Profiled compensation near net shape friction stir welding of a cylindrical segment

Abstract

The application provides a profile deviation compensation near-circular device and method for a barrel segment friction stir welding, comprising a base, a tool support, an upper inner support profile ring structure, a lower inner support profile ring structure and a vertical driving structure; a plurality of tool supports are equidistantly arranged on the base along a circumference, and the upper inner support profile ring structure and the lower inner support profile ring structure are arranged on the upper and lower sides of the tool support respectively; the vertical driving structure is arranged on the tool support, and the vertical driving structure can drive the upper inner support profile ring structure to move up and down along the tool support. The application has the beneficial effects that the circumference of the inner support profile ring is adjustable, which effectively ensures that the last wall plate can be smoothly placed, and the assembly-welding-shaping of three wall plates and six wall plates and different height barrel segments are considered.

Description

Technical Field

[0001] This invention belongs to the field of tank processing, and in particular relates to a near-circular device and method for friction stir welding of cylindrical sections for compensating for surface deviations. Background Technology

[0002] The propellant tank is the carrier of rocket fuel. The tank bottom and cylindrical sections are the most important core components, with the cylindrical sections accounting for the largest proportion of the entire tank. Currently, propellant tanks in service in my country typically consist of 1-8 cylindrical sections, with weld thicknesses ranging from 5-10 mm and heights from 250-2200 mm. The main diameters are Φ2250 mm, Φ3350 mm, and Φ5000 mm. Each cylindrical section is generally constructed by welding four wall plates together using friction stir welding. Its sealing performance, weld strength, and dimensional accuracy directly affect the tank's load-bearing capacity.

[0003] After the cylindrical section is welded, it is joined to the bottom and other cylindrical sections by circumferential welding to form the propellant tank. There are two types of joints for rocket propellant tank circumferential seams: bottom-to-cylinder section and section-to-cylinder section. Section-to-cylinder section weld dimensional matching and circumferential seam assembly control are relatively simple, resulting in better weld quality. However, the bottom-to-cylinder section circumferential seam has a weaker deformation capacity due to the bottom transition ring being a single aluminum forging with a heat treatment state of quenching + cold forging + artificial aging, while the cylindrical section heat treatment state is quenching + approximately 10% cold working deformation + artificial aging. Therefore, the cylindrical section circumference must be strictly controlled to be smaller than the bottom transition ring during welding. Currently, fusion welding is generally used for propellant tank circumferential seams. Firstly, fusion welding has relatively lower assembly quality requirements and a larger tolerance for misalignment. Secondly, the cylindrical section is relatively thin and has weak rigidity, allowing for roundness correction within the circumferential welding frame to meet docking requirements. Thirdly, the cylindrical section can be elastically deformed using internal support fixtures to compensate for circumference changes. In summary, the requirements for the roundness, circumference and welding deformation of the tank section are relatively low during circumference welding. The assembly and welding process can be adjusted by tooling to meet the welding requirements.

[0004] The longitudinal seam of the front cylinder section can be achieved by friction stir welding using only the welding backing plate and the main shaft of the equipment, with the assistance of the wall panel support lifting trolley. However, this method cannot guarantee the roundness, weld quality, or circumference of the cylinder section. First, the friction stir welding equipment for the longitudinal seam of the cylinder section lacks conformal tooling to maintain the roundness during the welding process, resulting in significant deviations in cylinder section roundness. Second, after the longitudinal seam of the cylinder section is positioned, a single formal weld is performed for full penetration, but due to the structural characteristics of the stirring tool, severe concave deformation occurs in the weld. Third, the circumference of the cylinder section that connects to the bottom transition ring must be less than the circumference of the bottom ring to compensate for assembly misalignment through the internal support of the circumferential welding frame; if the circumference of the cylinder section exceeds the circumference of the bottom transition ring, assembly welding is impossible. Summary of the Invention

[0005] In view of this, the present invention aims to provide a near-circular device and method for cylindrical section friction stir welding with profile deviation compensation, so as to solve at least one technical problem in the background art.

