Angle-adjustable conical cylinder ring joint friction stir welding device and welding method

Abstract

The application discloses an angle-adjustable conical cylinder ring joint friction stir welding device and a welding method, and belongs to the technical field of friction stir welding. The device comprises a base and a workpiece clamping mechanism. The workpiece clamping mechanism comprises a support frame. One end of the support frame is connected with the base through a head frame, a rotating shaft and a rotating assembly. The middle part of the support frame is movably connected with the base through a lifting support. A tail frame is movably arranged on the support frame. The tail frame can move under the drive of a translation driving assembly. The tail frame is provided with a tail frame locking assembly. After the device is installed and fixed once, it can be used for welding a cylindrical ring joint and a conical cylinder ring joint. The device does not need to be hoisted and disassembled multiple times, and the safety hidden danger is eliminated. Meanwhile, the ring joint welding efficiency of the product can be greatly improved. The inclination angle of the workpiece relative to the horizontal plane can be continuously adjusted through the lifting support, so that the device is suitable for welding a cylinder and a conical cylinder within a certain top angle range, and has high practicability.

Description

Technical Field

[0001] This invention relates to an angle-adjustable conical cylinder circumferential seam friction stir welding device and welding method, belonging to the field of friction stir welding technology. Background Technology

[0002] Friction stir welding (FSW) is an advanced solid-state joining technology that has seen rapid development in recent years. It boasts advantages such as high efficiency and low energy consumption, low welding temperature, low residual stress, minimal workpiece deformation, and low environmental requirements, gaining widespread recognition and attention from various industries including aerospace. The sophistication of welding equipment, to a certain extent, reflects a nation's industrial development level, and welding devices are increasingly moving towards automation and intelligence. Existing FSW equipment typically uses clamping claws to hold the workpiece, making it difficult to adjust the welding orientation and resulting in low welding efficiency. Circumferential welding devices are only suitable for welding cylindrical bodies and lack orientation or angle adjustment capabilities, thus limiting their ability to weld circumferential seams on conical bodies.

[0003] Chinese patent document CN211588901U discloses a conical circumferential friction stir welding device for aluminum alloy targets. This device allows for greater flexibility in the angle between the welding device and the horizontal plane through bases of varying angles, reducing the welding difficulty of conical targets and improving welding quality. In practical applications, side plates of different angles are assembled to match the welding of targets with different tapers.

[0004] However, this conical circumferential friction stir welding device has the following shortcomings:

[0005] 1. Before welding targets with different tapers, it is necessary to replace the side plates with matching angles. Each time the side plates are replaced, the fixed base needs to be assembled. Before disassembling and assembling the fixed base, the entire device needs to be lifted up. The assembly and disassembly of the device is time-consuming and poses significant safety hazards, resulting in a substantial reduction in product welding efficiency.

[0006] 2. The angle between the welding device and the horizontal plane cannot be continuously adjusted, resulting in poor practicality.

[0007] 3. The downward pressure cylinder drives the moving support and the pressure plate to move through the linkage mechanism. The pressure plate and the tensioning sleeve cooperate to clamp the conical target and the flange. It is a flexible clamping method. Under the action of the stirring head, the moving support will retract, which will lead to a decrease in the welding quality of the product.

[0008] 4. If the base is not effectively secured, the device will vibrate significantly during the welding process, or even shift, resulting in a decline in the welding quality of the product. Summary of the Invention

[0009] To solve the above-mentioned technical problems, the present invention provides an angle-adjustable conical cylinder circumferential seam friction stir welding device and welding method.

[0010] This invention is achieved through the following technical solution:

[0011] An angle-adjustable conical circumferential friction stir welding device includes a base and a workpiece clamping mechanism. The workpiece clamping mechanism includes a support frame. One end of the support frame is connected to the base via a head frame, a rotating shaft, and a rotary assembly. The middle part of the support frame is movably connected to the base via a lifting bracket. A tail frame is movably mounted on the support frame. The tail frame can be moved under the drive of a translation drive assembly. A tail frame locking assembly is provided on the tail frame.

