Socket and spigot type flexible connector steel pipe punch forming method

Abstract

The invention discloses a bell-and-spigot type flexible connector steel pipe punch forming method, and belongs to the technical field of bell-and-spigot type pipeline forming. The invention discloses a bell and spigot type flexible connector steel pipe punch forming method. The method comprises the following steps that the end of a steel pipe is treated; the steel pipe is fed into a stamping device, a punch is inserted into the heated end of the steel pipe, and stamping flaring forming is conducted on one end of the steel pipe; the steel pipe is fed into a flattening device, and the flaring end of the steel pipe is flattened; the steel pipe subjected to end flattening treatment is fed into a forming device, a bell end is formed through a bell end forming mechanism arranged at one end of the forming device, and a spigot end is formed through a spigot forming mechanism arranged at the other end of the forming device; and the formed steel pipe is fed into an inspection bench to be inspected, burrs at the two ends of the steel pipe are removed, polishing is conducted, and the socket type flexible connector steel pipe is obtained. By the adoption of the punch forming method for the socket type flexible connector steel pipe, the problems that an existing socket type flexible connector steel pipe is low in forming quality and high in defective rate can be solved.

Description

Technical Field

[0001] The invention relates to the technical field of socket-and-spigot pipe forming, and in particular to a method for stamping and forming a socket-and-spigot flexible interface steel pipe. Background Art

[0002] Socket-and-spigot steel pipe is the most commonly used laying pipeline in engineering construction. In daily use, socket-and-spigot steel pipe is the most effective and convenient connection method for steel pipe connection. Socket-and-spigot steel pipe requires the port at one end of the steel pipe to be expanded to form a steel pipe docking interface. The production of socket-and-spigot steel pipe generally adopts one-time expansion molding. During the processing of steel pipe, the hardness of the steel pipe increases due to work hardening. After expansion, the end face of the socket cannot be perpendicular to the pipe diameter, which affects the molding quality of the socket-and-spigot steel pipe.

[0003] The existing patent CN201511006231.4 discloses a socket-type steel pipe and a processing method thereof. First, the steel pipe is placed on a rolling and expanding machine, and the steel pipe is expanded by a rolling and expanding mechanism. Then, the steel pipe is placed on a flanging die press for flanging to form a socket part. Finally, the end of the spigot part is barbed and closed to obtain a socket-type steel pipe. The above patent uses a rotary expansion cold processing method to process the socket part of the steel pipe. During the processing, the steel pipe is driven to rotate by the grinding head of the rolling and expanding mechanism to form the socket part. In this processing method, the socket part of the steel pipe is formed during the rotation process, resulting in a relatively low processing accuracy of the socket part, and a relatively low processing accuracy of the sealing positioning groove, resulting in a slip ring of the sealing ring, which affects the sealing effect. In addition, the hardness of the socket part increases and the brittleness increases due to work hardening during the processing of the steel pipe, which easily causes the socket part to crack, affects the strength of the socket part, causes the socket part to be easily damaged, and affects the service life of the socket-type pipe. When forming small-diameter socket-type steel pipes, it is more likely to cause cracking and damage to 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 method for stamping and forming a socket-and-spigot type flexible joint steel pipe, so as to solve the problems of low forming quality and high defective rate of the existing socket-and-spigot type flexible joint steel pipe.

[0005] To achieve the above object, the present invention provides a method for stamping and forming a socket-type flexible joint steel pipe, comprising the following steps: S1. Process the ends of the steel pipe; S2, the processed steel pipe is fed into the stamping device through the feeding trolley, the punch is inserted into the heated steel pipe end, and one end of the steel pipe is stamped and expanded; S3, the expanded steel pipe is fed into the flattening device through the feeding trolley to flatten the expanded end of the steel pipe; S4, sending the flat-end processed steel pipe into a forming device, forming the socket end by a socket forming mechanism provided at one end of the forming device, and forming the spigot end by a spigot forming mechanism provided at the other end of the forming device; S5. Send the formed steel pipe to the inspection table for inspection, remove burrs at both ends of the steel pipe and grind it to obtain a socket-type flexible interface steel pipe.

