Aluminum alloy profile preparation method and aluminum alloy profile

Abstract

This invention discloses a method for preparing aluminum alloy profiles, comprising the following steps: Raw material preparation: using fine recycled aluminum pieces, large recycled aluminum pieces, pure aluminum, pure magnesium, and silicon-aluminum master alloy as raw materials; Melting and casting: heating and melting the large recycled aluminum pieces, pure aluminum, and silicon-aluminum master alloy, then adding the fine recycled aluminum pieces, continuing melting until all is melted and the melt temperature reaches 740-760℃, then adding pure magnesium, followed by multiple refining processes to remove slag and gas to obtain molten aluminum; casting the molten aluminum to obtain ingots; Homogenization and hot cutting: sending the ingots into a soaking furnace for homogenization followed by hot cutting; Extrusion: transferring the hot-cut ingots to an extrusion cylinder for extrusion; Quenching and aging: quenching and aging the extruded profiles. This invention can significantly reduce raw material costs, shorten the process flow, and greatly improve production efficiency, while effectively avoiding easy burn-off, slag formation, and delamination, thereby producing high-performance aluminum alloy profile products.

Description

Technical Field

[0001] The invention relates to the technical field of profile preparation, and in particular to a method for preparing an aluminum alloy profile and the aluminum alloy profile. Background Art

[0002] Aluminum alloy profiles are the main structural materials for new energy vehicles and are widely used in automotive parts such as motor housings, battery trays, structural beams, and anti-collision systems. The country is now widely promoting the green and low-carbon transformation of energy, and it is of great practical significance to develop greener, low-carbon, low-cost, better-performing and more efficient aluminum alloy profile manufacturing technologies.

[0003] In the prior art, when part of the recycled aluminum alloy is used to replace the original aluminum to reduce the cost of raw materials, the technical solution adopted is to mix the recycled aluminum alloy with other components and then perform homogenization, cold cutting, heating, pressurization and other processes in sequence. The products prepared by this process have problems such as long processing cycle, low efficiency and poor performance. The use of other technical solutions in the process of preparing aluminum alloy profiles also has high costs or slag inclusions, overburning, stratification and other phenomena in the product structure. Therefore, the development of an aluminum alloy profile preparation process that meets the comprehensive requirements of high performance, low cost and high efficiency is still a difficult point in research and development. Summary of the invention

[0004] The technical problem solved by the present invention is to provide a method for preparing an aluminum alloy profile, so as to reduce production costs, improve production efficiency, and thereby obtain a high-performance aluminum alloy profile product.

[0005] The technical problem solved by the present invention is achieved by adopting the following technical solutions:

[0006] A method for preparing an aluminum alloy profile comprises the following steps:

[0007] Batching: Using fine recycled aluminum, large recycled aluminum, pure aluminum, pure magnesium and auxiliary materials as raw materials, batching is carried out according to the proportion of each element in the aluminum alloy profile to be obtained;

[0008] Melting and casting: Heat and melt large pieces of recycled aluminum, pure aluminum, and auxiliary materials, then add fine pieces of recycled aluminum until all are melted and the melt temperature reaches 740-760°C, then add pure magnesium, and then perform multiple refining to remove slag and gas to obtain aluminum liquid; cast the aluminum liquid to obtain an ingot;

[0009] Homogenization and hot cutting: the ingot is sent to the soaking furnace for homogenization and then hot cutting;

[0010] Extrusion: The hot-cut ingot is transferred to the extrusion barrel for high-speed extrusion. The surface temperature of the ingot is controlled to be 420~500℃ when entering the extrusion barrel. After extrusion, the residual weight is controlled to be 3%~6% of the extruded ingot weight, and ensure that the surface metal of the ingot remains in the residual weight.

[0011] Quenching and aging: The extruded profile can be quenched and aged.

[0012] Furthermore, in the batching step, the mass proportion of fine recycled aluminum in the raw materials is 10-30%; the mass proportion of large recycled aluminum is 40-80%; the fine recycled aluminum includes aluminum chips, and the thickness of the fine recycled aluminum is less than 3mm; the large recycled aluminum includes ingot head and tail materials, and the thickness of the large recycled aluminum is greater than or equal to 3mm.

