Lining type hole net steel belt corrugated pipe, forming device and forming method

Abstract

The invention discloses a lining type hole net steel belt corrugated pipe, a forming device and a forming method.The lining type hole net steel belt corrugated pipe comprises a polyethylene outer layer formed through spiral winding, and the outer surface of the polyethylene outer layer is of an annular corrugated structure; the steel rib reinforcing body is completely wrapped in the polyethylene outer layer, the section of the steel rib is in a continuous inverted V shape, and the rib height is 15-25 mm; the polyethylene inner layer and the polyethylene outer layer are subjected to co-extrusion molding, and the inner surface is of a smooth structure; and the hole net steel belt layer is completely wrapped in the polyethylene inner layer, the thickness of a steel belt is 0.8-2.0 mm, and array holes with the hole diameter of 5-15 mm and the aperture ratio of 20%-40% are formed in the surface of the steel belt. According to the circular array hole steel belt, the internal pressure resistance is enhanced, mechanical anchoring is formed by permeating the molten PE material into the holes of the steel belt, and the anti-burst performance of the pipe during high-pressure fluid conveying is improved; the continuous spiral steel ribs similar to the inverted V shape improve the external pressure resistance, the geometric structure of the spiral steel ribs effectively disperses external loads, and the pipe body is prevented from deforming in the buried or heavy load environment.

Description

Technical Field

[0001] The present invention relates to the field of pipeline engineering, and in particular to a lined perforated steel belt corrugated pipe, a forming device and a forming method. Background Art

[0002] Traditional steel-plastic composite corrugated pipes usually use a single steel belt reinforcement structure, which has limited resistance to external pressure and insufficient ability to withstand internal pressure. In the existing technology, some corrugated pipes enhance performance by providing holes or corrugations on the surface of the steel belt, but there are the following problems:

[0003] It is difficult to balance internal and external pressures: a single reinforcement structure cannot balance internal and external pressures at the same time;

[0004] Poor structural stability: The bonding strength between the steel belt and the plastic layer is insufficient, and it is easy to delaminate;

[0005] Complex process: Multi-section reinforced structures require multiple processing, which is costly. Summary of the Invention

[0006] The object of the present invention is to provide a lined mesh steel belt corrugated pipe, a forming device and a forming method to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A lined perforated steel belt corrugated pipe, comprising

[0009] The outer layer of polyethylene is formed by spiral winding, and the outer surface has an annular corrugated structure;

[0010] The steel rib reinforcement is completely covered by the polyethylene outer layer. The steel rib cross section is continuous ∧-shaped and the rib height is 15 to 25 mm.

[0011] The inner layer of polyethylene is co-extruded with the outer layer of polyethylene, and the inner surface is a smooth structure;

[0012] The perforated steel belt layer is completely covered inside the polyethylene inner layer. The thickness of the steel belt is 0.8 to 2.0 mm, and the surface is provided with array holes with a pore diameter of 5 to 15 mm and an opening rate of 20% to 40%.

[0013] The top angle of the steel rib reinforcement is 60 to 90 degrees, the spacing between adjacent steel ribs is 1.2 to 1.5 times the corrugation pitch, the holes of the mesh steel belt layer are arranged in a diamond shape, the hole margin is ≥10 mm, the polyethylene outer layer and the ∧-shaped steel ribs are formed into a mechanical interlocking structure by melt coating, the coating layer thickness is ≥1.5 mm, the polyethylene inner layer and the mesh steel belt layer are completely coated by a co-extrusion process, and the coating layer thickness is ≥1.0 mm.

[0014] A forming device for a lined mesh steel belt corrugated pipe, comprising

[0015] The molding box has a circular heating chamber in the middle, a turntable is rotatably connected to the right wall of the circular heating chamber, and a heating mechanism is arranged on the front of the turntable along the circumferential direction;

[0016] A ceramic support sleeve is movably mounted on the front center of the turntable. Four arc-shaped clamping plates are provided on the inner side of the ceramic support sleeve with equal arcs. A clamping mechanism is provided between the arc-shaped clamping plates and the ceramic support sleeve.

[0017] The control box is fixedly connected to the right outer side of the forming box, and a rotating mechanism is provided between the control box and the turntable.

