Aluminum alloy tube with fine grain after welding and processing method thereof

Abstract

The invention discloses an aluminum alloy tube with excellent grains after welding, which is composed of the following components in mass percentage: ≤0.15% Si, 0.3%~0.5% Fe, 0.1%~0.15% Cu, 1.3%~1.4% Mn, ≤0.05% Mg, ≤0.1% Zn, 0.02%~0.05% Ti, ≤0.05% other elements and 97.55%~98.28% pure aluminum. The processing method of the aluminum alloy tube includes the steps of preparing aluminum liquid, casting into long material casting rods, homogenizing annealing, cutting extrusion, inverted disk drawing, fixed length cutting, high temperature rapid annealing, and straightening. The invention improves the mechanical properties of the aluminum tube after annealing by optimizing the content of alloy elements; during processing, the straightening process after annealing is coordinated and the reduction amount of the outer diameter of the aluminum tube during straightening is controlled to avoid the growth of grains after high temperature welding; and the high temperature rapid annealing method is adopted to ensure fine and uniform grains.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy pipes, and more particularly to an aluminum alloy pipe with excellent grains after welding and a processing method thereof. Background Art

[0002] In the era of lightweight and energy-saving and emission-reduction, aluminum alloy tubes are increasingly used in various industries due to their low density, especially in the automotive field. 3003H12 aluminum tubes are widely used in automotive air-conditioning pipes due to their good strength and processing formability. In order to reduce the number of processes and processing costs, more and more air-conditioning pipe processing plants will weld aluminum tubes to flanges before bending. At present, after high-temperature welding, ordinary 3003H12 aluminum tubes are affected by the heat-affected zone of welding, and the grains will grow abnormally, resulting in the abnormally rough surface of the aluminum tubes in the subsequent bending, which is like orange peel and affects the appearance quality. Summary of the invention

[0003] The technical problem to be solved by the present invention is to provide an aluminum alloy tube with excellent grains after welding and a processing method thereof, so as to solve the problems in the background technology.

[0004] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows.

[0005] The invention discloses an aluminum alloy tube with excellent grains after welding, which is composed of the following components in mass percentage: ≤0.15% of Si, 0.3%-0.5% of Fe, 0.1%-0.15% of Cu, 1.3%-1.4% of Mn, ≤0.05% of Mg, ≤0.1% of Zn, 0.02%-0.05% of Ti, ≤0.05% of other elements and 97.55%-98.28% of pure aluminum.

[0006] The present invention also provides a method for processing an aluminum alloy tube with fine grains after welding, which specifically comprises the following steps:

[0007] S1. Preparing aluminum liquid: adding aluminum alloy tube components into a smelting furnace in proportion to prepare aluminum liquid;

[0008] S2, casting into long material cast rods: the aluminum liquid obtained in step S1 is cast into long material aluminum alloy round cast rods at 680°C-730°C, and aluminum titanium boron wire is added online during the casting process to refine the ingot grains, and the adding speed is 75-85cm / min; high-purity argon gas with a content of more than 99.7% is introduced into the casting flow trough for online degassing, and then double-layer filtration is used to further purify the melt; and then a vacuum direct cooling casting system is used for casting, and the casting speed is 140±2mm / min;

[0009] S3, homogenization annealing: the long aluminum alloy cast rod prepared in step S2 is kept at 590° C. to 610° C. for 10 h to 12 h, and then rapidly cooled;

[0010] S4, cutting and extruding: cutting the long aluminum alloy round cast rods from step S3 to obtain short aluminum alloy cast rods of equal length suitable for extrusion; heating the short aluminum alloy round cast rods and then rapidly and continuously extruding them at low temperature to obtain aluminum alloy extrusion tube blanks with fine and uniform grains;

[0011] S5, inverted plate drawing: the aluminum alloy tube blank of step S4 is subjected to 2-6 inverted plate drawing according to different finished product specifications;

[0012] S6, cutting to length: the finished coil material drawn in step S5 is cut to length using a cutting system;

[0013] S7, high temperature rapid annealing: the aluminum tube cut in step S6 is subjected to a roller annealing furnace at a heating temperature of 540°C-560°C for 8-12 minutes;

[0014] S8, straightening: straighten the aluminum tube annealed in step S7 using a roller straightening machine.