[0013] Furthermore, in the smelting and casting steps, a refining agent is added during slag removal and refining for multiple refinings, the refining temperature is 740-760°C, the refining time is 20-40 minutes each time, and the slag is removed after standing for 20-40 minutes each time; after the last standing and slag removal, the melt is poured from the melting furnace into the holding furnace through the launder, and the air bricks are opened during the pouring process for degassing and refining, the air brick pressure is 650-950KPa, and the air brick flow rate is 50-80L / min.

[0014] Furthermore, in the smelting and casting step, the aluminum liquid after slag removal and degassing is semi-continuously directly cooled and cast, with a casting speed of 32-56 mm / min and a water flow rate of 80-150 m / min. 3 / h.

[0015] Furthermore, the homogenization process is carried out in a soaking furnace, and the temperature is raised to 550-570°C during homogenization and kept at this temperature for 8-15 hours.

[0016] Furthermore, the hot cutting process adopts a fixed-length sawing method; during hot cutting, the ingot sawing-transfer time is controlled to be 20-50 minutes.

[0017] Furthermore, during extrusion, the surface of the ingot rubs against the extrusion barrel, and the extrusion speed is 4-8 mm / s.

[0018] Furthermore, water mist cooling is used for online quenching, and the profile temperature is controlled at 510~540℃ before entering the water; after quenching, aging treatment is carried out, the aging temperature is 180~200℃, and the insulation is 4~8h.

[0019] Further, when the aluminum alloy profile to be obtained is a 6063 aluminum alloy profile, the auxiliary material is a silicon-aluminum master alloy, and the chemical composition mass percentage of the aluminum alloy profile is: Mg 0.4~0.5%, Si 0.7~0.8%, and the balance is Al; when the aluminum alloy profile to be obtained is a 6061 aluminum alloy profile, the auxiliary materials are pure copper, aluminum-chromium master alloy, and silicon-aluminum master alloy, and the chemical composition mass percentage of the aluminum alloy profile is: 0.8~1.2% Mg, 0.5~0.7% Si, 0.2~0.4% Cu, 0.1~0.3% Cr, and the balance is Al.

[0020] An aluminum alloy profile is prepared by any of the above methods. Beneficial Effects

[0021] The aluminum alloy profile preparation method described in the present invention uses fine block recycled aluminum materials and large block recycled aluminum materials as main raw materials, and controls the proportion of other components and combines the process, greatly reducing the cost of raw materials, shortening the process flow, improving material utilization, and greatly improving production efficiency under the premise of meeting high performance; combined with the smelting process and other processes of adding fine block recycled aluminum materials into the melt, the phenomenon of easy burning, easy slagging and stratification of the profile structure is avoided, thereby better meeting the product quality requirements.

[0022] In the traditional process of preparing aluminum alloy profiles, the raw materials are mostly homogenized, cooled to room temperature, and then cut into the required length by sawing, and then further heated to the extrusion temperature for extrusion; while the present invention directly cuts into the required length at high temperature after homogenization, and uses the homogenization temperature to control the temperature required for extrusion without reheating, thereby reducing costs and improving efficiency while well ensuring product quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the structure of the aluminum alloy profile in Example 1 under a microscope.

[0024] Figure 2 This is a schematic diagram of the structure of the aluminum alloy profile in Example 2 under a microscope.

[0025] Figure 3 This is a schematic diagram of the structure of the aluminum alloy profile in Example 3 under a microscope.

[0026] Figure 4 This is a schematic diagram of the structure of the aluminum alloy profile in Control Example 2 under a microscope.

[0027] Figure 5 This is a schematic diagram of the structure of the aluminum alloy profile in Control Example 3 under a microscope.