[0006] To achieve the above objectives, the technical solution of the present invention is implemented as follows: A near-circular device for cylindrical section friction stir welding with profile deviation compensation includes a base, a tooling bracket, an upper inner support conforming ring structure, a lower inner support conforming ring structure, and a vertical drive structure; Several tooling brackets are equidistantly arranged on the base along the circumference, and the upper inner support molding ring structure and the lower inner support molding ring structure are respectively arranged on the upper and lower sides of the tooling brackets. The vertical drive structure is mounted on the tooling bracket, and the vertical drive structure can drive the upper inner support conforming ring structure to move up and down along the tooling bracket.

[0007] Furthermore, the upper inner support shaping ring structure includes several upper inner support shaping ring devices, which are arranged circumferentially on the tooling bracket; The upper inner support shaping ring device includes a first worktable, an upper inner support adjusting table, and an upper clamping assembly; The first worktable is slidably mounted on the tooling bracket, and the upper inner support adjustment table slides along the first worktable via the first radial drive assembly; Several upper clamping components are arranged circumferentially on the upper inner support adjustment platform; The end face of the upper inner support adjustment platform is arc-shaped.

[0008] Furthermore, the first radial drive assembly includes a first drive cylinder, a first threaded rod, and a first sliding block; The mounting end of the first drive cylinder is set on the first worktable, and the output end of the first drive cylinder is connected to the first threaded rod. The first sliding block is located at the bottom of the upper inner support adjustment platform, and the first sliding block is threaded onto the first threaded rod. The first driving cylinder can drive the upper inner support adjustment platform to perform radial adjustment. The upper part of the first workbench is provided with a second sliding block, and the upper inner support adjustment platform is provided with a first slide rail corresponding to the second sliding block.

[0009] Furthermore, the vertical drive structure includes a drive motor, a second threaded rod, and a third sliding block; The drive motor is mounted on the tooling bracket, and the output end of the drive motor is connected to the second threaded rod. The upper inner support conformal ring structure is threadedly connected to the second threaded rod through the third sliding block.

[0010] Furthermore, the lower inner support shaping ring structure includes several lower inner support shaping ring devices, which are arranged circumferentially on the tooling bracket; The lower inner support shaping ring device includes a second worktable, a lower inner support adjusting table, and a lower clamping assembly; The second worktable is slidably mounted on the tooling bracket, and the lower inner support adjustment table slides along the second worktable via the second radial drive assembly; Several lower clamping components are arranged circumferentially on the lower inner support adjustment platform.

[0011] Furthermore, the second radial drive assembly includes a second drive cylinder, a third threaded rod, and a fourth sliding block; The mounting end of the second drive cylinder is set on the second workbench. The output end of the second drive cylinder drives the third threaded rod to rotate via a belt. The third threaded rod is mounted on the second workbench. The fourth sliding block is set at the bottom of the lower inner support adjustment platform. The fourth sliding block is threaded on the third threaded rod. The second drive cylinder can drive the lower inner support adjustment platform to perform radial adjustment. The upper part of the base is provided with a second slide rail, and the lower inner support adjustment platform is provided with a second slide rail corresponding to the fifth sliding block.

[0012] Furthermore, both the upper clamping assembly and the lower clamping assembly include a third drive cylinder, a cylinder base, a push block, a connecting rod, a rotating plate, and a clamping plate; The mounting end of the third cylinder is located above the cylinder base, and the cylinder base is located on the upper inner support adjustment platform or the lower inner support adjustment platform. The output end of the third cylinder is connected to the push block. The push block has a sixth sliding block on both sides, and the cylinder base has a groove corresponding to the sixth sliding block; A rotating rod is provided on the cylinder base, and a first movable hole corresponding to the rotating rod is provided on the rotating plate. The rotating rod is mounted on the cylinder base. One end of the rotating plate is equipped with a pulley, and the other end is equipped with a clamping plate. The connecting rod is mounted on the cylinder base, and the rotating plate has a second movable hole through which the connecting rod can pass, and the rotating plate can slide along the second movable hole.

