Heating and spinning forming method for super-long aluminum alloy cylindrical part

Abstract

The invention discloses a heating and spinning forming method for an ultra-long aluminum alloy cylindrical part, and relates to the technical field of aluminum alloy cylindrical part forming. Spinning forming process parameters such as the preheating temperature of a spinning core mold, the heating temperature of an aluminum alloy spinning blank, the axial and radial staggered distance amount of a spinning roller, the spinning feeding ratio and the traction force of a traction device are set; and the high-quality heating spinning forming effect of the super-long aluminum alloy cylindrical part is achieved. By adopting a heating mode, the plasticity and the spinning property of the material are improved, the deformation resistance of the material is reduced, and the problems that the low-plasticity aluminum alloy material is difficult to deform at room temperature and the spinning resistance of the thick-wall aluminum alloy blank is too large are solved; the blocking of the friction force between the spinning forming section of the aluminum alloy blank and the die on material flowing is eliminated, it is guaranteed that the material normally moves along the die, and spinning forming of the super-long aluminum alloy cylindrical part is achieved.

Description

Technical Field

[0001] This invention relates to the field of metal plastic forming technology, specifically a method for heating and spinning ultra-long aluminum alloy cylindrical parts. Background Technology

[0002] As key structural components in major equipment develop towards larger sizes, traditional methods face numerous technical challenges when using special forming processes to manufacture such components. Taking ultra-long aluminum alloy cylindrical parts with a length of 4-7m as an example, while spin forming is an effective way to achieve low-cost and high-efficiency manufacturing, problems such as the difficulty in deforming low-plasticity aluminum alloy materials and excessive spin forming resistance of thick-walled blanks are prominent under room temperature conditions. It is often necessary to use heating methods to improve the plasticity of the material, increase the total deformation rate between annealing processes, and reduce the spin forming deformation resistance to achieve stable plastic forming. However, while heating improves the plasticity of the material, it also leads to a decrease in its compressive strength. As the length of the formed section increases, the friction between the section and the mandrel continues to accumulate. When the friction reaches or exceeds the material's compressive strength, the formed section cannot slide normally along the mold surface. Subsequent material flows non-uniformly in the radial and circumferential directions due to axial flow obstruction, which in turn causes defects such as bulges, protrusions, and wrinkles, interrupting the spin forming process. If the diameter of the formed section is increased by adjusting the process parameters to reduce friction, the sliding resistance can be alleviated, but it will cause the geometric dimensions and form and position tolerances of the cylindrical part, such as diameter, wall thickness, roundness and generatrix straightness, to exceed the tolerance, resulting in product scrap.

[0003] Therefore, how to improve the plasticity of the material and reduce the deformation resistance by heating while ensuring the dimensional accuracy and shape tolerance of ultra-long cylindrical parts, and at the same time eliminate the frictional resistance between the formed section and the mold, and ensure the smooth flow of the material along the surface of the core mold, has become a technical bottleneck that urgently needs to be overcome. It is urgent to develop a special method and device for heating and spinning forming of ultra-long cylindrical parts. Summary of the Invention

[0004] The purpose of this invention is to provide a method for heating and spinning ultra-long aluminum alloy cylindrical parts to solve the problems mentioned in the prior art.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a method for hot spinning of ultra-long aluminum alloy cylindrical parts, comprising the following steps:

[0006] S1. Design of traction device: The traction device is designed according to the number of spinning passes of the formed workpiece, the length of the aluminum alloy spinning blank before spinning, and the length increase of the aluminum alloy spinning blank after spinning. The part of the traction device connected to the workpiece can also be replaced according to the number of spinning passes and the length of the workpiece.

[0007] S2. Preparation of aluminum alloy spinning annealed blanks: Set a fixed ring, a spinning wheel feed guide section and a corresponding chamfer at the starting end of the aluminum alloy spinning blank connected to the traction device. Then, vertically feed the aluminum alloy spinning blank into the annealing furnace for complete annealing heat treatment to obtain the aluminum alloy annealed spinning blank.

[0008] S3. Spinning tooling and mold debugging and preheating: Before spinning, the spinning core mold (6) is debugged. The runout of the working and guiding parts of the spinning core mold in contact with the aluminum alloy annealed spinning blank after debugging must meet the process requirements. Then, the automatic heating device matched with the spinning machine is used to heat the spinning core mold.

