Full anti-corrosion steel corrugated pipe forming method

Abstract

The invention belongs to the technical field of steel corrugated pipe manufacturing, and particularly relates to a full-anti-corrosion steel corrugated pipe forming method which comprises the steps that S1, a hot-dip galvanized punching steel belt or a hot-dip galvanized steel belt is selected as a base material layer; s2, the surface of the base material layer is sequentially and evenly coated with an adhesive and a polyolefin material through plastic coating equipment, a polyolefin plastic coating layer is formed, and a plastic coating strip is obtained; s3, feeding the plastic-coated strip into rolling equipment, and rolling the plastic-coated strip into a corrugated strip through a plurality of groups of first rollers; and S4, spirally winding the corrugated strip through spiral winding forming equipment to form a pipe body, extruding a polyolefin strip on the inner wall of the pipe body by utilizing extrusion equipment while winding, dynamically compacting the polyolefin strip on a wave crest of the inner wall of the pipe body through a second roller to form a smooth lining layer, and forming a cavity between the lining layer and a wave trough of the inner wall of the pipe body, and the full-anti-corrosion steel corrugated pipe is obtained. The problems that a traditional steel corrugated pipe is poor in comprehensive performance, short in service life and poor in fluid passing ability are solved.

Description

Technical Field

[0001] This invention belongs to the field of steel corrugated pipe manufacturing technology, specifically relating to a method for forming a fully corrosion-resistant steel corrugated pipe. Background Technology

[0002] Traditional steel corrugated pipes often face problems such as uneven inner walls and insufficient corrosion resistance during application. These issues not only affect the smooth flow of water but also significantly shorten the pipe's service life, especially in complex environments such as underground installations or when transporting corrosive media. Therefore, how to effectively improve the smoothness of the inner wall of steel corrugated pipes to ensure smooth water flow, while simultaneously enhancing their corrosion resistance and extending their service life, has become a key technical problem that urgently needs to be solved in the current steel corrugated pipe manufacturing technology field. Summary of the Invention

[0003] The purpose of this invention is to provide a method for forming a fully corrosion-resistant steel corrugated pipe, so as to at least solve the problems in the background art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution:

[0005] A method for forming a fully corrosion-resistant steel corrugated pipe includes the following steps:

[0006] Step S1: Select hot-dip galvanized perforated steel strip or hot-dip galvanized steel strip with a thickness of 0.5-10.0mm as the base material layer;

[0007] Step S2: Select adhesive and polyolefin material, and use a coating equipment to uniformly coat the adhesive and polyolefin material on the surface of the substrate layer in sequence to form a strong polyolefin coating layer, thereby obtaining the coated tape.

[0008] Step S3: The plastic-coated strip is fed into the rolling equipment and rolled into a corrugated shape by multiple sets of first rollers to obtain corrugated strip.

[0009] Step S4: The corrugated strip is spirally wound to form a pipe body using a spiral winding forming equipment. At the same time as winding, polyolefin strip is extruded onto the inner wall of the pipe body using an extrusion equipment. The polyolefin strip is dynamically compacted onto the crest of the inner wall of the pipe body by a second roller to form a smooth inner lining layer. A cavity is formed between the inner lining layer and the trough of the inner wall of the pipe body to obtain a fully anti-corrosion steel corrugated pipe.

[0010] Preferably, in step S4, the extrusion equipment extrudes polyolefin strip before the corrugated strip seam, so that the polyolefin strip is bonded to the surface of the corrugated strip. During the seam forming process of the corrugated strip, the end of the polyolefin strip is heat-fused and bonded to the seam to ensure the sealing of the seam, the smoothness of the inner liner, and the strong adhesion.

[0011] Preferably, in step S4, the extrusion equipment extrudes polyolefin strip after the corrugated strip is bitten. The ends of the polyolefin strip are overlapped by a spiral forming method and hot-melt bonded to the crest of the tube inner wall to form a smooth inner lining layer.

[0012] Preferably, the polyolefin tape described in step S4 is made of polyethylene or polypropylene, and the thickness of the inner lining layer is 2.0-15 mm.

[0013] Preferably, the first roller in step S3 is disc-shaped, and the second roller in step S4 is cylindrical, with the length of the second roller being the width of two adjacent wave crests of the tube.

[0014] Preferably, the hole diameter of the hot-dip galvanized perforated steel strip in step S1 is φ5-20mm, and the hole spacing is 10-50mm.