[0018] In the present invention, the heating mechanism includes a plurality of heating rollers arranged circumferentially on the front of the turntable, and a ceramic guide roller fixedly sleeved on the outer wall of the heating roller. A movable groove is opened in the middle of the control box, and a conductive slip ring is fixedly installed on the inner wall of the movable groove. The right end of the turntable is fixedly connected to a hollow shaft, and the hollow shaft is fixedly sleeved on the movable end of the conductive slip ring.

[0019] In the present invention, the clamping mechanism includes a transmission groove opened inside the right side of the ceramic support sleeve, and a motor 1 fixedly installed in the middle of the transmission groove. The output shaft of the motor 1 is located inside the transmission groove and a bevel gear 1 is fixedly installed at one end. Four guide grooves of equal curvature are opened on the front of the ceramic support sleeve. The inside of the guide groove is rotatably connected to a screw rod through a bearing. The screw rod is located inside the transmission groove and a bevel gear 2 meshing with the bevel gear 1 is fixedly installed at one end. A movable block threadedly connected to the screw rod is fixedly installed on the right end of the arc-shaped splint, and the movable block is slidably connected to the guide groove.

[0020] In the present invention, the rotating mechanism includes an annular mounting frame arranged circumferentially on the outer wall of the turntable, a gear ring is fixedly installed on the outside of the annular mounting frame, and a motor three is fixedly installed on the upper end of the left inner side of the control box, and the output shaft of the motor three is fixedly connected to a spur gear meshing with the gear ring.

[0021] A method for forming a lined perforated steel belt corrugated pipe comprises the following steps:

[0022] Step S1, inner layer prefabrication:

[0023] Step S101: punching a steel strip to form a circular array of holes with a hole margin of ≥8 mm and an opening rate of 25%-35%;

[0024] Step S102, preheating the mesh steel strip to 150-180° C. using a high-frequency induction heater;

[0025] Step S103, coating the steel strip with molten PE material in a plastic coating mold, with a coating thickness of ≥1.2 mm;

[0026] Step S104, water cooling and setting, and then coiling, with a cooling rate of ≤3°C / s;

[0027] Step S2, composite molding:

[0028] Step S201 is performed synchronously on the winding machine:

[0029] The outer layer of ∧-shaped steel ribs are pressed to continuously punch the steel strip into a ∧-shaped cross-section with a top angle of 60 to 90 degrees;

[0030] The inner prefabricated belt is unwound and aligned with the outer steel ribs;

[0031] Step S202, using a co-extruder at 150-220°C to simultaneously coat the inner and outer reinforcement layers with a polyethylene-based melt;

[0032] Step S203: spirally winding to form a pipe, with the overlap width between layers being 1.5 to 2 times the pipe wall thickness;

[0033] Step S204: water-cooled cutting, with a fixed length error of ≤0.5%.

[0034] In the present invention, the polyethylene-based material is any one of the following blending systems:

[0035] PE / PP blends, where PP accounts for 10-30wt%;

[0036] PE / glass fiber composite material, glass fiber length 3-8mm, accounting for 15-25wt%;

[0037] PE / basalt fiber composite material, fiber diameter 9-13μm, accounting for 10-20wt%;

[0038] PE / MPVE blend, MPVE accounts for 5-15wt%.

[0039] In the present invention, for the fiber-containing blending system, a melt gear pump is added to the co-extruder, and the shear rate is controlled at 500-800s -1 ; For the PE / MPVE system, the processing temperature is 10 to 15°C lower than that of pure polyethylene.

[0040] In the present invention, the melting temperature of the polyethylene is 180-220° C., and the water cooling setting rate is 0.5-2 m / min.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The circular array hole steel belt of the present invention enhances the ability to resist internal pressure. The molten PE material penetrates the holes of the steel belt to form a mechanical anchor, improving the pipe's burst resistance during high-pressure fluid transportation. The continuous, approximately ∧-shaped spiral steel ribs enhance the ability to resist external pressure. Its geometric structure effectively disperses external loads and prevents deformation of the pipe body when buried or under heavy loads.

[0043] 2. The steel strips and steel ribs of the present invention are completely coated with PE material in a hot-melt state, forming a metallurgical bonding interface, thus avoiding the common steel-plastic delamination problem of traditional composite pipes. The spiral winding process ensures seamless pipe walls and a continuous and uniform overall structure, significantly improving long-term reliability.

