Expansion forming method for socket and spigot type flexible connector steel pipe

Abstract

The invention discloses an expansion forming method for a socket and spigot type flexible connector steel pipe, and belongs to the technical field of socket and spigot type pipeline forming. The invention discloses a socket and spigot type flexible connector steel pipe expansion forming method. The method comprises the following steps that the end of a steel pipe is treated; one end of the steel pipe is inserted into an expanding mechanism of the expanding device, and the inner die moves outwards to conduct expanding flaring forming on the end of the steel pipe; flattening the flaring end of the steel pipe through a flattening device; a socket end is formed through a socket forming mechanism arranged at one end of the forming device, and a socket end is formed through a socket forming mechanism arranged at the other end of the forming device; and feeding the formed steel pipe into an inspection bench for inspection. By the adoption of the expansion forming method for the socket-and-spigot type flexible connector steel pipe, the problems that an existing socket-and-spigot type flexible connector steel pipe is low in forming efficiency, poor in socket forming quality and prone to cracking 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 expanding 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-and-spigot steel pipe and its processing method. First, the steel pipe is placed on a rolling and expanding machine, and the rolling and expanding mechanism is used to expand the steel pipe. Then, it is placed on a flanging die press to flanging to form a socket part. Finally, the end of the spigot part is barbed and closed to obtain a socket-and-spigot 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 rotated 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, which causes the sealing ring to slip and affects the sealing effect. In addition, when the socket end of the steel pipe is expanded, two expansion processes are required, and the expansion efficiency of the steel pipe is relatively low. The steel pipe is expanded twice, and the expanded end of the steel pipe undergoes two rounds of work hardening, resulting in relatively high residual stress inside the steel pipe. The expanded end of the steel pipe becomes harder, more brittle, prone to cracking, and also affects the subsequent socket forming. Summary of the invention

[0004] The purpose of the invention is to provide a method for expanding and forming a socket-and-spigot flexible joint steel pipe, so as to solve the problems of low forming efficiency, poor socket forming quality and easy cracking of the existing socket-and-spigot flexible joint steel pipe.

[0005] To achieve the above object, the present invention provides a method for expanding 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 expansion device through the feeding trolley, one end of the steel pipe is inserted into the expansion mechanism of the expansion device, and the inner mold and the outer mold of the expansion mechanism expand and flare the end of the steel pipe; 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 300 mm-1600 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 expansion device comprises a first base, a slide seat is slidably arranged on the first base, a power element for driving the slide seat to slide horizontally is arranged on the first base, and an expansion mechanism is arranged on the slide seat; a support mechanism for supporting the steel pipe is arranged on the ground.

[0009] Preferably, the expansion mechanism includes a mounting frame, which is located inside the slide seat, a mounting plate is fixedly provided on the mounting frame, a horizontal mounting shaft is provided on the mounting frame, a telescopic element for driving the mounting shaft to slide horizontally is provided on the mounting frame, a through hole for the main shaft to pass through is provided on the mounting plate, a conical inner cone block is fixed at one end of the main shaft, a plurality of outer cone blocks matched with the inner cone block are evenly arranged in a circular array on the mounting plate, a sliding groove for inserting the outer cone block is provided on the side wall of the inner cone block, the outer cone block is slidably connected with the inner cone block, a guide groove corresponding to the outer cone block one by one is provided on the mounting plate, an extension line of the guide groove passes through the axis of the mounting shaft, the outer cone block slides on the mounting plate along the guide groove, an inner mold is provided on the outer cone block, and an outer mold matched with the inner mold is provided on the mounting plate.

[0010] Preferably, the slide is provided with a lifting structure for driving the mounting frame to lift and lower, the lifting structure includes a first screw rod, the first screw rod is rotatably connected to the slide, the first screw rod is connected to the mounting frame through a threaded transmission, the slide is provided with a first motor that drives the first screw rod to rotate, the slide is provided with a guide rod that has a guiding effect on the lifting and lowering of the mounting frame, the mounting frame is provided with a guide hole for the guide rod to pass through, and the mounting frame is slidably connected to the guide rod.

