Roll bending welding near-forming method for high-precision hard aluminum alloy thin-walled cylindrical shell

Abstract

The invention discloses a roll bending welding near-forming method for a high-precision hard aluminum alloy thin-walled cylindrical shell, and relates to the technical field of welding. Comprising the following steps that S1, roll bending forming is conducted, specifically, an aluminum alloy plate with the thickness being 2 mm is adopted as a raw material, roll bending forming is conducted through a three-roller plate bending machine, and the aluminum alloy plate is in a barrel shape or a cone shape and used for manufacturing a cylindrical barrel and a conical barrel; s2, turning machining is conducted, specifically, after the cylindrical barrel and the conical barrel are subjected to roll bending and shape correction, turning is conducted, and the height size of the cylindrical barrel and the height size of the conical barrel are machined; s3, milling and boring: turning the cylindrical barrel and the conical barrel, turning to a milling and boring procedure, and accurately milling off the allowance of the butt joint surface; s4, electron beam welding: welding the shell by adopting a high-vacuum electron beam welding process with small heat input and concentrated capability; according to the method, accurate forming of the 2A14 thin-wall shell with the thickness being 2 mm can be achieved, the roundness can be controlled to be 0.3 mm, the cylindricity can be controlled to be within 0.8 mm, approximate deformation-free welding of butt joint faces can be achieved, and the joint quality meets the II-level requirement.

Description

Technical Field

[0001] The invention relates to the technical field of welding, in particular to a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method. Background Art

[0002] At present, the main forming process methods for thin-walled shells are: precision casting, spinning, hot expansion, roll bending, etc. Among them, precision casting uses a mold to form a liquid solution under high temperature and high pressure, and then heat treats it after forming to obtain the T6 state of the material. The formed parts have high precision, but the equipment and tooling are complex, the production process is long, and the cost is high. Using the spinning forming method, spinning must be carried out in the annealed state, and quenching and aging heat treatment processes are set during the spinning process. The heat treatment process will cause secondary deformation, and the accuracy is difficult to guarantee. Using the hot expansion forming process method, after calculating the sheet size according to the unfolded size, hot expansion is used for correction after preliminary rolling. However, the thermal expansion coefficient of aluminum alloy is large. In addition to relying on the expansion of the mold material itself, the expansion process also requires additional outward expansion force, which has high requirements for equipment and tooling, and the production process is complex and costly. The roll bending forming process uses traditional plate rolling machines for rolling, which is low in cost, but the arc precision size after rolling is difficult to accurately guarantee, the shell rigidity is insufficient, and it is difficult to accurately detect and obtain data to correct the rolling process. Taking into account the characteristics of various process methods, the roll bending process is simple and easy to implement, but the problems of insufficient rigidity and forming accuracy of thin-walled shells need to be solved. Summary of the invention

[0003] In view of the deficiencies in the prior art, the present invention provides a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method to solve the problems raised in the above background technology.

[0004] To achieve the above object, the present invention provides the following technical solution: a high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method, comprising the following steps: S1. Rolling and bending: The raw material is 2mm thick aluminum alloy sheet, which is rolled and bent by a three-roller rolling machine into a cylinder or cone shape for manufacturing cylindrical and conical cylinders. The process device is used to strengthen the rigidity and calibrate the shape to ensure the roundness and cylindricity accuracy requirements; S2. Turning: After the cylindrical and conical cylinders are rolled and calibrated, they are turned to the turning process to process the height dimensions of the cylindrical and conical cylinders to achieve the requirement of precise control of the height dimensions; S3, milling and boring processing: After the turning of the cylindrical barrel and the conical barrel is completed, the milling and boring process is carried out to accurately mill off the allowance of the butt joint surface to ensure that the circumference of the barrel shell is not greater than the circumference value corresponding to the required outer diameter of the barrel body, and to ensure the diameter size tolerance requirements; S4. Electron beam welding: The shell is welded using a high-vacuum electron beam welding process with small heat input and concentrated capacity. The fixed tooling during welding is made of non-magnetic aluminum and stainless steel to ensure that the butt gap and misalignment requirements are no more than 0.1mm. The shrinkage and deformation during the welding process are very small, and the accuracy indicators and joint quality requirements can be achieved. Pickling, degreasing and oxide film removal are performed before welding.