[0044] 3. The present invention uses a three-stage heat conduction system composed of a heating roller, a ceramic guide roller and a rotating support sleeve to construct a uniform and stable annular heat field, thus solving the problem of uneven heat transfer caused by concentricity deviation in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 This is a cross-sectional structural diagram of the bellows of the present invention;

[0046] Figure 2 This is a process flow chart of the bellows forming process of the present invention;

[0047] Figure 3 It is a schematic diagram of the overall front view structure of the molding device of the present invention;

[0048] Figure 4 It is a schematic diagram of the overall cross-sectional structure of the molding device of the present invention;

[0049] Figure 5 The molding device of the present invention Figure 4 A in the middle is an enlarged schematic diagram;

[0050] Figure 6 The molding device of the present invention Figure 4 A in the middle is an enlarged schematic diagram;

[0051] Figure 7 The molding device of the present invention Figure 4 Enlarged schematic diagram of point A in the middle.

[0052] In the figure: 1. Polyethylene outer layer; 2. Steel rib reinforcement; 3. Polyethylene inner layer; 4. Perforated steel belt layer; 8. Forming box; 9. Circular heating chamber; 10. Turntable; 11. Ceramic support sleeve; 12. Arc splint; 13. Control box; 14. Heating roller; 15. Ceramic guide roller; 16. Movable slot; 17. Conductive slip ring 1; 18. Hollow shaft; 20. Transmission slot; 21. Motor 1; 22. Bevel gear 1; 23. Guide slot; 24. Screw; 25. Bevel gear 2; 26. Movable block; 29. ​​Annular mounting bracket; 30. Ring gear; 31. Motor 3; 32. Spur gear. DETAILED DESCRIPTION

[0053] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0054] See also Figure 1 , the present invention provides a technical solution:

[0055] A lined perforated steel belt corrugated pipe comprises a polyethylene outer layer 1, which is formed by spiral winding and has an annular corrugated structure on the outer surface; a steel rib reinforcement 2, which is completely covered inside the polyethylene outer layer 1, and the steel rib cross section is continuous ∧-shaped, with a rib height of 15 to 25 mm; a polyethylene inner layer 3, which is co-extruded with the polyethylene outer layer 1 and has a smooth inner surface; a perforated steel belt layer 4, which is completely covered inside the polyethylene inner layer 3, with a thickness of 0.8 to 2.0 mm and a hole diameter of 5 to 15 mm on the surface. m, an array of holes with an opening rate of 20% to 40%; the top angle of the steel rib reinforcement 2 is 60 to 90 degrees, the spacing between adjacent steel ribs is 1.2 to 1.5 times the corrugation pitch, the holes of the mesh steel belt layer 4 are arranged in a diamond shape, the hole edge distance is ≥10mm, the polyethylene outer layer 1 and the ∧-shaped steel rib 2 are formed by melt coating to form a mechanical interlocking structure, the coating layer thickness is ≥1.5mm, the polyethylene inner layer 3 and the mesh steel belt layer 4 are completely coated by a co-extrusion process, and the coating layer thickness is ≥1.0mm.

[0056] See also Figure 2 A method for forming a lined mesh steel belt corrugated pipe comprises the following steps:

[0057] Step S1, inner layer prefabrication:

[0058] Step S101: punching a steel strip to form a circular array of holes with a hole margin of ≥8 mm and an opening rate of 25%-35%;

[0059] Step S102, preheating the mesh steel strip to 150-180° C. using a high-frequency induction heater;

[0060] Step S103: coating the steel strip with molten PE material in a coating mold to a coating thickness of ≥1.2 mm, wherein the polyethylene-based material is any one of the following blending systems:

[0061] PE / PP blends, where PP accounts for 10-30wt%;

[0062] PE / glass fiber composite material, glass fiber length 3-8mm, accounting for 15-25wt%;

[0063] PE / basalt fiber composite material, fiber diameter 9-13μm, accounting for 10-20wt%;

[0064] PE / MPVE blend, MPVE accounts for 5-15wt%;

[0065] For fiber-containing blending systems, a melt gear pump is added to the co-extruder, and the shear rate is controlled at 500-800s -1 ; For the PE / MPVE system, the processing temperature is 10-15°C lower than that of pure polyethylene. The melting temperature of polyethylene is 180-220°C, and the water cooling setting rate is 0.5-2m / min.