[0028] Figure 6This is a schematic diagram of the structure of the aluminum alloy profile in Control Example 4 under a low-power microscope. DETAILED DESCRIPTION

[0029] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below in conjunction with specific embodiments. Example 1

[0030] This embodiment takes the preparation of 6063 aluminum alloy profile as an example, the ingot diameter is Φ448mm, and the preparation method includes the following steps:

[0031] Ingredients: The chemical composition of the 6063 aluminum alloy profile to be obtained is as follows: 0.45% Mg, 0.75% Si, and the balance Al;

[0032] Using fine block recycled aluminum, large block recycled aluminum, pure aluminum, pure magnesium, and silicon-aluminum master alloy as raw materials, the materials are prepared according to the ratio of aluminum, magnesium, and silicon in the aluminum alloy profile to be obtained; the weight of fine block recycled aluminum accounts for 20% of the raw materials; the fine block recycled aluminum is the same brand of 6063 profile recycled aluminum chips, the thickness of the aluminum chips is less than 3mm, and the aluminum chips are compacted into blocks for standby; the weight of large block recycled aluminum accounts for 60% of the raw materials; the large block recycled aluminum is large block recycled aluminum such as ingot head and tail materials, and the thickness of the block recycled aluminum is greater than or equal to 3mm. Other raw materials such as pure aluminum, pure magnesium, and silicon-aluminum master alloy are further configured according to the element ratio in the 6063 aluminum alloy profile to be obtained;

[0033] Melting and casting: Put large pieces of recycled aluminum, pure aluminum, and silicon-aluminum intermediate alloy into a smelting furnace for heating and melting. After melting, add compacted blocks of recycled aluminum. The recycled aluminum melts inside the aluminum liquid, which can greatly reduce burning and slag formation. Continue to melt until all are melted and the melt temperature reaches 740°C, add pure magnesium, add it by scalding with a magnesium frame, and then add a refining agent for multiple deslagging and refining. The deslagging and refining temperature is 750°C, and the refining time is 30 minutes each time. After each refining, stand for 30 minutes before slagging; repeat the refining twice, in which the refining agent is a conventional choice. The replacement of the refining agent does not affect the test results. In this embodiment, a refining agent with a grade of J185 is selected. After the last standing and slagging, the melt is poured from the melting furnace into the insulation furnace through the launder. During the pouring process, the air brick is opened for degassing and refining. The air brick pressure is 780KPa and the air brick flow rate is 65L / min.

[0034] The degassed and deslagging aluminum liquid is semi-continuously directly cooled and cast at a casting speed of 38 mm / min and a water flow rate of 140 m 3 / h, to obtain an ingot;

[0035] Homogenization and hot cutting: send the ingot into the soaking furnace for homogenization, raise the temperature to 565℃ during homogenization, and keep it warm for 10 hours;

[0036] After the ingot is homogenized, the ingot is sawn to a fixed length while it is hot, and the ingot sawing and transportation time is controlled within 35 minutes.

[0037] Extrusion: The hot-cut ingot is transferred to the extrusion barrel for high-speed extrusion. The surface temperature of the ingot is controlled at 470°C when entering the extrusion barrel; the extrusion speed is 6 mm / s.

[0038] Quenching and aging: The extruded profiles are quenched by water mist online quenching. The temperature of the extruded profiles is controlled at 530°C before entering the water. After quenching, aging is carried out at 195°C for 6 hours.

[0039] The structure of the aluminum alloy profile prepared in Example 1 is as follows Figure 1 shown. Example 2

[0040] This embodiment takes the preparation of 6063 aluminum alloy profile as an example, the ingot diameter is Φ448mm, and the preparation method includes the following steps:

[0041] Ingredients: The chemical composition of the 6063 aluminum alloy profile to be obtained is as follows: 0.45% Mg, 0.75% Si, and the balance Al;

[0042] Using fine block recycled aluminum, large block recycled aluminum, pure aluminum, pure magnesium, and silicon-aluminum master alloy as raw materials, the materials are prepared according to the ratio of aluminum, magnesium, and silicon in the aluminum alloy profile to be obtained; the mass proportion of fine block recycled aluminum in the raw materials is 10%; the fine block recycled aluminum is recycled aluminum chips of the same brand, the thickness of the aluminum chips is less than 3mm, and the aluminum chips are compacted into blocks for standby; the mass proportion of large block recycled aluminum in the raw materials is 70%; the large block recycled aluminum is large block recycled aluminum such as ingot head and tail materials, and the thickness of the block recycled aluminum is greater than or equal to 3mm. Other raw materials such as pure aluminum, pure magnesium, and silicon-aluminum master alloy are further configured according to the element ratio in the 6063 aluminum alloy profile to be obtained;

