A smelting, casting and heat treatment process for 2-series aluminum alloy cast bars

Abstract

The present application relates to the technical fields of aluminum alloy casting, and discloses a smelting and casting and heat treatment process of 2-series aluminum alloy casting rod, which heats and smelts raw materials in a smelting furnace to form aluminum liquid, then delivers the aluminum liquid in the smelting furnace to a holding furnace, and adds refining agents in the holding furnace at a suitable temperature for multiple times to refine the aluminum liquid, and after each refining, the scum on the surface of the aluminum liquid or the aluminum slag at the bottom is cleaned by a rake to improve the purity of the aluminum liquid, thereby reducing the content of Si and Fe in the aluminum liquid, and finally, high-purity aluminum liquid is obtained through filtration, and when the aluminum liquid is cast in a casting machine, the casting speed of the casting machine is changed according to the casting position of the ingot, so that the casting speed of the head and tail of the ingot is slower, the risk of cracking and cracking of the head and tail of the ingot in the casting process is reduced, and the utilization rate of the head and tail of the aluminum alloy casting rod is improved.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy casting technology, and in particular to a melting, casting and heat treatment process for 2-series aluminum alloy casting rods. Background Technology

[0002] Aluminum is the most commonly used non-ferrous metal. Pure aluminum has excellent electrical and thermal conductivity, making it an important raw material in electrical equipment. Its surface is protected by a thin, almost transparent, and dense oxide film, giving it a glossy appearance. It exhibits good corrosion resistance in air, fresh water, and oxidizing acidic media. Various aluminum alloys, using aluminum as a base and adding different alloying elements, are formed, improving their mechanical properties. The 2-series aluminum alloys, as Al-Cu-Mg series hard aluminum alloys, possess irreplaceable application value in aerospace, high-end equipment manufacturing, and precision structural components due to their high strength, good machinability, and heat treatment strengthening properties. The performance advantages of these alloys rely on the precise proportions of alloying elements such as Cu, Mg, and Mn, and the control of compositional uniformity and microstructure density through smelting, casting, and heat treatment processes.

[0003] Compared with the casting process of Chinese invention patent CN112605352B entitled "A Casting Method for Aluminum Alloy Rods", the casting process described in this invention uses a controller to achieve more precise control over the temperature adjustment device, stirring speed, and stirring time. This ensures the uniformity of the internal temperature of the aluminum alloy melt, effectively reduces the breakage of interdendritic fragments in the aluminum alloy, thereby reducing the tendency of the rod to crack and improving the smelting quality and yield of the casting. In contrast, the casting process of this invention uses a constant casting speed, which can easily cause uneven initial solidification shell formation at the beginning and end of the aluminum alloy rod during the casting process due to high-speed billet pulling, leading to problems such as surface cold shuts and cracking.

[0004] Regarding the above and existing related technologies, the inventors believe that the following defects often exist: Existing smelting and casting processes mostly adopt a constant speed drawing mode throughout the process, without considering the differentiated solidification characteristics and cooling requirements of the head, middle and tail of the ingot. During the casting process, the high-speed drawing of the aluminum alloy ingot at the head and tail causes the cooling water to not completely cover the surface of the ingot, resulting in uneven initial solidification shell formation at the head and tail of the ingot. This poses a risk of central shrinkage porosity and cracks, requiring the cutting of scrap material at the head and tail of the ingot after casting, thus reducing the utilization rate of the ingot. Summary of the Invention

[0005] The technical problem to be solved by the present invention is that the existing smelting and casting process mostly adopts a constant speed drawing mode throughout the process, without considering the different solidification characteristics and cooling requirements of the head, middle and tail of the ingot. This results in uneven formation of the initial solidified shell at the head and tail of the ingot, and the risk of central shrinkage and cracking. To address this, we propose a smelting, casting and heat treatment process for 2-series aluminum alloy ingots.