[0066] Step S104, water cooling and setting, and then coiling, with a cooling rate of ≤3°C / s;

[0067] Step S2, composite molding:

[0068] Step S201 is performed synchronously on the winding machine:

[0069] The outer layer of ∧-shaped steel ribs are pressed to continuously punch the steel strip into a ∧-shaped cross-section with a top angle of 60 to 90 degrees;

[0070] The inner prefabricated belt is unwound and aligned with the outer steel ribs;

[0071] Step S202, using a co-extruder at 150-220°C to simultaneously coat the inner and outer reinforcement layers with a polyethylene-based melt;

[0072] Step S203: spirally winding to form a pipe, with the overlap width between layers being 1.5 to 2 times the pipe wall thickness;

[0073] Step S204: water-cooled cutting, with a fixed length error of ≤0.5%.

[0074] In this embodiment, the bellows forming method uses a process that combines spiral winding with water cooling to ensure efficient forming and structural stability of the steel-plastic composite strip. Its working principle is as follows:

[0075] First, a circular array-perforated steel strip is punched and then fed into a co-extrusion system along with a continuous, approximately ∧-shaped spiral steel rib. While molten at high temperature, it is completely coated with PE material to form a steel-plastic composite strip. This composite strip is then continuously wound through a spiral winding machine. During the winding process, the outer PE layer fuses with the inner PE layer in a hot-melt state, forming a seamless pipe wall structure.

[0076] Secondly, after winding, the pipe enters a water-cooling stage. By precisely controlling the cooling rate, the crystallinity of the PE material and the residual stress of the steel strip are optimally matched, thereby improving the overall mechanical properties of the pipe. This process not only reduces production costs but also improves production efficiency while ensuring the long-term stability of the corrugated pipe under complex operating conditions. Furthermore, by adjusting the steel strip thickness, opening density, and spiral winding parameters, customized production with different compressive strength levels can be achieved to meet diverse application requirements.

[0077] See also Figure 3-7 A forming device for a lined mesh steel belt corrugated pipe comprises a forming box 8, a circular heating chamber 9 is provided in the middle thereof, a turntable 10 is rotatably connected to the right wall of the circular heating chamber 9, a heating mechanism is provided in the circumferential direction on the front of the turntable 10, and the heating mechanism comprises a plurality of heating rollers 14 arranged in the circumferential direction on the front of the turntable 10, and a ceramic guide roller 15 fixedly sleeved on the outer wall of the heating roller 14, a movable groove 16 is provided in the middle of the control box 13, and a movable groove 16 is fixed on the inner wall of the movable groove 16. A conductive slip ring 17 is installed, and the right end of the turntable 10 is fixedly connected with a hollow shaft 18, and the hollow shaft 18 is fixedly sleeved with the movable end of the conductive slip ring 17. The ceramic support sleeve 11 is movably installed in the middle of the front of the turntable 10, and four arc-shaped clamping plates 12 are provided on the inner side of the ceramic support sleeve 11 with equal arcs. A clamping mechanism is provided between the arc-shaped clamping plates 12 and the ceramic support sleeve 11, and the clamping mechanism includes a transmission groove 20 opened on the right side of the ceramic support sleeve 11, and a fixedly installed The motor 1 21 is located in the middle of the transmission groove 20, and the output shaft of the motor 1 21 is located at one end of the interior of the transmission groove 20 and is fixedly installed with a bevel gear 1 22. Four guide grooves 23 are provided on the front of the ceramic support sleeve 11 with equal curvature. The inside of the guide groove 23 is rotatably connected with a screw rod 24 through a bearing. The screw rod 24 is located at one end of the interior of the transmission groove 20 and is fixedly installed with a bevel gear 25 meshing with the bevel gear 1 22. The right end of the arc splint 12 is fixedly installed with a movable block 26 threadedly connected to the screw rod 24. The movable block 26 is slidably connected to the guide groove 23. The control box 13 is fixedly connected to the right side outside of the molding box 8. A rotating mechanism is provided between the control box 13 and the turntable 10. The rotating mechanism includes an annular mounting frame 29 circumferentially arranged at the outer wall of the turntable 10. A gear ring 30 is fixedly installed on the outside of the annular mounting frame 29. A motor 31 is fixedly installed on the upper end of the left inner side of the control box 13. The output shaft of the motor 3 31 is fixedly connected with a spur gear 32 meshing with the gear ring 30.

