Device and method for repairing local out-of-roundness of pipe end of ultra-large-diameter steel pipe

Abstract

The invention provides an ultra-large-diameter steel pipe end local out-of-roundness repairing device and method.The repairing tool comprises a repairing body, a platform, a height adjusting support and a moving mechanism, the repairing body is fixedly arranged on the platform, and the height adjusting support is arranged between the platform and the moving mechanism; the repairing body comprises a jack and a filler strip, the jack and the filler strip are used in cooperation, and the filler strip is placed between the jack and the pipe end of the steel pipe. The sliding groove limiting blocks are arranged on the two sides of the containing platform, the jack can be prevented from shaking left and right, the jack is slidably connected with the sliding groove limiting blocks, the notch is formed in the main body box of the repairing main body, the jack can conveniently move to the pipe end, and finally local out-of-roundness is repaired through cooperation of the jack and the filler strip. The height of the repairing body can be adjusted through the height adjusting support, so that the lower elevation of the steel pipe is matched with the height of the notch, and the technical requirements of repairing work are met.

Description

Technical Field

[0001] The present invention belongs to the technical field of welded pipe production for oil steel pipes, and particularly relates to a device and method for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe. Background Art

[0002] During the production line of welded pipes and the transportation and stacking of steel pipes, as long as there is a problem of local non-circularity deformation at the pipe end of the steel pipe, the general process method is to cut off a section with unqualified roundness at the pipe end. This causes unnecessary losses. When it affects the specified length standard, the entire steel pipe has to be scrapped, resulting in more serious economic losses; at the offline steel pipe and the pipeline construction site, the work of pipe end cutting and roundness repair is very difficult; for small and medium diameter steel pipes with a diameter below D1000mm, the finishing repair method for the macroscopic oval non-circularity at the pipe end is to support the jack inside the pipe orifice, and locally press outwards on the concave part inside the pipe orifice through the jack and the ejector rod to achieve local roundness repair. However, for the local non-circularity caused by external force deformation or the local non-circularity repair of the pipe end of an extra-large diameter steel pipe with a diameter exceeding D2000mm, it is extremely difficult to use the traditional method of pressing through the ejector rod from the inside of the pipe end. With the development of pipeline butt joint technology, the macroscopic ovality of the pipe end can be compensated by the butt joint equipment technology or the like, but the influencing factors of local non-circularity become particularly prominent.

[0003] The disadvantages of the traditional manual method for repairing local non-circularity are as follows: ① When repairing local non-circularity, due to the use of over-top operation, it will exacerbate the local non-circularity at the 180° pipe orifice of the repair area and affect the macroscopic non-circularity of the steel pipe; ② Since the ejector rod is used, when the ejector rod is not balanced in force, there is a greater safety risk of the ejector rod popping out and injuring people; ③ The construction tools such as the ejector rod need to be manually carried and installed, and 1 - 2 people cannot complete it, which is time-consuming and laborious; ④ Using fire baking for repair will cause local mechanical and technological property changes of the steel pipe base material.

[0004] The cost of finishing the extra-large diameter pipe end increases, and many pipeline contracts have very strict requirements for the specified length of the steel pipe, making it impossible to cut off the waste at the pipe end. When repairing the local non-circularity of the pipe end of a steel pipe with a diameter greater than 2000mm, the original manual repair and the ejector rod operation method have greater safety risks, and the feasibility of the operation becomes zero. Especially for the pipe end deformation that occurs during pipeline construction sites and steel pipe transportation, it is very difficult to quickly repair the local non-circularity of the pipe end. Summary of the Invention

[0005] The purpose of the present invention is to provide a device for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe, so as to overcome the above-mentioned technical problems existing in the prior art.

[0006] Another object of the present invention is to provide a method for repairing local out-of-roundness at the pipe end of an extra-large diameter steel pipe, which specifically solves the technical problems of local out-of-roundness and deformation at the pipe end caused by external forces during the production process or for the steel pipes taken off the production line.

