A stamping forming method for socket and spigot flexible joint steel pipes

Abstract

The present invention discloses a stamping forming method for socket-type flexible joint steel pipes, belonging to the technical field of socket-type pipe forming. The stamping forming method for socket-type flexible joint steel pipes comprises the following steps: processing the end of the steel pipe; feeding the steel pipe into a stamping device, inserting a punch into the heated end of the steel pipe, and stamping and flaring one end of the steel pipe to form; feeding the steel pipe into a flat-mouth device to flat-mouth the flared end of the steel pipe; feeding the steel pipe after flat-mouth treatment into a forming device, forming the socket end through a socket forming mechanism arranged at one end of the forming device, and forming the spigot end through a spigot forming mechanism arranged at the other end of the forming device; feeding the formed steel pipe into an inspection table for inspection, removing burrs at both ends of the steel pipe and polishing to obtain a socket-type flexible joint steel pipe. By adopting the stamping forming method for socket-type flexible joint steel pipes of the present invention, the problems of low forming quality and high defective product rate of the existing socket-type flexible joint steel pipes can be solved.

Description

Technical Field

[0001] The present invention relates to the technical field of socket-and-spigot pipe forming, and particularly to a stamping forming method for socket-and-spigot flexible joint steel pipes. Background Art

[0002] Socket-and-spigot steel pipes are the most commonly used pipes for laying in engineering construction. In daily use, socket-and-spigot steel pipes are one of the most effective and convenient connection methods for steel pipes. For socket-and-spigot steel pipes, one end port of the steel pipe needs to be reamed to form a docking interface for the steel pipe. The production of socket-and-spigot steel pipes generally adopts one-time flaring forming. During the processing of the steel pipe, due to work hardening, the hardness of the steel pipe increases, and after flaring, the end face of the socket cannot be perpendicular to the pipe diameter, which affects the forming quality of the socket-and-spigot steel pipe.

[0003] The existing patent CN201511006231.4 discloses a socket-and-spigot steel pipe and its processing method. First, the steel pipe is placed on a rolling flaring machine, and the rolling flaring mechanism is used to flare the steel pipe. Then, it is placed on a flanging die machine for flanging to form the socket part. Finally, barbs and necking are performed on the end of the spigot part to obtain the socket-and-spigot steel pipe. The above patent uses the method of rotary expansion cold processing to process the socket part of the steel pipe. During the processing, the grinding head of the rolling flaring mechanism drives the steel pipe to rotate, thereby forming the socket part. In this processing method, the socket part of the steel pipe is formed during rotation, resulting in relatively low processing accuracy of the socket part and relatively low processing accuracy of the sealing positioning groove, causing the sealing ring to slip and affecting the sealing effect. Moreover, during the processing of the steel pipe, due to work hardening, the hardness of the socket part increases and the brittleness increases, which easily causes cracking of the socket part, affecting the strength of the socket part, resulting in easy damage to the socket part, and affecting the service life of the socket-and-spigot pipe. When forming small-diameter socket-and-spigot steel pipes, it is easier to cause cracking and damage of the socket part, affecting the forming rate and forming efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a stamping forming method for socket-and-spigot flexible joint steel pipes, so as to solve the problems of low forming quality and high defective rate of existing socket-and-spigot flexible joint steel pipes.

[0005] To achieve the above purpose, the present invention provides a stamping forming method for socket-and-spigot flexible joint steel pipes, including the following steps:

[0006] S1. Process the end of the steel pipe;

[0007] S2. Send the processed steel pipe into the stamping device through a feeding trolley, insert the punch into the heated end of the steel pipe, and perform stamping flaring forming on one end of the steel pipe;

[0008] S3. Send the flared steel pipe into the end-facing device through a feeding trolley, and end-face the flared end of the steel pipe;

[0009] S4. Feed the steel pipe with a flat end into the forming device. The socket end is formed by the socket forming mechanism provided at one end of the forming device, and the spigot end is formed by the spigot forming mechanism provided at the other end of the forming device.