[0005] As a preferred technical solution of the present invention, in step S1, after the cylindrical tube and the conical tube are unfolded according to the median diameter, a 2mm margin is left on one side in the height direction, and a 150mm straight line segment is left on one side in the length direction. A 2A14-T6 2mm thick aluminum plate is used as the blank, and a laser blanking method is adopted with a blanking accuracy of ±0.2mm. The interval along the length is 100mm, and a generatrix is ​​marked with a marker pen. The wall thickness is measured at the generatrix position and the measured value is recorded, which is usually 2±0.05mm.

[0006] As a preferred technical solution of the present invention, in the step S1, before rolling, check and clean the impurities on the outside of the shaft roller, use a three-roller plate rolling machine for rolling, ensure that the busbar is parallel to the shaft roller when rolling the cylindrical tube, and keep the inner diameter of the small end of the cone tube in contact with the middle support roller at all times when rolling the conical tube. After rolling, the busbar is parallel to the shaft roller. According to the length size after the middle diameter is unfolded, a margin of 2.8 to 3 mm is left on each side, and the straight segments at both ends are manually cut off.

[0007] As a preferred technical solution of the present invention, in step S1, the cylindrical cylinder and the conical cylinder are fixed on the inner tube of the corresponding tooling, and the upper and lower ends are both about 5 mm higher than the end face of the inner tube of the tooling. The outside is tightened with a hoop, and the hoop fits the outer wall of the cylinder shell. It is required that there is no light-transmitting gap. The cylindricity of the cylindrical cylinder is detected using a laser tracker, and the theoretical cylindricity can be controlled within 0.3 mm. The two ends of the fixed cylindrical cylinder are measured at three locations along the length using a π ruler, and the measured value of the outer wall diameter is recorded. The theoretical value is φ729.8~729.9mm. The inner diameter of the large end of the fixed conical cylinder is measured using a caliper, and it is required to be 0.4~0.8mm smaller than the inner diameter of the product.

[0008] As a preferred technical solution of the present invention, in step S2, the tooling is transferred to the vertical lathe workbench, and the outer circle is used as the reference. After the circle is found to within 0.2mm, the tooling base is pressed with a fixed block, and rough turning is performed to flatten the upper end face, requiring all positions to be basically flat, measure the height dimension, record the margin, and rough turn the lower end face, requiring all positions to be basically flat, measure the height, record the margin, and the total height margin is controlled at 1-1.5mm. Continue to turn the lower end face by 0.5mm to make the roughness meet the requirements of 3.2, leave a height margin of 1mm, turn the upper end face, and turn it to a height dimension of 381±0.1mm.

[0009] As a preferred technical solution of the present invention, when the upper end face of the tapered cylinder is turned in step S2, a caliper is used to detect the inner diameter size of the small end during the processing, and the inner diameter size of the small end is processed to φ682.28±0.1mm. The pressure plate is replaced, and the large end face is turned to make the height size processed to 118±0.1mm. After the turning process is completed, the external tooling is replaced to the milling and boring state.

[0010] As a preferred technical solution of the present invention, in step S3, after the cylindrical tube and the process device are fixed and placed on the workbench, the tool is centered at the gap position and then processed using a 5mm milling cutter. The cutting width after processing is measured and the required value is 5mm. If it does not meet the requirement, the processing allowance is adjusted during the next processing, and 0.5mm is further processed on each side to make the final size of the cutting width after processing 6mm.

[0011] As a preferred technical solution of the present invention, after the cone cylinder is installed and fixed in step S3, the tool is aligned at the gap position and then processed using a 5mm milling cutter. The cutting width after processing is measured and the required value is 5mm. If it does not meet the requirement, the processing allowance is adjusted during the next processing, and 0.5mm is further processed on each side to make the final size of the cutting width after processing 6mm. After the cone cylinder is formed, it is placed in a shape correction device to make the cone cylinder rigidly fixed, and the outer wall of the cone cylinder fits well with the inner wall of the shape correction device without a light-transmitting gap. The cone angle size 10±0.05°, the height size, and the inner diameter size of the large end are detected.