[0007] To this end, the technical solution provided by the present invention is as follows: An apparatus for repairing local out-of-roundness at the pipe end of an extra-large diameter steel pipe, comprising a repair main body, a platform, a height adjustment bracket and a moving mechanism. The repair main body is fixedly arranged on the platform, and the height adjustment bracket is arranged between the platform and the moving mechanism; The repair main body includes a jack and a cushion bar. The jack and the cushion bar are used in cooperation, and the cushion bar is placed between the jack and the pipe end of the steel pipe.

[0008] The repair main body further includes a main body box. A placement table is arranged inside the main body box. The jack is slidably connected to the placement table. Both opposite side surfaces of the main body box are open, and a notch is formed on the main body box. The position of the notch is lower than the placement table.

[0009] The height adjustment bracket includes a lifting bracket and a lifting power mechanism. The lifting bracket is connected to the lower end surface of the platform, and the lifting power mechanism is connected to the lifting bracket to push or pull the lifting bracket to move so as to realize lifting.

[0010] The moving mechanism includes a bottom plate and universal wheels arranged at the four corners of the bottom plate. The area of the bottom plate is larger than the area of the platform.

[0011] Chute limit blocks are arranged on both sides of the placement table. The jack is slidably connected to the chute limit blocks. One side of the chute limit blocks close to the notch extends outside the main body box.

[0012] The lifting bracket includes four connecting plates. Two connecting plates are cross-connected by a pin shaft to form a scissors structure. Two scissors structures are arranged in parallel and are respectively connected to the platform and the bottom plate of the moving mechanism at the upper and lower ends; The height adjustment bracket further includes a connecting shaft, a shaping shaft and a bracket positioning plate. The shaping shaft is located on the lower end surface of the platform. One upper end of the two scissors structures is connected by the shaping shaft, and the other upper ends are respectively connected to the bottom plate through a movable connecting plate and a pin shaft two. One lower end of the two scissors structures is connected by the connecting shaft, and the other lower ends are respectively connected to the bottom plate through a movable connecting plate and a pin shaft two. The shaping shaft is slidably connected to the lower end surface of the platform. A bracket positioning plate is arranged on the bottom plate. The connecting shaft is slidably connected to the bracket positioning plate. The connecting shaft and the shaping shaft are located at the same end.

[0013] The lifting power mechanism includes a swivel joint, a lead screw, a nut, and a handwheel. The swivel joint is fixedly connected to the connecting shaft. One end of the lead screw is threadedly connected to the swivel joint, and the other end of the lead screw is fixedly connected to the handwheel. The nut is fixedly arranged on the bottom plate. The nut is arranged between the swivel joint and the handwheel and is threadedly connected to the lead screw.

[0014] A long strip hole lug is provided on the repair main body.

[0015] A method for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe uses a tool for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe, and includes the following steps: Step 1): Rotate the pipe end of the steel pipe to the place to be repaired, so that the place to be repaired is at the 6 o'clock position of the clock. Push the tool for repairing local non-circularity through the moving mechanism so that the notch is inserted into the pipe end. Step 2): Place the cushion strip in the axial direction of the steel pipe at the place to be repaired at the pipe end. Push the jack so that the jack is pushed from the placement table to the cushion strip at the pipe end. Step 3): Normally operate to raise the ejector rod of the jack so that it slowly presses tightly against the top steel plate of the box body. Continue to operate the jack, and the jack acts downward on the cushion strip, causing the pipe orifice to elastically deform and bulge outwards, so as to realize the rounding and repair of the non-circularity deformation at the pipe orifice.

[0016] Before repair, when the elevation of the steel pipe does not match the height of the notch, adjust the height of the repair main body through the height adjustment bracket.