[0012] The front and rear sides of the head frame are connected to the base via a rotating shaft and a slewing assembly, respectively, and the front and rear sides of the middle part of the support frame are movably connected to the base via a lifting bracket.

[0013] The rotating shaft is fixed on the head frame. The rotating shafts on the front and rear sides of the head frame are coaxial. The axis of the rotating shaft is perpendicular to and intersects the axis of the head frame and the axis of the tail frame. The rotating assembly includes a rotating bracket and a bearing with a seat on the rotating bracket.

[0014] The rotating bracket is equipped with an angle plate with angle markings. The rotating shaft passes through the angle plate, and an angle pointer is fixed at one end of the rotating shaft.

[0015] The lifting support includes a hollow swing block and a lifting block. One end of the hollow swing block is rotatably connected to the base via a pin, and the other end is provided with a top plate. A lifting drive motor is provided on the top plate. A lead screw is movably provided inside the hollow swing block. The lead screw and the lifting drive motor are connected by gear transmission or chain transmission. The lifting block is threadedly connected to the lead screw. Two round shafts are coaxially provided on the lifting block. The two round shafts are connected to the support frame via a connecting block. An elongation hole is provided on the hollow swing block along the length direction at a position corresponding to the round shaft.

[0016] When the connecting block contacts the plane defined by the bottom surface of the base, the support frame is in a horizontal position.

[0017] The support frame has two guide rails arranged side by side, and the tail frame is slidably connected to the two guide rails. The translation drive assembly includes a rack on the support frame and a reduction motor on the tail frame. A gear is mounted on the output shaft of the reduction motor, and the gear meshes with the rack.

[0018] The tailstock locking assembly includes a cylinder and a pressure plate. The pressure plate passes through the tailstock and is slidably connected to it. The pressure plate is provided with a friction plate and a wedge-shaped hole. The cylinder is located on the tailstock, and a wedge-shaped block is provided on the piston rod of the cylinder. The wedge-shaped block is inserted into the wedge-shaped hole.

[0019] A welding method for an angle-adjustable conical cylinder circumferential seam friction stir welding device includes the following main steps:

[0020] Step 1: Use the translation drive assembly to move the tailstock away from the headstock, ensuring sufficient installation space between the headstock and tailstock.

[0021] Step 2: Install the workpiece onto the mandrel with internal support, and adjust the internal support to fix the workpiece. Use a crane or overhead crane to hoist the workpiece, mandrel, and internal support as a whole between the headstock and tailstock. Use the translation drive assembly to move the tailstock closer to the headstock. The tailstock cooperates with the headstock to clamp and fix the workpiece, ensuring that the workpiece is coaxial with the headstock and tailstock.

[0022] Step 3: Secure the tailstock using the tailstock locking assembly.

[0023] Step 4: Adjust the angle of the workpiece clamping mechanism using the lifting bracket according to the workpiece type to ensure that the axis of the stirring head is within the circumferential seam section.

[0024] Step 5: Using the headstock to rotate the workpiece, insert the stirring head into the weld seam and begin welding.

[0025] Step 6: After welding is completed, the tailstock locking assembly releases the tailstock, and the translation drive assembly drives the tailstock to move away from the headstock. At the same time, the workpiece, mandrel, and inner support are removed as a whole. Then, the inner support is manually released, and the workpiece is removed.

[0026] In step 2, if the workpiece is a conical cylinder, the larger end of the conical cylinder is close to the headstock and the smaller end is close to the tailstock. In step 4, if the workpiece is a cylindrical cylinder, the connecting block is driven downward by the lifting drive motor until its lower end contacts the ground. At this time, the angle pointer points to the zero mark on the angle plate. If the workpiece is a conical cylinder, the connecting block is driven upward or downward by the lifting drive motor until the angle value pointed to by the angle pointer on the angle plate is equal to 1 / 2 of the apex angle of the conical cylinder.

