Rotary friction welding general assembly and welding method for three-section type pipeline

Abstract

The invention discloses a three-section type pipeline rotary friction welding final assembly and a welding method, the three-section type pipeline rotary friction welding final assembly is used for welding a short section pipe between two end pipes, the three-section type pipeline rotary friction welding final assembly comprises a transmission ring, a driving mechanism, two shroud rings and a plurality of pull rods, the transmission ring is coaxially installed on the short section pipe, the two shroud rings are in one-to-one correspondence with the two end pipes, and the pull rods are connected with the driving mechanism. Each hoop is hooped on the corresponding end pipe, the two hoops are connected through a plurality of pull rods so as to coaxially clamp the short section pipe between the two end pipes, the driving mechanism is arranged beside the transmission ring and is in transmission connection with the transmission ring, the driving mechanism is used for driving the transmission ring to drive the short section pipe to rotate so as to carry out friction welding, and the friction welding device is simple in structure, convenient to disassemble and assemble and high in practicability. Meanwhile, the welding effect is good.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline welding, and in particular relates to a three-section pipeline rotary friction welding assembly and a welding method. Background Art

[0002] Coiled tubing is a high-strength, high-plasticity HFW welded steel pipe. The length of a single pipe can reach several thousand meters. It is continuously produced on the production line and wound on a reel at a certain length for use. Coiled tubing is mainly used for well repair, logging, drilling, completion and other operations. Coiled tubing operations have many advantages that ordinary tubing cannot match, such as small footprint, high efficiency, easy disassembly and assembly, and protection of oil layers. However, during the process of running down and pulling out of the well, the pipe body will be subjected to repeated bending, which will cause low-cycle bending fatigue. In addition, during the operation, fatigue cracking often occurs due to medium corrosion and various loads under the action of internal and external pressures and deadweight. After cracking, it needs to be repaired. The usual repair method is to cut off the damaged pipe section and then repair it by butt welding. However, the strength of the welded joints is often difficult to meet the requirements, resulting in reduced pressure bearing performance, and then failure again, causing huge economic losses.

[0003] In order to repair the coiled tubing, the document number is CN116412311A "A non-welding repair device for coiled tubing and its use method", which uses a connector made of shape memory alloy to achieve a shape memory alloy thread connection of the broken coiled tubing through temperature rise and fall. This method has high efficiency, but the similar connector structure will affect the bending of the coiled tubing, which may cause the coiled tubing to be unable to be rolled onto the drum, and may also affect the pressure bearing performance and sealing of the coiled tubing. The document number is CN108252672A "A coiled tubing incision recovery device", which uses special equipment to The incision of the letter "Font" is repaired to a circular incision, so that the liquid or gas output is restored to normal, and the regulations on exhaust gas emissions from oil wellheads are solved to avoid personal injury and environmental pollution. The device only provides an incision recovery device, and does not provide an incision connection method. The document number is CN113172311A "A welding method for CT80 steel grade continuous oil pipe butt welding", which mainly reduces the strain concentration of the heat affected zone of the continuous oil pipe weld joint in the low-cycle bending fatigue deformation process by arranging reinforcing welds on both sides of the butt ring weld, thereby increasing the fatigue cycle number. Summary of the invention

[0004] In order to solve the above technical problems, the purpose of the present invention is to provide a three-section pipeline rotation friction welding assembly with a simple structure and easy assembly. During welding, the end pipes at both ends can remain stationary, while only the short section pipe in the middle rotates for welding.

[0005] In order to achieve the above-mentioned purpose, the technical solution of the present invention is as follows: a three-section pipe rotation friction welding assembly, which is used to weld a short section pipe between two end pipes, including a transmission ring, a driving mechanism, two hoops and multiple pull rods, the transmission ring is coaxially installed on the short section pipe, the two hoops correspond to the two end pipes one by one, each of the hoops is clamped on the corresponding end pipe, and the two hoops are connected by multiple pull rods to coaxially clamp the short section pipe between the two end pipes, the driving mechanism is placed next to the transmission ring and is connected to the transmission ring, and the driving mechanism is used to drive the transmission ring to drive the short section pipe to rotate for friction welding.