[0017] The beneficial effects of the present invention are: For the device for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe provided by the present invention, by arranging chute limit blocks on both sides of the placement platform, the jack can be prevented from swaying left and right. By the sliding connection between the jack and the chute limit blocks and by opening a notch on the main body box of the repair main body, the jack can be conveniently moved to the pipe end. Finally, the local non-circularity is repaired by the cooperation of the jack and the cushion strip. Through the height adjustment bracket, the height of the repair main body can be adjusted to make the elevation of the steel pipe match the height of the notch, meeting the technical requirements of the repair work.

[0018] The present invention can repair all internal concave deformations at the pipe end caused by manufacturing processes and external forces, and can repair the local non-circularity to within 0.5%D specified by the ellipticity standard; eliminate the waste of pipe heads, the degradation and rejection of steel pipes, and the direct economic benefits are very considerable.

[0019] In the actual production application process, only one person is required to operate. It is easy to carry and simple to operate, and can quickly complete the training and master its working principle and usage method. Each pipe end can complete the repair work within 20 minutes. Compared with other methods, the work efficiency can be increased by more than 10 times. It can maximize the adaptation to various hard and soft materials and the repair of local non-circularity of pipe ends with different wall thicknesses. In particular, it can maximally repair high-grade large-wall-thickness oil and gas steel pipes with a material grade of ≥X80 and a thickness of ≥25 mm. Compared with the heating repair method, it will not cause changes in the microstructure and properties of the pipe end base material. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a schematic structural diagram of an embodiment of the present invention; Figure 2 is a schematic structural diagram of an embodiment of the placement table of the present invention; Figure 3 is a schematic diagram of the repair implementation of the present invention.

[0021] In the figure: 1. Repair main body; 1-1. Main body box; 1-2. Notch; 1-3. Jack; 1-4. Placement table; 1-41. Chute limit block; 1-5. Pad strip; 1-6. Lifting lug; 2. Platform; 2-1. Connecting screw; 3. Lifting bracket; 3-1. Connecting plate; 3-2. Pin shaft 1; 3-3. Connecting shaft; 3-4. Union joint; 3-5. Lead screw; 3-6. Nut; 3-7. Handwheel; 3-8. Bracket positioning plate; 3-9. Shaping shaft; 3-10. Union plate; 3-11. Pin shaft 2; 4. Bottom plate; 5. Universal wheel; 6. Pipe end. EMBODIMENT

[0022] The following specific embodiments illustrate the embodiments of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0023] Now refer to the accompanying drawings to introduce the exemplary embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to disclose the present invention in detail and completely, and to fully convey the scope of the present invention to those skilled in the art. The terms in the exemplary embodiments shown in the drawings are not intended to limit the present invention. In the drawings, the same units / components are denoted by the same reference numerals.

[0024] Unless otherwise specified, the terms (including scientific and technical terms) used herein have the ordinary meaning understood by those skilled in the art. In addition, it can be understood that the terms defined in the commonly used dictionary should be understood to have a meaning consistent with the context of their related fields, and should not be understood as idealized or overly formal meanings. EXAMPLE

[0025] This embodiment provides a repair tool for local non-circularity at the pipe end of an extra-large diameter steel pipe, which includes a repair main body 1, a platform 2, a height adjustment bracket, and a moving mechanism. The repair main body 1 is fixedly arranged on the platform 2, and the height adjustment bracket is arranged between the platform 2 and the moving mechanism; The repair main body 1 includes a jack 1-3 and a cushion strip 1-5. The jack 1-3 and the cushion strip 1-5 are used in cooperation, and the cushion strip 1-5 is placed between the jack 1-3 and the pipe end 6 of the steel pipe.