[0043] Melting and casting: Put large pieces of recycled aluminum, pure aluminum, and silicon-aluminum master alloy into the melting furnace for heating and melting. After melting, add compacted and blocky recycled aluminum. The fine recycled aluminum melts inside the aluminum liquid, which can greatly reduce burning and slag formation. Continue to melt until all are melted and the melt temperature reaches 740℃, add pure magnesium, add it by scalding with a magnesium frame, and then add a refining agent for multiple deslagging and refining. The deslagging and refining temperature is 750℃, and the refining time is 30min each time. After each refining, stand for 30min before slagging; repeat the refining twice, and after the last standing and slagging, pour the melt from the melting furnace through the launder into the insulation furnace. During the pouring process, open the air brick for degassing and refining. The air brick pressure is 780KPa, and the air brick flow rate is 65L / min; the degassing and refining temperature is 750℃, and the refining time is 30min.

[0044] The degassed and deslagging aluminum liquid is semi-continuously directly cooled and cast at a casting speed of 38 mm / min and a water flow rate of 140 m 3 / h, to obtain an ingot;

[0045] Homogenization and hot cutting: send the ingot into the soaking furnace for homogenization, raise the temperature to 565℃ during homogenization, and keep it warm for 10 hours;

[0046] After the ingot is homogenized, the ingot is sawn to a fixed length while it is hot, and the ingot sawing and transportation time is controlled within 25 minutes.

[0047] Extrusion: The hot-cut ingot is transferred to the extrusion barrel for extrusion. When entering the extrusion barrel, the surface temperature of the ingot is controlled to be 500°C and the extrusion speed is 5mm / s. The principle that the surface of the ingot rubs against the extrusion barrel and the temperature rise is greater than the core is used to control the overall temperature uniformity of the ingot during the extrusion process to prevent local overburning under high-speed extrusion; the residual weight is controlled to be 4% of the weight of the extruded ingot to ensure that the surface metal of the ingot remains in the residual weight; in this step, through the control of the extrusion residual weight, non-car skin ingots are used as extrusion blanks instead of traditional car skin ingots, thereby shortening the process flow and improving material utilization.

[0048] Quenching and aging: The extruded profiles are quenched by water mist online quenching. The temperature of the extruded profiles is controlled at 540°C before entering the water. After quenching, aging is carried out at 195°C for 6 hours.

[0049] The aluminum alloy profile structure prepared in this embodiment is as follows Figure 2 shown. Example 3

[0050] This embodiment takes the preparation of 6061 aluminum alloy profile as an example, the ingot diameter is Φ448mm, and the preparation method includes the following steps:

[0051] Ingredients: The chemical composition of the 6061 aluminum alloy profile to be obtained is as follows: 1% Mg, 0.6% Si, 0.3% Cu, 0.2% Cr, and the balance is Al;

[0052] Using fine block recycled aluminum, large block recycled aluminum, pure aluminum, pure magnesium, pure copper, aluminum-chromium master alloy, and silicon-aluminum master alloy as raw materials, the materials are prepared according to the proportion of aluminum, magnesium, silicon, copper, and chromium in the aluminum alloy profile to be obtained; the mass of fine block recycled aluminum accounts for 10% of the raw materials; the fine block recycled aluminum is recycled aluminum chips of the same brand, the thickness of the aluminum chips is less than 3mm, and the aluminum chips are compacted into blocks for standby; the mass of large block recycled aluminum accounts for 70% of the raw materials; the large block recycled aluminum is large block recycled aluminum such as ingot head and tail materials, and the thickness of the block recycled aluminum is greater than or equal to 3mm. Other raw materials such as pure aluminum, pure magnesium, and silicon-aluminum master alloy are further configured according to the element proportions in the 6061 aluminum alloy profile to be obtained;