[0006] 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 50 mm-250 mm.

[0007] Preferably, in S1, the steel pipe end treatment includes grinding and smoothing the inner weld and the outer weld of the steel pipe so that the weld is flush with the pipe wall.

[0008] Preferably, 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 on the outside of 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, and a baffle for blocking the steel pipe is arranged at the other end of the support frame.

[0009] Preferably, the stamping mechanism includes a stamping shaft, which is arranged on a slide, a supporting frame is provided with a pushing element for driving the slide to slide on the first base, a guide rail for guiding the sliding of the slide is arranged on the first base, a power source for driving the pushing element to move is arranged on the base, a punch is arranged on the end of the stamping shaft, and the punch is coaxially arranged with the stamping shaft.

[0010] Preferably, the heating structure includes a heating sleeve, which is sleeved on the outside of the punch. The heating sleeve and the punch are coaxially arranged, and the steel pipe is located between the heating sleeve and the punch. A heating coil is arranged inside the heating sleeve, and the heating coil is connected to the thermal effector. The thermal effector is connected to the slide seat through a connecting plate, and the slide seat drives the thermal effector to slide synchronously.

[0011] Preferably, a limiting groove of a limiting steel pipe is provided on the top of the feeding trolley in S2 and S3, and a roller is provided on the bottom of the feeding trolley.

[0012] Preferably, in S3, the flat-mouth device includes a second base, a cutting knife is provided at one end of the second base, the cutting knife is set on the ground through a fixed frame, a supporting wheel for supporting the steel pipe is provided above the second base, and a first motor for driving the supporting wheel to rotate is provided on the second base.

[0013] Preferably, 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, and a first lifting element for driving the socket outer mold to rise and fall is arranged on the first fixed seat; the plug forming mechanism includes a plug inner mold, which is rotatably arranged on a second fixed seat, a third motor for driving the plug inner mold to rotate is arranged on the second fixed seat, a plug outer mold is arranged above the plug inner mold, and a second lifting element for driving the plug outer mold to rise and fall is arranged on the second fixed seat; the first fixed seat and the second fixed seat are respectively arranged on a third base, a directional wheel for supporting the steel pipe is arranged on the third base, and a tightening mechanism for tightening the steel pipe is arranged at both ends of the directional wheel.

[0014] Preferably, the tightening mechanism includes a top wheel, which is arranged at one end of the sleeve, a screw rod for driving the top wheel to move is arranged inside 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 the support legs, and a lifting element for driving the support legs to rise and fall is arranged on the third base.

[0015] The advantages and positive effects of the punching and forming method of the socket-type flexible joint steel pipe described in the present invention are: 1. The present invention adopts a punching device to expand the end of the steel pipe, thereby realizing one-step forming of the expansion of the end of the steel pipe, which is beneficial to improving the processing efficiency of the socket expansion.

[0016] 2. The present invention sets a heating sleeve outside the punch, and the thermal effector heats the heating sleeve through the heating coil, thereby heating the steel pipe through the heating sleeve. Heating the steel pipe end is beneficial to improve the plasticity and toughness of the steel pipe end, avoid large work hardening and internal stress of small-diameter steel pipes during processing, avoid stamping cracking, improve the small-diameter steel pipe socket forming effect, and reduce the scrap rate.

[0017] 3. The present invention sets a flat-end process after punching and expanding. When the steel pipe is punched and expanded on the punching device, the deformation of the steel pipe end is inconsistent, resulting in a certain inclination of the steel pipe end, which affects the subsequent socket forming and restricts the turning angle of the flexible interface steel pipe, thereby affecting the sealing effect of the pipeline. The flat-end device is used to flat-cut the expanded pipe to ensure the straightness of the pipe end and make the port perpendicular to the axis, which is conducive to improving the forming effect and accuracy of the socket.