[0013] Furthermore, a first spring is provided on both sides of the cylinder base, and the end of the first spring is connected to the rotating plate; A second spring is provided on the rotating plate, and the end of the second spring is connected to the clamping plate.

[0014] Furthermore, the clamping plate is provided with adjustment holes, and the tooling bracket is provided with a ladder.

[0015] A method for preparing a near-circular cylindrical section by friction stir welding based on profile deviation compensation is provided. The method uses the above-mentioned profile deviation compensation device for near-circular cylindrical section friction stir welding. During welding, the diameter of the inner support conforming ring is adjusted to the inner diameter of the product and locked by the upper inner support conforming ring structure and the lower inner support conforming ring structure. The wall plate is reserved for welding shrinkage, but the final cylindrical section diameter after welding is smaller than the inner diameter of the product. Calculate the total perimeter of the cylindrical section, and then average the perimeter of the cylindrical section to 3 or 6 wall panels to calculate the arc length L of a single wall panel; The formula for calculating 6 wall panels is: ; The formula for calculating the number of wall panels is: L = ; Before welding the cylindrical section wall panels, first measure the circumference L1 of the bottom of the box, in mm; Allowance for shrinkage during friction stir welding, L2, in mm; L3 is the springback amount caused by machining allowance at both ends of the cylinder section, in mm. The assembly interference is L4, in mm.

[0016] Compared with existing technologies, the near-circular device and method for profile deviation compensation in cylindrical section friction stir welding described in this invention have the following advantages: This invention achieves the functions of synchronous positioning, circumferential / circumferential adjustment, assembly and fixing, and in-situ welding of all cylindrical wall panels through a set of tooling with upper and lower inner support conforming rings. The adjustable circumference of the inner support conforming rings effectively ensures that the last wall panel can be smoothly inserted, and also takes into account the assembly, welding and conforming of 3 and 6 wall panels as well as cylindrical sections of different heights.

[0017] In this invention, the arc length of the cylindrical section wall panel is taken into account with the coupling effects of welding shrinkage and springback of the cylindrical section edge, and the cylindrical section is set to be in an interference state with the inner support conformal ring after welding. Through the matching of product and tooling dimensions, high-precision roundness control is achieved. Attached Figure Description

[0018] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is an overall schematic diagram of the near-circular cylindrical section friction stir welding device for profile deviation compensation according to an embodiment of the present invention; Figure 2 This is a bottom schematic diagram of the upper inner support shaping ring device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the upper clamping assembly of the upper inner support conforming ring device according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the lower inner support shaping ring device according to an embodiment of the present invention; Figure 5 This is a schematic diagram of the upper part of the lower inner support shaping ring device according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the base as described in an embodiment of the present invention; Figure 7 The six cylindrical wall panels described in this embodiment of the invention are assembled and welded (a is the assembly, b is the weld). Figure 8 The three cylindrical wall panels described in this embodiment of the invention are assembled and welded (a is the assembly, b is the weld).

[0019] Explanation of reference numerals in the attached figures: 1. Base; 2. Tooling bracket; 3. Upper inner support molding ring device; 4. Lower inner support molding ring device; 5. Vertical drive structure; 6. First worktable; 7. Upper inner support adjusting platform; 8. Upper clamping assembly; 9. First drive cylinder; 10. First threaded rod; 11. First sliding block; 12. Second sliding block; 13. First slide rail; 14. Drive motor; 15. Second threaded rod; 16. Third sliding block; 17. Second worktable; 18. Lower inner support adjusting platform; 19. Lower clamping assembly; 20. Second drive cylinder; 21. Third threaded rod; 22. Sixth sliding block; 23. Fourth sliding block; 24. Second slide rail; 25. Third drive cylinder; 26. Cylinder base; 27. Push block; 28. Connecting rod; 29. ​​Rotating plate; 30. First spring; 31. Second spring; 32. Adjusting hole; 33. Ladder; 34. Clamping plate; 35. Fifth sliding block. Detailed Implementation

