A large steel pipe local shaping device and shaping method

Abstract

The present invention discloses a large steel pipe local shaping device, which includes a shaping machine. Conveying mechanisms for conveying steel pipes are arranged on both sides of the shaping machine, and the shaping machine and the conveying mechanisms are located on the same straight line. The shaping machine includes a base, a cross beam is arranged above the base, and a power element for driving the cross beam to move up and down along a column is arranged on the base, and the column is fixed on the base. A moving element for driving an upper die holder to move is arranged on the cross beam, a lower die holder adapted to the upper die holder is arranged on the base, die plates for placing steel pipes are arranged on both the upper die holder and the lower die holder, a local internal shaping structure of the steel pipe is arranged inside the steel pipe, and a local external shaping structure of the steel pipe is arranged between the steel pipe and the die plate of the upper die holder. The large steel pipe local shaping device and shaping method adopting the above structure can solve the problem that it is difficult to shape a large steel pipe locally, and has the advantages of simple structure and convenient use.

Description

Technical Field

[0001] The present invention relates to the technical field of shaping equipment, and in particular to a large steel pipe local shaping equipment and a shaping method. Background Art

[0002] The production of large steel pipes generally involves gradually pressing a steel plate multiple times using a pressing head or pressing rollers, and finally welding the two ends of the steel plate together using a welding machine to form a steel pipe. Since the steel pipe is gradually formed multiple times, there will be local protrusions or pits on the surface of the steel pipe, resulting in an uneven surface of the steel pipe, and the steel pipe needs to be shaped.

[0003] The existing patent CN212311628U discloses a stainless steel pipe shaping device, including an L-shaped support plate, a support mechanism is arranged above the support plate, a hydraulic mechanism is arranged on one side of the support plate, a limiting mechanism is arranged above the hydraulic mechanism, and a shaping mechanism is arranged below the support plate. However, this shaping device is only used for shaping the ends of stainless steel pipes and is not suitable for shaping the walls of stainless steel pipes. The existing patent CN215279236U discloses a large-diameter special steel pipe rapid shaping device, including a fixed bracket, a fixed plate, a driving cylinder, a push plate, a guide rail, a base, a first connecting plate, a first cylinder, a second connecting plate, and a second cylinder; the outer diameter of the steel pipe body is reduced by extruding the steel pipe body with a second mold by an external force; the steel pipe body is relatively fixed by the second mold, and the first mold without a cavity is used to block the linear movement of the steel pipe body, and the deformation mold is driven to move along the inside of the steel pipe body by an external force to increase the inner diameter of the steel pipe body. The shaping device in this patent is suitable for the expansion and reduction of the diameter of thin-walled steel pipes and is not suitable for the local shaping of large steel pipes. Therefore, the existing shaping devices are not suitable for the local shaping of large steel pipes.

[0004] Since the shaping of large thick-walled steel pipes is very difficult, a very large force is required for the thick-walled structure to be shaped. If the steel pipe is shaped by overall straightening or rounding, a very large equipment pressure is required, which undoubtedly increases the equipment cost and the shaping difficulty of thick-walled large-diameter steel pipes; and the overall shaping method cannot achieve the purpose of local defect shaping either. Summary of the Invention

[0005] The purpose of the present invention is to provide a large steel pipe local shaping equipment to solve the problem that it is not easy to locally shape large steel pipes, and it has the advantages of simple structure and convenient use. Another purpose of the present invention is to provide a shaping method for the large steel pipe local shaping equipment.

[0006] To achieve the above object, the present invention provides a large steel pipe local shaping device, including a shaping machine, and conveying mechanisms for conveying steel pipes are arranged on both sides of the shaping machine. The shaping machine and the conveying mechanisms are located on the same straight line. The shaping machine includes a base, a cross beam is arranged above the base, and a power element for driving the cross beam to move up and down along a column is arranged on the base. The column is fixed on the base. A moving element for driving the upper die holder to move is arranged on the cross beam, and a lower die holder adapted to the upper die holder is arranged on the base. Die plates for placing steel pipes are arranged on both the upper die holder and the lower die holder. A local internal shaping structure of the steel pipe is arranged inside the steel pipe, and a local external shaping structure of the steel pipe is arranged between the steel pipe and the die plate of the upper die holder.