[0027] The beneficial effects of this invention are as follows:

[0028] 1. Once installed and fixed, the device can be used to weld cylindrical and conical circumferential seams without the need for multiple hoisting and disassembly, eliminating safety hazards and significantly improving the efficiency of circumferential seam welding.

[0029] 2. The tilt angle of the workpiece relative to the horizontal plane can be continuously adjusted by the lifting bracket, making the device suitable for welding cylindrical tubes and conical tubes within a certain apex angle range, and highly practical.

[0030] 3. By referring to the relative position of the angle pointer and the angle plate, the inclined circumferential seam of the conical cylinder can be adjusted to be horizontal through the lifting bracket. This solves the defect that the swing angle of the stirring head is limited and cannot weld circumferential seams with large inclination angles, and helps to ensure the welding quality of the conical circumferential seam.

[0031] 4. After the tailstock is moved into place, it is locked and fixed by the tailstock locking assembly to prevent the tailstock from retracting. This ensures that the tailstock and headstock can stably and reliably clamp the workpiece, which helps to improve the quality of the circumferential weld.

[0032] 5. The entire device is fixedly installed on the ground via a base, which avoids large-scale vibrations during the welding process and helps improve the quality of the circumferential weld. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention;

[0034] Figure 2 This is a schematic diagram of the assembly structure of the base, rotating assembly, escalator, and lifting support of the present invention;

[0035] Figure 3 This is a schematic diagram of the assembly structure of the head frame, tail frame, and support frame of the present invention;

[0036] Figure 4 This is a cross-sectional view of the head frame, tail frame, and support frame of the present invention;

[0037] Figure 5 This is a schematic diagram of the assembly structure of the guide rail, tailstock, and tailstock locking assembly of the present invention;

[0038] Figure 6 This is a schematic diagram of the assembly structure of the rotary support, bearing with seat, angle plate and angle pointer of the present invention.

[0039] In the diagram: 1-Base, 2-Headframe, 3-Tailframe, 4-Slewing bracket, 5-Lifting bracket, 6-Ladder, 7-Headframe body, 8-Rear protective cover, 9-Crossed cylindrical roller bearing A, 10-Helical gear, 11-Planetary reducer, 12-Slewing drive motor, 13-Headframe slewing connecting plate, 14-Rack, 15-Guide rail, 16-Tailframe body, 17-Tailframe slewing connecting plate, 18-Gear motor, 19-Tailframe locking assembly, 20-Cylinder, 21-Friction plate, 22-Wedge block, 23-Pressure plate, 24-Lifting drive motor, 25-Angle plate, 26-Angle pointer. Detailed Implementation

[0040] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0041] like Figures 1 to 6As shown, the present invention discloses an angle-adjustable conical circumferential friction stir welding device, comprising a base 1 and a workpiece clamping mechanism. The workpiece clamping mechanism includes a support frame, one end of which is connected to the base 1 via a head frame 2, a rotating shaft, and a rotary assembly. The middle part of the support frame is rotatably connected to the base 1 via a lifting bracket 5. A tail frame 3 is movably mounted on the support frame, and the tail frame 3 can move under the drive of a translational drive assembly. A tail frame locking assembly 19 is mounted on the tail frame 3. In use, the base 1 has a U-shaped structure and is fixedly installed on the ground. Both ends of the base 1 are welded with double ear plates for easy rotatable connection to a hollow swing block via pins. The support frame also has a U-shaped structure, with reinforcing plates welded to its inner side. The support frame is located inside the base 1, and the head frame 2 is fixedly installed at the U-shaped opening end of the support frame. The head frame 2 and the tail frame 3 are coaxially mounted.

[0042] The front and rear sides of the head frame 2 are connected to the base 1 via a rotating shaft and a slewing assembly, respectively, and the front and rear sides of the middle part of the support frame are rotatably connected to the base 1 via a lifting bracket 5.