[0026] Principle of the present invention: Rotate the part to be repaired at the pipe end 6 of the steel pipe to the 6 o'clock position of the clock. Push the repair tool and insert the repair main body 1 into the repair position at the pipe end 6. Place a cushion strip 1-5 with a suitable area and size at the high point of the deformed part of the pipe end 6 according to technical requirements. Push the jack 1-3 and place it on the cushion strip 1-5. Raise the jack 1-3 to apply pressure to the high point of the deformed part of the pipe end 6. Measure and raise a certain height as required. After lowering the jack 1-3, measure whether the roundness of the pipe end 6 meets the standard. The high point of the repair area can be repeatedly found, and the same operation can be repeated again; the repair is completed.

[0027] The present invention repairs the local non-circularity through the cooperation of the jack 1-3 and the cushion strip 1-5; through the height adjustment bracket, the height of the repair main body 1 can be adjusted to make the lower elevation of the steel pipe match the height of the notch 1-2, meeting the technical requirements of the repair work. Embodiment

[0028] On the basis of Embodiment 1, this embodiment provides a repair tool for local non-circularity at the pipe end of an extra-large diameter steel pipe, as Figure 1 shown. The repair main body 1 further includes a main body box 1-1. A placement table 1-4 is arranged inside the main body box 1-1. The jack 1-3 is slidably connected to the placement table 1-4. Both opposite sides of the main body box 1-1 are open, and a notch 1-2 is opened on the main body box 1-1. The position of the notch 1-2 is lower than that of the placement table 1-4.

[0029] The center of the cylinder body of the jack 1-3 is aligned with the center line of the main body box 1-1; the main body box 1-1 is connected to the platform 2 through connecting screws 2-1. The base of the jack 1-3 slides in the chutes of the two sliding limit blocks on the platform 2; before work, finely adjust and rotate the repair point of the steel pipe to the center of the main body box 1-1, and confirm that the cushion strip 1-5 is placed at the position to be repaired; during work, manually push the jack 1-3 onto the cushion strip 1-5 to ensure that the center of the cushion strip 1-5 is aligned with the center of the jack 1-3; after work, pull the jack 1-3 back from the cushion strip 1-5 to the platform 2. The cushion strip 1-5 uses a smaller area to increase the pressure of the applied force.

[0030] Working process: As shown Figure 3 in the figure, utilize the relatively flat open space at the work site to rotate the deformed part of the steel pipe to the 6 o'clock position of the clock. Through the moving mechanism, the notch 1-2 is sleeved onto the pipe orifice to be repaired, and the backing plate is placed between the notch 1-2 and the pipe end 6; the spacer bar 1-5 is placed at the convex high point inside the pipe orifice, and the jack 1-3 on the placing table 1-4 is manually pushed into the pipe orifice to be in the working state, and then the jack rod of the jack 1-3 is normally operated to lift it, so that it slowly presses tightly against the top steel plate of the box body; continue to operate the jack 1-3, and the jack 1-3 acts downward on the spacer bar 1-5, causing the elastic deformation and outward bulging of the pipe orifice, so as to realize the roundness and repair of the non-roundness deformed part of the pipe orifice. Among them, the height of the placing table 1-4 is the same as the height of the top surface of the spacer bar 1-5, so that the jack 1-3 can be smoothly pushed onto the spacer bar 1-5 of the pipe orifice. Embodiment

[0031] On the basis of Embodiment 1, this embodiment provides a repair tool for local non-roundness of the pipe end of an extra-large diameter steel pipe. The height adjustment bracket includes a lifting bracket 3 and a lifting power mechanism. The lifting bracket 3 is connected to the lower end surface of the platform 2, and the lifting power mechanism is connected to the lifting bracket 3 to push or pull the lifting bracket 3 to move to realize lifting.

[0032] The height of the platform 2 is lifted and lowered through the height adjustment bracket, so as to adjust the height of the repair main body 1, make the lower elevation of the steel pipe match the height of the notch 1-2, and meet the technical requirements of the repair work. Embodiment

[0033] On the basis of Embodiment 1, this embodiment provides a repair tool for local non-roundness of the pipe end of an extra-large diameter steel pipe. The moving mechanism includes a bottom plate 4 and universal wheels 5 arranged at the four corners of the bottom plate 4. The area of the bottom plate 4 is larger than the area of the platform 2.