[0015] To further optimize the technical solution, step S1 includes the following steps:

[0016] S11. Furnace smelting: Weigh the components according to the proportion, first put the pure aluminum into a dry smelting furnace, heat the furnace to 730-760°C, and then add other alloys in sequence after the pure aluminum is melted into aluminum alloy solution;

[0017] S12, slag removal: add a slag remover to the solution obtained in S11, stir for 5 minutes, then add an iron agent, an aluminum-copper master alloy, a manganese agent and a titanium agent, stir for 10 minutes to 15 minutes and mix evenly;

[0018] S13, sampling and analysis: taking the sample in step S12 for spectral analysis of chemical composition;

[0019] S14, refining: adding fluorine-free and sodium-free granular refining agent, the amount of refining agent is 1-1.5 kg / ton aluminum, the refining time is 30 minutes, the melt temperature during refining is 750-790°C, high-purity argon is used during refining, and the argon content is more than 99.7%; then keep warm and stand for 20 minutes to 30 minutes to obtain aluminum liquid.

[0020] To further optimize the technical solution, the double-layer filtration in step S2 is performed using a 20-inch 40ppi and a 17-inch 60ppi ceramic filter plate.

[0021] To further optimize the technical solution, the length of the short aluminum alloy round cast rod in step S4 is 870 mm to 880 mm.

[0022] To further optimize the technical solution, the steps of low-temperature rapid continuous extrusion in step S4 are: preheating the short-stock aluminum alloy round cast rods, the mold barrel and the mold, installing the extrusion mold, loading the short-stock aluminum alloy round cast rods, low-temperature rapid continuous extrusion, rapid cooling, drying, oiling and coiling, to obtain the aluminum alloy extruded long material tube billet.

[0023] To further optimize the technical solution, the preheating process: the preheating temperature of short-stock aluminum alloy round cast rods is 470℃-490℃ for the head, the preheating temperature of the die barrel is 420℃~440℃, and the preheating temperature of the mold is 460℃~500℃; the preheating process adopts a gradient preheating method, that is, the preheating temperature of the cast rod at the advanced die barrel end is high, and the preheating temperature at the backward die barrel end is low, and the gradient is 3-5℃ / 100mm.

[0024] The technical solution is further optimized, and the extrusion speed of the ejector rod for low-temperature rapid continuous extrusion is 8.5 mm / s to 9.5 mm / s.

[0025] Due to the adoption of the above technical scheme, the technical progress achieved by the present invention is as follows.

[0026] The invention provides an aluminum alloy tube with excellent grains after welding. The content of alloy elements Mn, Fe and Cu is optimized to improve the mechanical properties of the aluminum tube after annealing. During processing, the straightening process after annealing is coordinated and the reduction amount of the outer diameter of the aluminum tube during straightening is controlled, so that the aluminum tube can not only meet the mechanical properties of national standard 3003H12, but also avoid the growth of grains after high-temperature welding. The invention adds trace element Ti during aluminum alloy smelting to inhibit grain growth, and simultaneously adopts high-temperature rapid annealing to make the aluminum tube quickly reach the recrystallization temperature, thereby ensuring that the grains of the aluminum tube after annealing are fine and uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a processing flow chart of the aluminum alloy tube in the present invention;

[0028] Figure 2 This is a grain map of the aluminum alloy tube after welding of the present invention;

[0029] Figure 3 This is the grain diagram of the aluminum alloy tube after welding in the comparative example of the present invention. DETAILED DESCRIPTION

[0030] The invention discloses an aluminum alloy tube with excellent grains after welding, which is composed of the following components in mass percentage: ≤0.15% of Si, 0.3%-0.5% of Fe, 0.1%-0.15% of Cu, 1.3%-1.4% of Mn, ≤0.05% of Mg, ≤0.1% of Zn, 0.02%-0.05% of Ti, ≤0.05% of other elements and 97.55%-98.28% of pure aluminum.

[0031] The processing method of the aluminum alloy tube with fine grain after welding specifically comprises the following steps:

[0032] S1. Prepare aluminum liquid: Add aluminum alloy tube components into a smelting furnace in proportion to prepare aluminum liquid, specifically including:

[0033] S11. Furnace smelting: Weigh the components according to the proportion, first load the pure aluminum into a dry smelting furnace, heat the furnace to 730-760℃, and then add other alloys in sequence after the pure aluminum is melted into aluminum alloy solution.

[0034] S12, slag removal: add slag remover to the solution obtained in S11, stir for 5 minutes, then add iron agent, aluminum-copper master alloy, manganese agent and titanium agent, stir for 10 minutes to 15 minutes and mix well.