[0009] S4. Installation of spinning tooling and traction device: Apply lubricant to the working and guiding parts of the spinning mandrel that are in contact with the annealed aluminum alloy spinning blank, as well as the inner surface of the annealed aluminum alloy spinning blank. Then, slip the lubricated annealed aluminum alloy spinning blank onto the spinning mandrel. Next, slip the unloading ring and the stop gear onto the spinning mandrel in sequence and fix them to the flange end of the spinning mandrel and to the main shaft of the spinning machine spindle box using locating pins. Connect and fix the fixing ring of the annealed aluminum alloy spinning blank to the traction device. Then, press the tail rod against the tail of the spinning mandrel and support the spinning mandrel. Finally, place the spinning wheel of the spinning machine at the preset position of the wheel feed guide section of the annealed aluminum alloy spinning blank.

[0010] S5. Spinning: The automatic heating device of the spinning machine is used to heat the annealed aluminum alloy spinning blank. The spinning machine is started to heat and spin the annealed aluminum alloy spinning blank in a staggered manner. During the spinning process, the traction device applies traction force to the spun section of the annealed aluminum alloy spinning blank. After each spinning pass, depending on the number of spinning passes and the length of the workpiece, it is selected whether to replace the part connecting the traction device to the workpiece. Then the spinning is performed. The workpiece is heated and spinned in a staggered manner in multiple passes until the target length is reached. It is then removed from the press to obtain an extra-long aluminum alloy cylindrical part.

[0011] As a preferred technical solution, the spinning tooling mold further includes a tailstock, and the tail ejector rod is fixed on the tailstock by a tail ejector rotating shaft and a tail ejector hydraulic cylinder arranged in sequence.

[0012] The traction device includes a connector connected to the workpiece and tension hydraulic cylinders symmetrically arranged on both sides of the tailstock. The front and rear ends of the connector are connected to the workpiece and the tension rotating assembly, respectively. The tension rotating assembly and the tension hydraulic cylinder are connected by a flange. The tension hydraulic cylinder is reinforced by the cylinder feet.

[0013] The connectors include two specifications. The first specification connector is used for the first and second spinning processes and has a length of not less than 2000 mm. The second specification connector is used for the third spinning process and has a length of not less than 1000 mm.

[0014] As a preferred technical solution, the connecting component includes a connecting cylinder with a built-in flange, and positioning rings are provided at both ends of the connecting cylinder. The positioning rings at both ends are respectively connected to the fixing rings and tension rotation components on the aluminum alloy annealed spinning blank.

[0015] The tension rotation assembly includes a tension shaft, on which two thrust ball bearings are sleeved. The thrust ball bearings are fixed by a thrust ball bearing sleeve sleeved on the outer ring, a washer ring arranged sequentially at the bottom, and a locking nut.

[0016] The positioning ring is fixedly connected to the tension shaft;

[0017] The tail rod passes through the inner hole of the connector and the tension shaft to tighten the spinning core mold.

[0018] As a preferred technical solution, in step S2, the wall thickness of the aluminum alloy spinning blank is 30-50mm, the thickness of the starting end of the aluminum alloy spinning blank and the fixed ring is 35mm, the length of the spinning wheel feed guide section is 70mm, and the chamfer is 25°.

[0019] The complete annealing heat treatment process is as follows: the aluminum alloy spinning blank is vertically fed into the annealing furnace and the furnace door is closed. It is heated to 300-350°C in the furnace and held at 300-350°C for 90-100 minutes. After the holding is completed, the furnace door is opened and the blank is taken out of the furnace and air-cooled to room temperature to obtain the aluminum alloy annealed spinning blank.

[0020] The total thinning rate of the annealed spun aluminum alloy blank after full annealing heat treatment is no more than 75%.

[0021] As a preferred technical solution, in step S3, the process requirement for the runout of the working and guiding part of the spinning mandrel in contact with the aluminum alloy annealed spinning blank is no more than 0.15mm.

[0022] The heating temperature of the spinning mandrel 6 is 150-200℃, and the heating time is 30-60 minutes.

[0023] As a preferred technical solution, the lubricant is a high-temperature grease; the spinning wheel 5 is composed of a front wheel A, an intermediate wheel B and a rear wheel C, which are evenly distributed along the circumference and have the same fillet radius R. The fillet radius of the spinning wheel 5 is in the range of 0.8 to 1.2 times the wall thickness of the aluminum alloy blank 4. The front wheel A is provided with a guide section to prevent serious material accumulation during the spinning process.