[0015] Preferably, the hot-dip galvanized perforated steel strip or hot-dip galvanized steel strip mentioned in step S1 has a yield strength ≥225MPa, a tensile strength ≥310MPa, and an elongation ≥25%; the single-sided adhesion of the galvanized layer is ≥300g / m. 2 The average thickness of the zinc coating is ≥42μm.

[0016] Preferably, the adhesive used in step S2 is maleic anhydride-grafted polyethylene, the polyolefin material is PE100 grade polyethylene, the thickness of the polyolefin coating layer on the surface of the substrate layer is 1.0-5.0 mm, the coating temperature is 200-230℃, and the coating pressure is 18±3 MPa.

[0017] Compared with the prior art, the present invention has the following technical effects:

[0018] 1. This invention forms a thick, continuous, and dense plastic protective layer (polyolefin coating) that is firmly bonded to the steel substrate by uniformly coating the surface of hot-dip galvanized steel strip with a plastic adhesive and polyolefin material. This effectively isolates the direct contact between the environmental medium (soil, water, oxygen, acids, alkalis, salts, etc.) and the steel substrate. During the molding process, the polyolefin strip is simultaneously extruded and compacted at the crest of the inner wall of the pipe to form a smooth inner lining. The inner lining provides chemical and physical isolation protection for the transported medium, preventing pipe corrosion or media contamination, effectively slowing down the erosion rate of external corrosive agents, exhibiting excellent anti-corrosion performance, and greatly extending the overall anti-corrosion life of the pipeline.

[0019] 2. This invention uses maleic anhydride-grafted polyethylene as an adhesive, which enables the polyethylene to form a strong plastic coating layer on the substrate surface, effectively preventing the plastic coating layer from falling off and improving the overall anti-corrosion performance. Furthermore, during the spiral winding process of the corrugated strip, the inner lining layer is extruded simultaneously, and the inner lining layer is dynamically compacted onto the crest of the inner wall of the pipe by a cylindrical second roller with a length matching the width of the adjacent crests of the pipe body. This effectively avoids the risks of weak bonding, hollowing, and delamination that may exist in traditional pipe linings, ensuring the uniformity of the thickness and smoothness of the inner lining layer, as well as the bonding strength with the corrugated strip. The peel strength between the plastic-coated galvanized steel strip and the inner lining layer is greater than 100 N / cm, significantly improving the integrity and density of the anti-corrosion layer.

[0020] 3. Traditional steel corrugated pipes have corrugations on their inner walls, which cause significant turbulence and energy loss during fluid flow. This invention, by forming a smooth inner lining structure on the inner wall of the corrugated pipe, can significantly reduce the resistance to fluid flow in the pipe and improve fluid transport efficiency. Under the same pipe diameter, its transport capacity can be increased by about 10% to 25%. The smooth inner wall can also significantly reduce deposits, scale, and microbial adhesion, maintain the design flow rate and hydraulic characteristics over a long period of time, and reduce maintenance costs.

[0021] 4. This invention ensures the sealing of the seam through a unique seam treatment method (polyolefin strip is hot-melted and bonded to the seam / polyolefin strip is hot-melted and bonded to the corrugated peak of the pipe wall), avoiding the problem that gaps may exist at the seam of traditional steel corrugated pipes, which can easily lead to fluid leakage (especially when transporting high pressure or corrosive fluids), and effectively improving the safety and reliability of the pipeline.

[0022] 5. The fully anti-corrosion steel corrugated pipe produced by this invention has excellent mechanical and structural properties. Its resistance to local impact and wear, anti-corrosion performance, structural stability and service life (greater than 100 years) are all superior to traditional steel corrugated pipes. It has a wide range of applications, especially suitable for key engineering fields with high requirements for anti-corrosion service life, high transportation efficiency and harsh environmental requirements (such as buried, corrosive media). Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the fully corrosion-resistant steel corrugated pipe manufactured according to the present invention.

[0024] Figure 2 This is a schematic diagram of one of the bite treatment methods of the present invention;

[0025] Figure 3 This is a schematic diagram of the second biting treatment method of the present invention;

[0026] In the figure: substrate layer 1, hole 11, plastic coating layer 2, inner liner layer 3, cavity 4, seam 5, corrugated tape 6, polyolefin tape 7. Detailed Implementation

[0027] The following detailed description illustrates the specific implementation method:

[0028] Example

[0029] A method for forming a fully corrosion-resistant steel corrugated pipe includes the following steps:

[0030] Step S1: Select hot-dip galvanized perforated steel strip or hot-dip galvanized steel strip as the substrate layer; in this embodiment, a hot-dip galvanized perforated steel strip with a thickness of 2mm, a hole diameter of φ5mm, and a hole spacing of 10mm is selected as the substrate layer, with a yield strength ≥225MPa, tensile strength ≥310MPa, elongation ≥25%, and a single-sided adhesion of the galvanized layer ≥300g / m 2 The average thickness of the zinc coating is ≥42μm.