[0035] S13, sampling and analysis: taking the sample in step S12 for spectral analysis of chemical composition.

[0036] S14, refining: adding fluorine-free and sodium-free granular refining agent, the amount of refining agent is 1-1.5 kg / ton aluminum, the refining time is 30 minutes, the melt temperature during refining is 750-790°C, high-purity argon is used during refining, and the argon content is more than 99.7%; then keep warm and stand for 20 minutes to 30 minutes to obtain aluminum liquid.

[0037] S2. Casting into long material cast rods: The aluminum liquid obtained in step S1 is cast into long material aluminum alloy round cast rods at 680℃~730℃, and aluminum titanium boron wire is added online during the casting process to refine the ingot grains, and the adding speed is 75-85cm / min; high-purity argon gas with a content of more than 99.7% is introduced into the casting flow trough for online degassing, and then double-layer filtration (using a 20-inch 40ppi and a 17-inch 60ppi ceramic filter plate for filtration) is used to further purify the melt; and then a vacuum direct cooling casting system is used for casting, and the casting speed is 140±2mm / min.

[0038] S3, homogenization annealing: the long aluminum alloy cast rod prepared in step S2 is kept at 590°C to 610°C for 10h to 12h, and then rapidly cooled to eliminate casting stress and intracrystalline segregation in the round cast rod, so as to make the grain structure uniform.

[0039] S4, cutting and extruding: cutting the long aluminum alloy round cast rods in step S3 into short aluminum alloy cast rods of equal length of 870 mm to 880 mm suitable for extrusion; heating the short aluminum alloy round cast rods and then rapidly and continuously extruding them at low temperature to obtain aluminum alloy extrusion tube blanks with fine and uniform grains, such as 3003R OD28*2.5T.

[0040] The steps of low-temperature rapid continuous extrusion are: preheating short aluminum alloy round cast bars, die barrels and dies, installing extrusion dies, loading short aluminum alloy round cast bars, low-temperature rapid continuous extrusion, rapid cooling, drying, oiling and coiling, and obtaining aluminum alloy extruded long tube billets. The extrusion speed of the ejector pin in low-temperature rapid continuous extrusion is 8.5 mm / s to 9.5 mm / s.

[0041] Preheating process: The preheating temperature of short aluminum alloy round castings is 470℃-490℃ for the head, 420℃~440℃ for the die barrel, and 460℃~500℃ for the mold. The preheating process adopts a gradient preheating method, that is, the preheating temperature of the casting at the advanced die barrel end is high, and the preheating temperature at the backward die barrel end is low, and the gradient is 3-5℃ / 100mm.

[0042] S5, inverted disc drawing: the aluminum alloy tube blank of step S4 is subjected to 2-6 inverted disc drawing according to different finished product specifications.

[0043] S6, cutting to length: the finished coil drawn in step S5 is cut to length by a cutting system; the cutting system has the functions of automatic straightening, continuous flaw detection, and automatic rejection of defective products; the flaw detection is eddy current flaw detection.

[0044] S7, high temperature rapid annealing: the aluminum tube cut in step S6 is subjected to a roller annealing furnace, the heating temperature is 540°C-560°C, and the heating time is 8-12 minutes; at the same time, the annealing equipment is provided with a temperature monitoring system, and the equipment will alarm when the temperature range is exceeded.

[0045] S8, straightening: the aluminum tube annealed in step S7 is straightened by a roller straightening machine; according to different finished product specifications, the outer diameter is reduced by 0.02-0.07 mm after straightening, further improving the yield strength of the aluminum tube.

[0046] The following will be combined with the attached Figure 1-3 The present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

[0047] Embodiment 1:

[0048] The aluminum alloy tube with fine grains after welding is composed of the following components in mass percentage: 0.1% Si, 0.32% Fe, 0.1% Cu, 1.31% Mn, 0.01% Mg, 0.02% Zn, 0.02% Ti, 0.05% other elements, and the remainder is pure aluminum.

[0049] The processing method of the aluminum alloy tube with fine grain after welding specifically comprises the following steps:

[0050] S1. Prepare aluminum liquid: Add aluminum alloy tube components into a smelting furnace in proportion to prepare aluminum liquid, specifically including:

[0051] S11. Furnace smelting: Weigh the components according to the proportion, first load the pure aluminum into a dry smelting furnace, heat the furnace to 730°C, and then add other alloys in sequence after the pure aluminum is melted into aluminum alloy solution.