[0024] As a preferred technical solution, the axial misalignment of the front wheel A, middle wheel B, and rear wheel C of the rotating wheel 5 is determined based on the working angle, the fillet radius R, and an empirical formula for the wheel misalignment. The empirical formula is as follows:

[0025] R = (0.8 ~ 1.2)t0;

[0026] a12≥Δt2 / tan(α);

[0027] a23≥Δt3 / tan(α);

[0028] Where R is the radius of the rotary wheel, t0 is the wall thickness of the aluminum alloy spinning blank; a12 and a23 are the axial misalignment between the front wheel A and the intermediate wheel B, and between the intermediate wheel B and the rear wheel C, respectively; Δt2 and Δt3 are the maximum reduction per pass between the intermediate wheel B and the rear wheel C, respectively; and α is the working angle of the rotary wheel.

[0029] As a preferred technical solution, the total reduction of the spinning wheel in each pass is 20-40% of the wall thickness of the spun aluminum alloy annealed spinning blank, and the ratio of the reduction of the front wheel A, the middle wheel B and the rear wheel C in each spinning process is 4:3:3; the working angle α of the spinning wheel is in the range of 15° to 30°.

[0030] As a preferred technical solution, in step S5, the heating temperature of the aluminum alloy annealed spinning blank is 180-300℃, and the heating time is 10-30min; the rotational speed of the spindle of the spindle box is 25-60r / min; and the feed ratio of the spinning wheel is 0.7-2.0mm / r.

[0031] As a preferred technical solution, the traction force applied by the traction device to the spun section of the aluminum alloy annealed spinning blank is not less than the frictional force between the spun section and the spinning mandrel, so as to ensure the normal flow of material and the normal progress of the spinning process.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] 1. This invention designs a traction device to meet the heating and spinning forming of ultra-long cylindrical parts. It can meet the requirements of heating low-plasticity aluminum alloy materials at room temperature to improve the plasticity and spinnability of the materials, and can also meet the requirements of heating thick-walled aluminum alloy spinning blanks to reduce deformation resistance. The traction force of the traction device can eliminate the influence of friction between the spun section of the aluminum alloy spinning annealed blank and the spinning mandrel on the flow resistance of the forming material, ensuring that the material slides normally along the surface of the spinning mandrel, and effectively realizing the heating and spinning forming effect of ultra-long aluminum alloy cylindrical parts.

[0034] 2. This invention achieves the spinning forming effect of ultra-long aluminum alloy cylindrical parts by designing the geometry and size of the spinning blank, the working surface and angle of the spinning wheel, the working fillet radius and size, the guide section angle and length, the axial misalignment between the spinning wheels and the radial reduction of each spinning pass, the annealing process of the aluminum alloy blank, and the spinning heating temperature.

[0035] 3. By selecting appropriate guide sections, front angles, and fillet radii for the spinning wheel, this invention effectively suppresses bulging, protrusion, severe material accumulation, surface peeling, and overlapping phenomena that occur in aluminum alloy materials during the heating and spinning process. It effectively controls the wall thickness, diameter expansion, diameter, roundness, and generatrix straightness of the product, and avoids the influence of friction between the spun section of the aluminum alloy spinning annealing blank and the spinning mandrel on the material flow. This ensures that the material is shaped and flows according to predetermined requirements during the spinning process, thereby significantly improving the geometric dimensions, form and position tolerances, and surface quality of the product. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of the spinning tooling mold, the annealed aluminum alloy spinning blank, the spinning wheel and the traction device in the spinning process of the present invention. Figure 2 This is a schematic diagram showing the connection of the aluminum alloy annealed spinning blank, the connecting parts, and the tension rotation assembly in this invention; Figure 3 This is a schematic cross-sectional view of the tension rotation component in this invention; Figure 4 This is a schematic diagram of the structure of the aluminum alloy annealed spinning blank in this invention; Figure 5 This is a schematic diagram of the connecting cylinder in this invention. Detailed Implementation

[0041] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0042] Example: Figures 1-5 As shown, this embodiment describes the preparation of an ultra-long cylindrical component of 5A06 aluminum alloy with a wall thickness of 12mm and a length of 6.2m, including the following steps:

[0043] S1. Design of traction device: The traction device is designed according to the number of spinning passes of the formed workpiece, the length of the aluminum alloy spinning blank before spinning, and the length increase of the aluminum alloy spinning blank after spinning. The part of the traction device connected to the workpiece can also be replaced according to the number of spinning passes and the length of the workpiece.