[0006] To achieve the above objectives, this application adopts the following technical solution: a smelting, casting, and heat treatment process for 2-series aluminum alloy casting rods, comprising the following steps: S1: First, add molten aluminum and scrap to the smelting furnace, along with copper ingot alloy and manganese-magnesium alloy. Then, start the smelting furnace to heat and melt the aluminum. Next, add Pyrotech refining agent and use an electromagnetic stirrer to stir and mix the molten aluminum inside the smelting furnace, ensuring that the molten aluminum and refining agent are evenly mixed and dissolved. Finally, use a rake to clean the slag on the surface of the molten aluminum to obtain molten aluminum-2024. The elements and mass percentages contained in molten aluminum-2024 are: Si≤0.2%, Fe≤0.11%, Cu 3.26%~4.54%, Mn 0.64%~0.74%, Mg 0.62%~1.48%, Cr≤0.08%, Ni≤0.06%, Zn≤0.01%, Ti≤0.011%, Zr≤0.01%, with the balance being Al. S2: First, the air inside the degassing box is vented. Then, the aluminum liquid-2024 from step S1 is transported to the placement furnace, and refining agent is added twice. After each addition of refining agent, the slag on the surface of the aluminum liquid-2024 is removed by the rake claw. Then, the wire feeder transports titanium boron wire into the aluminum liquid-2024. At the same time, the degassing box transports argon gas to the placement furnace through the graphite rotor to remove the gas in the aluminum liquid-2024 and let it stand. Finally, after plate filtration, aluminum liquid A-2024 is obtained. S3: The molten aluminum A-2024 from step S2 is transported to the casting machine, and the casting machine is used to cast at a speed limited by the casting machine. Cooling water is used to cool the aluminum ingot to obtain aluminum alloy ingot-2024. S4: The aluminum alloy ingot-2024 obtained in S3 is heated and held at a certain temperature, and then cooled by air cooling and water cooling to obtain aluminum alloy rod-2024. The elements and mass percentages contained in the aluminum alloy rod-2024 are as follows: Si≤0.5%, Fe≤0.5%, Cu 4.62%~5.62%, Mn 0.7%~1.05%, Mg 0.89%~1.93%, Cr≤0.12%, Ni≤0.3%, Zn≤0.3%, Ti≤0.15%, Zr≤0.04%, and the balance is Al.

[0007] Preferably, in step S1, the amount of molten aluminum is 5 tons, and the waste is 2A12 and 2A11 head and tail materials, the amount of copper ingot alloy is 200-300 kg, the amount of manganese and magnesium alloy is 50-100 kg, and the smelting capacity of the smelting furnace in step S1 is 14500±500 kg.

[0008] Preferably, the melting temperature in step S1 is 720-750℃, the refining agent is added in two batches in step S1, the amount of refining agent added is 5-15kg, the refining time is 10-15 minutes, and the refining temperature is 755-765℃, and the slag temperature in step S1 is 750-765℃.

[0009] Preferably, in step S2, the converter temperature is 755-765℃, the refining agent addition temperature is 734-745℃, the refining agent is added in two batches, the amount of refining agent added is 5-15kg, the refining time is 10-15 minutes, and the weight of aluminum slag removed by the rake claw in step S2 is 70-140kg.

[0010] Preferably, in step S2, the wire feeding speed of the wire feeder is 82-112 cm × 2 / min, and the titanium boron wires are of the following types: T5B1, AMGTi5B1, and Skendar Ti5B1.

[0011] Preferably, in step S2, the rotational speed of the graphite rotor in the degassing box is 450 rpm, the gas flow rate is 75×2L / min, the degassing time in step S2 is 30±5 minutes, and the furnace settling time is 40±5 minutes.

[0012] Preferably, in step S3, the converter temperature is 730±2℃, and the casting machine temperature is 700-715℃. In step S3, the aluminum alloy ingot diameter is 228mm and the length is 6000mm.

[0013] Preferably, in step S3, the casting speed of the casting machine is 83-105 mm / min, the casting speed at the head of the ingot is 83 mm / min, the casting speed in the middle of the ingot is 105 mm / min, and the casting speed at the tail of the ingot is 85 mm / min. In step S3, the cooling water temperature is 25±5℃ and the flow rate is 110±10 m³ / h.

[0014] Preferably, the heating temperature in step S4 is 490±5℃, and the heat preservation time is 24 hours.

[0015] Preferably, in step S4, the air cooling time is 160 minutes and the water cooling time is 30 minutes.

[0016] The technical effects and advantages of this invention are as follows: In this invention, molten aluminum, heated and smelted in a melting furnace, is transported to a placement furnace. In the placement furnace, refining agents are added multiple times at a suitable temperature for refining. After each refining process, slag on the surface or bottom layer of the molten aluminum is cleaned using rakes to improve its purity and reduce the Si and Fe content. Finally, after filtration, high-purity molten aluminum is obtained. Simultaneously, during casting in a casting machine, the casting speed is adjusted according to the casting location of the ingot, with slower casting speeds at the head and tail. This reduces the risk of tearing and cracking at the head and tail during casting, thereby improving the utilization rate of the aluminum alloy ingot head and tail. Finally, after heating and holding at a specific temperature, the cast aluminum alloy ingot is first air-cooled for a period before being water-cooled. This avoids the residual stress that can easily occur when the aluminum alloy ingot is directly cooled by water due to excessive temperature difference, leading to deformation and cracking during subsequent processing. Attached Figure Description