[0052] S12, slag removal: add slag remover to the solution obtained in S11, stir for 5 minutes, then add iron agent, aluminum-copper master alloy, manganese agent and titanium agent, stir for 10 minutes to 15 minutes and mix well.

[0053] S13, sampling and analysis: taking the sample in step S12 for spectral analysis of chemical composition.

[0054] S14, refining: adding fluorine-free and sodium-free granular refining agent, the amount of refining agent is 1-1.5 kg / ton aluminum, the refining time is 30 minutes, the melt temperature during refining is 750-790°C, high-purity argon is used during refining, and the argon content is more than 99.7%; then keep warm and stand for 30 minutes to obtain aluminum liquid.

[0055] S2. Casting into long material cast rods: The aluminum liquid prepared in step S1 is cast at 682°C into long material aluminum alloy round cast rods. During the casting process, aluminum titanium boron wire is added online to refine the grain size of the ingot, and the adding speed is 75cm / min. High-purity argon gas with a content of more than 99.7% is introduced into the casting flow trough for online degassing, and then double-layer filtration (using a 20-inch 40ppi and a 17-inch 60ppi ceramic filter plate for filtration) is used to further purify the melt; and then a vacuum direct cooling casting system is used for casting, and the casting speed is 138mm / min.

[0056] S3, homogenization annealing: the long aluminum alloy cast rod prepared in step S2 is kept at 590° C. for 10 hours, and then rapidly cooled to eliminate casting stress and intracrystalline segregation in the round cast rod, so as to make the grain structure uniform.

[0057] S4, cutting and extruding: cutting the long aluminum alloy round cast rods in step S3 into short aluminum alloy cast rods of equal length of 870 mm to 880 mm suitable for extrusion; heating the short aluminum alloy round cast rods and then rapidly and continuously extruding them at low temperature to obtain aluminum alloy extrusion tube blanks with fine and uniform grains, such as 3003R OD28*2.5T.

[0058] The steps of low-temperature rapid continuous extrusion are: preheating short aluminum alloy round cast bars, die barrels and dies, installing extrusion dies, loading short aluminum alloy round cast bars, low-temperature rapid continuous extrusion, rapid cooling, drying, oiling and coiling, and obtaining aluminum alloy extruded long tube billets. The extrusion speed of the ejector rod in low-temperature rapid continuous extrusion is 8.5 mm / s.

[0059] Preheating process: The preheating temperature of short aluminum alloy round castings is 470℃ for the head, 420℃~440℃ for the die barrel, and 460℃~500℃ for the mold. The preheating process adopts a gradient preheating method, that is, the preheating temperature of the casting at the advanced die barrel end is high, and the preheating temperature at the backward die barrel end is low, and the gradient is 3-5℃ / 100mm.

[0060] S5, inverted disc drawing: the aluminum alloy tube blank of step S4 is subjected to 2-6 inverted disc drawing according to different finished product specifications.

[0061] S6, cutting to length: the finished coil drawn in step S5 is cut to length by a cutting system; the cutting system has the functions of automatic straightening, continuous flaw detection, and automatic rejection of defective products; the flaw detection is eddy current flaw detection.

[0062] S7, high temperature rapid annealing: the aluminum tube cut in step S6 is subjected to a roller annealing furnace, the heating temperature is 540°C, and the heating time is 8 minutes; at the same time, the annealing equipment is provided with a temperature monitoring system, and the equipment will alarm when the temperature range is exceeded.

[0063] S8, straightening: the aluminum tube annealed in step S7 is straightened by a roller straightening machine; according to different finished product specifications, the outer diameter is reduced by 0.02 mm after straightening, and the yield strength of the aluminum tube is further improved.

[0064] Embodiment 2:

[0065] The aluminum alloy tube with fine grains after welding is composed of the following components in mass percentage: 0.13% Si, 0.47% Fe, 0.14% Cu, 1.39% Mn, 0.03% Mg, 0.07% Zn, 0.05% Ti, 0.05% other elements, and the remainder is pure aluminum.

[0066] The processing method of the aluminum alloy tube with fine grain after welding specifically comprises the following steps:

[0067] S1. Prepare aluminum liquid: Add aluminum alloy tube components into a smelting furnace in proportion to prepare aluminum liquid, specifically including:

[0068] S11. Furnace smelting: Weigh the components according to the proportion, first load the pure aluminum into a dry smelting furnace, heat the furnace to 760°C, and then add other alloys in sequence after the pure aluminum is melted into aluminum alloy solution.