[0031] Step S2: Select adhesive and polyolefin material; in this embodiment, the adhesive is maleic anhydride-grafted polyethylene, and the polyolefin material is PE100 grade polyethylene; the adhesive and polyolefin material are uniformly coated sequentially on the surface of the substrate layer using a coating equipment to form a firm polyolefin coating layer, thereby obtaining a coated strip. The coating temperature is 215℃, the coating pressure is 18MPa, and the thickness of the polyolefin coating layer is 1.5mm.

[0032] The adhesive and polyethylene melt and flow under high temperature conditions. High pressure forces the molten plastic to fully wet the metal surface and penetrate into the pores. After solidification, it forms a mechanical interlocking structure of "rivets" or "anchors" in the pores. Under high temperature and pressure, the adhesive reacts chemically with the metal to form chemical bonds. The polyethylene and the polyethylene part of the adhesive undergo molecular chain entanglement (physical bonding). A strong, continuous and complete first layer of plastic anti-corrosion barrier is formed on the surface of the metal substrate. This achieves a firm bond between the metal substrate and the polyolefin coating layer, effectively preventing delamination and media penetration, and significantly improving the overall corrosion resistance of the pipeline.

[0033] Step S3: The plastic-coated strip is fed into the rolling equipment and rolled into a corrugated shape by multiple sets of first rollers in the shape of discs to obtain corrugated strip.

[0034] Using disc-shaped rollers, continuous corrugated shapes can be rolled out efficiently. The corrugated structure can improve the ring stiffness and compressive strength of the pipe, enabling it to withstand greater external pressure (such as soil load when buried) without excessive deformation or crushing, while maintaining good flexibility to adapt to foundation settlement.

[0035] Step S4: The corrugated strip is spirally wound into a tube using a spiral winding forming equipment, with a single flat seam connection at the joint. Simultaneously with winding, a polyolefin strip is extruded onto the inner wall of the tube using an extrusion device. This polyolefin strip is then dynamically compacted onto the crests of the corrugations on the inner wall of the tube by a cylindrical second roller, forming a smooth inner liner. The polyolefin strip is made of polyethylene or polypropylene. The length of the second roller is equal to the width of two adjacent crests of the tube. The thickness of the smooth inner liner is 3mm. A cavity is formed between the inner liner and the troughs of the inner wall of the tube, resulting in a fully corrosion-resistant steel corrugated pipe (e.g., Figure 1 (As shown).

[0036] Utilizing a mechanical seaming process, continuous spiral reinforcing ribs four times the thickness of the coated strip are formed at the pipe seam. This reduces product weight while significantly improving rigidity, flexibility, and tensile and compressive strength; its compressive strength is three times that of plastic pipes and 1.5 times that of cement pipes. The inner lining effectively prevents corrosion of the pipe body by the internal medium, significantly improving the pipe's corrosion resistance. Dynamic compaction of the inner lining using cylindrical rollers with lengths matching the width of adjacent corrugations ensures uniform thickness, smoothness, and strong adhesion to the corrugated strip. (Coated galvanized steel strip) The bond peel strength with the inner lining is greater than 100 N / cm, which significantly improves the integrity and density of the anti-corrosion layer; the smooth inner lining can reduce the flow resistance of fluid in the pipeline, reduce the deposition structure in the pipe, and improve the transportation efficiency; the inner lining and the plastic-coated steel strip are bonded at the crest, which is equivalent to adding polymer "reinforcing ribs" to the "skeleton" (crest) of the corrugated pipe. At the same time, the cavity structure maintains the inherent high ring stiffness of the corrugated structure, and when the inner wall of the pipe deforms, the inner lining has free space in the trough area to adapt to displacement, reducing the risk of stress cracking of the inner lining.