[0006] The beneficial effect of the above technical solution is that the transmission ring can be pre-installed coaxially on the outer wall of the short section tube, and the two hoops can be connected to the two end tubes, and then the two hoops can be connected by multiple pull rods, so that the two end tubes can clamp the short section tube coaxially. When the driving mechanism is connected to the transmission ring, the driving mechanism can drive the transmission ring to drive the short section tube to rotate. At this time, the short section tube and the end tube melt due to friction and finally achieve welding, and the welding effect is good.

[0007] The hoop in the above technical solution includes two semicircular ring clamps, the two ends of the two clamps are detachably connected and clamp the end tube, and each clamp is connected to the corresponding end of at least one of the pull rods.

[0008] The beneficial effect of the above technical solution is that the two clamping plates can be easily assembled and disassembled on the end pipe.

[0009] In the above technical solution, both ends of the two clamps are provided with first connecting ears, each of the first connecting ears is provided with a first connecting hole, and the first connecting holes on the two first connecting ears close to each other are aligned with each other, and a first bolt is inserted, and the threaded end of each first bolt is threadedly connected to at least one first nut to connect the two first connecting ears close to each other.

[0010] The beneficial effect of the above technical solution is that: its structure is simple, and the two clamps are clamped on the end pipe in the form of pipe clamps.

[0011] In the above technical solution, both ends of the pull rod are provided with threads, and the clamp is provided with a second connecting hole passing through it. The second connecting holes on the two hoops are aligned with each other and pass through one pull rod, and both ends of each pull rod are threadedly connected with at least one second nut.

[0012] The beneficial effect of the above technical solution is that its structure is simple, and after the two clamping plates are clamped on the end pipe, their edges are similar to a flange structure, which facilitates the installation of the pull rods on the two hoop rings.

[0013] The transmission ring in the above technical solution is a gear ring, and the driving mechanism has three gears circumferentially spaced around the transmission ring, and the three gears are all engaged with the transmission ring, one of the gears is a driving gear, and the remaining two gears are driven gears, and the driving gear inputs power to drive the transmission ring to rotate.

[0014] The beneficial effect of the above technical solution is that the transmission ring is set as a gear ring, which makes it more convenient to connect with the drive mechanism, and the drive mechanism is provided with three gears, so that the driving gear among the three gears can drive the transmission ring to rotate, and the three gears jointly clamp the transmission ring for circumferential limitation, so as to avoid the driving gear causing uneven circumferential force on the short section pipe when driving the transmission ring to rotate, which can cause it to be misaligned with the two end pipes.

[0015] The transmission ring in the above technical solution includes two semicircular gear plates, and the ends of the two gear plates close to each other are detachably connected and clamped together on the short tube.

[0016] The beneficial effect of the above technical solution is that its structure is simple, and the outer arc edge of the gear plate is provided with tooth patterns, and the outer edges of the two gear plates form a full-circle gear structure on the short-section pipe.

[0017] In the above technical solution, second connecting ears are provided at both ends of the gear plate, and each of the second connecting ears is provided with a third connecting hole. The third connecting holes on two second connecting ears close to each other are aligned with each other, and a second bolt is inserted, and at least one third nut is threadedly connected to each second bolt to connect the two second connecting ears close to each other.

[0018] The beneficial effects of the above technical solution are: its structure is simple, and the two gear plates are clamped on the short-joint pipe in a manner similar to a pipe clamp.

[0019] The driving mechanism in the above technical solution also includes a driving motor and two arc-shaped seats, at least four pull rods are provided, and the multiple pull rods are evenly distributed in the circumferential direction, at least one gear is installed on the inner side of the arc of each arc-shaped seat, and at least two pull rods are penetrated through the edge of each arc-shaped seat, the driving motor is installed on any one of the arc-shaped seats, and its driving end is connected to any one of the gears.

[0020] The beneficial effect of the above technical solution is that its structure is simple, so that the arc-shaped seat pull rod is used as a supporting carrier, and the drive motor and three gears are supported by two arc-shaped seats, which is easy to install and occupies little space.

[0021] A second object of the present invention is to provide a three-section pipeline rotation friction welding method which has a simple structure and can weld a short tube between two end tubes.