[0012] As a preferred technical solution of the present invention, before the cylindrical tube and the conical tube are assembled and fixed in step S4, the debris, particles and other hard objects in the tooling and the surrounding environment are cleaned to prevent scratches, the machined butt surfaces at both ends of the cylindrical tube and the conical tube are fitted and aligned, the gap is not greater than 0.1mm, and the misalignment is not greater than 0.1mm. The ends are pressed tightly with a tooling, and the longitudinal welds formed by the cylindrical tube and the conical tube are fixed using a process device and placed on a welding tooling table. 40×40mm lead-out arc plates are set at both ends, and the longitudinal welds are welded using a vacuum electron beam welding process. After positioning welding, they are welded in sequence. After welding, the fixing process device is removed, and the cylindrical tube and the cylindrical tube are both a full circle. The weld quality is inspected by the X-ray detection process, which is required to meet the Level II requirements in GJB1718A-2005 "Electron Beam Welding".

[0013] As a preferred technical solution of the present invention, in step S4, the arc plates at both ends are processed and removed, the conical cylinder is fixed with an outer jig to assist in shape correction and detection, and the cylindrical cylinder uses an outer hoop to assist in shape correction and detect the outer diameter size after tightening.

[0014] Beneficial Effects Compared with the prior art, the present invention provides a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method, which has the following beneficial effects: The high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method uses a three-roller plate rolling machine to roll and form, preliminarily remove the straight section, use a rigid inner tube and a clamping device to fix the cylinder shell, accurately process the butt end, accurately turn the end face, and then use a vacuum electron beam welding method to perform longitudinal weld welding to form a whole. The method can achieve precise forming of a 2mm thick 2A14 thin-walled shell, the roundness can be controlled within 0.3mm, the cylindricity can be controlled within 0.8mm, and the butt surface can be welded without deformation. The joint quality meets the requirements of Level II and can be used for the welding production of thin-walled shell structures. It is an economical and reliable forming method. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the processing flow of a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 2 A schematic diagram of the cylindrical tube cutting structure of a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 3 A schematic diagram of the conical cylinder cutting structure of a high-precision hard aluminum alloy thin-wall cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 4 This is a diagram of the fixed state of a cylindrical vertical lathe in a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 5 This is a fixed state diagram of a tapered cylinder vertical lathe in a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 6 This is a cylindrical barrel milling and boring fixed state diagram of a high-precision hard aluminum alloy thin-walled barrel shell roll bending welding near-forming method proposed by the present invention; Figure 7 This is a cylindrical tube welding state diagram of a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Figure 8 This is a conical cylinder welding state diagram of a high-precision hard aluminum alloy thin-wall cylinder shell roll bending welding near-forming method proposed by the present invention; Fig. 9 This is a cylindrical tube correction state diagram of a high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method proposed by the present invention; Fig.10 This is a diagram of the conical cylinder correction state of a high-precision hard aluminum alloy thin-wall cylinder shell roll bending welding near-forming method proposed by the present invention; Fig.11 This is a vacuum electron beam welding parameter table for the butt joint of a cylindrical tube and a conical tube in a high-precision hard aluminum alloy thin-walled tube shell roll bending welding near-forming method proposed by the present invention. DETAILED DESCRIPTION

[0016] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0017] Please refer to Figure 1-Figure 11 The present invention discloses a high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method, comprising the following steps: S1. Rolling and bending: The raw material is 2mm thick aluminum alloy sheet, which is rolled and bent by a three-roller plate rolling machine into a tube or cone shape for manufacturing cylindrical and conical tubes. The process device is used to strengthen the rigidity and calibrate the shape to ensure the roundness and cylindricity accuracy requirements. The main control links are as follows; Specifically, after the cylindrical tube and the conical tube are unfolded according to the mid-diameter, a 2mm margin is left on one side in the height direction, and a 150mm straight section is left on one side in the length direction. 2A14-T6 2mm thick aluminum plate is used as the blank, and laser cutting is adopted. The cutting accuracy is ±0.2mm, and the interval along the length is 100mm. Please refer to the attached figure of the specification. Figure 2 and Figure 3 , use a marker to mark the busbar, measure the wall thickness at the busbar position and record the measured value, which is usually 2±0.05mm. Check and clean the impurities on the outside of the shaft roller before rolling. Use a three-roller plate rolling machine for rolling. When rolling the cylindrical tube, ensure that the busbar is parallel to the shaft roller. When rolling the conical tube, keep the inner diameter of the small end of the conical tube in contact with the middle support roller at all times. After rolling, the busbar is parallel to the shaft roller. According to the length size after the middle diameter is unfolded, leave a 2.8-3mm margin on each side, manually cut off the straight segments at both ends, and fix the cylindrical tube and conical tube on the inner tube of the corresponding tooling. Refer to the attached figure of the instruction manual Figure 4 and Figure 5 The upper and lower ends are about 5mm higher than the end face of the inner tube of the tooling. The outside is tightened with a hoop. The hoop fits the outer wall of the cylinder shell. There is no light-transmitting gap. The cylindricality of the cylinder is detected by a laser tracker. The theoretical cylindricity can be controlled within 0.3mm. The two ends of the fixed cylindrical cylinder are measured at three locations along the length using a π ruler. The actual measured value of the outer wall diameter is recorded. The theoretical value is φ729.8~729.9mm. The inner diameter of the large end of the fixed tapered cylinder is measured with a caliper, which is required to be 0.4~0.8mm smaller than the inner diameter of the product.