[0010] S5. Feed the formed steel pipe into the inspection table for inspection, remove the burrs at both ends of the steel pipe and polish it to obtain a socket and spigot flexible joint steel pipe.

[0011] Preferably, in S1, the steel pipe is a straight seam welded pipe, a spiral welded pipe or a seamless steel pipe, and the nominal diameter of the steel pipe is 50mm - 250mm.

[0012] Preferably, in S1, the treatment of the steel pipe end includes grinding and leveling the inner weld and outer weld of the steel pipe so that the weld is flush with the pipe wall.

[0013] Preferably, in S2, the stamping device includes a first base. Above the first base, there is a support frame. At one end of the support frame, there is a stamping mechanism for stamping the steel pipe end. On the support frame, there is a heating structure for heating the steel pipe end. The heating structure is sleeved outside the punch of the stamping mechanism. On the first base, there is a clamping seat for clamping the steel pipe and a positioning wheel for supporting and positioning the steel pipe. At the other end of the support frame, there is a baffle that has a blocking effect on the steel pipe.

[0014] Preferably, the stamping mechanism includes a stamping shaft. The stamping shaft is arranged on a sliding seat. On the support frame, there is a pushing element for driving the sliding seat to slide on the first base. On the first base, there is a guide rail for guiding the sliding of the sliding seat. On the base, there is a power source for driving the pushing element to act. The punch is arranged at the end of the stamping shaft, and the punch is coaxially arranged with the stamping shaft.

[0015] Preferably, the heating structure includes a heating sleeve. The heating sleeve is sleeved outside the punch. The heating sleeve is coaxially arranged with the punch. The steel pipe is located between the heating sleeve and the punch. Inside the heating sleeve, there is a heating coil. The heating coil is connected to a thermal effector. The thermal effector is connected to the sliding seat through a connecting plate, and the sliding seat drives the thermal effector to slide synchronously.

[0016] Preferably, on the top of the feeding trolley in S2 and S3, there is a limiting groove for limiting the steel pipe, and on the bottom of the feeding trolley, there are rollers.

[0017] Preferably, in S3, the flat end device includes a second base. At one end of the second base, there is a cutting knife. The cutting knife is arranged on the ground through a fixing frame. Above the second base, there is a support wheel for supporting the steel pipe. On the second base, there is a first motor for driving the support wheel to rotate.

[0018] Preferably, in S4, the socket forming mechanism includes a socket inner mold rotatably arranged on a first fixed seat. A second motor for driving the socket inner mold to rotate is arranged on the first fixed seat. A socket outer mold is arranged above the socket inner mold. A first lifting element for driving the socket outer mold to lift is arranged on the first fixed seat. The spigot forming mechanism includes a spigot inner mold rotatably arranged on a second fixed seat. A third motor for driving the spigot inner mold to rotate is arranged on the second fixed seat. A spigot outer mold is arranged above the spigot inner mold. A second lifting element for driving the spigot outer mold to lift is arranged on the second fixed seat. The first fixed seat and the second fixed seat are respectively arranged on a third base. Directional wheels for supporting the steel pipe are arranged on the third base. Tightening mechanisms for tightening the steel pipe are arranged at both ends of the directional wheels.

[0019] Preferably, the tightening mechanism includes a top wheel arranged at one end of a sleeve. A screw rod for driving the top wheel to move is arranged in the sleeve. The top wheel is rotatably connected to the screw rod. The screw rod is threadedly connected to the sleeve. A fourth motor for driving the screw rod to rotate is arranged on the sleeve. The sleeve is arranged on the third base through a support leg. A lifting element for driving the support leg to lift is arranged on the third base.

[0020] The advantages and positive effects of the socket and spigot flexible joint steel pipe stamping forming method of the present invention are as follows:

[0021] 1. The present invention uses a stamping device to flare the end of the steel pipe, realizing one-step forming of the flare of the steel pipe end, which is beneficial to improving the processing efficiency of the socket flare.