[0018] 4. During the stamping and expanding process of the steel pipe, the steel pipe is heated by the heating coil, which changes the internal structure of the steel pipe, reduces the residual stress at the socket end of the steel pipe, and alleviates the work hardening of the socket end of the steel pipe, which is beneficial to the forming of the socket end; the rib is perpendicular to the axis of the steel pipe, and the width of the rib is consistent, ensuring the verticality of the two sides of the positioning groove, so that the positioning groove is in full contact with the sealing rubber ring, improving the stability of the installation of the sealing rubber ring, and is beneficial to improving the sealing effect.

[0019] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart of an embodiment of the present invention; Figure 2 It is a schematic structural diagram of a punching device according to an embodiment of the present invention; Figure 3 A schematic diagram of the punch structure of an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of the feeding trolley according to an embodiment of the present invention; Figure 5 It is a schematic diagram of the structure of the flat-mouth device according to an embodiment of the present invention; Figure 6 It is a structural schematic diagram of a molding device according to an embodiment of the present invention; Figure 7 It is a schematic diagram of the structure of the tightening mechanism according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the structure of a steel pipe after stamping according to an embodiment of the present invention; Fig. 9 This is a schematic diagram of the flat-end rear steel pipe structure according to an embodiment of the present invention; Fig.10 This is a schematic diagram of the socket steel pipe structure according to an embodiment of the present invention.

[0021] Reference numerals 1. First base; 2. Support frame; 3. Slide seat; 4. Pushing element; 5. Power source; 6. Punching 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. Limiting groove; 17. Roller; 18. Second base; 19. Support wheel; 20. First motor; 21. Fixing frame; 22. Cutting knife; 23. The third base; 24, the first fixed seat; 25, the inner mold of the socket; 26, the outer mold of the socket; 27, the first lifting element; 28, the second motor; 29, the second fixed seat; 30, the third motor; 31, the inner mold of the socket; 32, the outer mold of the socket; 33, the second lifting element; 34, the directional wheel; 35, the top wheel; 36, the sleeve; 37, the fourth motor; 38, the supporting leg; 39, the socket end; 40, the socket end; 41, the positioning groove; 42, the retaining edge. DETAILED DESCRIPTION

[0022] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the invented product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In the description of the present invention, it should also be noted that, unless otherwise clearly specified and limited, the terms "setting", "installation", and "connection" 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 a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the 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 circumstances.

[0023] The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] like Figure 1 A method for stamping and forming a socket-type flexible joint steel pipe comprises the following steps: S1. Process the ends of the steel pipe.

[0025] The steel pipe is a straight seam welded pipe, a spiral welded pipe or a seamless steel pipe. When the liquid pressure in the steel pipe is high, a seamless steel pipe is used. When the liquid pressure in the steel pipe is low, 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 50mm-250mm, which is a small-diameter steel pipe.

[0026] For straight seam welded pipes or threaded welded pipes, the end treatment of the steel pipe includes grinding and smoothing the inner and outer welds at the socket and spigot of the steel pipe, so that the welds are flush with the pipe wall to facilitate a smooth transition of the mold.

[0027] S2, the processed steel pipe is fed into the punching device through the feeding trolley 15, and the punch 7 is inserted into the heated steel pipe end to perform punching and expanding on one end of the steel pipe. Figure 8 shown.

[0028] like Figure 2 As shown. The stamping device includes a first base 1, which is fixed on the ground. A support frame 2 is fixedly arranged above the first base 1. A stamping mechanism for stamping the end of the steel pipe is arranged at one end of the support frame 2. A heating structure for heating the end of the steel pipe is arranged on the support frame 2, and the heating structure is sleeved on the outside of the punch 7 of the stamping mechanism.