[0043] The rotating shaft is fixedly welded to the headstock 2. The rotating shafts on the front and rear sides of the headstock 2 are coaxial. The axis of the rotating shaft is perpendicular to and intersects the axis of the headstock 2 and the axis of the tailstock 3. The rotating assembly includes a rotating bracket 4 and a seated bearing mounted on the rotating bracket 4. The axis of the rotating shaft is perpendicular to and intersects the axis of the headstock 2 and the axis of the tailstock 3. When the workpiece is coaxial with the headstock 2 and the tailstock 3, the axis of the workpiece will rotate around the rotating shaft by the same number of degrees as the rotation of the rotating shaft.

[0044] An angle plate 25 is mounted on the rotating bracket 4. Angle lines are machined on the angle plate 25. A rotating shaft passes through the angle plate 25, and an angle pointer 26 is fixedly mounted on one end of the rotating shaft. By referring to the angle pointer 26 and the angle plate 25, the support frame and the workpiece can be quickly and accurately rotated to the required angle by the lifting bracket 5.

[0045] The lifting support 5 includes a hollow swing block and a lifting block. One end of the hollow swing block is rotatably connected to the base 1 via a pin, and the other end is fitted with a top plate. A lifting drive motor 24 is mounted on the top plate. A lead screw is movably installed inside the hollow swing block, and the lead screw and the lifting drive motor 24 are connected by gear or chain transmission. The lifting block is threadedly connected to the lead screw. Two round shafts are coaxially welded on the lifting block, and the two round shafts are connected to the support frame via a connecting block. An elongated hole is machined along the length direction at a position corresponding to the round shafts on the hollow swing block. The lifting drive motor 24 drives the lead screw to rotate via gear or chain transmission. Because the lifting block is threadedly connected to the lead screw, the lifting block moves along the length direction of the lead screw, thereby driving the support frame, head frame 2, and tail frame 3 to rotate around the axis through the round shafts and connecting block, achieving the purpose of adjusting the workpiece angle.

[0046] When the connecting block contacts the plane (i.e., the ground) defined by the bottom surface of the base 1, the support frame is in a horizontal position. When the connecting block contacts the ground, the angle pointer 26 points to the zero mark on the angle plate 25, which helps to increase the speed at which the support frame is adjusted to a horizontal position.

[0047] Two guide rails 15 are mounted side by side on the support frame. The tailstock 3 is slidably connected to the two guide rails 15. The translation drive assembly includes a rack 14 mounted on the support frame and a geared motor 18 mounted on the tailstock 3. A gear is mounted on the output shaft of the geared motor 18, and the gear meshes with the rack 14. The geared motor 18 drives the tailstock 3 to move closer to or further away from the headstock 2 through the gear and rack mechanism.

[0048] The tailstock locking assembly 19 includes a cylinder 20 and a pressure plate 23. The pressure plate 23 passes through the tailstock 3 and is slidably connected to it. A friction plate 21 is mounted on the pressure plate 23, and a wedge-shaped hole is machined on the pressure plate 23. The cylinder 20 is mounted on the tailstock 3, and a wedge-shaped block 22 is mounted on the piston rod of the cylinder 20. The wedge-shaped block 22 is inserted into the wedge-shaped hole. Figure 5 As shown, the wedge block 22 is slidably connected to the wedge hole. When the piston rod of the cylinder 20 extends, it pushes the wedge block 22 to move to the left. At the same time, the wedge block 22 pulls the pressure plate 23 upward, so that the friction plate 21 presses on the guide rail 15, thereby keeping the tailstock 3 fixed. When the piston rod of the cylinder 20 retracts, it pulls the wedge block 22 to move to the right. The pressure plate 23 moves downward under its own weight, and the friction plate 21 separates from the guide rail 15.

[0049] A welding method for an angle-adjustable conical cylinder circumferential seam friction stir welding device includes the following main steps:

[0050] Step 1: Drive the tailstock 3 away from the headstock 2 using the translation drive assembly to ensure sufficient installation space between the headstock 2 and the tailstock 3.