[0007] Preferably, the power element is a lifting hydraulic cylinder. The lifting hydraulic cylinder is fixed on the base, and the telescopic rod of the lifting hydraulic cylinder is fixedly connected to the cross beam. Through holes for the column to pass through are arranged at both ends of the cross beam, and the cross beam is slidably connected to the column.

[0008] Preferably, the moving element is a pressing hydraulic cylinder. The pressing hydraulic cylinder is fixed on the cross beam, and the telescopic rod of the pressing hydraulic cylinder is fixedly connected to the upper die holder.

[0009] Preferably, a semi-circular upper die frame is arranged on the lower surface of the upper die holder, and a semi-circular lower die frame is arranged on the upper surface of the lower die holder. The die plate is fixed on the upper die frame and the lower die frame by bolts. A plurality of stiffening plates are evenly arranged between the upper die frame and the upper die holder, and a plurality of stiffening plates are evenly arranged between the lower die frame and the lower die holder.

[0010] Preferably, the local internal shaping structure includes a shaping hydraulic cylinder. A support seat is arranged at the bottom of the shaping hydraulic cylinder. The lower surface of the support seat is an arc surface adapted to the inner wall of the steel pipe. An inner support die is arranged on the telescopic rod of the shaping hydraulic cylinder.

[0011] Preferably, the top surface of the inner support die is an arc surface adapted to the inner wall of the steel pipe.

[0012] Preferably, the local external shaping structure includes an outer support die. The lower surface of the outer support die is provided with an arc surface adapted to the outer wall of the steel pipe.

[0013] Preferably, the conveying mechanisms are symmetrically arranged on both sides of the shaping machine. The conveying mechanism includes a plurality of conveying rollers. The steel pipe is located above the conveying rollers. A rotating roller is arranged between the conveying rollers. The rotating direction of the rotating roller is perpendicular to the rotating direction of the conveying rollers. The two rollers of the rotating roller are symmetrically arranged on both sides of the steel pipe.

[0014] The shaping method of the above large steel pipe local shaping device includes the following steps:

[0015] S1. According to the size of the steel pipe to be shaped, fix die plates adapted to the steel pipe on the upper die frame and the lower die frame by bolts;

[0016] S2. Lift the steel pipe onto the conveying rollers. The steel pipe moves under the action of the conveying rollers and is conveyed above the die plate of the lower die seat of the shaping machine.

[0017] S3. Start the rotating rollers. Drive the steel pipe to rotate around its axis through the rotating rollers, so as to adjust the part of the steel pipe to be shaped to directly above the steel pipe.

[0018] S4. Place the support base together with the shaping hydraulic cylinder inside the steel pipe. Adjust the position of the shaping hydraulic cylinder so that the shaping hydraulic cylinder is directly below the part to be shaped. Place the inner support die on the top of the telescopic rod of the shaping hydraulic cylinder. The inner support die is directly below or on both sides of the part to be shaped. Adjust the distance between the inner support dies. The shaping hydraulic cylinder extends to make the inner support die contact with the inner wall of the steel pipe.

[0019] S5. Place the outer support die on the outer wall of the steel pipe. The outer support die is on both sides or directly above the part to be shaped. Adjust the distance between the outer support dies. Start the pressing hydraulic cylinder. The pressing hydraulic cylinder drives the upper die seat to move downward to press the outer support die between the steel pipe and the die plate of the upper die seat.

[0020] S6. Start the shaping hydraulic cylinder. The shaping hydraulic cylinder drives the inner support die to move upward, or the pressing hydraulic cylinder drives the upper die seat to move downward to shape a part of the steel pipe. After shaping is completed, the shaping hydraulic cylinder moves downward, and the upper die seat moves upward under the action of the pressing hydraulic cylinder to remove the outer support die.

[0021] S7. Start the conveying rollers and the rotating rollers to drive the steel pipe to continue moving and rotating until the next part to be shaped, and shape the next part to be shaped.

[0022] Preferably, the inner diameter of the steel pipe is not less than 508 mm, and the wall thickness is not less than 10 mm.

[0023] The advantages and positive effects of a large steel pipe local shaping device and a shaping method according to the present invention are as follows:

[0024] 1. Two conveying mechanisms are arranged on both sides of the shaping machine. The steel pipe is conveyed and supported by the conveying mechanisms, which is beneficial to improving the stability of the steel pipe during the shaping process, facilitating the conveying and shaping of large steel pipes, and facilitating the movement of the local defect position of the large steel pipe into the shaping device.