[0018] S2. Turning: After the cylindrical and conical cylinders are rolled and calibrated, they are turned to the turning process to process the height dimensions of the cylindrical and conical cylinders to achieve the requirements of precise control of the height dimensions. The main control links are as follows; Specifically, the tooling is transferred to the vertical lathe workbench, and the outer circle is used as the reference. After the circle is found to within 0.2mm, the tooling base is pressed with a fixed block, and rough turning is performed to level the upper end face. All positions are required to be basically leveled. The height dimension is measured and the allowance is recorded. The lower end face is rough turned. All positions are required to be basically leveled. The height is measured and the allowance is recorded. The total height allowance is controlled within 1-1.5mm. Continue to turn the lower end face by 0.5mm to make the roughness meet the requirements of 3.2, and leave a height allowance of 1mm. Turn the upper end face to a height dimension of 381±0.1mm. When turning the upper end face of the tapered cylinder, use a caliper to detect the inner diameter size of the small end during the processing. The inner diameter size of the small end is processed to φ682.28±0.1mm, replace the pressure plate, turn the large end face to make the height dimension processed to 118±0.1mm. After the turning process is completed, replace the external tooling to the milling and boring state, refer to the attached figure of the instruction manual Figure 5 and Figure 6 .

[0019] S3, milling and boring processing: After the turning of the cylindrical barrel and the conical barrel is completed, the milling and boring process is started to accurately mill the docking surface allowance to ensure that the circumference of the barrel shell is not greater than the circumference value corresponding to the required outer diameter of the barrel body and the diameter size tolerance requirements are met. The main control links are as follows; Specifically, after the cylindrical tube and the process device are fixed and placed on the workbench, the tool is aligned in the gap position, and a 5mm milling cutter is used for processing. The cutting width after processing is measured, and the required value is 5mm. If it does not meet the requirements, the processing allowance is adjusted during the next processing, and 0.5mm is removed from each side of each side so that the final size after cutting width processing is 6mm. After the conical tube is installed and fixed, the tool is aligned in the gap position, and a 5mm milling cutter is used for processing. The cutting width after processing is measured, and the required value is 5mm. If it does not meet the requirements, the processing allowance is adjusted during the next processing, and 0.5mm is removed from each side of each side so that the final size after cutting width processing is 6mm. After the conical tube is formed, it is placed in the correction device, refer to the attached figure of the instruction manual. Fig. 9 and Fig.10 , so that the cone is rigidly fixed, the outer wall of the cone fits well with the inner wall of the correction device, with no light-transmitting gap, and the cone angle size of 10±0.05°, height size, and large end inner diameter size are detected.