[0017] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts: Fig. 1 This is a flowchart illustrating the specific process of the experiment described in this invention; Fig. 2 The results are the element content test results for the 2-series aluminum alloy cast rods of this invention. Detailed Implementation

[0018] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0019] Example 1 Reference Figs. 1-2 As shown, a smelting, casting, and heat treatment process for 2-series aluminum alloy ingots includes the following steps: S1: First, add 5 tons of molten aluminum to the melting furnace, then replenish with 2A12 and 2A11 head and tail materials, and add 200 kg of copper ingot alloy and 50 kg of manganese and magnesium alloy, so that the melting amount in the melting furnace is 14500±500 kg. Raise the melting temperature to 720-750℃ to melt the aluminum, and raise the melting furnace temperature to 755-765℃. Add the Pyrotech refining agent in two stages. The first stage adds 5 kg of refining agent, and the first refining time is ≥10 minutes. Then, use an electromagnetic stirrer to stir and mix the molten aluminum inside the melting furnace. The second stage adds 10 kg of refining agent, and the second refining time is ≥15 minutes, so that the molten aluminum and... The refining agent is thoroughly mixed and dissolved, and the aluminum liquid and refining agent are fully dissolved and reacted at 755-765℃ to make the internal composition of the aluminum liquid uniform. Finally, the temperature of the smelting furnace is maintained at 750-765℃, and the slag on the surface of the aluminum liquid is cleaned by rake claws to obtain aluminum liquid-2024. The elements and mass percentages contained in aluminum liquid-2024 are as follows: Si 0.05%, Fe 0.08%, Cu 3.26%, Mn 0.64%, Mg 1.32%, Cr 0.003%, Ni 0.04%, Zn 0.01%, Ti 0.007%, Zr 0.001%, with the balance being Al. S2: First, vent the air inside the degassing box. Then, at a temperature of 755-765℃, transfer the molten aluminum-2024 from the smelting furnace to the placement furnace. Add the refining agent in two stages at 734-745℃. The first addition is 5kg of refining agent, and the first refining time is ≥10 minutes. After the first refining, remove the dross from the surface of the molten aluminum-2024 using a rake. The weight of dross removed in the first refining is 140kg. Then, add 10kg of refining agent a second time, and the second refining time is ≥15 minutes. After the second refining, remove the dross from the surface of the molten aluminum-2024 using a rake. The dross on the surface of the aluminum liquid-2024 is removed. The weight of the second dross removal is 70 kg. Then, the wire feeder feeds T5B1 titanium boron wire into the aluminum liquid-2024 at a speed of 82 cm × 2 / min. At the same time, the graphite rotor is inserted into the aluminum liquid-2024 in the degassing box. Argon gas is delivered to the placement furnace at a speed of 450 rpm and a flow rate of 75 × 2 L / min to remove the gas in the aluminum liquid-2024. The degassing time is 30 ± 5 minutes. Then, the placement furnace is allowed to stand for 40 ± 5 minutes. After passing through the plate filter, aluminum liquid A-2024 is obtained. S3: At 730±2℃, aluminum liquid A-2024 is transported to the casting machine, and the casting machine is used to cast at 700-715℃. The aluminum liquid A-2024 in S2 is cast at a speed of 83-105mm / min. The casting speed at the head of the ingot is 83mm / min, the casting speed in the middle of the ingot is 105mm / min, and the casting speed at the tail of the ingot is 85mm / min. The aluminum ingot is cooled with cooling water at a flow rate of 110±10m³ / h and a water temperature of 25±5℃. Aluminum alloy ingot-2024 with a diameter of 228mm and a length of 6000mm can be obtained. S4: The aluminum alloy ingot-2024 obtained in S3 is first heated to 490±5℃ and held at that temperature for 24 hours. After the holding time is completed, it is first cooled by air for 160 minutes, and then cooled to room temperature by water for 30 minutes to obtain aluminum alloy rod-2024. The elements and mass percentages contained in aluminum alloy rod-2024 are as follows: Si 0.03%, Fe 0.06%, Cu 4.62%, Mn 0.74%, Mg 1.43%, Cr 0.05%, Ni 0.04%, Zn 0.05%, Ti 0.04%, Zr 0.018%, and the balance is Al.