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0021] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0022] like Figures 1 to 8 As shown, the near-circular device for cylindrical section friction stir welding with profile deviation compensation includes a base 1, a tooling bracket 2, an upper inner support conforming ring structure, a lower inner support conforming ring structure, and a vertical drive structure 5. Several tooling brackets 2 are equidistantly arranged on the base 1 along the circumference. The upper inner support conforming ring structure and the lower inner support conforming ring structure are respectively arranged on the upper and lower sides of the tooling bracket 2. The vertical drive structure 5 is arranged on the tooling bracket 2 and can drive the upper inner support conforming ring structure to move up and down along the tooling bracket 2.

[0023] The upper inner support molding ring structure includes several upper inner support molding ring devices 3, which are arranged circumferentially on the tooling bracket 2. The upper inner support molding ring device 3 includes a first worktable 6, an upper inner support adjusting platform 7, and an upper clamping assembly 8. The first worktable 6 is slidably arranged on the tooling bracket 2, and the upper inner support adjusting platform 7 slides along the first worktable 6 through a first radial drive assembly. Several upper clamping assemblies 8 are arranged circumferentially on the upper inner support adjusting platform 7. The end face of the upper inner support adjusting platform 7 is arc-shaped.

[0024] The first radial drive assembly includes a first drive cylinder 9, a first threaded rod 10, and a first sliding block 11. The mounting end of the first drive cylinder 9 is disposed on the first worktable 6, and the output end of the first drive cylinder 9 is connected to the first threaded rod 10. The first sliding block 11 is disposed at the bottom of the upper inner support adjustment platform 7, and the first sliding block 11 is threaded onto the first threaded rod 10. The first drive cylinder 9 can drive the upper inner support adjustment platform 7 to perform radial adjustment. A second sliding block 12 is provided on the upper part of the first worktable 6, and a first slide rail 13 corresponding to the second sliding block 12 is provided on the upper inner support adjustment platform 7.

[0025] The vertical drive structure 5 includes a drive motor 14, a second threaded rod 15, and a third sliding block 16. The mounting end of the drive motor 14 is set on the tooling bracket 2, and the output end of the drive motor 14 is connected to the second threaded rod 15. The upper inner support conforming ring structure is threadedly connected to the second threaded rod 15 through the third sliding block 16.

[0026] The lower inner support molding ring structure includes several lower inner support molding ring devices 4, which are arranged circumferentially on the tooling bracket 2. Each lower inner support molding ring device 4 includes a second worktable 17, a lower inner support adjusting table 18, and a lower clamping assembly 19. The second worktable 17 is slidably arranged on the tooling bracket 2, and the lower inner support adjusting table 18 slides along the second worktable via a second radial drive assembly. Several lower clamping assemblies 19 are arranged circumferentially on the lower inner support adjusting table 18.

[0027] The second radial drive assembly includes a second drive cylinder 20, a third threaded rod 21, and a fourth sliding block 23. The mounting end of the second drive cylinder 20 is located on the second worktable 17, and the output end of the second drive cylinder 20 drives the third threaded rod 21 to rotate via a belt. The third threaded rod 21 is mounted on the second worktable 17. The fourth sliding block 23 is located at the bottom of the lower inner support adjustment platform 18, and the fourth sliding block 23 is threaded onto the third threaded rod 21. The second drive cylinder 20 can drive the lower inner support adjustment platform 18 to perform radial adjustment. The upper part of the base 1 is provided with a second slide rail 24, and the lower inner support adjustment platform 18 is provided with a second slide rail 24 corresponding to the fifth sliding block 35.