[0044] S2. Preparation of aluminum alloy spinning annealing blank: Select an aluminum alloy spinning blank with an initial thickness of 33mm. Set a fixing ring 41 connected to the connector 7, a spinning wheel infeed guide section 42 and a corresponding chamfer at the starting end of the aluminum alloy spinning blank. The thickness of the starting end and the fixing ring 42 is 35mm, the length of the spinning wheel infeed guide section is 70mm and the chamfer is 25°. Then, vertically send the aluminum alloy spinning blank into the annealing furnace and close the furnace door. Heat it in the furnace to 300-350℃ and hold it at 300-350℃ for 90-100min. After the holding is completed, open the furnace door, take the aluminum alloy spinning blank out of the furnace and air cool it to room temperature to obtain the aluminum alloy annealed spinning blank 4.

[0045] In this step, the total thinning rate of the aluminum alloy annealed spinning blank 4 is 63.6%.

[0046] S3. Spinning tooling and mold debugging and preheating: Before spinning, the spinning mandrel 6 is debugged. After debugging, the runout of the working and guiding parts of the spinning mandrel 6 in contact with the aluminum alloy annealed spinning blank 4 does not exceed 0.15mm. Then, the automatic heating device matched with the spinning machine is used to heat the spinning mandrel 6. The heating temperature is 150~200℃ and the heating time is 30~60min.

[0047] S4. Installation of spinning tooling and traction device: Apply high-temperature grease to the working and guiding parts of the spinning core mold 6 that have been heated and come into contact with the aluminum alloy annealed spinning blank 4, as well as the inner surface of the aluminum alloy annealed spinning blank 4. Then, the unloading ring 2 and the stop toothed disc 3 are sequentially fitted into the spinning core mold 6 and fixed by the positioning pin. Continue to fit the aluminum alloy annealed spinning blank 4 coated with high-temperature grease onto the spinning core mold 6 and fix it on the main shaft of the spinning machine spindle box 1. Then, the connecting cylinder 71 of the traction device is connected to the fixing ring 41 of the aluminum alloy annealed spinning blank 4 through the positioning ring 72 and fixed by bolts. The other positioning ring 41 of the connecting cylinder 71 is connected to the tension shaft 81 of the tension rotating assembly 8. At the same time, the tail hydraulic cylinder 12 drives the tail rod 10 to pass through the connecting cylinder 71 and the tension shaft 81 to press the tail of the spinning core mold 6 and support the spinning core mold 6. Then, the spinning wheel 5 is placed at the preset position of the spinning wheel feed guide section 42 of the aluminum alloy annealed spinning blank 4.

[0048] S5. Spinning: The automatic heating device of the machine heats the annealed aluminum alloy spinning blank 4 at a temperature of 180-300℃. The spinning machine is started to heat and spin the annealed aluminum alloy spinning blank 4 in a staggered manner. The spinning process consists of three passes. The first and second passes use the first specification connector 7 with a length of 2500mm. The third pass uses the second specification connector 7 with a length of 1500mm. The reduction of the first, second, and third spinning passes is 25%, 2%, and 2% of the wall thickness of the 33mm aluminum alloy spinning blank, respectively. 8% and 32.7%, the ratio of the pressing amount of the front wheel A, the middle wheel B and the rear wheel C in each spinning process is 4:3:3, the spindle speed of the spinning machine tool in the first, second and third spinning processes is 35 r / min, the feed ratio of the spinning wheel 5 in the first, second and third spinning processes is 1.2 mm / r, 1.0 mm / r and 0.85 mm / r respectively, the working angle α of the spinning wheel 5 in each process is 22°, during the spinning process, the tension hydraulic cylinder 14 applies traction force to the spun section of the aluminum alloy annealed spinning blank 4;