[0029] The stamping mechanism includes a stamping shaft 6, which is fixedly arranged on the slide 3. A pushing element 4 is fixedly arranged on the support frame 2 to drive the slide 3 to slide on the first base 1. The pushing element 4 is a hydraulic cylinder. The piston rod of the hydraulic cylinder is fixedly connected to the slide 3, and the hydraulic cylinder is fixedly arranged on the support frame 2. A power source 5 is arranged on the base to drive the hydraulic cylinder to move. The power source 5 is an existing hydraulic system. A guide rail that guides the sliding of the slide 3 is fixedly arranged on the first base 1, and the slide 3 moves along the axis of the steel pipe under the action of the guide rail. The punch 7 is fixedly arranged on the end of the stamping shaft 6, and the punch 7 is coaxially arranged with the stamping shaft 6.

[0030] like Figure 3 As shown. The heating structure includes a heating sleeve 10, and the heating sleeve 10 can be made of metal copper and has a good thermal conductivity. The heating sleeve 10 is sleeved on the outside of the punch 7, and the heating sleeve 10 and the punch 7 are coaxially arranged. 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 to the thermal effector 8. The thermal effector 8 is fixedly connected to the slide 3 through the connecting plate 9, and the slide 3 drives the thermal effector 8 to slide synchronously, so that the heating coil 11 moves synchronously with the punch 7, and the steel pipe is heated while stamping.

[0031] The thermal effector 8 heats the heating sleeve 10 through the heating coil 11, thereby heating the steel pipe through the heating sleeve 10. Heating the end of the steel pipe is beneficial to improving the plasticity and toughness of the end of the steel pipe, avoiding large work hardening and internal stress of the small-diameter steel pipe during processing, avoiding stamping cracking, improving the socket forming effect of the small-diameter steel pipe, and reducing the scrap rate. Using the punch 7 to punch the steel pipe can achieve one-step expansion of the socket and improve the efficiency of the socket expansion.

[0032] The first base 1 is provided with a clamping seat 13 for clamping the steel pipe and a positioning wheel 14 for supporting and positioning the steel pipe. The height of the clamping seat 13 can be adjusted by a cylinder or a hydraulic cylinder, and the steel pipe is fixed by a clamp on the clamping seat 13 to prevent the steel pipe from moving and rotating during the expansion 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 is provided at the other end of the support frame 2 to block the steel pipe.

[0033] S3, the expanded steel pipe is sent to the flattening device by the feeding trolley 15, and the expanded end of the steel pipe is flattened. Fig. 9 shown.

[0034] like Figure 5 As shown. The flat-end 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 fixed on the ground through a fixing frame 21. The cutting knife 22 is used to flat-end the end of the steel pipe. A supporting wheel 19 for supporting the steel pipe is provided above the second base 18, and a first motor 20 for driving the supporting wheel 19 to rotate is provided on the second base 18. The first motor 20 drives the steel pipe to rotate through the supporting wheel 19, so that the end of the steel pipe is flat-end cut by the cutting knife 22.

[0035] When the steel pipe is punched and expanded on the punching device, the deformation of the steel pipe end is inconsistent, resulting in a certain inclination of the steel pipe end, which affects the subsequent socket forming and restricts the turning angle of the flexible interface steel pipe, thereby affecting the sealing effect of the pipeline. The flat-end cutting of the expanded pipe is performed by the flat-end device to ensure the straightness of the pipe end and make the port perpendicular to the axis, which is conducive to improving the forming effect and accuracy of the socket.

[0036] like Figure 4 The top of the feeding trolley 15 is provided with a limiting groove 16 for limiting the steel pipe, and the bottom of the feeding trolley 15 is provided with a roller 17. The feeding trolley 15 is used to transfer the pipe between the stamping device and the flat-end device.

[0037] S4, the flat-end steel pipe is sent to 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. Fig.10 shown.