[0051] Step 2: Install the workpiece onto the mandrel with inner support, and adjust the inner support to fix the workpiece. Use a crane or overhead crane to hoist the workpiece, mandrel and inner support together between the head frame 2 and the tail frame 3. Use the translation drive assembly to drive the tail frame 3 to move closer to the head frame 2. The tail frame 3 cooperates with the head frame 2 to clamp and fix the workpiece, and ensure that the workpiece is coaxial with the head frame 2 and the tail frame 3.

[0052] Step 3: Secure the tailstock 3 by locking the tailstock locking assembly 19.

[0053] Step 4: According to the type of workpiece, adjust the angle of the workpiece clamping mechanism through the lifting bracket 5 to ensure that the axis of the stirring head is located within the circumferential seam section.

[0054] Step 5: Drive the workpiece to rotate using headstock 2, insert the stirring head into the weld seam, and begin welding.

[0055] Step 6: After welding is completed, the tailstock locking assembly 19 releases the tailstock 3, and the translation drive assembly drives the tailstock 3 to move away from the headstock 2. At the same time, the workpiece, mandrel and inner support are removed as a whole. Then, the inner support is manually released and the workpiece is removed.

[0056] In step 2, if the workpiece is a conical cylinder, the larger end of the conical cylinder is close to the headstock 2 and the smaller end is close to the tailstock 3. In step 4, if the workpiece is a cylindrical cylinder, the connecting block is driven downward by the lifting drive motor 24 until its lower end contacts the ground. At this time, the angle pointer 26 points to the zero mark on the angle plate 25. If the workpiece is a conical cylinder, the connecting block is driven upward or downward by the lifting drive motor 24 until the angle value pointed to by the angle pointer 26 on the angle plate 25 is equal to 1 / 2 of the apex angle of the conical cylinder.

[0057] Specifically, a ladder 6 is welded to the outside of the rotating support 4 on the base 1.

[0058] The headframe 2 includes a headframe body 7, a planetary reducer 11, a rotary drive motor 12, a crossed cylindrical roller bearing A9, and a headframe rotary connecting plate 13. The planetary reducer 11 is mounted on the headframe body 7. The rotary drive motor 12 is connected to the input end of the planetary reducer 11. A helical gear 10 is mounted on the output shaft of the planetary reducer 11. The crossed cylindrical roller bearing A9 is coaxial with the headframe 2. The inner ring of the crossed cylindrical roller bearing A9 is fixedly connected to the headframe body 7, and the outer ring is machined with helical teeth. The outer ring of the crossed cylindrical roller bearing A9 meshes with the helical gear 10. The headframe rotary connecting plate 13 is coaxially fixedly mounted on the outer ring of the crossed cylindrical roller bearing A9. A secondary transition fixture is coaxially mounted on the headframe rotary connecting plate 13. In addition, a rear protective cover 8 is installed on one side of the headframe body 7.

[0059] The tailstock 3 includes a tailstock body 16 and a crossed cylindrical roller bearing B. The crossed cylindrical roller bearing B is coaxial with the tailstock 3. The inner ring of the crossed cylindrical roller bearing B is fixedly connected to the tailstock body 16, and the outer ring is coaxially fixedly mounted on the tailstock rotary connecting plate 17. A secondary transition fixture is coaxially mounted on the tailstock rotary connecting plate 17. The two ends of the workpiece are positioned by the headstock rotary connecting plate 13 and the secondary transition fixture on the tailstock rotary connecting plate 17, ensuring the coaxiality of the headstock rotary connecting plate 13, the workpiece, and the tailstock rotary connecting plate 17.

[0060] The adjustable-angle conical cylinder circumferential seam friction stir welding device of the present invention works on the following principle:

[0061] The workpiece is installed on the mandrel with internal support, and the internal support is adjusted to fix the workpiece. The workpiece, mandrel and internal support are hoisted as a whole between the head frame 2 and the tail frame 3 by a crane or gantry crane. The two ends of the workpiece are positioned by the secondary transfer tooling on the head frame rotary connecting plate 13 and the tail frame rotary connecting plate 17 to ensure the coaxiality of the head frame rotary connecting plate 13, the workpiece and the tail frame rotary connecting plate 17.