[0025] 2. The rotating rollers arranged on the conveying mechanism are used to rotate the steel pipe, so as to facilitate the shaping of the pipe walls at different positions of the steel pipe.

[0026] 3. The shaping machine clamps the steel pipe through the die pieces of the upper die base and the lower die base, and drives the inner support die to move through the shaping hydraulic cylinder, or drives the outer support die to move through the upper die base, so as to realize the shaping of local depressions and protrusions on the side wall of the steel pipe. The present invention uses the inner support die and the outer support die to perform local shaping on the steel pipe, which can not only reduce the external force required for shaping, but also effectively shape the local defects of the steel pipe; it has the advantages of simple structure, convenient operation, small tonnage of the hydraulic cylinder required, and good shaping effect.

[0027] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Brief Description of the Drawings

[0028] Figure 1 It is a schematic structural diagram of an embodiment of a large steel pipe local shaping device and shaping method of the present invention;

[0029] Figure 2 It is a schematic structural diagram of the shaping machine of an embodiment of a large steel pipe local shaping device and shaping method of the present invention;

[0030] Figure 3 It is a schematic partial structural diagram of the conveying mechanism of an embodiment of a large steel pipe local shaping device and shaping method of the present invention.

[0031] Reference Signs

[0032] 1. Base; 2. Column; 3. Cross beam; 4. Jacking hydraulic cylinder; 5. Compacting hydraulic cylinder; 6. Upper die base; 7. Lower die base; 8. Upper die frame; 9. Lower die frame; 10. Die piece; 11. Reinforcing plate; 12. Support seat; 13. Shaping hydraulic cylinder; 14. Inner support die; 15. Outer support die; 16. Steel pipe; 17. Conveying roller; 18. Rotating roller. Detailed Embodiment

[0033] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings as understood by those of ordinary skill in the art to which the present invention pertains. The terms "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. Words such as "comprising" or "including" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. Words such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Words such as "upper", "lower", "left" and "right" are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship may also change accordingly.

[0035] Embodiment

[0036] Figure 1 It is a schematic structural diagram of an embodiment of a local shaping device and a shaping method for a large steel pipe according to the present invention. Figure 3 It is a partial structural schematic diagram of a conveying mechanism of an embodiment of a local shaping device and a shaping method for a large steel pipe according to the present invention. As shown in the figure, a local shaping device for a large steel pipe includes a shaping machine. Conveying mechanisms for conveying the steel pipe 16 are arranged on both sides of the shaping machine. The shaping machine and the conveying mechanisms are located on the same straight line. The conveying mechanisms are symmetrically arranged on both sides of the shaping machine. The conveying mechanism includes a plurality of conveying rollers 17. The motor drives the conveying rollers 17 to rotate. The axis of the conveying roller 17 is perpendicular to the steel pipe 16. The steel pipe 16 is placed above the conveying rollers 17. The conveying rollers 17 convey the steel pipe 16 by means of friction, so as to convey the steel pipe 16 into the interior of the shaping machine. A rotating roller 18 is arranged between the conveying rollers 17. The motor drives the rotating roller 18 to rotate. The axis of the rotating roller 18 is parallel to the moving direction of the steel pipe 16. The rotating direction of the rotating roller 18 is perpendicular to the rotating direction of the conveying roller 17. The two rollers of the rotating roller 18 are symmetrically arranged on both sides of the steel pipe 16. The rotating directions of the two rollers are the same, which improves the stability of the steel pipe 16 during rotation. The rotating roller 18 is used to rotate the steel pipe 16 and adjust the position of the part of the steel pipe 16 to be shaped, so that the part to be shaped is located directly above the steel pipe 16.

[0037] Figure 2This is a schematic structural diagram of a shaping machine for an embodiment of a large steel pipe local shaping device and a shaping method of the present invention. As shown in the figure, the shaping machine includes a base 1, and the base 1 is fixed on the ground. Above the base 1, there is a cross beam 3, and on the base 1, there is a power element that drives the cross beam 3 to move up and down along the column 2. The bottom end of the column 2 is fixed on the base 1, and at the top end of the column 2, there is a limit block to prevent the cross beam 3 from slipping off the column 2. The power element is a lifting hydraulic cylinder 4, the lifting hydraulic cylinder 4 is fixed on the base 1, and the telescopic rod of the lifting hydraulic cylinder 4 is fixedly connected to the cross beam 3. Through holes for the column 2 to pass through are provided at both ends of the cross beam 3, and the cross beam 3 is slidably connected to the column 2. The column 2 plays a guiding role in the up and down movement of the cross beam 3 to ensure the moving direction of the cross beam 3.