[0053] Melting and casting: Put large pieces of recycled aluminum, pure aluminum, and silicon-aluminum master alloy into the melting furnace for heating and melting. After melting, add compacted and blocky recycled aluminum. The fine recycled aluminum melts inside the aluminum liquid, which can greatly reduce burning and slag formation. Continue to melt until all are melted and the melt temperature reaches 740℃, add pure magnesium, add it by adding magnesium frame scalding, and then add refining agent for multiple deslagging and refining. The deslagging and refining temperature is 750℃, and the refining time is 30min each time. After each refining, stand for 30min before slagging; repeat the refining twice, and after the last standing and slagging, pour the melt from the melting furnace through the launder into the insulation furnace. During the pouring process, open the air brick for degassing and refining. The air brick pressure is 780KPa, the air brick flow is 65L / min, the degassing and refining temperature is 750℃, and the refining time is 30min.

[0054] The degassed and deslagging aluminum liquid is semi-continuously directly cooled and cast at a casting speed of 38 mm / min and a water flow rate of 140 m 3 / h, to obtain an ingot;

[0055] Homogenization and hot cutting: send the ingot into the soaking furnace for homogenization, raise the temperature to 565℃ during homogenization, and keep it warm for 10 hours;

[0056] After the ingot is homogenized, the ingot is sawn to a fixed length while it is hot, and the ingot sawing and transportation time is controlled within 25 minutes.

[0057] Extrusion: The hot-cut ingot is transferred to the extrusion barrel for extrusion treatment. The surface temperature of the ingot is controlled at 500°C when entering the extrusion barrel; the extrusion speed is 5mm / s.

[0058] Quenching and aging: The extruded profiles are quenched by water mist online quenching. The temperature of the extruded profiles is controlled at 540°C before entering the water. After quenching, aging is carried out at 182°C for 8 hours.

[0059] The aluminum alloy profile structure prepared in this embodiment is as follows Figure 3 shown.

[0060] Comparative Example 1

[0061] In this comparative example, a 6063 aluminum alloy profile is prepared in a conventional manner, the ingot diameter is Φ448 mm, and the chemical composition of the 6063 aluminum alloy profile to be obtained is as follows: 0.45% Mg, 0.75% Si, and the remainder Al.

[0062] Including the following processes:

[0063] Batching: Large pieces of recycled aluminum such as ingot heads and tails with a thickness greater than or equal to 3 mm are used as the main raw materials, of which 40% by weight are recycled aluminum, and the rest are pure aluminum, pure magnesium, and aluminum-silicon master alloys. Batching is performed according to the ratio of aluminum, magnesium, and silicon in the 6063 aluminum alloy profile to be obtained;

[0064] Melting and casting: Put large pieces of recycled aluminum, pure aluminum, and aluminum-silicon master alloy into the melting furnace, heat and melt. After the melting is completed, use a magnesium frame to add hot water when the melt temperature reaches 740°C, and then refine with a refining agent. After standing and slagging, take samples for analysis, and adjust the composition if necessary. Continue to use refining agents for refining after the composition is qualified. The refining temperature is 750°C, the refining time is 30min, and each refining is allowed to stand for 30min before slagging. The last time the melt is allowed to stand and slag is poured from the melting furnace through the launder into the insulation furnace. During the pouring process, the air brick refining is turned on, the air brick pressure is 780KPa, and the air brick flow rate is 65L / min.

[0065] The degassed and deslagging aluminum liquid is introduced into the crystallizer through the launder for semi-continuous direct cooling casting. The casting speed is 38mm / min and the water flow rate is 140m 3 / h.

[0066] Homogenization and cold cutting: send the ingot into the soaking furnace for homogenization, heat it to 565℃ and keep it warm for 10 hours; after the ingot cools to room temperature, cut it to the required length. After cutting, remove the surface of the ingot and turn it to a diameter of Φ440mm;

[0067] Extrusion: Use induction heating to heat the ingot to 490°C, then transfer the ingot to the extrusion barrel and start extrusion at a speed of 3 mm / s; control the residual weight to be 3% of the extruded ingot weight.