[0038] like Figure 6As shown. The socket forming mechanism includes a socket inner mold 25, which is rotatably arranged on a first fixed seat 24 through a bearing. A second motor 28 is fixedly arranged on the first fixed seat 24 to drive the socket inner mold 25 to rotate. A socket outer mold 26 is arranged above the socket inner mold 25, and a first lifting element 27 is fixedly arranged on the first fixed seat 24 to drive the socket outer mold 26 to rise and fall. The first lifting element 27 can be a hydraulic cylinder or a pneumatic cylinder, and the socket outer mold 26 is driven to rise and fall by the first lifting element 27.

[0039] The socket forming mechanism includes a socket inner mold 31, which is rotatably arranged on the second fixed seat 29 through a bearing. A third motor 30 is fixedly arranged on the second fixed seat 29 to drive the socket inner mold 31 to rotate. A socket outer mold 32 is arranged above the socket inner mold 31, and a second lifting element 33 is fixedly arranged on the second fixed seat 29 to drive the socket outer mold 32 to rise and fall. The second lifting element 33 is a cylinder or a hydraulic cylinder.

[0040] The first fixing seat 24 and the second fixing seat 29 are both fixedly arranged on the third base 23. The third base 23 is provided with a directional wheel 34 for supporting the steel pipe, and the directional wheel 34 is located between the first fixing seat 24 and the second fixing seat 29. The third base 23 is provided with a cylinder or a hydraulic cylinder for driving the directional wheel 34 to rise and fall, so that the steel pipe is supported by the directional wheel 34.

[0041] like Figure 7 As shown. Both ends of the directional wheel 34 are provided with a tightening mechanism for tightening the steel pipe. The two tightening mechanisms are used during the socket forming and the spigot forming respectively. 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 and the sleeve 36 are connected by threaded transmission. 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 the support leg 38, and the third base 23 is provided with a lifting element for driving the support leg 38 to rise and fall, and the lifting element can be a cylinder or a hydraulic cylinder. The height of the top wheel 35 is adjusted by the lifting element to prevent the top wheel 35 from hindering the placement and forming of the steel pipe.

[0042] When forming the steel pipe, the socket end 39 of the steel pipe is inserted into the outside of the socket inner mold 25, the socket inner mold 25 contacts the inner wall of the steel pipe, and the directional wheel 34 is lifted, and the directional wheel 34 supports the bottom of the steel pipe. The top wheel 35 is moved to the tail end of the steel pipe, and the fourth motor 37 drives the top wheel 35 to move through the screw, and the top wheel 35 is pressed 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, and the first lifting element 27 drives the socket outer mold 26 to descend, and the socket outer mold 26 is pressed on the outside of the steel pipe to form the socket of the steel pipe.

[0043] After the processing of the socket is completed, the fourth motor 37 drives the screw to reverse, and the top wheel 35 moves out from the tail end of the steel pipe, and the steel pipe is moved out from the socket inner mold 25. The steel pipe is slid, and the other end of the steel pipe is inserted into the outside of the socket 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, and the top wheel 35 is pressed tightly against the socket end 39 of the steel pipe. The third motor 30 drives the socket inner mold 31 to rotate, and the socket inner mold 31 drives the steel pipe to rotate synchronously, and the second lifting element 33 drives the socket outer mold 32 to descend, and the socket outer mold 32 is pressed on the outside of the steel pipe to form the socket of the steel pipe.

[0044] During the stamping and expanding process of the steel pipe, the steel pipe is heated by the heating coil 11, which changes the internal organizational structure of the steel pipe, reduces the residual stress of the socket end 39 of the steel pipe, and alleviates the work hardening of the socket end 39 of the steel pipe, which is beneficial to the forming of the socket end 39; the rib 42 is made perpendicular to the axis of the steel pipe, and the width of the rib 42 is consistent, ensuring the verticality of the two sides of the positioning groove 41, so that the positioning groove 41 is in full contact with the sealing rubber ring, thereby improving the stability of the installation of the sealing rubber ring, and is beneficial to improving the sealing effect.