[0038] On the cross beam 3, there is a moving element that drives the upper die base 6 to move. The moving element is a pressing hydraulic cylinder 5, the pressing hydraulic cylinder 5 is fixed in the middle of the cross beam 3, and the telescopic rod of the pressing hydraulic cylinder 5 is fixedly connected to the upper die base 6. The pressing hydraulic cylinder 5 drives the upper die base 6 to move up and down through the telescopic movement of the telescopic rod.

[0039] On the base 1, there is a lower die base 7 adapted to the upper die base 6, and the lower die base 7 is located directly below the upper die base 6. On the lower surface of the upper die base 6, there is a semi-circular upper die frame 8, and on the upper surface of the lower die base 7, there is a semi-circular lower die frame 9. The die piece 10 is fixed on the upper die frame 8 and the lower die frame 9 by bolts. The die piece 10 can be replaced according to the outer diameter of the steel pipe 16 to meet the shaping requirements of steel pipes 16 with different outer diameters. The diameter of the circle formed by the two die pieces 10 is equal to the outer diameter of the steel pipe 16.

[0040] Between the upper die frame 8 and the upper die base 6, a number of stiffening plates 11 are evenly arranged, and between the lower die frame 9 and the lower die base 7, a number of stiffening plates 11 are evenly arranged, which is beneficial to improving the strength of the upper die frame 8 and the lower die frame 9.

[0041] Inside the steel pipe 16, there is a local internal shaping structure of the steel pipe 16. The local internal shaping structure includes a shaping hydraulic cylinder 13. At the bottom of the shaping hydraulic cylinder 13, there is a support seat 12 fixedly arranged, and the shaping hydraulic cylinder 13 and the support seat 12 are fixedly connected by bolts or screws. The lower surface of the support seat 12 is an arc surface adapted to the inner wall of the steel pipe 16, which improves the stability of the support seat 12 placed inside the steel pipe 16. On the telescopic rod of the shaping hydraulic cylinder 13, there is an inner support die 14. The inner support die 14 is placed on the telescopic rod of the shaping hydraulic cylinder 13. The number of the inner support dies 14 and the distance between the inner support dies 14 can be adjusted according to the type of local defect to be shaped. The inner support die 14 is placed on the hydraulic cylinder 13, which improves the flexibility of the adjustment of the inner support die 14. The hydraulic cylinder 13 presses the inner support die 14 against the inner wall of the steel pipe 16 through the jacking force of the telescopic rod. The top surface of the inner support die 14 is an arc surface adapted to the inner wall of the steel pipe 16.

[0042] A local external shaping structure of the steel pipe 16 is provided between the steel pipe 16 and the die piece 10 of the upper die base 6. The external shaping structure includes an external support die 15. The lower surface of the external support die 15 is provided with an arc surface adapted to the outer wall of the steel pipe 16, and the upper surface of the external support die 15 is provided with an arc surface adapted to the inner wall of the die piece 10. The external support die 15 is also a free steel plate and does not need to be fixed to the die piece or the steel pipe. The external support die 15 is fixed between the die piece 10 and the steel pipe 16 by the pressure of the pressing hydraulic cylinder 5 to shape the steel pipe 16. Since the external support die 15 needs to adjust the quantity and spacing according to the types and sizes of local defects of the steel pipe 16, the free external support die 15 improves the flexibility of the external support die 15, which is beneficial to improving the local shaping efficiency of the large-sized thick-walled steel pipe 16.

[0043] The shaping method of the above-mentioned large-sized steel pipe 16 local shaping equipment includes the following steps:

[0044] S1. According to the size of the steel pipe 16 to be shaped, the die piece 10 adapted to the steel pipe 16 is fixed on the upper die frame 8 and the lower die frame 9 by bolts.