[0034] As shown Figure 1 in the figure, the bottom plate 4 of the moving mechanism is larger than the plane area of the platform 2, and the purpose is to ensure the stability of the chassis of the moving mechanism; the bottom plate 4 is connected with four universal wheels 5, which can move flexibly and is convenient for safe movement at the steel pipe finishing site and the stacking site. Embodiment

[0035] On the basis of Embodiment 2, this embodiment provides a repair tool for local non-roundness of the pipe end of an extra-large diameter steel pipe. As shown Figure 2 in the figure, chute limit blocks 1-41 are arranged on both sides of the placing table 1-4. The jack 1-3 is slidably connected with the chute limit blocks 1-41, and the chute limit blocks 1-41 extend to the outside of the main body box 1-1 on the side close to the notch 1-2.

[0036] Place the spacer bars 1-5 parallel to the length direction (or along the deformation direction) at the repair position of the pipe end 6. Push the jacks 1-3 manually to slide along the chute of the chute limit block 1-41, and move them from the platform 2 to above the pipe orifice spacer bars 1-5; Place the backing plate below the notch 1-2 and the pipe orifice to increase the bearing area and prevent damage to the outer surface of the steel pipe. Embodiment

[0037] Based on Embodiment 3, this embodiment provides a repair tool for local non-circularity of the pipe end of an extra-large diameter steel pipe. The lifting bracket 3 includes four connecting plates 3-1. Two connecting plates 3-1 are cross-connected by a pin shaft 3-2 to form a scissors structure. Two scissors structures are arranged in parallel, and the upper and lower ends are respectively connected to the platform 2 and the bottom plate 4 of the moving mechanism. The height adjustment bracket further includes a connecting shaft 3-3, a shaping shaft 3-9, and a bracket positioning plate 3-8. The shaping shaft 3-9 is located on the lower end surface of the platform 2. One upper end of the two scissors structures is connected by the shaping shaft 3-9, and the other upper ends are respectively connected to the bottom plate 4 through a movable connecting plate 3-10 and a pin shaft 3-11. One lower end of the two scissors structures is connected by the connecting shaft 3-3, and the other lower ends are respectively connected to the bottom plate 4 through a movable connecting plate 3-10 and a pin shaft 3-11. The shaping shaft 3-9 is slidably connected to the lower end surface of the platform 2. The bottom plate 4 is provided with a bracket positioning plate 3-8. The connecting shaft 3-3 is slidably connected to the bracket positioning plate 3-8. The connecting shaft 3-3 and the shaping shaft 3-9 are located at the same end.

[0038] The connecting shaft 3-3 and the shaping shaft 3-9 are both welded to the lifting bracket 3; The connecting plate 3-1 is connected to the movable connecting plate 3-10 by a pin shaft 3-11; The movable connecting plate 3-10 is welded to the platform 2, and the other movable connecting plate 3-10 is welded to the bottom plate 4.

[0039] When the elevation of the steel pipe is inconsistent with the height of the notch 1-2 of the repair main body 1, the height of the repair main body 1 can be adjusted finely by the height adjustment bracket. The angle interaction function is realized through the movable pin shaft 3-11, so that the height difference distance between the platform 2 and the bottom plate 4 changes, and the height lifting function of the platform 2 and the repair main body 1 is realized, so as to meet the relative height matching requirements of the pipe orifice and the pipe end 6 inserted into the notch 1-2. Taking the height increase as an example, as Figure 1 shown, the lifting power mechanism pushes the connecting shaft 3-3, and the connecting shaft 3-3 slides along the bracket positioning plate 3-8, so that point C moves to point D. At the same time, the shaping shaft 3-9 slides along the platform 2, so that point A moves to point B. Finally, ∠1 becomes smaller, ∠2 becomes larger, the distances between points A and B and between points C and D become smaller respectively, so that the distances between points A and C and between points B and D become larger respectively, and the platform 2 is raised accordingly and maintains the original levelness. Embodiment