[0020] Example 2 Reference Figs. 1-2 As shown, a smelting, casting, and heat treatment process for 2-series aluminum alloy ingots includes the following steps: S1: First, add 5 tons of molten aluminum to the melting furnace, then replenish with 2A12 and 2A11 head and tail materials, and add 200 kg of copper ingot alloy and 50 kg of manganese and magnesium alloy, so that the melting amount in the melting furnace is 14500±500 kg. Raise the melting temperature to 720-750℃ to melt the aluminum, and raise the melting furnace temperature to 755-765℃. Add the Pyrotech refining agent in two stages. The first stage adds 10 kg of refining agent, and the first refining time is ≥10 minutes. Then, use an electromagnetic stirrer to stir and mix the molten aluminum inside the melting furnace. The second stage adds 15 kg of refining agent, and the second refining time is ≥15 minutes, so that the molten aluminum... The aluminum liquid is thoroughly mixed and dissolved with the refining agent, and the reaction is carried out at 745-755℃ to ensure a uniform internal composition. Finally, the furnace temperature is maintained at 720-750℃, and the slag on the surface of the aluminum liquid is removed by a rake to obtain aluminum liquid-2024A. The elements and mass percentages contained in aluminum liquid-2024A are as follows: Si 0.19%, Fe 0.1%, Cu 3.42%, Mn 0.72%, Mg 0.62%, Cr 0.08%, Ni 0.06%, Zn 0.01%, Ti 0.011%, Zr 0.005%, with the balance being Al. S2: First, vent the air inside the degassing box. Then, at a temperature of 755-765℃, transfer the molten aluminum-2024A from the smelting furnace to the placement furnace. Add the refining agent in two stages at 734-745℃. The first addition is 5kg of refining agent, and the first refining time is ≥10 minutes. After the first refining, remove the dross from the surface of the molten aluminum-2024A using a rake. The weight of dross removed in the first refining is 140kg. Then, add 10kg of refining agent a second time, and the second refining time is ≥15 minutes. After the second refining, remove the dross from the surface of the molten aluminum-2024A using a rake. The slag on the surface of the aluminum liquid-2024A is removed. The weight of the second slag removal is 70kg. Then, the wire feeder feeds T5B1 titanium boron wire into the aluminum liquid-2024A at a speed of 82CM×2 / min. At the same time, the degassing box inserts the graphite rotor into the aluminum liquid-2024A and delivers argon gas to the placement furnace at a speed of 450rpm and a flow rate of 75×2L / min to remove the gas in the aluminum liquid-2024A. The degassing time is 30±5 minutes. After that, the placement furnace is allowed to stand for 40±5 minutes. After passing through the plate filter, aluminum liquid A-2024A is obtained. S3: The molten aluminum A-2024A is fed into the casting machine at 730±2℃, and the casting machine is used to cast at 700-715℃. The molten aluminum A-2024A in S2 is cast at a speed of 83-105mm / min. The casting speed at the head of the ingot is 83mm / min, the casting speed in the middle of the ingot is 105mm / min, and the casting speed at the tail of the ingot is 85mm / min. The aluminum ingot is cooled with cooling water at a flow rate of 110±10m³ / h and a water temperature of 25±5℃. Aluminum alloy ingot-2024A with a diameter of 228mm and a length of 6000mm can be obtained. S4: The aluminum alloy ingot-2024A obtained in S3 is first heated to 490±5℃ and held at that temperature for 24 hours. After the holding time, it is first cooled by air for 160 minutes, and then cooled to room temperature by water for 30 minutes. This yields aluminum alloy rod-2024A. The elements and their mass percentages contained in aluminum alloy rod-2024A are as follows: Si 0.3%, Fe 0.35%, Cu 4.87%, Mn 0.7%, Mg 0.89%, Cr 0.05%, Ni 0.97%, Zn 0.14%, Ti 0.15%, Zr 0.015%, with the balance being Al.

[0021] A comparison of the elements contained in aluminum alloy cast rod-2024 and aluminum alloy cast rod-2024A shows that the Si content in aluminum alloy cast rod-2024A is 0.3% and the Fe content is 0.35% higher than that in aluminum alloy cast rod-2024. This makes it easier for the Al-Fe-Si brittle phase to form inside aluminum alloy cast rod-2024A, which affects the chemical stability and corrosion resistance of the grains inside aluminum alloy cast rod-2024A.