[0049] Based on R = (0.8~1.2)t0, t0 = 33mm, in this step, the fillet radii R of the front wheel A, middle wheel B, and rear wheel C of the spinning wheel 5 are all the same, 30mm. The axial misalignment of the front wheel A, middle wheel B, and rear wheel C of the spinning wheel 5 is determined according to the working angle α, the fillet radius R, and the empirical formula for wheel misalignment. The empirical formula is:

[0050] a12≥Δt2 / tan(α);

[0051] a23≥Δt3 / tan(α);

[0052] Where Δt2 and Δt3 are the maximum pass reductions of the intermediate wheel 2 and the rear wheel 3, respectively, Δt2 is 2.475mm and Δt3 is 2.475mm; the working angle α of the spinning wheel 5 is 22°;

[0053] Calculations using empirical formulas yield the following:

[0054] The axial misalignment a12 between the front wheel A and the middle wheel B is ≥ 6.13;

[0055] The axial misalignment a23 between the intermediate wheel B and the rear wheel C is ≥ 6.13.

[0056] After the workpiece is heated and staggered in three passes and then spun, the spun workpiece is removed from the spinning machine to obtain an extra-long cylindrical part of 5A06 aluminum alloy with a wall thickness of 12mm and a length of 6.2m.

[0057] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for hot spinning and forming an ultra-long aluminum alloy cylindrical part, characterized in that, Includes the following steps: S1. Design of traction device: The traction device is designed according to the number of spinning passes of the formed workpiece, the length of the aluminum alloy spinning blank before spinning, and the length increase of the aluminum alloy spinning blank after spinning. The part of the traction device connected to the workpiece can also be replaced according to the number of spinning passes and the length of the workpiece. S2. Preparation of aluminum alloy spinning annealed blank: Set a fixed ring (41) connected to the traction device, a spinning wheel feed guide section (42) and a corresponding chamfer at the starting end of the aluminum alloy spinning blank. Then, vertically feed the aluminum alloy spinning blank into the annealing furnace for complete annealing heat treatment to obtain aluminum alloy annealed spinning blank (4). S3. Spinning tooling and mold debugging and preheating: Before spinning, the spinning core mold (6) is debugged. The runout of the working and guiding parts of the spinning core mold (6) in contact with the aluminum alloy annealed spinning blank (4) after debugging must meet the process requirements. Then, the automatic heating device matched with the spinning machine is used to heat the spinning core mold (6). S4. Installation of spinning tooling and traction device: Apply lubricant to the working and guiding parts of the spinning core mold (6) after heating and contacting the aluminum alloy annealed spinning blank (4) and the inner surface of the aluminum alloy annealed spinning blank (4). First, put the unloading ring (2) and the stop toothed disc (3) into the spinning core mold (6) in sequence. Then, put the aluminum alloy annealed spinning blank (4) coated with lubricant into the spinning core mold (6) and fix it on the main shaft of the main shaft box (1). Then, connect and fix the fixing ring (41) of the aluminum alloy annealed spinning blank (4) to the traction device. The tail rod (10) presses against the tail of the spinning core mold (6) and supports the spinning core mold (6). Finally, place the spinning wheel (5) of the spinning machine in the preset position of the spinning wheel feed guide section (42) of the aluminum alloy annealed spinning blank (4). S5. Spin forming: The aluminum alloy annealed spin forming blank (4) is heated by the automatic heating device of the spinning machine. The spinning machine is started to heat and spin forming the aluminum alloy annealed spin forming blank (4) in a staggered manner. During the spinning process, the traction device applies traction force to the spun section of the aluminum alloy annealed spin forming blank (4). After each spin forming pass, the traction device is replaced with the part connected to the workpiece according to the number of spinning passes and the length of the workpiece. Then the spinning forming continues. The workpiece is heated and spin formed in multiple passes until the target length is reached. After completion, the spun forming workpiece is removed from the spinning machine to obtain an ultra-long aluminum alloy cylindrical part.

2. The method for hot spinning and forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, The spinning tooling mold also includes a tailstock (13), and the tail rod (10) is fixed on the tailstock (13) by a tail rotating shaft (11) and a tail hydraulic cylinder (12) arranged in sequence. The traction device includes a connector (7) connected to the workpiece and tension hydraulic cylinders (14) symmetrically arranged on both sides of the tailstock (13). The front and rear ends of the connector (7) are connected to the workpiece and the tension rotating assembly (8) respectively. The tension rotating assembly (8) and the tension hydraulic cylinder (14) are connected by a flange (9). The tension hydraulic cylinder (14) is reinforced by a tension hydraulic cylinder foot (15). The connector (7) includes two specifications. The first specification connector (7) is used for the first and second spinning forming, and its length is not less than 2000mm. The second specification connector (7) is used for the third spinning forming, and its length is not less than 1000mm.

3. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, The connector (7) includes a connecting cylinder (71) with a flange. The connecting cylinder (71) has positioning rings (72) at both ends. The positioning rings (72) at both ends are connected to the fixing rings (41) on the aluminum alloy annealed spinning blank (4) and the tension rotating assembly (8), respectively. The tension rotation assembly (8) includes a tension shaft (81), on which two thrust ball bearings (82) are sleeved. The thrust ball bearings (82) are fixed by a thrust ball bearing (82) sleeve (83) on the outer ring, a washer (84) arranged sequentially at the bottom, and a locking nut (85). The positioning ring (72) is fixedly connected to the tension shaft (81); The tail rod (10) passes through the inner hole of the connector (7) and the tension shaft (81) to tighten the spinning core mold (6).

4. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, In step S2, the wall thickness of the aluminum alloy spinning blank is 30-50mm, the thickness of the starting end and the fixing ring of the aluminum alloy spinning blank is 35mm, the length of the spinning wheel feed guide section is 70mm, and the chamfer is 25°. The complete annealing heat treatment process is as follows: the aluminum alloy spinning blank is vertically fed into the annealing furnace and the furnace door is closed. It is heated to 300-350°C and held at 300-350°C for 90-100 minutes. After the holding is completed, the furnace door is opened and the blank is taken out of the furnace and air-cooled to room temperature to obtain the aluminum alloy annealed spinning blank (4). The total thinning rate of the annealed spun aluminum alloy blank (4) after full annealing heat treatment is no more than 75%.

5. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, In step S3, the runout of the working and guiding parts of the spinning mandrel (6) in contact with the aluminum alloy annealed spinning blank (4) is required to be no more than 0.15 mm. The heating temperature of the spinning mandrel 6 is 150-200℃, and the heating time is 30-60 minutes.

6. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, In step S4, the lubricant is a high-temperature grease; the spinning wheel 5 is composed of a front wheel A, an intermediate wheel B and a rear wheel C, which are evenly distributed along the circumference and have the same fillet radius R. The fillet radius of the spinning wheel 5 is in the range of 0.8 to 1.2 times the wall thickness of the aluminum alloy blank 4. The front wheel A is provided with a guide section to prevent serious material accumulation during the spinning process.

7. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 6, characterized in that, The axial misalignment of the front wheel A, middle wheel B, and rear wheel C of the rotating wheel 5 is determined based on the working angle, the fillet radius R, and an empirical formula for wheel misalignment. The empirical formula is as follows: R = (0.8 ~ 1.2)t0; a12≥Δt2 / tan(α); a23≥Δt3 / tan(α); Where R is the radius of the fillet of the spinning wheel (5), t0 is the wall thickness of the aluminum alloy spinning blank; a12 and a23 are the axial misalignment between the front wheel A and the middle wheel B, and between the middle wheel B and the rear wheel C, respectively; Δt2 and Δt3 are the maximum pressing amount per pass between the middle wheel B and the rear wheel C, respectively; α is the working angle of the spinning wheel (5).

8. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 7, characterized in that, The total reduction of the spinning wheel (5) per pass is 20-40% of the wall thickness of the spun aluminum alloy annealed spinning blank (4). The ratio of the reduction of the front wheel A, the middle wheel B and the rear wheel C in each spinning process is 4:3:

3. The working angle α of the spinning wheel (5) ranges from 15° to 30°.

9. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, In step S5, the heating temperature of the aluminum alloy annealed spinning blank (4) is 180-300℃ and the heating time is 10-30min; the spindle speed of the spindle box (1) is 25-60r / min; and the feed ratio of the spinning wheel (5) is 0.7-2.0mm / r.

10. The method for hot spinning forming of an ultra-long aluminum alloy cylindrical part according to claim 1, characterized in that, In step S5, the traction force applied by the traction device to the spun section of the aluminum alloy annealed spinning blank (4) is not less than the frictional force between the spun section and the spinning mandrel (6), ensuring the normal flow of material and the normal progress of the spinning process.

Images