[0011] Preferably, the support mechanism includes a support seat, which is arranged on the ground in a linear array, a support wheel is arranged above the support seat, a second screw rod is rotatably arranged on the support seat, the second screw rod is connected to the wheel seat of the support wheel through a threaded transmission, and a second motor is arranged on the support seat to drive the second screw rod to rotate.

[0012] Preferably, in S3, the flat-mouth device includes a second base, a cutting knife is provided on the second base, the cutting knife is arranged on the second base through a fixing frame, a rotating wheel for supporting the steel pipe is provided on one side of the second base, and a second motor for driving the rotating wheel to rotate is provided on the rotating wheel.

[0013] Preferably, in S4, the socket forming mechanism includes a socket inner mold, which is rotatably arranged on a fixed seat, a third motor for driving the socket inner mold to rotate is arranged on the fixed seat, the fixed seat is arranged on a third base, 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 fixed seat.

[0014] Preferably, the socket forming mechanism includes a socket inner mold, which is rotatably arranged on a movable seat, a fourth motor for driving the socket inner mold to rotate is arranged on the movable seat, the movable seat is slidably connected to the ground, a socket outer mold is arranged above the socket inner mold, and a second lifting element for driving the socket outer mold to rise and fall is arranged on the movable seat; a directional wheel for supporting the steel pipe is arranged between the fixed seat and the movable seat, and a lifting element for driving the directional wheel to rise and fall is arranged on the ground.

[0015] The advantages and positive effects of the bell-and-spigot flexible joint steel pipe expansion forming method of the present invention are: 1. The present invention uses an inner mold and an outer mold to form the steel pipe, which can complete the expansion operation of the steel pipe at one time, thereby improving the expansion efficiency of the steel pipe. The steel pipe expansion is formed at one time, which reduces the work hardening of the steel pipe, is conducive to reducing the internal stress of the steel pipe, reduces the generation of cracks at the socket end, and improves the yield rate.

[0016] 2. The present invention drives the inner cone block to slide horizontally through the installation shaft, and the inner cone block slides along the outer cone block. Since the inner cone block and the outer cone block are connected by an inclined surface, the inner cone block drives the outer cone block to slide in the guide groove of the installation plate, and then drives the inner mold to slide outward or inward to expand the steel pipe between the inner mold and the outer mold. The outer mold is used to limit the steel pipe and improve the forming effect and forming accuracy of the steel pipe.

[0017] 3. The present invention sets a flat-end process after expansion and flaring. When the steel pipe is expanded and flared on the expansion 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 precision of the socket.

[0018] 4. During the expansion process, the inner and outer molds are used to expand the steel pipe in one step, which 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 an expansion device according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the expansion mechanism 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 This is a schematic diagram of the structure of a steel pipe after expansion according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the flat-end rear steel pipe structure according to an embodiment of the present invention; Fig. 9 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. Sliding seat; 3. Mounting frame; 4. Mounting shaft; 5. Telescopic element; 6. Inner cone block; 7. Outer cone block; 8. Inner mold; 9. Outer mold; 10. Mounting plate; 11. First motor; 12. First screw rod; 13. Support seat; 14. Support wheel; 15. Second motor; 16. Second screw rod; 17. Feeding trolley; 18. Support table; 19. V-shaped block; 20. Roller; 21. Second base; 22. Rotation Wheel; 23, second motor; 24, fixed frame; 25, cutting knife; 26, third base; 27, fixed seat; 28, socket inner mold; 29, socket outer mold; 30, first lifting element; 31, third motor; 32, movable seat; 33, fourth motor; 34, socket inner mold; 35, socket outer mold; 36, second lifting element; 37, directional wheel; 38, socket end; 39, socket end; 40, positioning groove; 41, 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 expanding 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 spiral welded pipe is used to reduce the cost of the steel pipe. The nominal diameter of the steel pipe is 300mm-1600mm, which is a large-diameter steel pipe.