[0022] Example 3 Reference Figs. 1-2 As shown, a smelting, casting, and heat treatment process for 2-series aluminum alloy ingots includes the following steps: S1: First, add 5 tons of molten aluminum to the melting furnace, then replenish with 2A12 and 2A11 head and tail materials, and add 200 kg of copper ingot alloy and 50 kg of manganese and magnesium alloy, so that the melting amount in the melting furnace is 14500±500 kg. Raise the melting temperature to 720-750℃ to melt the aluminum, and raise the melting furnace temperature to 755-765℃. Add the Pyrotech refining agent in two stages. The first stage adds 5 kg of refining agent, and the first refining time is ≥10 minutes. Then, use an electromagnetic stirrer to stir and mix the molten aluminum inside the melting furnace. The second stage adds 10 kg of refining agent, and the second refining time is ≥15 minutes, so that the molten aluminum and refined aluminum are mixed. The refining agent is thoroughly mixed and dissolved, and the aluminum liquid and refining agent are fully dissolved and reacted at 755-765℃ to ensure uniform composition within the aluminum liquid. Finally, the furnace temperature is maintained at 750-765℃, and the slag on the surface of the aluminum liquid is cleaned by rakes to obtain aluminum liquid-2024B. The elements and mass percentages contained in aluminum liquid-2024B are as follows: Si 0.05%, Fe 0.08%, Cu 3.26%, Mn 0.64%, Mg 1.32%, Cr 0.003%, Ni 0.04%, Zn 0.01%, Ti 0.007%, Zr 0.001%, with the balance being Al. S2: First, vent the air inside the degassing box. Then, at a temperature of 755-765℃, transfer the molten aluminum-2024B from the smelting furnace to the placement furnace. Add the refining agent in two stages at 734-745℃. The first addition is 10kg of refining agent, and the first refining time is ≥10 minutes. After the first refining, remove the dross from the surface of the molten aluminum-2024B using a rake. The weight of dross removed in the first refining is 140kg. Then, add 15kg of refining agent a second time, and the second refining time is ≥15 minutes. After the second refining, remove the dross from the surface of the molten aluminum-2024B using a rake. The slag on the surface of 2024B is removed. The weight of the second aluminum slag removal is 70kg. Then, the wire feeder conveys AMGTi5B1 titanium boron wire into the aluminum liquid-2024B at a speed of 105CM×2 / min. At the same time, the degassing box inserts the graphite rotor into the aluminum liquid-2024B and delivers argon gas to the placement furnace at a speed of 450rpm and a flow rate of 75×2L / min to remove the gas in the aluminum liquid-2024B. The degassing time is 30±5 minutes. After that, the placement furnace is allowed to stand for 40±5 minutes. After plate filtration, aluminum liquid A-2024B is obtained. S3: At 730±2℃, aluminum liquid A-2024 is transported to the casting machine, and the casting machine is used to cast at 700-715℃. The aluminum liquid A-2024B in S2 is cast at a speed of 83-105mm / min. The casting speed at the head of the ingot is 83mm / min, the casting speed in the middle of the ingot is 105mm / min, and the casting speed at the tail of the ingot is 85mm / min. The aluminum ingot is cooled with cooling water at a flow rate of 110±10m³ / h and a water temperature of 25±5℃. This yields an aluminum alloy ingot-2024B with a diameter of 228mm and a length of 6000mm. S4: The aluminum alloy ingot-2024B obtained in S3 is first heated to 490±5℃ and held at that temperature for 24 hours. After the holding time is completed, it is first cooled by air for 160 minutes, and then cooled to room temperature by water cooling for 30 minutes. This yields aluminum alloy rod-2024B. The elements and their mass percentages contained in aluminum alloy rod-2024B are as follows: Si 0.36%, Fe 0.4%, Cu 4.97%, Mn 0.8%, Mg 1.7%, Cr 0.12%, Ni 0.11%, Zn 0.1%, Ti 0.13%, Zr 0.019%, with the balance being Al.

[0023] A comparison of the elements contained in aluminum alloy cast rod-2024 and aluminum alloy cast rod-2024B shows that aluminum alloy cast rod-2024B has higher Cu and Mg content. However, although excessive Cu can improve the strength of aluminum alloy cast rod-2024B, it will reduce its corrosion resistance. Furthermore, excessive Si and Fe will affect the chemical purity and grain boundary stability of aluminum alloy cast rod-2024B.