[0062] The geared motor 18 drives the tailstock 3 to move closer to the headstock 2 through the gear and rack mechanism. The tailstock 3 cooperates with the headstock 2 to clamp and fix the workpiece. The cylinder 20 is activated, and its piston rod extends to push the wedge block 22 to move to the left. At the same time, the wedge block 22 pulls the pressure plate 23 upward, so that the friction plate 21 presses on the guide rail 15, thereby keeping the tailstock 3 fixed.

[0063] Depending on the type of workpiece (i.e., the type of circumferential seam), the connecting block is moved up or down by the lifting drive motor 24 to adjust the workpiece to the required angle.

[0064] The rotary drive motor 12 drives the helical gear 10 to rotate through the planetary reducer 11, and then drives the head frame rotary connecting plate 13, the workpiece and the tail frame rotary connecting plate 17 to rotate through the gear transmission. The stirring head is then inserted into the weld seam, and the circumferential weld work can begin.

[0065] The adjustable-angle conical cylinder circumferential seam friction stir welding device and welding method provided by this invention have the following advantages:

[0066] 1. Once installed and fixed, the device can be used to weld cylindrical and conical circumferential seams without the need for multiple hoisting and disassembly, eliminating safety hazards and significantly improving the efficiency of circumferential seam welding.

[0067] 2. The tilt angle of the workpiece relative to the horizontal plane can be continuously adjusted by the lifting bracket 5, making the device suitable for welding cylindrical tubes and conical tubes within a certain apex angle range, and highly practical.

[0068] 3. By referring to the relative positions of the angle pointer 26 and the angle plate 25, the inclined circumferential seam of the conical cylinder can be adjusted to be horizontal through the lifting bracket 5. This solves the defect that the swing angle of the stirring head is limited and cannot weld circumferential seams with large inclination angles, and helps to ensure the welding quality of the conical circumferential seam.

[0069] 4. After the tailstock 3 is moved into place, the tailstock 3 is locked and fixed by the tailstock locking assembly 19 to prevent the tailstock 3 from retracting. This allows the tailstock 3 and the headstock 2 to stably and reliably clamp the workpiece, which helps to improve the quality of the circumferential weld of the product.

[0070] 5. The entire device is fixedly installed on the ground via base 1, which avoids large-scale vibrations during the welding process and helps improve the quality of the circumferential weld.