[0028] Both the upper clamping assembly 8 and the lower clamping assembly 19 include a third drive cylinder 25, a cylinder base 26, a push block 27, a connecting rod 28, a rotating plate 29, and a clamping plate 34. The mounting end of the third cylinder is located above the cylinder base 26, which is mounted on the upper inner support adjusting platform 7 or the lower inner support adjusting platform 18. The output end of the third cylinder is connected to the push block 27. The push block 27 has a sixth sliding block 22 on both sides, and the cylinder base 26 has a sliding groove corresponding to the sixth sliding block. The cylinder base 26 has a rotating rod, and the rotating plate 29 has a first movable hole corresponding to the rotating rod. The rotating rod is mounted on the cylinder base 26. One end of the rotating plate 29 is equipped with a pulley, and the other end is equipped with a clamping plate 34. A connecting rod 28 is mounted on the cylinder base 26. The rotating plate 29 has a second movable hole through which the connecting rod 28 can pass, and the rotating plate 29 can slide along the second movable hole. Both sides of the cylinder base 26 are equipped with first springs 30, the ends of which are connected to the rotating plate 29. The rotating plate 29 is equipped with second springs 31, the ends of which are connected to the clamping plate 34.

[0029] The clamping plate 34 is provided with an adjustment hole 32, and the tooling bracket 2 is provided with a ladder 33.

[0030] A method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation is disclosed. The method utilizes the aforementioned profile deviation compensation device for near-circular cylindrical section friction stir welding. During welding, the diameter of the inner support conformal ring is adjusted to the inner diameter of the product, and locked using an upper and lower inner support conformal ring structure. The wall panels are designed to accommodate welding shrinkage, but the final cylindrical section diameter after welding is smaller than the product's inner diameter. The total circumference of the cylindrical section is calculated, and then the circumference is averaged across 3 or 6 wall panels to calculate the arc length L of a single wall panel. The formula for calculating 6 wall panels is: L= : The formula for calculating the number of wall panels is: L = .

[0031] Before welding the cylindrical section wall panels, first measure the circumference L1 of the bottom of the box, in mm; Allowance for shrinkage during friction stir welding, L2, in mm; L3 is the springback amount caused by machining allowance at both ends of the cylinder section, in mm. The assembly interference is L4, in mm.

[0032] The springback amount L3 caused by machining allowance at both ends of the cylinder section is 80-120mm, and the assembly interference amount L4 is 3-4mm.

[0033] Example 1: The new generation of manned launch vehicles is described in terms of its 12-20mm thick and 700-7000mm high cylindrical sections. Each section consists of 3 / 6 wall panels, which are welded together using a friction stir method.

[0034] Conformal fixture for cylindrical section wall panel assembly: One of the features of this fixture is that all 3 / 6 cylindrical section wall panels can be assembled and fixed simultaneously on the conformal fixture, and then rotated ±360° as a whole to achieve welding of the longitudinal seam of the cylindrical section.

[0035] Driven by the reducer of the drive motor 14, the upper inner support conforming ring device 3 can move up and down along the tooling bracket 2, taking into account the conforming of the welding of cylinder sections with different heights of 500-7000mm. The lower inner support conforming ring device 4 can move radially by ±20mm based on the inner diameter of the cylinder section Φ4992mm, and the upper inner support conforming ring can move radially by -100-20mm based on Φ4992mm. It is used for cylinder section wall panel assembly, roundness correction by tensioning force, and easy unloading. In particular, by adjusting the diameter of the upper and lower inner support conforming rings to be greater than Φ4992mm, it can ensure that the last wall panel can be put in. The upper and lower inner support conformal rings of the welding fixture have functions such as panel positioning, clamping, circumferential adjustment, and height adjustment. This allows for butt welding with adjacent panels even when the longitudinal seam of the cylindrical panel is not perpendicular. The conformal fixture for friction stir welding of the longitudinal seam of the cylindrical panel is as follows: Figure 1 As shown.