[0022] 2. The present invention sets a heating sleeve outside the punch. The thermal effector heats the heating sleeve through a heating coil, and then heats the steel pipe through the heating sleeve. Heating the end of the steel pipe is beneficial to improving the plasticity and toughness of the steel pipe end, avoiding large work hardening and internal stress during the processing of small-diameter steel pipes, avoiding stamping cracking, improving the forming effect of the socket of small-diameter steel pipes, and reducing the rejection rate.

[0023] 3. The present invention sets a flat-end process after stamping and flaring. When the steel pipe is stamped and flared on the stamping device, the deformation amounts of the ends of the steel pipe are inconsistent, resulting in a certain inclination of the ends of the steel pipe, affecting the subsequent socket forming, restricting the corner of the flexible joint steel pipe, and further affecting the sealing effect of the pipeline. By using a flat-end device to perform flat-end cutting on the flared pipeline, the straightness of the pipeline end is ensured, and the port is perpendicular to the axis, which is beneficial to improving the forming effect and accuracy of the socket.

[0024] 4. During the stamping and flaring process of the steel pipe, the steel pipe is heated by a heating coil, which changes the internal tissue structure of the steel pipe, reduces the residual stress at the socket end of the steel pipe, and alleviates the work hardening at the socket end of the steel pipe, thus facilitating the forming of the socket end; making the rib perpendicular to the axis of the steel pipe and having a consistent width of the rib, ensuring the perpendicularity on both sides of the positioning groove, enabling the positioning groove to be in full contact with the sealing rubber ring, improving the stability of the installation of the sealing rubber ring, and being conducive to enhancing the sealing effect.

[0025] The following will further describe the technical solutions of the present invention in detail through the accompanying drawings and embodiments. Description of the Drawings

[0026] Figure 1 is the flowchart of the embodiment of the present invention;

[0027] Figure 2 is the structural schematic diagram of the stamping device of the embodiment of the present invention;

[0028] Figure 3 is the structural schematic diagram of the punch of the embodiment of the present invention;

[0029] Figure 4 is the structural schematic diagram of the feeding trolley of the embodiment of the present invention;

[0030] Figure 5 is the structural schematic diagram of the flat - mouth device of the embodiment of the present invention;

[0031] Figure 6 is the structural schematic diagram of the forming device of the embodiment of the present invention;

[0032] Figure 7 is the structural schematic diagram of the jacking mechanism of the embodiment of the present invention;

[0033] Figure 8 is the structural schematic diagram of the steel pipe after stamping of the embodiment of the present invention;

[0034] Figure 9 is the structural schematic diagram of the steel pipe after flat - mouthing of the embodiment of the present invention;

[0035] Figure 10 is the structural schematic diagram of the socket - and - spigot steel pipe of the embodiment of the present invention.

[0036] Reference Signs

[0037] 1. First base; 2. Support frame; 3. Slide base; 4. Pushing element; 5. Power source; 6. Stamping shaft; 7. Punch; 8. Thermal effector; 9. Connecting plate; 10. Heating sleeve; 11. Heating coil; 12. Baffle; 13. Clamping seat; 14. Positioning wheel; 15. Feeding trolley; 16. Limit groove; 17. Roller; 18. Second base; 19. Support wheel; 20. First motor; 21. Fixed frame; 22. Cutting knife; 23. Third base; 24. First fixing seat; 25. Socket inner mold; 26. Socket outer mold; 27. First lifting element; 28. Second motor; 29. Second fixing seat; 30. Third motor; 31. Spigot inner mold; 32. Spigot outer mold; 33. Second lifting element; 34. Directional wheel; 35. Top wheel; 36. Sleeve; 37. Fourth motor; 38. Support leg; 39. Socket end; 40. Spigot end; 41. Positioning groove; 42. Rib. Detailed implementation manners

[0038] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention. In the description of the present invention, it should also be noted that unless otherwise clearly specified and limited, the terms "set", "installed", "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0039] The following will describe the implementation manners of the present invention in detail with reference to the drawings.