[0045] S5. Send the formed steel pipe to the inspection table for inspection, remove burrs at both ends of the steel pipe and grind it to obtain a socket-type flexible interface steel pipe.

[0046] Therefore, the method for stamping and forming a socket-type flexible joint steel pipe described in the present invention can solve the problems of low forming quality and high defective rate of existing socket-type flexible joint steel pipes.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that they can still modify or replace the technical solution of the present invention with equivalents, and these modifications or equivalent replacements cannot cause the modified technical solution to deviate from the spirit and scope of the technical solution of the present invention.

Claims

1. A method for stamping and forming a socket-type flexible joint steel pipe, characterized in that: The following steps are involved: S1. Process the ends of the steel pipe; S2, the processed steel pipe is fed into the stamping device through the feeding trolley, the punch is inserted into the heated steel pipe end, and one end of the steel pipe is stamped and expanded; S3, the expanded steel pipe is fed into the flattening device through the feeding trolley to flatten the expanded end of the steel pipe; S4, sending the flat-end processed steel pipe into a forming device, forming the socket end by a socket forming mechanism provided at one end of the forming device, and forming the spigot end by a spigot forming mechanism provided at the other end of the forming device; S5. Send the formed steel pipe to the inspection table for inspection, remove burrs at both ends of the steel pipe and grind it to obtain a socket-type flexible interface steel pipe.

2. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: 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 50 mm-250 mm.

3. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: In S1, the steel pipe end treatment includes grinding and smoothing the inner weld and the outer weld of the steel pipe so that the weld is flush with the pipe wall.

4. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: 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, and the heating structure is sleeved on the outside of 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, and a baffle for blocking the steel pipe is arranged at the other end of the support frame.

5. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 4, characterized in that: The stamping mechanism includes a stamping shaft, which is arranged on a slide, a supporting frame is provided with a pushing element that drives the slide to slide on a first base, a guide rail that guides the sliding of the slide is provided on the first base, a power source that drives the pushing element to move is provided on the base, a punch is provided on the end of the stamping shaft, and the punch is coaxially arranged with the stamping shaft.

6. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 5, characterized in that: The heating structure includes a heating sleeve, which is sleeved on the outside of the punch. The heating sleeve and the punch are coaxially arranged. 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 the thermal effector. The thermal effector is connected to the slide seat through a connecting plate, and the slide seat drives the thermal effector to slide synchronously.

7. The method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: The top of the feeding trolley in S2 and S3 is provided with a limiting groove of a limiting steel pipe, and the bottom of the feeding trolley is provided with a roller.

8. The method for stamping and forming a socket-and-spigot 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 provided at one end of the second base, the cutting knife is set on the ground through a fixed frame, a supporting wheel for supporting the steel pipe is provided above the second base, and a first motor for driving the supporting wheel to rotate is provided on the second base.

9. The method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: In the S4, the socket forming mechanism includes a socket inner mold, which is rotatably arranged on the 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, and a first lifting element for driving the socket outer mold to rise and fall is arranged on the first fixed seat; the spigot forming mechanism includes a spigot inner mold, which is rotatably arranged on the 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, and a second lifting element for driving the spigot outer mold to rise and fall is arranged on the second fixed seat; the first fixed seat and the second fixed seat are respectively arranged on the third base, a directional wheel for supporting the steel pipe is arranged on the third base, and a tightening mechanism for tightening the steel pipe is arranged at both ends of the directional wheel.

10. A method for stamping and forming a socket-and-spigot type flexible joint steel pipe according to claim 9, characterized in that: The tightening mechanism includes a top wheel, which is arranged at one end of the 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 the support legs, and the third base is provided with a lifting element for driving the support legs to rise and fall.

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