[0026] For straight seam welded pipes or spiral 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 expansion device through the feeding trolley 17, one end of the steel pipe is inserted into the expansion mechanism of the expansion device, the steel pipe is located between the inner die 8 and the outer die 9 of the expansion mechanism, and the inner die 8 moves outward to expand and expand the end of the steel pipe. Figure 7 shown.

[0028] like Figure 2As shown. The expansion device includes a first base 1, which is fixed on the ground. A slide 2 is slidably arranged on the first base 1, and a power element for driving the slide 2 to slide horizontally is arranged on the first base 1. The power element can be an existing hydraulic cylinder, which is connected to the hydraulic system and is used to drive the piston rod of the hydraulic cylinder to extend. The piston rod of the hydraulic cylinder is fixedly connected to the slide 2. A guide rail is arranged on the first base 1 to guide the sliding of the slide 2, so that the slide 2 slides along the axis of the steel pipe.

[0029] like Figure 3 As shown. An expansion mechanism is provided on the slide 2. The expansion mechanism includes a mounting frame 3, and the mounting frame 3 is located inside the slide 2. A horizontal mounting shaft 4 is provided on the mounting frame 3. A telescopic element 5 for driving the mounting shaft 4 to slide horizontally is fixedly provided on the mounting frame 3. The telescopic element 5 is a hydraulic cylinder, and the piston rod of the hydraulic cylinder is fixedly connected to the mounting shaft 4, which is used to drive the mounting shaft 4 to slide horizontally. A through hole for the mounting shaft 4 to pass through is provided on the mounting frame 3, and the through hole has a guiding function for the sliding of the mounting shaft 4. A mounting plate 10 is fixedly provided on the mounting frame 3, and a through hole for the main shaft to pass through is provided on the mounting plate 10, and the through hole has a limiting and guiding function for the horizontal sliding of the mounting shaft 4.

[0030] A conical inner cone block 6 is fixed at one end of the main shaft, and the inner cone block 6 is coaxially arranged with the main shaft. A plurality of outer cone blocks 7 adapted to the inner cone block 6 are evenly arranged in a circular array on the mounting plate 10, and the outer cone block 7 is located outside the inner cone block 6. A sliding groove for inserting the outer cone block 7 is arranged on the side wall of the inner cone block 6, and the outer cone block 7 is slidably connected with the inner cone block 6. The slider is a T-slot or a dovetail groove, so that the inner cone block 6 and the outer cone block 7 will not separate during the mutual sliding process, thereby improving the stability of the movement of the outer cone block 7. A guide groove corresponding to the outer cone block 7 is arranged on the mounting plate 10, and the extension line of the guide groove passes through the axis of the mounting shaft 4. A guide block adapted to the guide groove is arranged at the bottom of the outer cone block 7, and the guide block is located in the guide groove and is slidably connected with the guide groove. The outer cone block 7 slides on the mounting plate 10 along the guide groove. The guide groove is a T-slot or a dovetail groove, so that the outer cone block 7 cannot be separated from the mounting plate 10. An inner mold 8 is arranged on the outer cone block 7 , and an outer mold 9 matched with the inner mold 8 is fixedly arranged on the mounting plate 10 .

[0031] When the mounting shaft 4 drives the inner cone block 6 to slide horizontally, the inner cone block 6 slides along the outer cone block 7. Since the inner cone block 6 and the outer cone block 7 are connected by an inclined surface, the inner cone block 6 drives the outer cone block 7 to slide in the guide groove of the mounting plate 10, thereby driving the inner mold 8 to slide outward or inward, and performing a flaring operation on the steel pipe between the inner mold 8 and the outer mold 9. The outer mold 9 is used to limit the steel pipe and improve the forming effect and forming accuracy of the steel pipe. The steel pipe is formed by the inner mold 8 and the outer mold 9, and the flaring operation of the steel pipe can be completed at one time, thereby improving the flaring efficiency of the steel pipe. The one-time flaring of the steel pipe reduces the work hardening of the steel pipe, which is beneficial to reducing the internal stress of the steel pipe, reducing the generation of cracks at the socket end 38, and improving the yield rate.