[0024] Example 4 Reference Figs. 1-2 As shown, a smelting, casting, and heat treatment process for 2-series aluminum alloy ingots includes the following steps: S1: First, add 5 tons of molten aluminum to the melting furnace, then replenish with 2A12 and 2A11 head and tail materials, and add 200 kg of copper ingot alloy and 50 kg of manganese and magnesium alloy, so that the melting amount in the melting furnace is 14500±500 kg. Raise the melting temperature to 720-750℃ to melt the aluminum, and raise the melting furnace temperature to 755-765℃. Add the Pyrotech refining agent in two stages. The first stage adds 5 kg of refining agent, and the first refining time is ≥10 minutes. Then, use an electromagnetic stirrer to stir and mix the molten aluminum inside the melting furnace. The second stage adds 10 kg of refining agent, and the second refining time is ≥15 minutes, so that the molten aluminum and refined aluminum are mixed. The refining agent is thoroughly mixed and dissolved, and the aluminum liquid and refining agent are fully dissolved and reacted at 755-765℃ to ensure uniform composition within the aluminum liquid. Finally, the furnace temperature is maintained at 750-765℃, and the slag on the surface of the aluminum liquid is cleaned by rakes to obtain aluminum liquid-2024C. The elements and mass percentages contained in aluminum liquid-2024C are as follows: Si 0.05%, Fe 0.08%, Cu 3.26%, Mn 0.64%, Mg 1.32%, Cr 0.003%, Ni 0.04%, Zn 0.01%, Ti 0.007%, Zr 0.001%, with the balance being Al. S2: First, vent the air inside the degassing box. Then, at a temperature of 755-765℃, transfer the molten aluminum-2024C from the smelting furnace to the placement furnace. Add the refining agent in two stages at 734-745℃. The first addition is 5kg of refining agent, and the first refining time is ≥10 minutes. After the first refining, remove the dross from the surface of the molten aluminum-2024C using a rake. The weight of dross removed in the first refining is 140kg. Then, add 10kg of refining agent a second time, and the second refining time is ≥15 minutes. After the second refining, remove the dross from the surface of the molten aluminum-2024C using a rake. The slag on the surface of 2024C is removed. The weight of the second aluminum slag removal is 70kg. Then, the wire feeder conveys Skendar Ti5B1 titanium boron wire into the aluminum liquid-2024C at a speed of 112CM×2 / min. At the same time, the degassing box inserts the graphite rotor into the aluminum liquid-2024C and delivers argon gas to the placement furnace at a speed of 450rpm and a flow rate of 75×2L / min to remove the gas in the aluminum liquid-2024C. The degassing time is 30±5 minutes. After that, the placement furnace is allowed to stand for 40±5 minutes. After plate filtration, aluminum liquid A-2024C is obtained. S3: At 730±2℃, aluminum liquid A-2024C is transported to the casting machine, and the casting machine is used to cast at 700-715℃. The aluminum liquid A-2024C in S2 is cast at a speed of 83-105mm / min. The casting speed at the head of the ingot is 83mm / min, the casting speed in the middle of the ingot is 105mm / min, and the casting speed at the tail of the ingot is 85mm / min. The aluminum ingot is cooled with cooling water at a flow rate of 110±10m³ / h and a water temperature of 25±5℃. Aluminum alloy ingot-2024C with a diameter of 228mm and a length of 6000mm can be obtained. S4: The aluminum alloy ingot-2024C obtained in S3 is first heated to 490±5℃ and held at that temperature for 24 hours. After the holding time, it is first cooled by air for 160 minutes, and then cooled to room temperature by water cooling for 30 minutes to obtain aluminum alloy rod-2024C. The elements and mass percentages contained in aluminum alloy rod-2024C are as follows: Si 0.25%, Fe 0.3%, Cu 4.81%, Mn 0.77%, Mg 1.33%, Cr 0.097%, Ni 0.1%, Zn 0.2%, Ti 0.08%, Zr 0.013%, and the balance is Al.

[0025] A comparison of the elements contained in aluminum alloy cast rod-2024 and aluminum alloy cast rod-2024C shows that the chemical element contents of the two are relatively similar. However, the Si and Fe contents in aluminum alloy cast rod-2024C are much higher than those in aluminum alloy cast rod-2024, resulting in weaker chemical purity and grain boundary stability compared to aluminum alloy cast rod-2024.