[0040] As Figure 1 shown. A stamping forming method for a socket-and-spigot flexible joint steel pipe includes the following steps:

[0041] S1. Process the end of the steel pipe.

[0042] The steel pipe is a straight seam welded pipe, a spiral welded pipe or a seamless steel pipe. When the liquid pressure inside the steel pipe is relatively large, a seamless steel pipe is used. When the liquid pressure inside the steel pipe is relatively small, a straight seam welded pipe or a threaded welded pipe is used to reduce the cost of the steel pipe. The nominal diameter of the steel pipe is 50 mm - 250 mm, belonging to small-diameter steel pipes.

[0043] For straight seam welded pipes or threaded welded pipes, the treatment of the pipe ends includes grinding and leveling the internal and external welds at the positions where the pipe is processed into socket and spigot ends, making the welds flush with the pipe wall to facilitate the smooth transition of the die.

[0044] S2. Feed the treated steel pipe into the stamping device through the feeding trolley 15. Insert the punch 7 into the heated pipe end of the steel pipe to perform stamping and flaring on one end of the steel pipe. The state of the steel pipe after stamping and flaring is as Figure 8 shown.

[0045] As Figure 2 shown. The stamping device includes a first base 1, and the first base 1 is fixed on the ground. A support frame 2 is fixedly arranged above the first base 1. One end of the support frame 2 is provided with a stamping mechanism for stamping the pipe end. A heating structure for heating the pipe end is arranged on the support frame 2, and the heating structure is sleeved outside the punch 7 of the stamping mechanism.

[0046] The stamping mechanism includes a stamping shaft 6, and the stamping shaft 6 is fixedly arranged on the sliding seat 3. A pushing element 4 for driving the sliding seat 3 to slide on the first base 1 is fixedly arranged on the support frame 2. The pushing element 4 is selected as a hydraulic cylinder, the piston rod of the hydraulic cylinder is fixedly connected with the sliding seat 3, and the hydraulic cylinder is fixedly arranged on the support frame 2. A power source 5 for driving the hydraulic cylinder to act is arranged on the base, and the power source 5 is an existing hydraulic system. A guide rail for guiding the sliding of the sliding seat 3 is fixedly arranged on the first base 1, and the sliding seat 3 moves along the axis of the steel pipe under the action of the guide rail. The punch 7 is fixedly arranged at the end of the stamping shaft 6, and the punch 7 is coaxially arranged with the stamping shaft 6.

[0047] As Figure 3 shown. The heating structure includes a heating sleeve 10, and the heating sleeve 10 can be made of metal copper material, which has a good heat conduction effect. The heating sleeve 10 is sleeved outside the punch 7, and the heating sleeve 10 is coaxially arranged with the punch 7. The steel pipe is located between the heating sleeve 10 and the punch 7. A heating coil 11 is arranged inside the heating sleeve 10, and the heating coil 11 is connected with the thermal effector 8. The thermal effector 8 is fixedly connected with the sliding seat 3 through the connecting plate 9. The sliding seat 3 drives the thermal effector 8 to slide synchronously, so that the heating coil 11 moves synchronously with the punch 7 to heat the steel pipe while stamping.

[0048] The thermal effector 8 heats the heating sleeve 10 through the heating coil 11, and then heats the steel pipe through the heating sleeve 10. Heating the pipe end is beneficial to improving the plasticity and toughness of the pipe end, avoiding large work hardening and internal stress during the processing of small-diameter steel pipes, preventing stamping cracking, improving the forming effect of the socket of small-diameter steel pipes, and reducing the rejection rate. Using the punch 7 to stamp the steel pipe can achieve one-step forming of the socket flaring and improve the socket flaring efficiency.