[0078] In this embodiment, the working principle of the lined perforated steel belt corrugated pipe in which the perforated steel belt layer 4 is coated inside the polyethylene inner layer 3 is as follows:

[0079] First, the prefabricated mesh steel belt layer 4 is sleeved on the ceramic support sleeve 11, and the bevel gear 1 22 is driven to rotate by the motor 1 21, which drives the four meshed bevel gears 25 to rotate synchronously, so that the four screw rods 24 rotate in the guide groove 23, and the movable block 26 drives the four arc-shaped clamping plates 12 to expand radially until they are tightly fitted to the inner surface of the mesh steel belt layer 4 to form a stable clamp; after the fixation is completed, the motor 3 31 drives the spur gear 32 to mesh with the gear ring 30, driving the annular mounting frame 29 and the turntable 10 to rotate as a whole, and at the same time, the heat generated by the heating roller 14 is conducted to the ceramic support sleeve 11 through the ceramic guide roller 15, so that the mesh steel belt layer 4 is evenly heated to a temperature of condensation. Ethylene melting temperature; at this time, the co-extruder extrude the molten polyethylene through the die head to the inner and outer sides of the porous steel belt layer 4 at the same time. Under the action of the rotating centrifugal force, the melt penetrates into the array holes of the porous steel belt layer 4 and forms a mechanical interlock. As the turntable 10 continues to rotate, the inner and outer polyethylene melts are completely coated on the surface of the steel belt to form a polyethylene inner layer 3 with uniform thickness; when the coating layer reaches the predetermined thickness, the heating state is maintained and the rotation is continued to complete the molecular chain orientation. Finally, the heating system is turned off and the rotation is maintained until the temperature drops below the crystallization point. The clamping mechanism is released to take out the finished product. At this time, the porous steel belt layer 4 has been completely coated by the polyethylene inner layer 3 and the interface bonding reaches metallurgical grade strength.

[0080] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0081] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A lined perforated steel belt corrugated pipe, characterized by: include The polyethylene outer layer (1) is formed by spiral winding, and the outer surface thereof has an annular corrugated structure; The steel rib reinforcement (2) is completely covered inside the polyethylene outer layer (1), the steel rib cross section is continuous ∧-shaped, and the rib height is 15 to 25 mm; The polyethylene inner layer (3) is co-extruded with the polyethylene outer layer (1), and the inner surface thereof is a smooth structure; A mesh steel belt layer (4) is completely covered inside the polyethylene inner layer (3), the steel belt has a thickness of 0.8 to 2.0 mm, and is provided with array holes on its surface with a pore diameter of 5 to 15 mm and an opening rate of 20% to 40%; The top angle of the steel rib reinforcement (2) is 60 to 90 degrees, the spacing between adjacent steel ribs is 1.2 to 1.5 times the corrugation pitch, the holes of the mesh steel belt layer (4) are arranged in a diamond shape, and the hole margin is ≥10 mm, the polyethylene outer layer (1) and the ∧-shaped steel rib (2) are formed into a mechanical interlocking structure by melt coating, and the coating layer thickness is ≥1.5 mm, and the polyethylene inner layer (3) and the mesh steel belt layer (4) are completely coated by a co-extrusion process, and the coating layer thickness is ≥1.0 mm.

2. A forming device for a lined mesh steel belt corrugated pipe, characterized in that: include A molding box (8) is provided with a circular heating chamber (9) in the middle thereof, a turntable (10) is rotatably connected to the right wall of the circular heating chamber (9), and a heating mechanism is provided on the front side of the turntable (10) along the circumferential direction; A ceramic support sleeve (11) is movably mounted on the middle portion of the front face of the turntable (10), four arc-shaped clamping plates (12) are provided on the inner side of the ceramic support sleeve (11) with equal arcs, and a clamping mechanism is provided between the arc-shaped clamping plates (12) and the ceramic support sleeve (11); A control box (13) is fixedly connected to the right side of the molding box (8), and a rotating mechanism is provided between the control box (13) and the turntable (10).