[0026] Comparative Example 1 Reference Figs. 1-2 As shown, a smelting, casting, and heat treatment process for 2-series aluminum alloy ingots includes the following steps: S1: First, add 5 tons of aluminum ingots to the melting furnace, then replenish with 2A12 and 2A11 head and tail materials and profiles, and add 300 kg of copper alloy and 100 kg of manganese and magnesium alloy, so that the melting amount in the melting furnace is 14500±500 kg. Raise the melting temperature to 720-750℃ to melt the aluminum, and raise the melting furnace temperature to 755-765℃. Add the Pyrotech refining agent in two stages. The first stage adds 5 kg of refining agent, and the first refining time is ≥10 minutes. Then, stir and mix the aluminum liquid inside the melting furnace with a stirring rod. The second stage adds 10 kg of refining agent, and the second refining time is ≥15 minutes, so that the aluminum liquid and the aluminum liquid are mixed together. The refining agent is thoroughly mixed and dissolved, and the aluminum liquid and refining agent are fully dissolved and reacted at 755-765℃ to make the internal composition of the aluminum liquid uniform. Finally, the temperature of the smelting furnace is maintained at 750-765℃, and the slag on the surface of the aluminum liquid is cleaned by rake claws to obtain aluminum liquid-2024D. The elements and mass percentages contained in aluminum liquid-2024D are as follows: Si 0.08%, Fe 0.11%, Cu 4.54%, Mn 0.74%, Mg 1.48%, Cr 0.003%, Ni 0.02%, Zn 0.009%, Ti 0.006%, Zr 0.01%, and the balance is Al. S2: First, vent the air inside the degassing box. Then, at a temperature of 755-765℃, transfer the molten aluminum-2024D from the smelting furnace to the placement furnace. Add refining agent twice at a temperature of 734-745℃. Add 5kg of refining agent for the first time, and the first refining time is ≥10 minutes. Add 10kg of refining agent for the second time, and the second refining time is ≥15 minutes. Then, the wire feeder feeds T5B1 titanium boron wire into the molten aluminum-2024D at a speed of 82CM×2 / min. At the same time, insert the graphite rotor into the molten aluminum-2024D in the degassing box and deliver argon gas to the placement furnace at a speed of 450rpm and a flow rate of 75×2L / min to remove the gas in the molten aluminum-2024D. The degassing time is 30±5 minutes. Then, let it stand in the placement furnace for 40±5 minutes. After passing through a plate filter, molten aluminum A-2024D is obtained. S3: The molten aluminum A-2024D is fed into the casting machine at 730±2℃, and the casting machine is used to cast at 700-715℃. The molten aluminum A-2024 in S2 is cast at a speed of 105mm / min. The aluminum ingot is cooled with cooling water at a flow rate of 110±10m³ / h and a water temperature of 25±5℃. This yields an aluminum alloy ingot-2024D with a diameter of 228mm and a length of 6000mm. S4: The aluminum alloy ingot-2024D obtained in S3 is first heated to 490±5℃ and held at that temperature for 24 hours. After the holding time is completed, it is cooled to room temperature by water cooling for 120 minutes to obtain aluminum alloy rod-2024D. The elements and mass percentages contained in aluminum alloy rod-2024D are as follows: Si 0.5%, Fe 0.5%, Cu 5.62%, Mn 1.05%, Mg 1.93%, Cr 0.5%, Ni 0.3%, Zn 0.3%, Ti 0.006%, Zr 0.04%, and the balance is Al.

[0027] A comparison of the elements contained in aluminum alloy cast rod-2024 and aluminum alloy cast rod-2024D reveals that the Si and Fe contents in aluminum alloy cast rod-2024D produced by the existing process are too high. This seriously affects the chemical stability of the internal grains of aluminum alloy cast rod-2024D, significantly increasing the risk of failure such as cracking and insufficient plasticity during subsequent processing. Furthermore, although excessive Cu can improve the strength of aluminum alloy cast rod-2024D itself, excessive Cu will reduce the corrosion resistance of aluminum alloy cast rod-2024D during subsequent processing.

[0028] This invention involves conveying molten aluminum heated and smelted in a melting furnace to a placement furnace, where it is refined multiple times with the addition of refining agents at a suitable temperature. After each refining process, a rake is used to clean the slag on the surface or the bottom layer of aluminum slag, improving the purity of the molten aluminum and reducing the content of Si and Fe elements. Finally, after filtration, high-purity molten aluminum is obtained. Simultaneously, during casting in a casting machine, the casting speed is adjusted according to the casting location of the ingot, with slower casting speeds at the head and tail. This reduces the risk of tearing and cracking at the head and tail of the ingot during casting, thereby improving the utilization rate of the aluminum alloy ingot head and tail. Finally, after heating and holding at a specific temperature, the cast aluminum alloy ingot is first air-cooled for a period of time before being water-cooled. This avoids the residual stress that can easily occur when the aluminum alloy ingot is directly cooled by water due to excessive temperature difference, leading to deformation and cracking during subsequent processing.