[0049] A clamping seat 13 for clamping the steel pipe and a positioning wheel 14 for supporting and positioning the steel pipe are provided on the first base 1. The height of the clamping seat 13 can be adjusted by a cylinder or a hydraulic cylinder, and the steel pipe is fixed by the clamp on the clamping seat 13 to prevent the steel pipe from moving and rotating during the flaring process. The height of the positioning wheel 14 can also be adjusted by a cylinder or a hydraulic cylinder, and the positioning wheel 14 is used to support and position the steel pipe. A baffle 12 that blocks the steel pipe is provided at the other end of the support frame 2.

[0050] S3. The flared steel pipe is sent into the end-facing device by the feeding trolley 15 to face the flared end of the steel pipe. The state of the steel pipe after end-facing is as Figure 9 shown.

[0051] As Figure 5 shown. The end-facing device includes a second base 18, and the second base 18 is fixed on the ground. A cutting knife 22 is provided at one end of the second base 18, and the cutting knife 22 is fixedly arranged on the ground through a fixing frame 21. The cutting knife 22 is used to face and cut the end of the steel pipe. A support wheel 19 for supporting the steel pipe is provided above the second base 18, and a first motor 20 for driving the support wheel 19 to rotate is provided on the second base 18. The first motor 20 drives the steel pipe to rotate through the support wheel 19, so as to face and cut the end of the steel pipe by the cutting knife 22.

[0052] When the steel pipe is flared by stamping on the stamping device, the deformation amounts at the ends of the steel pipe are inconsistent, resulting in a certain inclination at the ends of the steel pipe, which affects the subsequent formation of the socket, restricts the corner of the flexible joint steel pipe, and further affects the sealing effect of the pipeline. By using the end-facing device to face and cut the flared pipeline, the straightness of the pipeline end is ensured, and the port is perpendicular to the axis, which is beneficial to improving the forming effect and accuracy of the socket.

[0053] As Figure 4 shown. A limiting groove 16 for limiting the steel pipe is provided at the top of the feeding trolley 15, and rollers 17 are provided at the bottom of the feeding trolley 15. The pipeline is transported between the stamping device and the end-facing device by the feeding trolley 15.

[0054] S4. The steel pipe after end-facing treatment is sent into the forming device, and the socket end 39 is formed by the socket forming mechanism provided at one end of the forming device, and the spigot end 40 is formed by the spigot forming mechanism provided at the other end of the forming device. The state of the steel pipe after forming is as Figure 10 shown.

[0055] As Figure 6As shown in the figure. The socket forming mechanism includes a socket inner mold 25, and the socket inner mold 25 is rotatably arranged on the first fixed seat 24 through a bearing. A second motor 28 for driving the socket inner mold 25 to rotate is fixedly arranged on the first fixed seat 24. A socket outer mold 26 is arranged above the socket inner mold 25, and a first lifting element 27 for driving the socket outer mold 26 to lift is fixedly arranged on the first fixed seat 24. The first lifting element 27 can be a hydraulic cylinder or a pneumatic cylinder, and the socket outer mold 26 is driven to lift by the first lifting element 27.

[0056] The spigot forming mechanism includes a spigot inner mold 31, and the spigot inner mold 31 is rotatably arranged on the second fixed seat 29 through a bearing. A third motor 30 for driving the spigot inner mold 31 to rotate is fixedly arranged on the second fixed seat 29. A spigot outer mold 32 is arranged above the spigot inner mold 31, and a second lifting element 33 for driving the spigot outer mold 32 to lift is fixedly arranged on the second fixed seat 29. The second lifting element 33 is a pneumatic cylinder or a hydraulic cylinder.

[0057] The first fixed seat 24 and the second fixed seat 29 are both fixedly arranged on the third base 23. A directional wheel 34 for supporting the steel pipe is arranged on the third base 23, and the directional wheel 34 is located between the first fixed seat 24 and the second fixed seat 29. A pneumatic cylinder or a hydraulic cylinder for driving the directional wheel 34 to lift is arranged on the third base 23, so as to support the steel pipe through the directional wheel 34.