[0020] S4, electron beam welding: The shell is welded using a high vacuum electron beam welding process with low heat input and concentrated capacity. The fixed tooling during welding is made of non-magnetic aluminum and stainless steel to ensure that the butt gap and misalignment requirements are no more than 0.1mm. The shrinkage and deformation during the welding process are very small, and the accuracy index and joint quality requirements can be achieved. Pickling, oil removal and oxide film removal are performed before welding. The main control links are as follows; Specifically, before assembling and fixing the cylindrical tube and the conical tube, clean up the debris, particles and other hard objects in the tooling and the surrounding environment to prevent scratches, fit and align the machined butt surfaces at both ends of the cylindrical tube and the conical tube, with a gap of no more than 0.1mm and a misalignment of no more than 0.1mm, use the tooling to press the ends, and fix the longitudinal weld formed by the cylindrical tube and the conical tube using the process device, refer to the attached figure of the instruction manual Figure 7 and Figure 8 , placed on the welding tooling table, set 40×40mm lead-out arc plates at both ends, use vacuum electron beam welding process to weld the longitudinal weld, after positioning welding, weld and form in sequence, remove the fixing process device after welding, the cylindrical tube and the cylindrical tube are a full circle, and the weld quality is inspected by the X-ray detection process, which is required to meet the Level II requirements of GJB1718A-2005 "Electron Beam Welding". The lead-out arc plates at both ends are removed by processing, the conical tube is fixed with an outer jig, assisted in shape correction and inspection, and the cylindrical tube uses an outer hoop, which is tightened to assist in shape correction and inspect the outer diameter size. Refer to the attached figure of the instruction manual Fig.11 .

[0021] The working principle and use process of the present invention are as follows: when in use, 2A14-T6 2mm thick aluminum plate is used as the blank, laser blanking is adopted, the blanking accuracy is ±0.2mm, the interval along the length is 100mm, the busbar is marked with a marker, the wall thickness is measured at the busbar position and the measured value is recorded, which is usually 2±0.05mm, the impurities on the outside of the shaft roller are checked and cleaned before rolling, and a three-roller plate rolling machine is used for rolling. When rolling the cylindrical cylinder, ensure that the busbar and the shaft roller are in a parallel state. When rolling the conical cylinder, the inner diameter of the small end of the conical cylinder is kept in contact with the middle support roller at all times. After rolling, the busbar and the shaft roller are in a parallel state. According to the length size after the middle diameter is unfolded, 2.8-3mm margin is left on each side, and the straight line segments at both ends are manually cut off. The cylindrical cylinder and the conical cylinder are fixed on the inner tube of the corresponding tooling, and the upper and lower ends are both higher than the tooling. The end face of the inner tube is about 5mm, and the outside is tightened with a hoop. The hoop fits the outer wall of the cylinder shell, and there is no light-transmitting gap. The cylindrical cylinder is detected by a laser tracker. The theoretical cylindricality can be controlled within 0.3mm. The two ends of the fixed cylindrical cylinder are measured at three locations along the length using a π ruler, and the measured value of the outer wall diameter is recorded. The theoretical value is φ729.8~729.9mm. The inner diameter of the large end of the fixed conical cylinder is measured with a caliper, which is required to be 0.4~0.8mm smaller than the inner diameter of the product. The tooling is transferred to the vertical lathe workbench, and the outer circle is used as the reference. After finding the circle to within 0.2mm, the fixed block is used to press the tooling base, and the rough turning is performed to flatten the upper end face. All positions are required to be basically flat. Measure the height dimension, record the allowance, rough turn the lower end face, require all positions to be basically turned flat, measure the height, record the allowance, control the total height allowance within 1~1.5mm, continue to turn the lower end face 0.5mm, make the roughness meet the requirements of 3.2, leave 1mm height allowance, turn the upper end face, turn to a height dimension of 381±0.1mm, when turning the upper end face of the tapered cylinder, use a caliper to detect the inner diameter of the small end during the processing, and the inner diameter of the small end is processed to φ682.28±0.1mm, replace the pressure plate, turn the large end face to make the height dimension processed to 118±0.1mm, after the turning process is completed, replace the external tooling to the milling and boring state, fix the cylindrical cylinder and the process device and place it on the workbench, and fix it with the clearance position After the tool is aligned in the middle, a 5mm milling cutter is used for processing. The cutting width after processing is measured. The required value is 5mm. If it does not meet the requirements, the machining allowance is adjusted during the next tooling process. 0.5mm is removed from each side of the two sides to make the final size of the cutting width after processing 6mm. After the cone is installed and fixed, the tool is aligned at the clearance position. A 5mm milling cutter is used for processing. The cutting width after processing is measured. The required value is 5mm. If it does not meet the requirements, the machining allowance is adjusted during the next tooling process. 0.5mm is removed from each side of the two sides to make the final size of the cutting width after processing 6mm. After the cone is formed, it is placed in the shape correction device to make the cone rigid and fixed. The outer wall of the cone fits well with the inner wall of the shape correction device without light transmission gap. The cone angle size is detected to be 10±0.05°, height dimension, and large end inner diameter dimension. Before assembling and fixing the cylindrical and conical cylinders, clean up the debris, particles and other hard objects in the tooling and surrounding environment to prevent scratches. Fit and align the machined butt surfaces of the cylindrical and conical cylinders at both ends. The gap is not more than 0.1mm and the misalignment is not more than 0.1mm. Use the tooling to press the ends. The longitudinal welds formed by the cylindrical and conical cylinders are fixed by the process device and placed on the welding tooling table. 40×40mm lead-out arc plates are set at both ends. The longitudinal welds are welded by vacuum electron beam welding process. After positioning welding, they are welded in sequence. After welding, the fixed process device is removed. The cylindrical and cylindrical cylinders are both a full circle. The weld quality is inspected by the X-ray detection process. It is required to meet the requirements of Level II in GJB1718A-2005 "Electron Beam Welding". The lead-out arc plates at both ends are removed by processing. The conical cylinder is fixed with an outer jig to assist in shape adjustment and inspection. The cylindrical cylinder uses an outer hoop to assist in shape adjustment and inspect the outer diameter after tightening. .