[0068] Quenching and aging: The extruded profiles are quenched by water mist online quenching. The temperature of the extruded profiles is controlled at 520°C before entering the water. After quenching, aging is carried out at 195°C for 6 hours.

[0069] Comparative Example 2

[0070] Compared with Example 1, the difference between this comparative example and Example 1 is that the mass proportion of fine recycled aluminum in the raw material is 40%, the mass proportion of large recycled aluminum is 40%, and the rest is pure aluminum, pure magnesium, and aluminum-silicon master alloy. During smelting, the fine recycled aluminum and large recycled materials in the raw material are added at the same time, and then heated and melted. When all are melted and the melt temperature reaches 740°C, pure magnesium is added, and the rest is the same. The structural diagram of the aluminum alloy profile obtained in this comparative example is shown in Figure 4 shown.

[0071] Comparative Example 3

[0072] The difference between this comparative example and Example 1 is that the sawing-transfer time of the ingot is controlled at 10 minutes during hot cutting, and the surface temperature of the ingot is controlled at 530°C when it enters the extrusion cylinder, and the rest is the same. The structure diagram of the aluminum alloy profile obtained in this comparative example is shown in FIG. Figure 5 shown.

[0073] Comparative Example 4

[0074] The difference between this comparative example and Example 1 is that the pressure margin is controlled to be 2% during extrusion, and the rest is the same. The structure diagram of the aluminum alloy profile obtained in this comparative example is as follows: Figure 6 shown.

[0075] Comparing the embodiment 1 of the invention with the conventional process of the control example 1, the raw material cost of pure aluminum is calculated at a price of 20,000 yuan / ton, and the price of aluminum scrap recycled aluminum is discounted by 75%. The raw material cost per ton of profile in the present invention is reduced by 1,500 yuan, which can greatly reduce the raw material cost in mass production.

[0076] The processing cycle and material utilization rate of Example 1, Example 2 and each control example were statistically analyzed, and the performance of the final product was tested, and the results are shown in Table 1. The mechanical properties were mainly based on the method of GB / T228.1, and the MTSE44.304 microcomputer-controlled electronic universal testing machine was used for testing; the organization inspection was mainly based on the methods of GB / T3246.1 and GB / T3246.2.

[0077] Table 1

[0078]

[0079] As can be seen from Table 1, the aluminum alloy profile prepared by the method of the present invention has better performance than the aluminum alloy profile prepared by the traditional method, such as better tensile strength, yield strength and elongation, and has lower preparation cost, shorter processing cycle, higher processing efficiency and improved material utilization.

[0080] Referring to Control Examples 2-4, it can be seen that in the present invention, when the raw material ratio is improperly controlled, or the extrusion parameters are improperly controlled, or the extrusion margin is improperly controlled, the prepared aluminum alloy profiles have slag inclusions, overburning and stratification, and it is impossible to obtain high-performance aluminum alloy profile products on the basis of saving costs and improving efficiency.

[0081] In the present invention, the ingot is naturally cooled after hot cutting. The temperature of the outer surface of the ingot decreases due to contact with the air. The heat of the core of the ingot needs to be diffused through heat exchange between the surface of the ingot and the air to take away the heat. Therefore, the cooling rate of the surface and the core is different. The core temperature is high, while the surface temperature is low. There is a temperature gradient between the core and the surface of the ingot. In practical application, it is extremely inconvenient to detect the core temperature alone, and destructive testing is required; in the present invention, the temperature difference is cleverly used to control the surface temperature of the ingot within a relatively low predetermined range, and there is no need to detect the core temperature. Through the high-speed friction between the surface of the ingot and the extrusion barrel, the surface temperature rise is greater than the core, thereby controlling the overall temperature uniformity of the ingot during the extrusion process, and preventing the occurrence of local overburning under high-speed extrusion, thereby further improving the processing efficiency while ensuring the excellent performance of the product.