[0058] As Figure 7 shown. Tightening mechanisms for tightening the steel pipe are arranged at both ends of the directional wheel 34. The two tightening mechanisms are used respectively during socket forming and spigot forming. The tightening mechanism includes a top wheel 35, and the top wheel 35 is arranged at one end of the sleeve 36. A screw rod for driving the top wheel 35 to move is arranged in the sleeve 36, and the top wheel 35 is rotatably connected to the screw rod through a bearing. The screw rod is in threaded transmission connection with the sleeve 36. A fourth motor 37 for driving the screw rod to rotate is arranged on the sleeve 36. The sleeve 36 is arranged on the third base 23 through a support leg 38, and a lifting element for driving the support leg 38 to lift is arranged on the third base 23. The lifting element can be a pneumatic cylinder or a hydraulic cylinder. The height of the top wheel 35 is adjusted through the lifting element to prevent the top wheel 35 from hindering the placement and forming of the steel pipe.

[0059] When forming the steel pipe, insert the socket end 39 of the steel pipe into the outside of the socket inner mold 25. The socket inner mold 25 contacts the inner wall of the steel pipe, lift the directional wheel 34, and the directional wheel 34 supports below the steel pipe. Move the top wheel 35 to the tail end of the steel pipe. The fourth motor 37 drives the top wheel 35 to move through the screw rod, and the top wheel 35 is tightened against the tail end of the steel pipe. The second motor 28 drives the socket inner mold 25 to rotate, and the socket inner mold 25 drives the steel pipe to rotate synchronously. The first lifting element 27 drives the socket outer mold 26 to descend, and the socket outer mold 26 presses on the outside of the steel pipe to form the socket of the steel pipe.

[0060] After the socket machining is completed, the fourth motor 37 drives the screw rod to reverse, the top wheel 35 moves out from the tail end of the steel pipe, and the steel pipe is removed from the socket inner mold 25. Slide the steel pipe and insert the other end of the steel pipe into the outside of the spigot inner mold 31. The top wheel 35 moves to the socket end 39 of the steel pipe, and the fourth motor 37 drives the top wheel 35 to move through the screw rod. The top wheel 35 presses tightly against the socket end 39 of the steel pipe. The third motor 30 drives the spigot inner mold 31 to rotate, the spigot inner mold 31 drives the steel pipe to rotate synchronously, the second lifting element 33 drives the spigot outer mold 32 to descend, and the spigot outer mold 32 presses against the outside of the steel pipe to form the spigot of the steel pipe.

[0061] During the stamping and flaring process of the steel pipe, the steel pipe is heated by the heating coil 11, which changes the internal tissue structure of the steel pipe, reduces the residual stress at the socket end 39 of the steel pipe, and alleviates the work hardening at the socket end 39 of the steel pipe, thus being beneficial to the forming of the socket end 39; making the flange 42 perpendicular to the axis of the steel pipe and the width of the flange 42 consistent, ensuring the perpendicularity on both sides of the positioning groove 41, enabling the positioning groove 41 to be in full contact with the sealing rubber ring, improving the stability of the installation of the sealing rubber ring, and being beneficial to improving the sealing effect.

[0062] S5. Send the formed steel pipe to the inspection table for inspection, remove the burrs at both ends of the steel pipe and polish it to obtain a socket and spigot flexible joint steel pipe.

[0063] Therefore, by adopting the stamping forming method of the socket and spigot flexible joint steel pipe of the present invention, the problems of low forming quality and high defective rate of the existing socket and spigot flexible joint steel pipe can be solved.