Claims

1. An angle-adjustable conical cylinder circumferential seam friction stir welding device, characterized in that: It includes a base (1) and a workpiece clamping mechanism. The workpiece clamping mechanism includes a support frame. One end of the support frame is connected to the base (1) through a head frame (2), a rotating shaft, and a rotary assembly. The middle part of the support frame is movably connected to the base (1) through a lifting bracket (5). A tail frame (3) is movably provided on the support frame. The tail frame (3) can move under the drive of the translation drive assembly. A tail frame locking assembly (19) is provided on the tail frame (3). The base (1) is a U-shaped structure and is fixedly installed on the ground. The support frame is a U-shaped structure with a reinforcing plate welded to the inside of the support frame. The support frame is located inside the base (1), and the head frame (2) is fixedly installed at the U-shaped opening end of the support frame. The front and rear sides of the head frame (2) are connected to the base (1) via a rotating shaft and a slewing assembly, respectively; the front and rear sides of the middle part of the support frame are movably connected to the base (1) via a lifting bracket (5); The rotating shaft is fixed on the head frame (2). The rotating shafts on the front and rear sides of the head frame (2) are coaxial. The axis of the rotating shaft is perpendicular to and intersects the axis of the head frame (2) and the axis of the tail frame (3). The rotating assembly includes a rotating bracket (4) and a bearing with a seat on the rotating bracket (4). An angle plate (25) is provided on the rotating bracket (4), and angle markings are provided on the angle plate (25). The rotating shaft passes through the angle plate (25), and an angle pointer (26) is fixedly provided at one end of the rotating shaft. The lifting bracket (5) includes a hollow swing block and a lifting block. One end of the hollow swing block is rotatably connected to the base (1) through a pin, and the other end is provided with a top plate. The top plate is provided with a lifting drive motor (24). A lead screw is movably provided inside the hollow swing block. The lead screw and the lifting drive motor (24) are driven by gear or chain. The lifting block is threadedly connected to the lead screw. Two round shafts are coaxially provided on the lifting block. The two round shafts are connected to the support frame through a connecting block. An elongation hole is provided on the hollow swing block along the length direction at a position corresponding to the round shaft. When the connecting block contacts the plane defined by the bottom surface of the base (1), the support frame is in a horizontal position; The tailstock (3) includes a tailstock body (16) and a cross cylindrical roller bearing B. The cross cylindrical roller bearing B is coaxial with the tailstock (3). The inner ring of the cross cylindrical roller bearing B is fixedly connected to the tailstock body (16). A tailstock rotary connecting plate (17) is coaxially fixedly installed on the outer ring. A secondary transfer tool is coaxially installed on the tailstock rotary connecting plate (17).

2. The adjustable-angle conical cylinder circumferential friction stir welding device as described in claim 1, characterized in that: The support frame has two guide rails (15) arranged side by side, and the tail frame (3) is slidably connected to the two guide rails (15); the translation drive assembly includes a rack (14) on the support frame and a geared motor (18) on the tail frame (3). The output shaft of the geared motor (18) is fitted with a gear, which meshes with the rack (14).

3. The angle-adjustable conical cylinder circumferential friction stir welding device as described in claim 1, characterized in that: The tailstock locking assembly (19) includes a cylinder (20) and a pressure plate (23). The pressure plate (23) passes through the tailstock (3) and is slidably connected to the tailstock (3). The pressure plate (23) is provided with a friction plate (21) and a wedge-shaped hole. The cylinder (20) is located on the tailstock (3). The piston rod of the cylinder (20) is provided with a wedge-shaped block (22), which is inserted into the wedge-shaped hole.

4. A welding method for an angle-adjustable conical cylinder circumferential seam friction stir welding apparatus as described in any one of claims 1 to 3, characterized in that: Includes the following steps: Step 1: Drive the tailstock (3) away from the headstock (2) by the translation drive assembly to ensure that there is sufficient installation space between the headstock (2) and the tailstock (3); Step 2: Install the workpiece onto the mandrel with inner support, and adjust the inner support to fix the workpiece. Use a crane or overhead crane to hoist the workpiece, mandrel and inner support together between the head frame (2) and the tail frame (3). Drive the tail frame (3) to move closer to the head frame (2) through the translation drive assembly. The tail frame (3) cooperates with the head frame (2) to clamp and fix the workpiece, and ensure that the workpiece is coaxial with the head frame (2) and the tail frame (3). Step 3: Secure the tailstock (3) by using the tailstock locking assembly (19); Step 4: According to the type of workpiece, adjust the angle of the workpiece clamping mechanism by using the lifting bracket (5) to ensure that the axis of the stirring head is located within the circumferential seam section; Step 5: Drive the workpiece to rotate by the headstock (2), insert the stirring head into the weld, and start the welding work; Step 6: After welding is completed, the tailstock locking assembly (19) releases the tailstock (3), and the translation drive assembly drives the tailstock (3) to move away from the headstock (2). At the same time, the workpiece, mandrel and inner support are removed as a whole. Then, the inner support is manually released and the workpiece is removed.

5. The welding method of the angle-adjustable conical cylinder circumferential seam friction stir welding device as described in claim 4, characterized in that: In step 2, the large end of the conical tube is close to the head frame (2), and the small end is close to the tail frame (3).

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