[0022] In order to achieve the above object, the technical solution of the present invention is as follows: a three-section pipeline rotation friction welding method, which comprises the following steps:

[0023] Step 1: Grinding and rounding the ends of the two end pipes to be welded;

[0024] Step 2: Assemble the short tube, two end tubes and the three-section pipeline rotation friction welding assembly as described above;

[0025] Step 3: starting the driving mechanism, and driving the short tube to rotate coaxially relative to the two end tubes until the short tube and the two end tubes are coaxially welded, and then removing the three-section pipeline rotation friction welding assembly from the short tube and the end tubes;

[0026] Step 4: Use an angle grinder to grind the weld between the short section pipe and the end pipe and correct it to a smooth state.

[0027] The beneficial effects of the above technical solution are: high welding efficiency and convenient assembly.

[0028] In the above technical solution, the clamping pressure of the end pipe on the short tube is 20-80MPa, and the rotation speed of the short tube driven by the driving mechanism is 30-100r / s.

[0029] The beneficial effect of the above technical solution is that the friction force of the short tube and the end tube during rotation and friction is large, so the melting is rapid. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic diagram of the butt joint between the short tube and two end tubes in Example 1 of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure of the three-section pipeline rotary friction welding assembly after assembly according to Example 1 of the present invention;

[0032] Figure 3 It is a schematic structural diagram of the three-section pipeline rotary friction welding assembly described in Example 1 of the present invention except for the driving mechanism;

[0033] Figure 4 This is a schematic diagram of the structure of the hoop ring in Embodiment 1 of the present invention being tightly clamped on the end pipe;

[0034] Figure 5 This is a schematic diagram of the structure of the splint described in Example 1 of the present invention;

[0035] Figure 6 Schematic diagram of the structure of the transmission ring in Embodiment 1 of the present invention;

[0036] Figure 7 It is a schematic diagram of the structure in which the driving mechanism described in Example 1 of the present invention is installed on the pull rod.

[0037] In the figure: 1. transmission ring; 11. gear plate; 111. second connecting ear; 112. third connecting hole; 121. second bolt; 122. third nut; 2. driving mechanism; 21. gear; 21a. driving gear; 21b. driven gear; 22. driving motor; 23. arc seat; 3. hoop; 31. clamping plate; 311. first connecting ear; 312. first connecting hole; 313. second connecting hole; 321. first bolt; 322. first nut; 4. pull rod; 41. second nut; 51. short tube; 52. end tube. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0039] Example 1

[0040] like Figure 1-Figure 3 As shown, this embodiment provides a three-section pipeline rotation friction welding assembly, which is used to weld a short tube 51 between two end tubes 52, including a transmission ring 1, a driving mechanism 2, two hoop rings 3 and a plurality of tie rods 4, wherein the transmission ring 1 is coaxially mounted on the short tube 51, the two hoop rings 3 correspond to the two end tubes 52 one by one, each hoop ring 3 is clamped on the corresponding end tube 52, and the two hoop rings 3 are connected by the plurality of tie rods 4 to coaxially clamp the short tube 51 between the two end tubes 52, and the driving mechanism 2 is placed beside the transmission ring 1. and is connected to the transmission ring 1 in transmission connection. The driving mechanism 2 is used to drive the transmission ring 1 to drive the short section tube 51 to rotate for friction welding. In this way, the transmission ring can be pre-coaxially installed on the outer wall of the short section tube, and the two hoops are connected to the two end tubes at the same time. The two hoops are then connected through multiple tie rods, so that the two end tubes can coaxially clamp the short section tube. When the driving mechanism is connected to the transmission ring in transmission connection, the driving mechanism can drive the transmission ring to drive the short section tube to rotate. At this time, the short section tube and the end tube melt due to friction and finally achieve welding, and the welding effect is good.

[0041] like Figure 4 and Figure 5As shown, the hoop 3 in the above technical solution includes two semicircular ring clamps 31, and the two ends of the two clamps 31 are detachably connected to clamp the end tube 52, and each of the clamps 31 is connected to at least one corresponding end of the pull rod 4, so that the two clamps are easy to disassemble and assemble on the end tube, wherein, the two ends of the two clamps 31 are provided with first connecting ears 311, and each of the first connecting ears 311 is provided with a first connecting hole 312, and the first connecting holes 312 on the two first connecting ears 311 close to each other are aligned with each other, and a first bolt 321 is inserted, and the threaded end of each first bolt 321 is threadedly connected to at least one first nut 322 to connect the two first connecting ears 311 close to each other, and its structure is simple. At this time, the two clamps are clamped on the end tube in the form of a pipe clamp. Among them, both ends of the pull rod 4 are provided with threads, and the clamp plate 31 is provided with a second connecting hole 313 passing through it. The second connecting holes 313 on the two hoops 3 are aligned with each other and pass through one pull rod 4. Both ends of each pull rod 4 are threadedly connected with at least one second nut 41. The structure is simple, and after the two clamp plates are clamped on the end pipes, the edges thereof are similar to a flange structure, which is convenient for the installation of the pull rods on the two hoops.

