred into a low-pressure casting holding furnace using a crucible to make aluminum alloy castings.

[0051] Heat treatment: The prepared aluminum alloy castings were placed in a solution furnace at 537°C, kept warm for 10 hours and then water quenched; the aluminum alloy castings were then transferred to an aging furnace at 220°C, kept warm for 4 hours and then air-cooled. The time for the aluminum alloy castings to be transferred from the solution furnace to the aging furnace was 0.5 hours, and the process time from taking out of the solution furnace to water quenching was 50 seconds.

[0052] After machining, the aluminum alloy casting of this embodiment was sampled and tested, and the conductivity at room temperature was 52% IACS and the tensile strength was 298 MPa.

[0053] The high-conductivity aluminum alloy casting comprises the following components in percentage by mass: Si: 4.3%, Mg: 1.0%, Cu: 0.5%, and the rest is aluminum, and the content of impurity Fe element is controlled, Fe≤0.2%, and the content of other impurity elements individually ≤0.01%, and the total content ≤0.1%.

[0054] Embodiment 3:

[0055] Before use, the charge must be dry and clean. The parts of the tools that come into contact with the aluminum liquid must be cleaned to remove rust, residual flux and other adhesions on the surface. Preheat to 200℃, apply a certain thickness of zinc oxide paint, and then fully dry at 400℃.

[0056] Melting aluminum alloy: adding weighed 356Z.2 aluminum-silicon alloy into a natural gas melting furnace for melting at a melting temperature of 730°C. After the aluminum-silicon alloy is completely melted, an aluminum-silicon alloy melt A is obtained;

[0057] Pre-furnace metamorphic treatment: According to production requirements, it needs to be transferred to a refining metamorphic furnace, and the outlet temperature of the refining metamorphic furnace is 710℃.

[0058] Before transferring, the aluminum strontium alloy is weighed (the amount of aluminum strontium alloy added is 0.06% of the weight of the aluminum silicon alloy, and the Sr content is 0.004% after chemical composition detection) and preheated, and then placed in an empty crucible, and then the aluminum alloy melt A in the natural gas melting furnace is placed in the crucible, and the crucible is placed in the furnace of the refining and metamorphic furnace, the aluminum liquid temperature of the aluminum alloy melt is maintained at 700°C, and stirred with a bell jar for 4 minutes;

[0059] The weighed and prepared magnesium block and Al-Cu alloy block are pressed into the above aluminum alloy melt by using a bell jar, the addition amount of magnesium accounts for 0.8% of the total addition amount, and the addition amount of copper accounts for 0.35% of the total addition amount. After they are completely melted, they are stirred evenly, and allowed to stand and heat-insulated. The temperature is maintained at 710° C. to obtain aluminum alloy melt B;

[0060] Melt degassing and slag refining: a layer of slag removal agent is evenly sprinkled on the liquid surface of the aluminum alloy melt B after standing and heat preservation for 10 minutes, and the surface scum is scraped off after rubbing for 3 minutes; another layer of slag removal agent is evenly sprinkled on the liquid surface (the amount added is the same as above), wherein the total amount of slag removal agent added is 0.18% of the weight of the aluminum silicon alloy; the slag removal agent in the middle part of the liquid surface is scraped to the periphery, and a rotating air blowing refining rotor is inserted for degassing and refining; the aluminum liquid temperature is maintained at 710°C, and the aluminum melt is kept standing and heat-insulated for 8 minutes to obtain aluminum alloy melt C;

[0061] The gas content of the aluminum liquid is checked. If it meets the requirements, it is transferred into a low-pressure casting holding furnace using a crucible to make aluminum alloy castings.

[0062] Heat treatment: The prepared aluminum alloy castings are placed in a solution furnace at 525°C, kept warm for 8 hours and then water quenched; the aluminum alloy castings are then transferred to an aging furnace at 200°C, kept warm for 3 hours and then air-cooled. The time for the aluminum alloy castings to be transferred from the solution furnace to the aging furnace is 0.5 hours, and the process time from taking out of the solution furnace to water quenching is 55 seconds.

[0063] After machining, the aluminum alloy casting of this embodiment was sampled and tested, and the conductivity at room temperature was 52% IACS and the tensile strength was 301 MPa.

[0064] The high-conductivity aluminum alloy casting comprises the following components in percentage by mass: Si: 4.2%, Mg: 0.8%, Cu: 0.35%, and the rest is aluminum, and the content of impurity Fe element is controlled, Fe≤0.2%, and the content of other impurity elements individually ≤0.01%, and the total content ≤0.1%.

[0065] Embodiment 4:

[0066] Before use, the charge must be dry and clean. The parts of the tools that come into contact with the aluminum liquid must be cleaned to remove rust, residual flux and other adhesions on the surface. Preheat to 220℃, apply a certain thickness of zinc oxide paint, and then fully dry at 500℃.