[0029] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods, characterized in that, Includes the following steps: S1: First, add molten aluminum and scrap to the smelting furnace, along with copper ingot alloy and manganese-magnesium alloy. Then, start the smelting furnace to heat and melt the aluminum. Next, add Pyrotech refining agent and use an electromagnetic stirrer to stir and mix the molten aluminum inside the smelting furnace, ensuring that the molten aluminum and refining agent are evenly mixed and dissolved. Finally, use a rake to clean the slag on the surface of the molten aluminum to obtain molten aluminum-2024. The elements and mass percentages contained in molten aluminum-2024 are: Si≤0.2%, Fe≤0.11%, Cu 3.26%~4.54%, Mn 0.64%~0.74%, Mg 0.62%~1.48%, Cr≤0.08%, Ni≤0.06%, Zn≤0.01%, Ti≤0.011%, Zr≤0.01%, with the balance being Al. S2: First, the air inside the degassing box is vented. Then, the aluminum liquid-2024 from step S1 is transported to the placement furnace, and refining agent is added twice. After each addition of refining agent, the slag on the surface of the aluminum liquid-2024 is removed by the rake claw. Then, the wire feeder transports titanium boron wire into the aluminum liquid-2024. At the same time, the degassing box transports argon gas to the placement furnace through the graphite rotor to remove the gas in the aluminum liquid-2024 and let it stand. Finally, after plate filtration, aluminum liquid A-2024 is obtained. S3: The molten aluminum A-2024 from step S2 is transported to the casting machine, and the casting machine is used to cast at a speed limited by the casting machine. Cooling water is used to cool the aluminum ingot to obtain aluminum alloy ingot-2024. S4: The aluminum alloy ingot-2024 obtained in S3 is heated and held at a certain temperature, and then cooled by air cooling and water cooling to obtain aluminum alloy rod-2024. The elements and mass percentages contained in the aluminum alloy rod-2024 are as follows: Si≤0.5%, Fe≤0.5%, Cu 4.62%~5.62%, Mn 0.7%~1.05%, Mg 0.89%~1.93%, Cr≤0.12%, Ni≤0.3%, Zn≤0.3%, Ti≤0.15%, Zr≤0.04%, and the balance is Al.

2. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: In step S1, 5 tons of molten aluminum are provided, and the scrap consists of 2A12 and 2A11 head and tail materials. 200-300 kg of copper ingot alloy is provided, and 50-100 kg of manganese and magnesium alloy is provided. The smelting capacity of the smelting furnace in step S1 is 14500±500 kg.

3. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: The smelting temperature in step S1 is 720-750℃. The refining agent is added in two batches in step S1, with an addition amount of 5-15kg. The refining time is 10-15 minutes, and the refining temperature is 755-765℃. The slag temperature in step S1 is 750-765℃.

4. The smelting, casting, and heat treatment process for 2-series aluminum alloy casting rods according to claim 1, characterized in that: In step S2, the converter temperature is 755-765℃, the refining agent addition temperature is 734-745℃, and the refining agent is added in two batches, with an addition amount of 5-15kg and a refining time of 10-15 minutes. In step S2, the weight of aluminum slag removed by the rake claw is 70-140kg.

5. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: In step S2, the wire feeding speed of the wire feeder is 82-112CM×2 / min, and the types of titanium boron wire are T5B1, AMGTi5B1 and Skendar Ti5B1.

6. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: In step S2, the speed of the graphite rotor in the degassing box is 450 rpm and the gas flow rate is 75×2L / min. The degassing time in step S2 is 30±5 minutes and the furnace settling time is 40±5 minutes.

7. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: In step S3, the converter temperature is 730±2℃, and the casting machine temperature is 700-715℃. In step S3, the aluminum alloy ingot diameter is 228mm and the length is 6000mm.

8. The smelting, casting, and heat treatment process for 2-series aluminum alloy casting rods according to claim 1, characterized in that: In step S3, the casting speed of the casting machine is 83-105 mm / min, the casting speed at the head of the ingot is 83 mm / min, the casting speed in the middle of the ingot is 105 mm / min, and the casting speed at the tail of the ingot is 85 mm / min. In step S3, the cooling water temperature is 25±5℃ and the flow rate is 110±10 m³ / h.

9. The smelting, casting, and heat treatment process for 2-series aluminum alloy cast rods according to claim 1, characterized in that: In step S4, the heating temperature is 490±5℃ and the holding time is 24 hours.

10. The smelting, casting, and heat treatment process for 2-series aluminum alloy ingots according to claim 1, characterized in that: In step S4, the air cooling time is 160 minutes and the water cooling time is 30 minutes.

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