[0069] S12, slag removal: add slag remover to the solution obtained in S11, stir for 5 minutes, then add iron agent, aluminum-copper master alloy, manganese agent and titanium agent, stir for 10 minutes to 15 minutes and mix well.

[0070] S13, sampling and analysis: taking the sample in step S12 for spectral analysis of chemical composition.

[0071] S14, refining: adding fluorine-free and sodium-free granular refining agent, the amount of refining agent is 1-1.5 kg / ton aluminum, the refining time is 35 minutes, the melt temperature during refining is 750-790°C, high-purity argon is used during refining, and the argon content is more than 99.7%; then keep warm and stand for 30 minutes to obtain aluminum liquid.

[0072] S2. Casting into long material cast rods: The aluminum liquid prepared in step S1 is cast at 728°C into long material aluminum alloy round cast rods. During the casting process, aluminum titanium boron wire is added online to refine the ingot grains, and the adding speed is 85cm / min; high-purity argon gas with a content of more than 99.7% is introduced into the casting flow trough for online degassing, and then double-layer filtration (using a 20-inch 40ppi and a 17-inch 60ppi ceramic filter plate for filtration) is used to further purify the melt; and then a vacuum direct cooling casting system is used for casting, and the casting speed is 142mm / min.

[0073] S3, homogenization annealing: the long aluminum alloy cast rod prepared in step S2 is kept at 610° C. for 12 hours, and then rapidly cooled to eliminate casting stress and intracrystalline segregation in the round cast rod, so as to make the grain structure uniform.

[0074] S4, cutting and extruding: cutting the long aluminum alloy round cast rods in step S3 into short aluminum alloy cast rods of equal length of 870 mm to 880 mm suitable for extrusion; heating the short aluminum alloy round cast rods and then rapidly and continuously extruding them at low temperature to obtain aluminum alloy extrusion tube blanks with fine and uniform grains, such as 3003R OD28*2.5T.

[0075] The steps of low-temperature rapid continuous extrusion are: preheating short aluminum alloy round cast bars, die barrels and dies, installing extrusion dies, loading short aluminum alloy round cast bars, low-temperature rapid continuous extrusion, rapid cooling, drying, oiling and coiling, and obtaining aluminum alloy extruded long tube billets. The extrusion speed of the ejector rod in low-temperature rapid continuous extrusion is 9.5 mm / s.

[0076] Preheating process: The preheating temperature of short aluminum alloy round castings is 490℃ for the head, 420℃~440℃ for the die barrel, and 460℃~500℃ for the mold. The preheating process adopts a gradient preheating method, that is, the preheating temperature of the casting at the advanced die barrel end is high, and the preheating temperature at the backward die barrel end is low, and the gradient is 3-5℃ / 100mm.

[0077] S5, inverted disc drawing: the aluminum alloy tube blank of step S4 is subjected to 2-6 inverted disc drawing according to different finished product specifications.

[0078] S6, cutting to length: the finished coil drawn in step S5 is cut to length by a cutting system; the cutting system has the functions of automatic straightening, continuous flaw detection, and automatic rejection of defective products; the flaw detection is eddy current flaw detection.

[0079] S7, high temperature rapid annealing: the aluminum tube cut in step S6 is subjected to a roller annealing furnace, the heating temperature is 560°C, and the heating time is 12 minutes; at the same time, the annealing equipment is provided with a temperature monitoring system, and the equipment will alarm when the temperature range is exceeded.

[0080] S8, straightening: the aluminum tube annealed in step S7 is straightened by a roller straightening machine; according to different finished product specifications, the outer diameter is reduced by 0.05 mm after straightening, so as to further improve the yield strength of the aluminum tube.

[0081] The aluminum alloy tubes prepared in Examples 1 and 2 were tested for performance, and the average grain size after welding was also tested, and the average grain size of the existing aluminum alloy tubes after welding was tested. The aluminum alloy tube prepared in Example 1 had a tensile strength of 126Mpa, a yield strength of 83Mpa, and an elongation of 43%; the average grain size after welding was 40um. The aluminum alloy tube prepared in Example 2 had a tensile strength of 130Mpa, a yield strength of 92Mpa, and an elongation of 40%; the average grain size after welding was 38um.