3. The forming device of the lined mesh steel belt corrugated pipe according to claim 2, characterized in that: The heating mechanism comprises a plurality of heating rollers (14) arranged circumferentially on the front of the turntable (10), and a ceramic guide roller (15) fixedly sleeved on the outer wall of the heating roller (14); a movable groove (16) is provided in the middle of the control box (13); a conductive slip ring (17) is fixedly installed on the inner wall of the movable groove (16); a hollow shaft (18) is fixedly connected to the right end of the turntable (10); and the hollow shaft (18) is fixedly sleeved on the movable end of the conductive slip ring (17).

4. The forming device of the lined mesh steel belt corrugated pipe according to claim 2, characterized in that: The clamping mechanism comprises a transmission groove (20) provided inside the right side of the ceramic support sleeve (11), and a motor (21) fixedly installed in the middle of the transmission groove (20); an output shaft of the motor (21) is located inside the transmission groove (20) and fixedly installed with a bevel gear (22) at one end; four guide grooves (23) are provided on the front of the ceramic support sleeve (11) at equal arcs; a screw rod (24) is rotatably connected to the inside of the guide groove (23) through a bearing; a bevel gear (25) meshing with the bevel gear (22) is fixedly installed at one end of the screw rod (24) located inside the transmission groove (20); a movable block (26) threadedly connected to the screw rod (24) is fixedly installed at the right end of the arc clamping plate (12); and the movable block (26) is slidably connected to the guide groove (23).

5. The forming device of the lined mesh steel belt corrugated pipe according to claim 2, characterized in that: The rotating mechanism comprises an annular mounting frame (29) arranged circumferentially on the outer wall of the turntable (10), a gear ring (30) being fixedly mounted on the outside of the annular mounting frame (29), a motor three (31) being fixedly mounted on the upper end of the left inner portion of the control box (13), and an output shaft of the motor three (31) being fixedly connected to a spur gear (32) meshing with the gear ring (30).

6. A method for forming a lined perforated steel belt corrugated pipe, characterized in that: The following steps are included Step S1, inner layer prefabrication: Step S101: punching a steel strip to form a circular array of holes with a hole margin of ≥8 mm and an opening rate of 25%-35%; Step S102, preheating the mesh steel strip to 150-180° C. using a high-frequency induction heater; Step S103, coating the steel strip with molten PE material in a plastic coating mold, with a coating thickness of ≥1.2 mm; Step S104, water cooling and setting, and then coiling, with a cooling rate of ≤3°C / s; Step S2, composite molding: Step S201 is performed synchronously on the winding machine: The outer layer of ∧-shaped steel ribs are pressed to continuously punch the steel strip into a ∧-shaped cross-section with a top angle of 60 to 90 degrees; The inner prefabricated belt is unwound and aligned with the outer steel ribs; Step S202, using a co-extruder at 150-220°C to simultaneously coat the inner and outer reinforcement layers with a polyethylene-based melt; Step S203: spirally winding to form a pipe, with the overlap width between layers being 1.5 to 2 times the pipe wall thickness; Step S204: water-cooled cutting, with a fixed length error of ≤0.5%.

7. The method for forming a lined perforated steel belt corrugated pipe according to claim 6, characterized in that: The polyethylene-based material is any of the following blending systems: PE / PP blends, in which PP accounts for 10-30wt%; PE / glass fiber composite material, glass fiber length 3-8mm, accounting for 15-25wt%; PE / basalt fiber composite material, fiber diameter 9-13μm, accounting for 10-20wt%; PE / MPVE blend, MPVE accounts for 5-15wt%.

8. The method for forming a lined perforated steel belt corrugated pipe according to claim 6, characterized in that: For fiber-containing blending systems, a melt gear pump is added to the co-extruder, and the shear rate is controlled at 500-800s -1 ; For the PE / MPVE system, the processing temperature is 10 to 15°C lower than that of pure polyethylene.

9. The method for forming a lined perforated steel belt corrugated pipe according to claim 6, characterized in that: The polyethylene has a melting temperature of 180-220° C., and a water cooling setting rate of 0.5-2 m / min.

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