[0064] 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 stamping forming method for socket and spigot flexible joint steel pipes, characterized in that, It includes the following steps: S1. Process the end of the steel pipe; S2. Feed the processed steel pipe into the stamping device through a feeding trolley. The punch is inserted into the heated end of the steel pipe to stamp and flare one end of the steel pipe; S3. Feed the flared steel pipe into the end-facing device through a feeding trolley to face the flared end of the steel pipe; S4. Feed the steel pipe after end-facing into the forming device. The socket forming mechanism arranged at one end of the forming device forms the socket end, and the spigot forming mechanism arranged at the other end of the forming device forms the spigot end; S5. Feed the formed steel pipe into the inspection table for inspection, remove the burrs at both ends of the steel pipe and polish it to obtain a socket and spigot flexible joint steel pipe; In S1, the steel pipe is a straight seam welded pipe, a spiral welded pipe or a seamless steel pipe, and the nominal diameter of the steel pipe is 50mm - 250mm; In S4, the socket forming mechanism includes a socket inner mold which is rotatably arranged on a first fixed seat. A second motor for driving the socket inner mold to rotate is arranged on the first fixed seat. A socket outer mold is arranged above the socket inner mold. A first lifting element for driving the socket outer mold to lift is arranged on the first fixed seat. The spigot forming mechanism includes a spigot inner mold which is rotatably arranged on a second fixed seat. A third motor for driving the spigot inner mold to rotate is arranged on the second fixed seat. A spigot outer mold is arranged above the spigot inner mold. A second lifting element for driving the spigot outer mold to lift is arranged on the second fixed seat. The first fixed seat and the second fixed seat are respectively arranged on a third base. Directional wheels for supporting the steel pipe are arranged on the third base. Tightening mechanisms for tightening the steel pipe are arranged at both ends of the directional wheels; The tightening mechanism includes a top wheel which is arranged at one end of a sleeve. A screw rod for driving the top wheel to move is arranged in the sleeve. The top wheel is rotatably connected to the screw rod. The screw rod is threadedly connected to the sleeve. A fourth motor for driving the screw rod to rotate is arranged on the sleeve. The sleeve is arranged on the third base through a support leg. A lifting element for driving the support leg to lift is arranged on the third base; In S2, the stamping device includes a first base. A support frame is arranged above the first base. A stamping mechanism for stamping the end of the steel pipe is arranged at one end of the support frame. A heating structure for heating the end of the steel pipe is arranged on the support frame. The heating structure is sleeved outside the punch of the stamping mechanism. A clamping seat for clamping the steel pipe and a positioning wheel for supporting and positioning the steel pipe are arranged on the first base. A baffle for blocking the steel pipe is arranged at the other end of the support frame; The heating structure includes a heating sleeve which is sleeved outside the punch. The heating sleeve is coaxially arranged with the punch. The steel pipe is located between the heating sleeve and the punch. A heating coil is arranged inside the heating sleeve. The heating coil is connected to a thermal effector. The thermal effector is connected to a sliding seat through a connecting plate. The sliding seat drives the thermal effector to slide synchronously; 2. A stamping forming method for a socket-type flexible joint steel pipe according to claim 1, characterized in that: In S1, the processing of the steel pipe end includes grinding and leveling the inner weld and outer weld of the steel pipe so that the weld is flush with the pipe wall.

3. A stamping forming method for a socket-type flexible joint steel pipe according to claim 1, characterized in that: The stamping mechanism includes a stamping shaft, the stamping shaft is arranged on a sliding seat, a pushing element for driving the sliding seat to slide on the first base is arranged on the support frame, a guide rail for guiding the sliding of the sliding seat is arranged on the first base, a power source for driving the pushing element to act is arranged on the base, a punch is arranged at the end of the stamping shaft, and the punch is coaxially arranged with the stamping shaft.

4. A stamping forming method for a socket-type flexible joint steel pipe according to claim 1, characterized in that: In S2 and S3, a limiting groove for a limiting steel pipe is arranged at the top of the feeding trolley, and rollers are arranged at the bottom of the feeding trolley.

5. A punching and forming method for a socket-type flexible joint steel pipe according to claim 1, characterized in that: In S3, the flat mouth device includes a second base, a cutting knife is arranged at one end of the second base, the cutting knife is arranged on the ground through a fixing frame, a supporting wheel for supporting the steel pipe is arranged above the second base, and a first motor for driving the supporting wheel to rotate is arranged on the second base.

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