[0067] Melting aluminum alloy: adding weighed 356Z.2 aluminum-silicon alloy into a natural gas melting furnace for melting at a melting temperature of 730°C. After the aluminum-silicon alloy is completely melted, an aluminum-silicon alloy melt A is obtained;

[0068] Pre-furnace metamorphic treatment: According to production requirements, it needs to be transferred to a refining metamorphic furnace, and the outlet temperature of the refining metamorphic furnace is 710℃.

[0069] Before transferring, the aluminum strontium alloy is weighed (the amount of aluminum strontium alloy added is 0.05% of the weight of the aluminum silicon alloy, and the Sr content is 0.003% after chemical composition detection) and preheated, and then placed in an empty crucible, and then the aluminum alloy melt A in the natural gas melting furnace is placed in the crucible, and the crucible is placed in the furnace of the refining and metamorphic furnace, the aluminum liquid temperature of the aluminum alloy melt is maintained at 710°C, and stirred with a bell jar for 5 minutes;

[0070] The weighed and prepared magnesium block and Al-Cu alloy block are pressed into the above aluminum alloy melt by using a bell jar, the addition amount of magnesium accounts for 0.6% of the total addition amount, and the addition amount of copper accounts for 0.25% of the total addition amount. After they are completely melted, they are stirred evenly, and allowed to stand and heat-insulated. The temperature is maintained at 710° C. to obtain aluminum alloy melt B;

[0071] Melt degassing and slag refining: a layer of slag removal agent is evenly sprinkled on the liquid surface of the aluminum alloy melt B after standing and heat preservation for 10 minutes, and the surface scum is scraped off after rubbing for 5 minutes; another layer of slag removal agent is evenly sprinkled on the liquid surface (the amount added is the same as above), wherein the total amount of slag removal agent added is 0.16% of the weight of the aluminum silicon alloy; the slag removal agent in the middle part of the liquid surface is scraped to the periphery, and a rotating air blowing refining rotor is inserted for degassing and refining; the aluminum liquid temperature is maintained at 710°C, and the aluminum melt is kept standing and heat-insulated for 6 minutes to obtain aluminum alloy melt C;

[0072] The gas content of the aluminum liquid is checked. If it meets the requirements, it is transferred into a low-pressure casting holding furnace using a crucible to make aluminum alloy castings.

[0073] Heat treatment: The prepared aluminum alloy castings are placed in a solution furnace at 545°C, kept warm for 6 hours and then water quenched; the aluminum alloy castings are then transferred to an aging furnace at 250°C, kept warm for 2 hours and then air-cooled. The time for the aluminum alloy castings to be transferred from the solution furnace to the aging furnace is 0.5 hours, and the process time from taking out of the solution furnace to water quenching is 30 seconds.

[0074] After machining, the aluminum alloy casting of this embodiment was sampled and tested, and the conductivity at room temperature was 52.5% IACS and the tensile strength was 300 MPa.

[0075] The high-conductivity aluminum alloy casting comprises the following components in percentage by mass: Si: 2.0%, Mg: 0.6%, Cu: 0.25%, and the rest is aluminum, and the content of impurity Fe element is controlled, Fe≤0.2%, and the content of other impurity elements individually ≤0.01%, and the total content ≤0.1%.

[0076] The refining and metamorphism furnace of the present invention refers to a device for refining and metamorphism of metals, which is generally used in the field of metallurgy and metal processing to heat, melt and process raw metals to remove impurities and improve the quality and performance of the metal. After the refining and metamorphism treatment, this can increase the hardness, strength and other properties of the metal. It should be noted that the specific design and operation method of the refining and metamorphism furnace may vary depending on different metals and processes. Different types of metals and alloys may require different types of furnaces and treatment processes. In addition, safe operation and environmental protection are also very important considerations in metal smelting and processing.

[0077] Degassing and deslagging refining is a metal smelting process that improves the purity and quality of the metal by removing oxygen, dross and other impurities from the aluminum alloy melt. These steps play an important role in different metal smelting processes to ensure the production of high-quality metal products that meet the requirements.

[0078] The pre-furnace modification of aluminum-silicon alloy refers to the addition of an appropriate amount of modifier during the smelting process of aluminum-silicon alloy to adjust the alloy's structure and improve its performance. The addition of aluminum-strontium alloy modifier can change the solidification behavior of aluminum-silicon alloy, promote the precipitation of fine silicon phase, and thus refine the alloy's grains; it can make the aluminum-silicon alloy obtain higher strength, hardness and wear resistance.