[0032] The slide 2 is provided with a lifting structure for driving the mounting frame 3 to rise and fall. The lifting structure includes a first screw rod 12, and the first screw rod 12 is rotatably connected to the slide 2 through a bearing. The first screw rod 12 is connected to the mounting frame 3 through a threaded transmission. A first motor 11 is fixedly provided on the slide 2 to drive the first screw rod 12 to rotate. A guide rod that has a guiding effect on the lifting and lowering of the mounting frame 3 is fixedly provided on the slide 2, and a guide hole for the guide rod to pass through is provided on the mounting frame 3, and the mounting frame 3 is slidably connected to the guide rod. The guide rod is parallel to the first screw rod 12. The height of the mounting frame 3 is adjusted by the first screw rod 12, and then the height of the expansion mechanism is adjusted to meet the expansion operation of the steel pipe located on axes at different heights.

[0033] A support mechanism for supporting the steel pipe is provided on one side of the first base 1. The support mechanism includes a support seat 13, which is fixedly arranged on the ground in a linear array. A support wheel 14 is provided above the support seat 13, and a second screw rod 16 is rotatably arranged on the support seat 13 through a bearing, and the second screw rod 16 is connected to the wheel seat of the support wheel 14 through a threaded transmission. A second motor 23 is fixedly arranged on the support seat 13 to drive the second screw rod 16 to rotate. The height of the support wheel 14 is adjusted by the second screw rod 16 to meet the support of steel pipes of different calibers.

[0034] A baffle plate having a blocking effect on the steel pipe can be provided at the other end of the support frame. When the steel pipe is expanded, the steel pipe can be blocked to avoid displacement of the steel pipe and improve the expansion quality.

[0035] S3, the expanded steel pipe is sent to the flattening device by the feeding trolley 17, and the expanded end of the steel pipe is flattened. Figure 8 shown.

[0036] like Figure 5As shown. The flat-end device includes a second base 21, and the second base 21 is fixed on the ground. A cutting knife 25 is arranged on the second base 21, and the cutting knife 25 is fixedly arranged on the second base 21 through a fixing frame 24. The cutting knife 25 is used to flat-end the end of the steel pipe. A rotating wheel 22 for supporting the steel pipe is arranged on one side of the second base 21, and a second motor 23 for driving the rotating wheel 22 to rotate is arranged on the rotating wheel 22. The second motor 23 drives the steel pipe to rotate through the rotating wheel 22, so that the end of the steel pipe is flat-end cut by the cutting knife 25.

[0037] When the steel pipe is expanded and expanded on the expansion 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.

[0038] like Figure 4 As shown. A support platform 18 is fixedly arranged on the top of the feeding trolley 17, and a V-shaped block 19 for supporting the steel pipe is fixedly arranged above the support platform 18. The feeding trolley 17 is provided with a cylinder or a hydraulic cylinder for adjusting the height of the support platform 18, so as to facilitate the transfer of the steel pipe to the V-shaped block 19. A roller 20 is arranged at the bottom of the feeding trolley 17. The feeding trolley 17 is used to transfer the pipe between the expansion device, the flat-end device, and the forming device.

[0039] S4, the flat-end steel pipe is sent to the forming device, and the socket end 38 is formed by the socket forming mechanism provided at one end of the forming device, and the spigot end 39 is formed by the spigot forming mechanism provided at the other end of the forming device. Fig. 9 shown.

[0040] like Figure 6 As shown. The socket forming mechanism includes a socket inner mold 28, which is rotatably arranged on a fixed seat 27 through a bearing. A third motor 31 is fixedly arranged on the fixed seat 27 to drive the socket inner mold 28 to rotate. A socket outer mold 29 is arranged above the socket inner mold 28, and a first lifting element 30 is fixedly arranged on the fixed seat 27 to drive the socket outer mold 29 to rise and fall. The first lifting element 30 can be a hydraulic cylinder or a pneumatic cylinder, and the socket outer mold 29 is driven to rise and fall by the first lifting element 30.