[0022] In summary, the high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method uses a three-roll plate rolling machine to roll and form, preliminarily remove the straight section, use a rigid inner tube and a clamping device to fix the cylinder shell, accurately process the butt end, and accurately turn the end face. Then, a vacuum electron beam welding method is used for longitudinal welding to form a whole. The precise forming of 2mm thick 2A14 thin-walled shell can be achieved, the roundness can be controlled within 0.3mm, the cylindricity can be controlled within 0.8mm, and the butt surface can be welded without deformation. The joint quality meets the requirements of Level II and can be used for the welding production of thin-walled shell structures. It is an economical and reliable forming method.

[0023] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method, characterized in that: The following steps are involved: S1. Rolling and bending: The raw material is 2mm thick aluminum alloy sheet, which is rolled and bent by a three-roller rolling machine into a cylinder or cone shape for manufacturing cylindrical and conical cylinders. The process device is used to strengthen the rigidity and calibrate the shape to ensure the roundness and cylindricity accuracy requirements; S2. Turning: After the cylindrical and conical cylinders are rolled and calibrated, they are turned to the turning process to process the height dimensions of the cylindrical and conical cylinders to achieve the requirement of precise control of the height dimensions; S3, milling and boring processing: After the turning of the cylindrical barrel and the conical barrel is completed, the milling and boring process is carried out to accurately mill off the allowance of the butt joint surface to ensure that the circumference of the barrel shell is not greater than the circumference value corresponding to the required outer diameter of the barrel body, and to ensure the diameter size tolerance requirements; S4. Electron beam welding: The shell is welded using a high-vacuum electron beam welding process with small heat input and concentrated capacity. The fixed tooling during welding is made of non-magnetic aluminum and stainless steel to ensure that the butt gap and misalignment requirements are no more than 0.1mm. The shrinkage and deformation during the welding process are very small, and the accuracy indicators and joint quality requirements can be achieved. Pickling, degreasing and oxide film removal are performed before welding.

2. A high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method according to claim 1, characterized in that: In the step S1, after the cylindrical tube and the conical tube are unfolded according to the median diameter, a 2mm margin is left on one side in the height direction, and a 150mm straight line segment is left on one side in the length direction. A 2A14-T6 2mm thick aluminum plate is used as the blank, and a laser blanking method is adopted. The blanking accuracy is ±0.2mm, and the interval along the length is 100mm. The generatrix is ​​marked with a marker pen, and the wall thickness is measured at the generatrix position and the measured value is recorded, which is usually 2±0.05mm.

3. The high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method according to claim 1 is characterized in that: In the step S1, before rolling, check and clean the impurities on the outside of the shaft roller, use a three-roller plate rolling machine for rolling, ensure that the generatrix and the shaft roller are in a parallel state when rolling the cylindrical tube, and keep the inner diameter of the small end of the cone tube in contact with the middle support roller at all times when rolling the conical tube. After rolling, the generatrix and the shaft roller are in a parallel state. According to the length size after the middle diameter is unfolded, a margin of 2.8 to 3 mm is left on each side, and the straight segments at both ends are manually cut off.

4. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: In the step S1, the cylindrical cylinder and the conical cylinder are fixed on the inner tube of the corresponding tooling, and the upper and lower ends are both about 5 mm higher than the end face of the inner tube of the tooling. The outer side is tightened with a hoop, and the hoop fits the outer wall of the cylinder shell. It is required that there is no light-transmitting gap. The cylindricity of the cylindrical cylinder is detected using a laser tracker. The theoretical cylindricity can be controlled within 0.3 mm. The two ends of the fixed cylindrical cylinder are measured at three locations along the length using a π ruler, and the measured value of the outer wall diameter is recorded. The theoretical value is φ729.8~729.9mm. The inner diameter of the large end of the fixed conical cylinder is measured using a caliper, which is required to be 0.4~0.8mm smaller than the inner diameter of the product.

5. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: In step S2, the tooling is transferred to the vertical lathe workbench, and the outer circle is used as a reference. After the circle is found to within 0.2mm, the tooling base is pressed with a fixed block, and rough turning is performed to flatten the upper end face, requiring all positions to be basically flat, measure the height dimension, record the margin, and rough turn the lower end face, requiring all positions to be basically flat, measure the height, record the margin, and control the total height margin to be 1-1.5mm. Continue to turn the lower end face by 0.5mm to make the roughness meet the requirements of 3.2, leave a height margin of 1mm, and turn the upper end face to a height dimension of 381±0.1mm.

6. The high-precision hard aluminum alloy thin-walled cylinder shell rolling welding near-forming method according to claim 1 is characterized in that: When the upper end face of the tapered cylinder is turned in step S2, a caliper is used to detect the inner diameter size of the small end during the processing. The inner diameter size of the small end is processed to φ682.28±0.1mm, the pressure plate is replaced, and the large end face is turned to make the height size processed to 118±0.1mm. After the turning process is completed, the external tooling is replaced to the milling and boring state.

7. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: In step S3, after the cylinder and the process device are fixed and placed on the workbench, the tool is aligned in the center of the gap position, and a 5mm milling cutter is used for processing. The cutting width after processing is measured, and the required value is 5mm. If it does not meet the requirement, the processing allowance is adjusted during the next processing, and 0.5mm is further processed on each side to make the final size of the cutting width after processing 6mm.

8. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: In the step S3, after the cone is installed and fixed, the tool is aligned at the gap position, and then a 5mm milling cutter is used for processing. The cutting width after processing is measured, and the required value is 5mm. If it does not meet the requirement, the processing allowance is adjusted during the next processing, and 0.5mm is further processed on each side to make the final size of the cutting width after processing 6mm. After the cone is formed, it is placed in a shape correction device to make the cone rigid and fixed, and the outer wall of the cone fits well with the inner wall of the shape correction device without a light-transmitting gap. The cone angle size 10±0.05°, the height size, and the inner diameter size of the large end are detected.

9. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: Before the cylindrical tube and the conical tube are assembled and fixed in the step S4, the debris, particles and other hard objects in the tooling and the surrounding environment are cleaned to prevent scratches, the machined butt surfaces at both ends of the cylindrical tube and the conical tube are fitted and aligned, with a gap of no more than 0.1 mm and a misalignment of no more than 0.1 mm, and the ends are pressed tightly with a tooling. The longitudinal weld formed by the cylindrical tube and the conical tube is fixed with a process device and placed on a welding tooling table. 40×40 mm lead-out arc plates are set at both ends, and the longitudinal weld is welded with a vacuum electron beam welding process. After positioning welding, the longitudinal welds are welded in sequence. After welding, the fixing process device is removed, and the cylindrical tube and the cylindrical tube are both a full circle. The weld quality is inspected by the X-ray detection process.

10. The high-precision hard aluminum alloy thin-walled cylinder shell roll bending welding near-forming method according to claim 1 is characterized in that: In step S4, the arc plates at both ends are removed by processing, the conical cylinder is fixed with an outer jig, and the shape is assisted and tested, and the cylindrical cylinder is tightened with an outer hoop to assist in shape correction and test the outer diameter.

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