[0079] Aging furnaces are usually used for aging treatment of aluminum alloys, because aluminum alloys need to be aged after solution treatment (solution treatment) to achieve optimal material properties. Solution treatment is achieved by heating to dissolve the solute elements in the metal material into the matrix, and then rapidly cooling; after solution treatment, the mechanical properties of the material have not yet fully reached the optimal state, so aging treatment is required. The heat treatment process involved in the present invention increases the artificial aging temperature. As the artificial aging temperature increases, the supersaturated solid solution obtained by quenching will gradually precipitate solute atoms, which reduces the degree of lattice distortion of the alloy and reduces the internal stress, thereby facilitating the movement of electrons and gradually increasing the conductivity. As the aging temperature increases, the precipitation of the strengthening phase is more sufficient, and the conductivity of the alloy increases.

[0080] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician in the industry can smoothly implement the present invention as shown in the specification and described above. However, any equivalent changes, modifications and evolutions made by technicians familiar with the profession without departing from the scope of the technical solution of the present invention using the technical content disclosed above are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the technical solution of the present invention.

Claims

1. A high conductivity aluminum alloy casting, characterized in that: According to the mass percentage, it includes: Si: 2.0%-4.3%, Mg: 0.6%-1.0%, Cu: 0.1%-0.5%, and the rest is aluminum; The impurity elements in the high conductivity aluminum alloy casting include Fe and other impurity elements, wherein Fe is ≤0.2%, the content of the other impurity elements is ≤0.1% as a whole, and the content of the other impurity elements is ≤0.01% individually; the method for preparing a high conductivity aluminum alloy casting comprises the following steps: S1, melting the aluminum-silicon alloy to obtain an aluminum alloy melt A, and keeping it still at a temperature; S2, adding aluminum-strontium alloy to aluminum alloy melt A for furnace pre-modification treatment, and then adding magnesium block and Al-Cu alloy block, and after they are completely melted, obtaining aluminum alloy melt B; S3, evenly sprinkle a layer of slag removal agent on the surface of aluminum alloy melt B, rub for 2-5 minutes and then scrape off the surface slag; evenly sprinkle another layer of slag removal agent on the liquid surface, scrape the slag removal agent in the middle part of the liquid surface to the periphery, insert a rotating air blowing refining rotor to perform degassing refining; after refining, scrape off the slag on the surface of the aluminum alloy melt, and obtain aluminum alloy melt C after degassing and deslagging refining treatment; S4, preparing an aluminum alloy casting from the refined aluminum alloy melt C, and subjecting the aluminum alloy casting to heat treatment to obtain an aluminum alloy casting with high conductivity; The amount of the slag cleaning agent added in S3 is 0.15%-0.2% of the weight of the aluminum alloy melt; the amount of the aluminum strontium alloy added in S2 is 0.05%-0.15% of the weight of the aluminum silicon alloy; The high-conductivity aluminum alloy casting has a conductivity of 51%-52.5% IACS at room temperature and a tensile strength exceeding 275 MPa.

2. A high conductivity aluminum alloy casting according to claim 1, characterized in that: Before use, the tools that come into contact with the aluminum liquid of aluminum-silicon alloy need to be preheated to 150-250℃, then painted with zinc oxide paint, and then dried at 300-600℃.

3. The high conductivity aluminum alloy casting according to claim 1, characterized in that: The specific process of the furnace-front deterioration treatment in S2 is as follows: Before the aluminum alloy melt is transferred into the refining and metamorphic furnace, the aluminum strontium alloy is preheated and placed in a crucible, and then the aluminum alloy melt A is poured in. The crucible is placed in the refining and metamorphic furnace, and the temperature of the aluminum alloy melt is maintained at 690-720°C. Stir with a bell jar for 3-5 minutes, so that the aluminum alloy melt A is metamorphosed in front of the furnace, wherein the outlet temperature of the refining and metamorphic furnace is 700-720°C.

4. The high conductivity aluminum alloy casting according to claim 1, characterized in that: The treatment temperature of the degassing and deslagging refining treatment in S3 is 690-720°C, and the treatment time is 15-60min.

5. The method for preparing a high conductivity aluminum alloy casting according to claim 1, characterized in that: The aluminum-silicon alloy is melted in a natural gas melting furnace, the outlet temperature of the natural gas melting furnace is 720-740°C, and the insulation temperature of the aluminum alloy melt A is 690-720°C.

6. The high conductivity aluminum alloy casting according to claim 1, characterized in that: The heat treatment process is as follows: The aluminum alloy casting is placed in a solution furnace at a temperature of 525-545°C, kept warm for 4-10 hours, and then water quenched; after water quenching, the aluminum alloy casting is transferred to an aging furnace at a temperature of 200-250°C, kept warm for 1-4 hours, and then air-cooled to obtain a high conductivity aluminum alloy casting; wherein, the time for the aluminum alloy casting to be transferred from the solution furnace to the aging furnace does not exceed 24 hours, and the process time from taking out of the solution furnace to water quenching does not exceed 1 minute.