[0036] Cylindrical segment circumference control: The upper inner support conforming ring structure consists of 6 upper inner support conforming ring devices 3. A welding pad is left in the middle of each pair of segments for friction stir welding. One of the advantages of the inner support conforming ring is that the 6-segment structure can simultaneously handle the welding of 3-piece and 6-piece wall panels. This application allows for individual adjustment of the radius of each support segment to correct the wall panel shape based on the deviation of the wall panel profile. During welding, the diameter of the inner support conforming ring is adjusted to Φ4992mm and locked. The wall panel allows for welding shrinkage, but the final diameter of the cylinder section after welding is less than Φ4992mm. At this point, the wall panel and the inner support conforming ring are not completely flush with the mold after assembly on the conforming fixture. However, as the number of welds increases, the cylinder section wall panel and the inner support conforming ring become increasingly flush with the mold until the last weld is completed, at which point the cylinder section and the inner support conforming ring are tightly fitted, effectively providing the conforming function. The fit of the cylinder section wall panel after assembly and welding with the conforming fixture is as follows: Figure 2 and Figure 3 As shown.

[0037] Before welding the cylindrical section wall panels, first measure the circumference L1 of the transition ring at the bottom of the tank (if it is the middle section of the tank). Then, reserve the shrinkage amount L2 of friction stir welding, the springback amount L3 caused by machining the allowance at both ends of the cylindrical section, and the assembly interference amount L4. Calculate the total circumference of the cylindrical section. Then, average the circumference of the cylindrical section to 3 / 6 of the wall panels to calculate the arc length L of a single wall panel.

[0038] The formula for calculating 6 wall panels is: L= : The formula for calculating the number of wall panels is: L = .

[0039] L3 requires pre-addition or pre-subtraction based on the changes in the circumference of the front and rear ends of the cylinder section.

[0040] This application proposes an innovative set of high-precision synchronous assembly-welding flexible conformal tooling for compensating the surface profile of the cylindrical section wall panel, and proposes a cylindrical section circumference compensation control method that takes into account conformal preservation. After the cylindrical section is welded, the inner circumference and the inner support conformal ring are in an interference fit state, which achieves the purpose of cylindrical section roundness correction and meets the requirements of tank circumferential seam assembly and welding.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation, characterized in that: A device for near-circular cylindrical section friction stir welding using profile deviation compensation, the device includes a base, a tooling bracket, an upper inner support conforming ring structure, a lower inner support conforming ring structure, and a vertical drive structure; Several tooling brackets are equidistantly arranged on the base along the circumference, and the upper inner support molding ring structure and the lower inner support molding ring structure are respectively arranged on the upper and lower sides of the tooling brackets. The vertical drive structure is mounted on the tooling bracket, and the vertical drive structure can drive the upper inner support conforming ring structure to move up and down along the tooling bracket; The upper inner support molding ring structure includes several upper inner support molding ring devices, which are arranged circumferentially on the tooling bracket; The upper inner support shaping ring device includes a first worktable, an upper inner support adjusting table, and an upper clamping assembly; The first worktable is slidably mounted on the tooling bracket, and the upper inner support adjustment table slides along the first worktable via the first radial drive assembly; Several upper clamping components are arranged circumferentially on the upper inner support adjustment platform; The end face of the upper inner support adjustment platform is arc-shaped; The first radial drive assembly includes a first drive cylinder, a first threaded rod, and a first sliding block; The mounting end of the first drive cylinder is set on the first worktable, and the output end of the first drive cylinder is connected to the first threaded rod. The first sliding block is located at the bottom of the upper inner support adjustment platform, and the first sliding block is threaded onto the first threaded rod. The first driving cylinder can drive the upper inner support adjustment platform to perform radial adjustment. The upper part of the first workbench is provided with a second sliding block, and the upper inner support adjustment platform is provided with a first slide rail corresponding to the second sliding block; During welding, the diameter of the inner support ring is adjusted to the inner diameter of the product, and locked by the upper inner support ring structure and the lower inner support ring structure. The wall panel is reserved for welding shrinkage, but the final diameter of the cylinder section after welding is smaller than the inner diameter of the product. At this point, after the wall panel is assembled on the conformal fixture, it is not completely flush with the inner support conformal ring. However, as the number of welds increases, the wall panel and the inner support conformal ring become increasingly flush with the fixture until the last weld is completed and the wall panel and the inner support conformal ring are tightly flush. Calculate the total circumference of the wall panel, and then average the circumference of the wall panel to 3 or 6 wall panels to calculate the arc length L of a single wall panel. The formula for calculating 6 wall panels is: L= ; The formula for calculating the number of wall panels is: L = ; Before welding the cylindrical section wall panels, first measure the circumference L1 of the bottom of the box, in mm; Allowance for shrinkage during friction stir welding, L2, in mm; L3 is the springback amount caused by machining allowance at both ends of the cylinder section, in mm. The assembly interference is L4, in mm.

2. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 1, characterized in that: The vertical drive structure includes a drive motor, a second threaded rod, and a third sliding block; The drive motor is mounted on the tooling bracket, and the output end of the drive motor is connected to the second threaded rod. The upper inner support conformal ring structure is threadedly connected to the second threaded rod through the third sliding block.

3. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 1, characterized in that: The lower inner support molding ring structure includes several lower inner support molding ring devices, which are arranged circumferentially on the tooling bracket; The lower inner support shaping ring device includes a second worktable, a lower inner support adjusting table, and a lower clamping assembly; The second worktable is slidably mounted on the tooling bracket, and the lower inner support adjustment table slides along the second worktable via the second radial drive assembly; Several lower clamping components are arranged circumferentially on the lower inner support adjustment platform.

4. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 2, characterized in that: The second radial drive assembly includes a second drive cylinder, a third threaded rod, and a fourth sliding block; The mounting end of the second drive cylinder is set on the second workbench. The output end of the second drive cylinder drives the third threaded rod to rotate via a belt. The third threaded rod is mounted on the second workbench. The fourth sliding block is set at the bottom of the lower inner support adjustment platform. The fourth sliding block is threaded on the third threaded rod. The second drive cylinder can drive the lower inner support adjustment platform to perform radial adjustment. The upper part of the base is provided with a second slide rail, and the lower inner support adjustment platform is provided with a second slide rail corresponding to the fifth sliding block.

5. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 3, characterized in that: Both the upper clamping assembly and the lower clamping assembly include a third drive cylinder, a cylinder base, a push block, a connecting rod, a rotating plate, and a clamping plate; The mounting end of the third cylinder is located above the cylinder base, and the cylinder base is located on the upper inner support adjustment platform or the lower inner support adjustment platform. The output end of the third cylinder is connected to the push block. The push block has a sixth sliding block on both sides, and the cylinder base has a groove corresponding to the sixth sliding block; A rotating rod is provided on the cylinder base, and a first movable hole corresponding to the rotating rod is provided on the rotating plate. The rotating rod is mounted on the cylinder base. One end of the rotating plate is equipped with a pulley, and the other end is equipped with a clamping plate. The connecting rod is mounted on the cylinder base, and the rotating plate has a second movable hole through which the connecting rod can pass, and the rotating plate can slide along the second movable hole.

6. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 5, characterized in that: The cylinder base is equipped with a first spring on both sides, and the end of the first spring is connected to the rotating plate. A second spring is provided on the rotating plate, and the end of the second spring is connected to the clamping plate.

7. The method for preparing near-circular cylindrical sections by friction stir welding based on profile deviation compensation according to claim 5, characterized in that: The clamping plate has adjustment holes, and the tooling bracket has a ladder.

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