[0042] Among them, the first connecting ears at both ends of each of the clamps are perpendicular to the clamps. Of course, the inner arc side and both ends of the clamps can be flanged to the same side or to both sides for thickening, and the flanges at both ends constitute the first connecting ears, so that the flanges are similar to a pipe clamp structure for clamping the clamps on the end pipe, and the outer arc sides of the two clamps form a circular structure, and second connecting holes are arranged on the clamps, and multiple second connecting holes on the same hoop can be evenly distributed circumferentially on the circular structure formed by the two clamps. At this time, the two clamps are clamped on the end pipe and combined into a flange structure. The hoop provided in this embodiment is actually to realize the coaxial clamping of a flexibly detachable flange on the end pipe for the connection of the pull rod.

[0043] In this embodiment, when the multiple pull rods are connected to the two hoops, they are distributed in the same circle, and the circle where they are located is coaxial with the hoops.

[0044] like Figure 6As shown, the transmission ring 1 in the above technical solution is a gear ring, and the driving mechanism 2 has three gears 21 circumferentially spaced around the transmission ring 1, and the three gears 21 are all meshed with the transmission ring 1, one of the gears 21 is a driving gear 21a, and the remaining two gears 21 are driven gears 21b, the driving gear 21a inputs power to drive the transmission ring 1 to rotate, and the transmission ring is set as a gear ring, which makes it more convenient to connect with the driving mechanism for transmission, and the driving mechanism is provided with three gears, so that the driving gear can drive the transmission ring to rotate among the three gears, and the three gears clamp the transmission ring together for circumferential limiting, so as to avoid the driving gear from causing the short section pipe to be unevenly stressed in the circumferential direction when driving the transmission ring to rotate, and it can be moved to be misaligned with the two end pipes. Preferably, the three gears are distributed at the three corners of a triangle, and each vertex angle of the triangle is an acute angle, so that the three gears have a better clamping effect on the transmission ring.

[0045] The transmission ring 1 in the above technical solution includes two semicircular gear plates 11, and the ends of the two gear plates 11 close to each other are detachably connected and clamped together on the short section tube 51. Its structure is simple, and the outer arc edge of the gear plate is provided with tooth patterns, and the outer edges of the two gear plates form a full-circle gear structure on the short section tube.

[0046] In the above technical solution, both ends of the gear plate 11 are provided with second connecting ears 111, and each of the second connecting ears 111 is provided with a third connecting hole 112. The third connecting holes 112 on the two second connecting ears 111 close to each other are aligned with each other, and a second bolt 121 is inserted, and at least one third nut 122 is threadedly connected to each of the second bolts 121 to connect the two adjacent second connecting ears 111. The structure is simple, and the two gear plates are clamped on the short section pipe in the form of a pipe clamp.

[0047] The structure of the transmission ring described in this embodiment is similar to that of the hoop ring. The only difference between the two is that a plurality of second connecting holes are provided on the splint so that the two splints eventually form a flange structure, while the transmission ring has tooth patterns on the outer arc edge of the gear plate, so that the two gear plates eventually form a gear structure on the short section tube. Since the short section tube will eventually be welded to the two end tubes, in order to facilitate disassembly of the transmission ring, two semicircular gear plates are provided. Of course, the diameter of the gear structure needs to be smaller than the diameter of the circle where the multiple pull rods are located.