[0041] The socket forming mechanism includes a socket inner mold 34, which is rotatably arranged on a movable seat 32 through a bearing. A fourth motor 33 is fixedly arranged on the movable seat 32 to drive the socket inner mold 34 to rotate. A socket outer mold 35 is arranged above the socket inner mold 34, and a second lifting element 36 is fixedly arranged on the movable seat 32 to drive the socket outer mold 35 to rise and fall. The second lifting element 36 is a cylinder or a hydraulic cylinder.

[0042] The fixed seat 27 is fixedly arranged on the third base 26, and the movable seat 32 is slidably arranged on the ground. A hydraulic cylinder is arranged on the ground to drive the movable seat 32 to slide on the ground. A directional wheel 37 is arranged on the ground to support the steel pipe, and the directional wheel 37 is located between the fixed seat 27 and the movable seat 32. A cylinder or a hydraulic cylinder is arranged on the ground to drive the directional wheel 37 to rise and fall, so that steel pipes of different diameters can be supported by the directional wheel 37, and the installation of the steel pipe is convenient. The installation of the directional wheel 37 can also adopt the same structure as the support wheel 14 for height adjustment. The rotation of the directional wheel 37 drives the steel pipe to slide along the axial direction of the steel pipe, so as to facilitate the insertion or extraction of the steel pipe into or out of the socket inner membrane 28.

[0043] When the steel pipe is formed, the steel pipe falls above the directional wheel 37. The directional wheel 37 drives the steel pipe to rise under the action of the cylinder or hydraulic cylinder. The directional wheel 37 rotates and drives the steel pipe to move along its axis, inserting the socket end 38 of the steel pipe into the outside of the socket inner mold 28. The socket inner mold 28 contacts the inner wall of the steel pipe, lifting the directional wheel 37, and supporting the directional wheel 37 below the steel pipe. The movable seat 32 is driven to slide by the hydraulic cylinder, and the socket end 39 of the steel pipe is inserted into the outside of the socket inner mold 34. The socket inner mold 34 contacts the inner wall of the socket end 39, and the socket inner mold 34 presses the socket end 39 of the steel pipe. The third motor 31 drives the socket inner mold 28 to rotate, and the socket inner mold 28 drives the steel pipe to rotate synchronously. The first lifting element 30 drives the socket outer mold 29 to descend, and the socket outer mold 29 presses on the outside of the steel pipe to form the socket of the steel pipe.

[0044] After the socket processing is completed, the fourth motor 33 of the socket end 38 drives the socket inner mold 34 to rotate, and the socket inner mold 34 drives the steel pipe to rotate synchronously, and the second lifting element 36 drives the socket outer mold 35 to descend, and the socket outer mold 35 is pressed on the outside of the steel pipe to form the socket of the steel pipe.

[0045] After the socket processing is completed, the hydraulic cylinder drives the movable seat to slide backward, and the socket inner mold 34 slides out from the steel pipe socket end 39. The directional wheel 37 rotates in the opposite direction, and the directional wheel 37 drives the steel pipe to be pulled out from the socket inner mold 28; the steel pipe is transferred from the directional wheel 37 to the feeding trolley 17 and sent to the next process.

[0046] During the expansion process, the inner mold 8 and the outer mold 9 are used to expand the steel pipe in one step, which reduces the residual stress of the socket end 38 of the steel pipe and alleviates the work hardening of the socket end 38 of the steel pipe, thereby facilitating the forming of the socket end 38; the rib 41 is made perpendicular to the axis of the steel pipe, and the width of the rib 41 is consistent, ensuring the perpendicularity of the two sides of the positioning groove 40, so that the positioning groove 40 is in full contact with the sealing rubber ring, thereby improving the stability of the installation of the sealing rubber ring, and facilitating improving the sealing effect.

[0047] 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.

[0048] Therefore, the expansion and forming method of the socket-and-spigot flexible joint steel pipe described in the present invention can solve the problems of low forming efficiency, poor socket forming quality and easy cracking of the existing socket-and-spigot flexible joint steel pipe.