[0082] Usually, there is a segregation layer of a certain thickness on the surface of the ingot. In the traditional process, the segregation layer of the ingot surface needs to be turned before subsequent processing. In the invention, there is no need to turn the segregation layer. The high-speed extrusion process is directly used to make the surface metal preferentially remain in the last extruded billet. The surface metal of the ingot can be controlled not to enter the extruded profile by pressing the excess, which further improves production efficiency, shortens production time, and improves material utilization.

[0083] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention to be protected. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for preparing an aluminum alloy profile, characterized in that: The steps include: Ingredients: fine recycled aluminum, large recycled aluminum, pure aluminum, pure magnesium and auxiliary materials are used as raw materials, and the ingredients are prepared according to the proportion of each element in the aluminum alloy profile to be obtained; the mass proportion of fine recycled aluminum in the raw materials is 10-30%; the mass proportion of large recycled aluminum is 40-80%; when the aluminum alloy profile to be obtained is a 6063 aluminum alloy profile, the auxiliary material is a silicon-aluminum master alloy, and the chemical composition mass percentage of the aluminum alloy profile is: Mg 0.4-0.5%, Si 0.7-0.8%, and the balance is Al; when the aluminum alloy profile to be obtained is a 6061 aluminum alloy profile, the auxiliary materials are pure copper, aluminum-chromium master alloy, and silicon-aluminum master alloy, and the chemical composition mass percentage of the aluminum alloy profile is: 0.8-1.2% Mg, 0.5-0.7% Si, 0.2-0.4% Cu, 0.1-0.3% Cr, and the balance is Al; Melting and casting: Heat and melt large pieces of recycled aluminum, pure aluminum, and auxiliary materials, then add fine pieces of recycled aluminum until all are melted and the melt temperature reaches 740-760°C, then add pure magnesium, and then perform multiple refining to remove slag and gas to obtain aluminum liquid; cast the aluminum liquid to obtain an ingot; Homogenization and hot cutting: the ingot is sent to the soaking furnace for homogenization and then hot cutting; Extrusion: The hot-cut ingot is transferred to the extrusion barrel for high-speed extrusion. The surface temperature of the ingot is controlled to be 420~500℃ when entering the extrusion barrel. After extrusion, the residual weight is controlled to be 3%~6% of the extruded ingot weight, and ensure that the surface metal of the ingot remains in the residual weight. Quenching and aging: The extruded profile can be quenched and aged.

2. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: In the batching step, the fine recycled aluminum material includes aluminum chips, and the thickness of the fine recycled aluminum material is less than 3 mm; the large recycled aluminum material includes ingot head and tail materials, and the thickness of the large recycled aluminum material is greater than or equal to 3 mm.

3. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: In the smelting and casting steps, refining agents are added during slag removal and refining for multiple refinings. The refining temperature is 740-760°C, the refining time is 20-40 minutes each time, and the slag is removed after standing for 20-40 minutes each time. After the last standing and slag removal, the melt is poured from the melting furnace into the holding furnace through the launder. During the pouring process, the air bricks are opened for degassing and refining. The air brick pressure is 650-950KPa, and the air brick flow rate is 50-80L / min.

4. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: In the smelting and casting step, the aluminum liquid after slag removal and degassing is semi-continuously directly cooled and cast, with a casting speed of 32~56mm / min and a water flow rate of 80~150m 3 / h.

5. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: The homogenization process is carried out in a soaking furnace, and the temperature is raised to 550~570℃ during homogenization and kept warm for 8~15h.

6. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: The hot cutting process adopts the fixed-length sawing method; during hot cutting, the ingot sawing-transfer time is controlled to be 20~50min.

7. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: During extrusion, the surface of the ingot rubs against the extrusion barrel, and the extrusion speed is 4~8mm / s.

8. The method for preparing an aluminum alloy profile according to claim 1, characterized in that: Water mist cooling is used for online quenching, and the profile temperature is controlled at 510~540℃ before entering the water; after quenching, aging treatment is carried out at a temperature of 180~200℃ for 4~8h.

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