[0037] In step S4, the extrusion method of the polyolefin tape includes:

[0038] Method 1: The extrusion equipment extrudes polyolefin strip before the corrugated strip seam, causing the polyolefin strip to adhere to the surface of the corrugated strip. During the seam forming process, the ends of the polyolefin strip are heat-fused and bonded to the seam (e.g., Figure 2 As shown in the diagram, this improves the sealing performance of the joint. Molten plastic fills the microscopic gaps at the metal interlocking interface, forming a continuous plastic sealing strip. This fundamentally solves the problem of easy leakage at the joint of traditional metal spiral wound pipes, significantly improving the sealing performance at the joint. Furthermore, the plastic hot-melt bonding at the joint also increases the connection strength at the joint, improving the tensile strength of the pipe.

[0039] Method 2: After the corrugated strip is seamed, the extrusion equipment extrudes a polyolefin strip. The ends of the polyolefin strip are overlapped by a spiral forming method and then heat-fused to the crests of the corrugations on the inner wall of the tube to form a smooth inner lining layer (e.g., Figure 3 (As shown).

[0040] The fully corrosion-resistant steel corrugated pipe manufactured using this invention achieves a significant improvement in overall pipe performance through a triple composite anti-corrosion structure (galvanized substrate layer + double-sided plastic coating layer + inner lining layer) and a smooth inner lining design. It exhibits excellent mechanical properties, corrosion resistance, sealing performance, and conveying efficiency, making it a promising material for infrastructure construction, chemical, and petroleum industries. Especially in applications requiring the transport of corrosive media or demanding extremely high pipe sealing performance, this fully corrosion-resistant steel corrugated pipe demonstrates its unique advantages.

[0041] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for forming a fully corrosion-resistant steel corrugated pipe, characterized in that, Includes the following steps: Step S1: Select hot-dip galvanized perforated steel strip or hot-dip galvanized steel strip with a thickness of 0.5-10.0mm as the base material layer; Step S2: Select adhesive and polyolefin material, and use a coating equipment to uniformly coat the adhesive and polyolefin material on the surface of the substrate layer in sequence to form a strong polyolefin coating layer, thereby obtaining the coated tape. Step S3: The plastic-coated strip is fed into the rolling equipment and rolled into a corrugated shape by multiple sets of first rollers to obtain corrugated strip. Step S4: The corrugated strip is spirally wound to form a pipe body using a spiral winding forming equipment. At the same time as winding, polyolefin strip is extruded onto the inner wall of the pipe body using an extrusion equipment. The polyolefin strip is dynamically compacted onto the crest of the inner wall of the pipe body by a second roller to form a smooth inner lining layer. A cavity is formed between the inner lining layer and the trough of the inner wall of the pipe body to obtain a fully anti-corrosion steel corrugated pipe.

2. The molding method according to claim 1, characterized in that, In step S4, the extrusion equipment extrudes polyolefin strip before the corrugated strip bites, so that the polyolefin strip is bonded to the surface of the corrugated strip. During the corrugated strip bite forming process, the ends of the polyolefin strip are thermally bonded to the bite.

3. The molding method according to claim 1, characterized in that, In step S4, the extrusion equipment extrudes polyolefin strip after the corrugated strip is bitten. The ends of the polyolefin strip are overlapped by a spiral forming method and hot-melt bonded to the crest of the inner wall of the tube to form a smooth inner lining layer.

4. The molding method according to any one of claims 1-3, characterized in that, The polyolefin tape described in step S4 is made of polyethylene or polypropylene, and the thickness of the inner lining is 2.0-15 mm.

5. The molding method according to claim 4, characterized in that, The first roller in step S3 is disc-shaped, and the second roller in step S4 is cylindrical. The length of the second roller is the width of two adjacent peaks of the tube.

6. The molding method according to claim 5, characterized in that, The hole diameter of the hot-dip galvanized perforated steel strip mentioned in step S1 is φ5-20mm, and the hole spacing is 10-50mm.

7. The molding method according to claim 6, characterized in that, The hot-dip galvanized perforated steel strip or hot-dip galvanized steel strip mentioned in step S1 has a yield strength ≥225MPa, tensile strength ≥310MPa, and elongation ≥25%; the single-sided adhesion of the galvanized layer is ≥300g / m. 2 The average thickness of the zinc coating is ≥42μm.

8. The molding method according to claim 7, characterized in that, The adhesive used in step S2 is maleic anhydride-grafted polyethylene, the polyolefin material is PE100 grade polyethylene, the thickness of the polyolefin coating layer on the surface of the substrate layer is 1.0-5.0 mm, the coating temperature is 200-230℃, and the coating pressure is 18±3 MPa.

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