[0049] 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 expanding 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 expansion device through the feeding trolley, one end of the steel pipe is inserted into the expansion mechanism of the expansion device, and the inner mold and the outer mold of the expansion mechanism expand and flare the end of the steel pipe; 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 expanding 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 300mm-1600mm.

3. The method for expanding 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. The method for expanding and forming a socket-and-spigot type flexible joint steel pipe according to claim 1, characterized in that: In S2, the expansion device includes a first base, a slide seat is slidably arranged on the first base, a power element for driving the slide seat to slide horizontally is arranged on the first base, and an expansion mechanism is arranged on the slide seat; a support mechanism for supporting the steel pipe is arranged on the ground.

5. A method for expanding and forming a socket-and-spigot type flexible joint steel pipe according to claim 4, characterized in that: The expansion mechanism includes a mounting frame, which is located inside the slide seat, a mounting plate is fixedly arranged on the mounting frame, a horizontal mounting shaft is arranged on the mounting frame, a telescopic element for driving the mounting shaft to slide horizontally is arranged on the mounting frame, a through hole for the main shaft to pass through is arranged on the mounting plate, a conical inner cone block is fixed at one end of the main shaft, a plurality of outer cone blocks matched with the inner cone block are evenly arranged in a circular array on the mounting plate, a sliding groove for inserting the outer cone block is arranged on the side wall of the inner cone block, the outer cone block is slidably connected with the inner cone block, a guide groove corresponding to the outer cone block one by one is arranged on the mounting plate, an extension line of the guide groove passes through the axis of the mounting shaft, the outer cone block slides on the mounting plate along the guide groove, an inner mold is arranged on the outer cone block, and an outer mold matched with the inner mold is arranged on the mounting plate.

6. A method for expanding and forming a socket-and-spigot type flexible joint steel pipe according to claim 5, characterized in that: The slide is provided with a lifting structure for driving the mounting frame to lift and lower, the lifting structure includes a first screw rod, the first screw rod is rotatably connected to the slide, the first screw rod is connected to the mounting frame through a threaded transmission, the slide is provided with a first motor that drives the first screw rod to rotate, the slide is provided with a guide rod that has a guiding effect on the lifting and lowering of the mounting frame, the mounting frame is provided with a guide hole for the guide rod to pass through, and the mounting frame is slidably connected to the guide rod.

7. The method for expanding and forming a socket-and-spigot type flexible joint steel pipe according to claim 4, characterized in that: The support mechanism includes a support seat, which is arranged on the ground in a linear array. A support wheel is arranged above the support seat. A second screw rod is rotatably arranged on the support seat. The second screw rod is connected to the wheel seat of the support wheel through a threaded transmission. A second motor is arranged on the support seat to drive the second screw rod to rotate.

8. The method for expanding 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 arranged on the second base, and the cutting knife is arranged on the second base through a fixing frame. A rotating wheel for supporting the steel pipe is arranged on one side of the second base, and a second motor for driving the rotating wheel to rotate is arranged on the rotating wheel.

9. The method for expanding and forming a socket-and-spigot flexible joint steel pipe according to claim 1, characterized in that: In S4, the socket forming mechanism includes a socket inner mold, which is rotatably arranged on a fixed seat, and a third motor for driving the socket inner mold to rotate is arranged on the fixed seat, and the fixed seat is arranged on a third base, and 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 fixed seat.

10. A method for expanding and forming a socket-and-spigot type flexible joint steel pipe according to claim 9, characterized in that: The socket forming mechanism includes a socket inner mold, which is rotatably arranged on a movable seat, and a fourth motor for driving the socket inner mold to rotate is arranged on the movable seat, and the movable seat is slidably connected to the ground. A socket outer mold is arranged above the socket inner mold, and a second lifting element for driving the socket outer mold to rise and fall is arranged on the movable seat; a directional wheel for supporting the steel pipe is arranged between the fixed seat and the movable seat, and a lifting element for driving the directional wheel to rise and fall is arranged on the ground.

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