[0040] On the basis of Embodiment 6, this embodiment provides a repair tool for local non-circularity of the pipe end of an extra-large diameter steel pipe. The lifting power mechanism includes a union 3-4, a lead screw 3-5, a nut 3-6, and a handwheel 3-7. The union 3-4 is fixedly connected to the connecting shaft 3-3. One end of the lead screw 3-5 is threadedly connected to the union 3-4, and the other end of the lead screw 3-5 is fixedly connected to the handwheel 3-7. The nut 3-6 is fixedly arranged on the bottom plate 4, and the nut 3-6 is arranged between the union 3-4 and the handwheel 3-7 and is threadedly connected to the lead screw 3-5.

[0041] As Figure 1 shown, the lead screw 3-5 is fixed to the bottom plate 4 through the nut 3-6. When the height needs to be adjusted, the handwheel 3-7 is rotated, and the lead screw 3-5 rotates, causing the union 3-4 to move linearly along the lead screw 3-5, thereby pushing or pulling the connecting shaft 3-3 to slide along the bottom plate 4.

[0042] A long strip hole lug 1-6 is formed on the repair main body 1. As Figure 3 shown, by loosening the connecting screw 2-1, the main body box 1-1 can be removed from the platform 2 and used alone. Through the strip hole lug 1-6, it is beneficial to balance the lifting of the box body in the side-lying position and implement the roundness repair of the non-circularity deformation points at other positions such as the 3 o'clock or 9 o'clock positions of the pipe orifice. Embodiment

[0043] This embodiment provides a method for repairing local non-circularity of the pipe end of an extra-large diameter steel pipe. Using a repair tool for local non-circularity of the pipe end of an extra-large diameter steel pipe, it includes the following steps: Step 1) Rotate the pipe end 6 of the steel pipe to the place to be repaired, make the place to be repaired located at the 6 o'clock position of the clock, and push the local non-circularity repair tool through the moving mechanism to insert the notch 1-2 into the pipe end 6; Step 2) Place the cushion strip 1-5 along the axial direction of the steel pipe at the place to be repaired of the pipe end 6, and push the jack 1-3 so that the jack 1-3 is pushed from the placement table 1-4 onto the cushion strip 1-5 of the pipe end 6; Step 3) Normally operate to raise the ejector rod of the jack 1-3 so that it slowly presses tightly against the top steel plate of the box body; continue to operate the jack 1-3, and the jack 1-3 acts downward on the cushion strip 1-5, causing the elastic deformation and outward bulging of the pipe orifice, so as to realize the roundness and repair of the non-circularity deformation part of the pipe orifice.

[0044] Before repair, when the lower elevation of the steel pipe does not match the height of the notch 1-2, adjust the height of the repair main body 1 through the height adjustment bracket.

[0045] Use a scale ruler to measure the extension amount of the ejector rod, control an appropriate force, and a radian plate detection tool can be used in combination to inspect the roundness of the repaired pipe end 6. The above actions can be repeated until the roundness is qualified.

[0046] AsFigure 3 As shown, lifting lugs 1-6 are symmetrically arranged on both sides of the main body box 1-1. It is also possible to remove the main body box 1-1 and use a crane to lift and transport the expansion repair tool to perform the necessary repair work on the out-of-roundness at other parts of the pipe end.

[0047] The above examples are only illustrative of the present invention and do not constitute a limitation on the protection scope of the present invention. Any design identical or similar to the present invention falls within the protection scope of the present invention.