[0048] like Figure 7As shown, the driving mechanism 2 in the above technical solution also includes a driving motor 22 and two arc-shaped seats 23, at least four pull rods 4 are provided, and the plurality of pull rods 4 are evenly distributed in the circumferential direction, at least one gear 21 is installed on the inner side of the arc of each arc-shaped seat 23, and at least two pull rods 4 are penetrated through the edge of each arc-shaped seat 23, the driving motor 22 is installed on any one of the arc-shaped seats 23, and its driving end is transmission-connected with any one of the gears 21, and its structure is simple, so that the arc-shaped seat pull rod is a supporting carrier, and the driving motor and the three gears are carried by the two arc-shaped seats, which is easy to install and occupies little space. Preferably, the Four pull rods are arranged, and each arc seat is provided with two pull rods passing therethrough, the arc openings of the two arc seats are close to each other, the driving gear is installed on one of the arc seats (the driving motor is installed on the arc seat and is connected to the wheel shaft of the driving gear in a transmission manner, the driving gear is coaxially fixedly connected to its wheel shaft, and its wheel shaft is rotationally connected to the arc seat, and the driving motor can adopt a reduction motor), and the two driven gears are rotationally installed on the other arc seat, and the three gears are all meshed with the transmission ring, so that the driving gear rotates under the drive of the driving motor, and drives the transmission ring and the short section tube to rotate, and the transmission ring will not move under the circumferential clamping of the three gears.

[0049] The arc seat can be fixedly connected to the pull rod, so that the arc seat will not slip relative to the length of the pull rod, and the fixing effect is good.

[0050] The three-section pipeline rotation friction welding assembly provided in this embodiment is particularly suitable for situations where the end pipe cannot rotate due to its long length or fixed installation. In this case, only the short-section pipe can be used for rotation welding, and it is best if the material and diameter of the short-section pipe and the end pipe are consistent.

[0051] Wherein, the arc center angle of the arc seat is an obtuse angle.

[0052] Example 2

[0053] This embodiment provides a three-section pipeline rotation friction welding method, which includes the following steps:

[0054] Step 1: Grinding and rounding the ends of the two end pipes 52 to be welded (using an expander, a cutting machine, a wire brush, etc. to grind and round the ends of the end pipes to be welded);

[0055] Step 2: Assemble the short tube 51, the two end tubes 52 and the three-section pipeline rotation friction welding assembly as described in Example 1;

[0056] Step 3: Start the driving mechanism 2, and drive the short tube 51 to rotate coaxially relative to the two end tubes 52 by the driving mechanism 2 until the short tube 51 and the two end tubes 52 are coaxially welded, and then remove the three-section pipeline rotation friction welding assembly from the short tube 51 and the end tubes 52;

[0057] Step 4: Use an angle grinder to grind and correct the weld between the short tube 51 and the end tube 52 to a smooth state, which has high welding efficiency and convenient assembly.

[0058] In the above technical solution, the clamping pressure of the end tube 52 on the short tube 51 is 20-80MPa, and the rotation speed of the short tube 51 driven by the driving mechanism 2 is 30-100r / s, so that the friction force of the short tube 51 when rotating and rubbing against the end tube is large, so it melts quickly.

[0059] The rotation direction of the short tube section can be the same direction or reciprocating rotation, the reciprocating rotation angle should be greater than ±10°, the welding time is 5-20s, and the welding parameters should be selected according to the material structure phase diagram.

[0060] Furthermore, in order to control the shape of the inner side of the weld, a water-soluble paper plug can be placed in the welding short section before welding. After welding, it is dissolved by water medium. The water-soluble paper plug should be made of water-soluble vinylon. By inserting the water-soluble paper plug, the inner side of the weld can be made smoother.

[0061] The three-section pipeline rotary friction welding assembly described in this embodiment can be used to repair the continuous oil pipe. When a defect or damage occurs somewhere in the continuous oil pipe, it can be cut off, and a section can be cut from either end after the cut off as a short section pipe, and the continuous oil pipes at both ends of the cut off are used as end pipes. At this time, the three-section pipeline rotary friction welding assembly provided in this embodiment can be used to weld them. During welding, the coaxiality of the short section pipe and the end pipe should be less than 0.3mm, and the ovality of the end pipe with welding end after grinding and rounding should be less than 0.8%.

[0062] 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 principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A three-section pipeline rotary friction welding assembly, which is used to weld a short tube (51) between two end tubes (52), It is characterized in that It comprises a transmission ring (1), a driving mechanism (2), two hoop rings (3) and a plurality of pull rods (4); the transmission ring (1) is coaxially mounted on the short tube section (51); the two hoop rings (3) correspond one to one with the two end tubes (52); each hoop ring (3) is clamped on the corresponding end tube (52); and the two hoop rings (3) are connected by a plurality of pull rods (4) so ​​as to coaxially clamp the short tube section (51) between the two end tubes (52); the driving mechanism (2) is placed beside the transmission ring (1) and is in transmission connection with the transmission ring (1); the driving mechanism (2) is used to drive the transmission ring (1) to drive the short tube section (51) to rotate for friction welding.