[0045] S2. Hoist the steel pipe 16 onto the conveying roller 17. The steel pipe 16 moves under the action of the conveying roller 17 and is conveyed above the die piece 10 of the lower die base 7 of the shaping machine. The die piece 10 supports the steel pipe 16, so that the part to be shaped of the steel pipe 16 moves directly above the lower die base 7.

[0046] S3. Start the rotating roller 18, drive the steel pipe 16 to rotate around the axis through the rotating roller 18, so as to adjust the part to be shaped of the steel pipe 16 to directly above the steel pipe 16.

[0047] S4. The staff manually or through an existing conveying mechanism puts the support seat 12 together with the shaping hydraulic cylinder 13 into the steel pipe 16, adjusts the position of the shaping hydraulic cylinder 13 so that the shaping hydraulic cylinder 13 is directly below the part to be shaped, places the internal support die 14 on the top of the telescopic rod of the shaping hydraulic cylinder 14. The internal support die 14 is directly below or on both sides of the part to be shaped, adjusts the distance between the internal support dies 14, and the shaping hydraulic cylinder 13 extends to make the internal support die 14 contact with the inner wall of the steel pipe 16 to realize the fixation of the internal support die 14.

[0048] S5. Place the external support die 15 on the outer wall of the steel pipe 16. The external support die 15 is on both sides or directly above the part to be shaped, adjusts the distance between the external support dies 15, starts the pressing hydraulic cylinder 5, and the pressing hydraulic cylinder 5 drives the upper die base 6 to move downward to press the external support die 15 between the steel pipe 16 and the die piece 10 of the upper die base 6 to realize the fixation of the external support die 15.

[0049] S6. Start the shaping hydraulic cylinder 13. The shaping hydraulic cylinder 13 drives the inner support die 14 to move upward, or the pressing hydraulic cylinder 5 drives the upper die base 6 to move downward to shape the local defects of the steel pipe 16. After shaping, the shaping hydraulic cylinder 13 moves downward, and the upper die base 6 moves upward under the action of the pressing hydraulic cylinder 5, and the outer support die 15 is removed.

[0050] When shaping the depression on the steel pipe 16, one inner support die 14 is provided and two outer support dies 15 are provided. The inner support die 14 is driven by the shaping hydraulic cylinder 13 to move upward to shape the depression. When shaping the protrusion on the steel pipe 16, two inner support dies 14 are provided and one outer support die 15 is provided. The outer support die 15 is driven by the upper die base 6 to move downward to shape the protrusion.

[0051] For the shaping of large thick-walled steel pipes, it is completely unworkable to achieve local shaping through overall deformation. The present invention uses the pressure of the outer support die or the inner support die to perform local shaping on the steel pipe, without the need for overall deformation of the steel pipe. Only local deformation of the steel pipe is required to achieve local shaping of the steel pipe. The tonnage of the required hydraulic cylinder is small, which saves energy, simplifies the structure, and improves the shaping effect.

[0052] S7. Start the conveying roller 17 and the rotating roller 18 to drive the steel pipe 16 to continue to move and rotate until the next part to be shaped moves to directly above the lower die base 7. Repeat steps S3 - S6 to shape the next part to be shaped, and proceed in sequence until the shaping of the entire steel pipe 16 is completed.

[0053] The shaping equipment described in the present invention is applicable to large thick-walled steel pipes with an inner diameter of not less than 508 mm and a wall thickness of not less than 10 mm.