[0082] The experimental data show that the aluminum alloy tubes obtained in Examples 1 and 2 meet the mechanical properties of the national standard GB / T 6893: tensile strength 115-150 MPa; yield strength ≥75 MPa; elongation ≥12%, and can ensure that the grains are fine and there is no abnormal growth after high-temperature welding.

Claims

1. An aluminum alloy tube with fine grain after welding, It is characterized in that It is composed of the following components in mass percentage: ≤0.15% Si, 0.3%~0.5% Fe, 0.1%~0.15% Cu, 1.3%~1.4% Mn, ≤0.05% Mg, ≤0.1% Zn, 0.02%~0.05% Ti, ≤0.05% other elements and 97.55%~98.28% pure aluminum; A method for processing an aluminum alloy tube with fine grains after welding, specifically The following steps are involved: S1. Preparing aluminum liquid: adding aluminum alloy tube components into a smelting furnace in proportion to prepare aluminum liquid; S11. Furnace smelting: Weigh the components according to the proportion, first put the pure aluminum into a dry smelting furnace, heat the furnace to 730-760°C, and then add other alloys in sequence after the pure aluminum is melted into aluminum alloy solution; S12, slag removal: add a slag remover to the solution obtained in S11, stir for 5 minutes, then add an iron agent, an aluminum-copper master alloy, a manganese agent and a titanium agent, stir for 10 minutes to 15 minutes and mix well; S13, sampling and analysis: taking the sample in step S12 for spectral analysis of chemical composition; S14, refining: adding fluorine-free and sodium-free granular refining agent, the amount of refining agent is 1-1.5 kg / ton aluminum, the refining time is 30 minutes, the melt temperature during refining is 750-790°C, high-purity argon is used during refining, and the argon content is more than 99.7%; then keep warm and stand for 20 minutes to 30 minutes to obtain aluminum liquid; S2, casting into long material cast rods: the aluminum liquid obtained in step S1 is cast into long material aluminum alloy round cast rods at 680℃~730℃, and aluminum titanium boron wire is added online during the casting process to refine the ingot grains, and the adding speed is 75-85cm / min; high-purity argon gas with a content of more than 99.7% is introduced into the casting flow trough for online degassing, and then double-layer filtration is used to further purify the melt; and then a vacuum direct cooling casting system is used for casting, and the casting speed is 140±2mm / min; the double-layer filtration is carried out by filtering with a 20-inch 40ppi and a 17-inch 60ppi ceramic filter plate; S3, homogenization annealing: the long aluminum alloy cast rod prepared in step S2 is kept at 590° C. to 610° C. for 10 h to 12 h, and then rapidly cooled; S4, cutting and extruding: cutting the long aluminum alloy round cast rods in step S3 to obtain short aluminum alloy cast rods of equal length suitable for extrusion; heating the short aluminum alloy round cast rods and then rapidly and continuously extruding them at low temperature to obtain aluminum alloy extrusion tube blanks with fine and uniform grains; the length of the short aluminum alloy round cast rods is 870 mm to 880 mm; The steps of low-temperature rapid and continuous extrusion are: preheating short-stock aluminum alloy round cast bars, a die barrel and a die, installing an extrusion die, loading short-stock aluminum alloy round cast bars, low-temperature rapid and continuous extrusion, rapid cooling, drying, oiling and coiling, and obtaining aluminum alloy extruded long-stock tube billets; Preheating process: the preheating temperature of the short aluminum alloy round casting rod is 470℃-490℃ for the head, 420℃~440℃ for the die barrel, and 460℃~500℃ for the mold; the preheating process adopts a gradient preheating method, that is, the preheating temperature of the casting rod at the advanced die barrel end is high, and the preheating temperature at the backward die barrel end is low, and the gradient is 3-5℃ / 100 mm; The ejector extrusion speed of low-temperature rapid continuous extrusion is 8.5mm / s to 9.5mm / s; S5, inverted plate drawing: the aluminum alloy tube blank of step S4 is subjected to 2-6 inverted plate drawing according to different finished product specifications; S6, cutting to length: the finished coil material drawn in step S5 is cut to length using a cutting system; S7, high temperature rapid annealing: the aluminum tube cut in step S6 is subjected to a roller annealing furnace at a heating temperature of 540°C-560°C for 8-12 minutes; S8, straightening: straighten the aluminum tube annealed in step S7 using a roller straightening machine.

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