2. The three-section pipeline rotary friction welding assembly according to claim 1, It is characterized in that The hoop (3) comprises two semicircular ring clamps (31), the two ends of the two clamps (31) are detachably connected and clamp the end tube (52), and each clamp (31) is connected to the corresponding end of at least one of the pull rods (4).

3. The three-section pipeline rotary friction welding assembly according to claim 2, It is characterized in that Both ends of the two clamping plates (31) are provided with first connecting ears (311), each of the first connecting ears (311) is provided with a first connecting hole (312), and the first connecting holes (312) on the two first connecting ears (311) close to each other are aligned with each other and a first bolt (321) is inserted therein, and the threaded end of each first bolt (321) is threadedly connected with at least one first nut (322) to connect the two first connecting ears (311) close to each other.

4. The three-section pipeline rotary friction welding assembly according to claim 3, It is characterized in that Both ends of the pull rod (4) are provided with threads, and the clamping plate (31) is provided with a second connection hole (313) passing through it. The second connection holes (313) on the two hoops (3) are aligned with each other and pass through one of the pull rods (4), and both ends of each of the pull rods (4) are threadedly connected to at least one second nut (41).

5. The three-section pipeline rotary friction welding assembly according to claim 1, It is characterized in that The transmission ring (1) is a gear ring, and the driving mechanism (2) has three gears (21) that are circumferentially spaced and distributed around the transmission ring (1), and the three gears (21) are all meshed with the transmission ring (1), one of the gears (21) is a driving gear (21a), and the remaining two gears (21) are driven gears (21b), and the driving gear (21a) inputs power to drive the transmission ring (1) to rotate.

6. The three-section pipeline rotary friction welding assembly according to claim 5, It is characterized in that The transmission ring (1) comprises two semicircular gear plates (11), and the two gear plates (11) are detachably connected at their mutually adjacent ends and are clamped together on the short tube section (51).

7. The three-section pipeline rotary friction welding assembly according to claim 6, It is characterized in that Both ends of the gear plate (11) are provided with second connecting ears (111), and each of the second connecting ears (111) is provided with a third connecting hole (112), the third connecting holes (112) on two second connecting ears (111) adjacent to each other are aligned with each other, and a second bolt (121) is inserted therein, and each of the second bolts (121) is threadedly connected with at least one third nut (122) to connect the two adjacent second connecting ears (111).

8. The three-section pipeline rotary friction welding assembly according to any one of claims 5 to 7, It is characterized in that The driving mechanism (2) also includes a driving motor (22) and two arc-shaped seats (23). At least four pull rods (4) are provided, and the plurality of pull rods (4) are evenly distributed in the circumferential direction. At least one gear (21) is installed on the inner side of the arc of each arc-shaped seat (23), and at least two pull rods (4) are provided through the edge of each arc-shaped seat (23). The driving motor (22) is installed on any one of the arc-shaped seats (23), and its driving end is connected to any one of the gears (21) in a transmission manner.

9. A three-section pipeline rotation friction welding method, It is characterized in that It includes the following steps: Step 1: Grinding and rounding the ends of the two end pipes (52) to be welded; Step 2: Assembling the short tube (51), the two end tubes (52) and the three-section pipeline rotation friction welding assembly according to any one of claims 1 to 8; Step 3: starting the driving mechanism (2), and driving the short tube section (51) with the driving mechanism (2) to rotate coaxially relative to the two end tubes (52) until the short tube section (51) and the two end tubes (52) are coaxially welded, and then removing the three-section pipeline rotation friction welding assembly from the short tube section (51) and the end tubes (52); Step 4: Use an angle grinder to grind the weld between the short tube (51) and the end tube (52) and correct it to a smooth state.

10. The three-section pipeline rotation friction welding method according to claim 9, It is characterized in that The clamping pressure of the end pipe (52) on the short tube (51) is 20-80 MPa, and the rotation speed of the short tube (51) driven by the driving mechanism (2) is 30-100 r / s.

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