[0054] Therefore, the large steel pipe local shaping equipment and shaping method with the above structure of the present invention can solve the problem that it is difficult to shape the local part of large steel pipes, and has the advantages of simple structure and convenient use.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A shaping method for a local shaping device of large steel pipes, characterized in that: It includes the following steps: S1. According to the size of the steel pipe to be shaped, fix the die pieces adapted to the steel pipe on the upper die frame and the lower die frame through bolts. S2. Lift and place the steel pipe onto the conveying rollers. The steel pipe moves under the action of the conveying rollers and is conveyed above the die piece of the lower die frame of the shaping machine. S3. Start the rotating rollers, drive the steel pipe to rotate around the axis through the rotating rollers, so as to adjust the part of the steel pipe to be shaped to directly above the steel pipe. S4. Place the support seat together with the shaping hydraulic cylinder inside the steel pipe, adjust the position of the shaping hydraulic cylinder, and place the inner support die on the top of the telescopic rod of the shaping hydraulic cylinder. S5. Place the outer support die on the outer wall of the steel pipe. When shaping the depression on the steel pipe, one inner support die is set and two outer support dies are set. The inner support die is located directly below the part to be shaped, and the outer support dies are located on both sides of the part to be shaped. The depression is shaped by driving the inner support die to move upward through the shaping hydraulic cylinder. When shaping the protrusion on the steel pipe, two inner support dies are set and one outer support die is set. The outer support die is located directly above the part to be shaped, and the inner support dies are located on both sides of the part to be shaped. The protrusion is shaped by driving the outer support die to move downward through the upper die seat. Drive the upper die seat to move downward through the pressing hydraulic cylinder, thereby driving the outer support die to move downward, and then pressing the outer support die between the steel pipe and the die piece of the upper die seat to shape the protrusion. S6. After shaping is completed, the shaping hydraulic cylinder moves downward, and the upper die seat moves upward under the action of the pressing hydraulic cylinder, and the outer support die is removed. S7. Start the conveying rollers and the rotating rollers, drive the steel pipe to continue to move and rotate until the next part to be shaped, and shape the next part to be shaped. The large steel pipe local shaping equipment includes a shaping machine. Conveying mechanisms for conveying steel pipes are arranged on both sides of the shaping machine, and the shaping machine and the conveying mechanisms are located on the same straight line. The shaping machine includes a base, a cross beam is arranged above the base, a power element for driving the cross beam to move up and down along the column is arranged on the base, and the column is fixed on the base. A moving element for driving the upper die seat to move is arranged on the cross beam, a lower die seat adapted to the upper die seat is arranged on the base, die pieces for placing the steel pipe are arranged on both the upper die seat and the lower die seat, a local inner shaping structure of the steel pipe is arranged inside the steel pipe, and a local outer shaping structure of the steel pipe is arranged between the steel pipe and the die piece of the upper die seat. The moving element is a pressing hydraulic cylinder. The pressing hydraulic cylinder is fixed on the cross beam, and the telescopic rod of the pressing hydraulic cylinder is fixedly connected with the upper die seat. A semi-circular upper die frame is arranged on the lower surface of the upper die seat, and a semi-circular lower die frame is arranged on the upper surface of the lower die seat. The local inner shaping structure includes a shaping hydraulic cylinder. A support seat is arranged at the bottom of the shaping hydraulic cylinder. The lower surface of the support seat is an arc surface adapted to the inner wall of the steel pipe, and an inner support die is arranged on the telescopic rod of the shaping hydraulic cylinder. The local outer shaping structure includes an outer support die. The lower surface of the outer support die is an arc surface adapted to the outer wall of the steel pipe. The outer support die is a free steel plate and does not need to be fixed on the die piece or the steel pipe. The outer support die is fixed between the die piece and the steel pipe by the pressure of the pressing hydraulic cylinder to shape the steel pipe. The conveying mechanism is symmetrically arranged on both sides of the shaping machine. The conveying mechanism includes a number of conveying rollers, and the steel pipe is located above the conveying rollers. A rotating roller is arranged between the conveying rollers, and the rotating direction of the rotating roller is perpendicular to the rotating direction of the conveying rollers; the two rollers of the rotating roller are symmetrically arranged on both sides of the steel pipe.

2. The shaping method of a local shaping device for large steel pipes according to claim 1, characterized in that: The power element is a jacking hydraulic cylinder, and the jacking hydraulic cylinder is fixed on the base. The telescopic rod of the jacking hydraulic cylinder is fixedly connected to the cross beam; through holes for the upright columns to pass through are arranged at both ends of the cross beam, and the cross beam is slidably connected to the upright columns.

3. The shaping method of a local shaping device for large steel pipes according to claim 1, characterized in that: The die plate is fixed on the upper die frame and the lower die frame by bolts; a number of stiffening plates are evenly arranged between the upper die frame and the upper die base, and a number of stiffening plates are evenly arranged between the lower die frame and the lower die base.

4. The shaping method of a large steel pipe partial shaping device according to claim 1, characterized in that: The top surface of the inner support die is an arc surface adapted to the inner wall of the steel pipe.

5. The shaping method of a large steel pipe partial shaping device according to claim 1, characterized in that: The inner diameter of the steel pipe is not less than 508 mm, and the wall thickness is not less than 10 mm.

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