Claims

1. A repair tool for local non-circularity at the end of an extra-large diameter steel pipe, Characterized in that: It includes a repair main body, a platform, a height adjustment bracket and a moving mechanism. The repair main body is fixedly arranged on the platform, and the height adjustment bracket is arranged between the platform and the moving mechanism; The repair main body includes a jack and a cushion bar. The jack and the cushion bar are used in cooperation, and the cushion bar is placed between the jack and the end of the steel pipe.

2. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 1, Characterized in that: The repair main body further includes a main body box. A placement table is arranged in the main body box. The jack is slidably connected to the placement table. Both opposite side surfaces of the main body box are open, and a notch is formed on the main body box. The position of the notch is lower than the placement table.

3. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 1, Characterized in that: The height adjustment bracket includes a lifting bracket and a lifting power mechanism. The lifting bracket is connected to the lower end surface of the platform, and the lifting power mechanism is connected to the lifting bracket to push or pull the lifting bracket to move to achieve lifting.

4. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 1, Characterized in that: The moving mechanism includes a bottom plate and universal wheels arranged at the four corners of the bottom plate. The area of the bottom plate is larger than the area of the platform.

5. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 2, Characterized in that: Chute limit blocks are arranged on both sides of the placement table. The jack is slidably connected to the chute limit blocks. The chute limit blocks extend outside the main body box on the side close to the notch.

6. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 3, Characterized in that: The lifting bracket includes four connecting plates. Two connecting plates are cross-connected by a pin shaft to form a scissors structure. Two scissors structures are arranged in parallel and are respectively connected to the platform and the bottom plate of the moving mechanism at the upper and lower ends; The height adjustment bracket further includes a connecting shaft, a shaping shaft and a bracket positioning plate. The shaping shaft is located on the lower end surface of the platform. One upper end of the two scissors structures is connected by the shaping shaft, and the other upper ends are respectively connected to the bottom plate through a movable connection plate and a pin shaft two. One lower end of the two scissors structures is connected by the connecting shaft, and the other lower ends are respectively connected to the bottom plate through a movable connection plate and a pin shaft two. The shaping shaft is slidably connected to the lower end surface of the platform. A bracket positioning plate is arranged on the bottom plate. The connecting shaft is slidably connected to the bracket positioning plate. The connecting shaft and the shaping shaft are located at the same end.

7. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to claim 6, Characterized in that: The lifting power mechanism includes a swivel joint, a lead screw, a nut and a hand wheel. The swivel joint is fixedly connected to the connecting shaft. One end of the lead screw is threadedly connected to the swivel joint. The other end of the lead screw is fixedly connected to the hand wheel. The nut is fixedly arranged on the bottom plate. The nut is arranged between the swivel joint and the hand wheel and is threadedly connected to the lead screw.

8. The repair tool for local non-circularity at the end of an extra-large diameter steel pipe according to any one of claims 1-7, Characterized in that: A long strip hole lifting lug is formed on the repair main body.

9. A method for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe, using the local non-circularity repair tool for the pipe end of the extra-large diameter steel pipe described in claim 2, characterized in that: it includes the following steps: Step 1) Rotate the pipe end of the steel pipe to the place to be repaired, so that the place to be repaired is at the six o'clock position of the clock. Push the local non-circularity repair tool through the moving mechanism, and insert the notch into the pipe end; Step 2) Place the cushion strip in the axial direction of the steel pipe at the place to be repaired at the pipe end, and push the jack so that the jack is pushed from the placement table to the cushion strip at the pipe end; Step 3) Normally operate to raise the ejector rod of the jack so that it slowly presses tightly against the top steel plate of the box body; Continue to operate the jack. The jack acts downward on the cushion strip, causing elastic deformation and outward bulging of the pipe orifice, so as to realize the rounding and repair of the non-circularity deformation part of the pipe orifice.

10. A method for repairing local non-circularity at the pipe end of an extra-large diameter steel pipe according to claim 9, characterized in that: Before repair, when the elevation of the steel pipe does not match the height of the notch, the height of the repair main body is adjusted through the height adjustment bracket.

Images