Construction method of anti-corrosion coating of offshore wind power pile foundation steel pile

Abstract

The invention provides a construction method of an anti-corrosion coating of a foundation steel pile of an offshore wind power pile, which adopts a flexible composite sheet formed by an adhesive layer, a fiber reinforced layer and a fluorocarbon resin protective layer through a gradient hot-pressing composite process, and simplifies a plurality of traditional complex on-site coating processes into a standardized installation process. The construction efficiency and the quality controllability are remarkably improved, the offshore operation period is shortened, super-strong marine environment corrosion resistance, impact resistance and lasting bonding performance are achieved by means of the innovative composite structure of the coating material, and therefore the construction efficiency of the offshore wind power steel pile, especially a splash zone and a water change zone, is greatly improved, and the service life of the offshore wind power steel pile is prolonged. An efficient, reliable and ultra-long-life anti-corrosion protection solution is provided, the structural safety is effectively guaranteed, and the full-life-cycle maintenance cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of wind power equipment corrosion protection technology, and in particular to a method for constructing an anti-corrosion coating for offshore wind turbine foundation steel piles. Background Technology

[0002] Offshore wind power, as an important component of clean energy, is developing towards large-scale and deep-sea deployment. The steel piles supporting the entire wind turbine structure are constantly exposed to the extremely harsh marine corrosive environment, and their corrosion resistance directly affects structural safety, operating costs, and service life. Offshore wind turbine foundation steel piles, especially those located in the splash zone and water level fluctuation zone, face the most severe corrosion challenges. These areas are not only subjected to high humidity and high salt spray environments, but also suffer from extremely high chloride ion concentrations due to wave impact, alternating wet and dry conditions, and sunlight exposure, leading to strong penetrating corrosion of the steel structure.

[0003] Currently, corrosion protection of offshore wind power foundation steel piles is mainly achieved by mechanically applying anti-corrosion coatings to form a surface coating. However, this coating is exposed to the marine environment for a long time, and corrosive media such as chloride ions can easily penetrate into the substrate through the microscopic defects of the coating, causing the coating to rust, blister, peel off, and ultimately fail to provide protection. The existing mechanical coatings have a short service life and poor anti-corrosion effect.

[0004] In summary, existing corrosion protection technologies for offshore wind turbine steel piles face the dual challenges of extremely harsh external environments and inherent defects in internal processes. Environmental factors require the protection system to possess superior corrosion resistance, impermeability, and long service life; while existing process defects lead to unstable protective layer quality, poor reliability, and high safety costs. Summary of the Invention

[0005] The first aspect of this disclosure provides a method for constructing an anti-corrosion coating for steel piles used in offshore wind turbine foundations, comprising the following steps: S1: Prefabricated flexible composite sheet, the structure of which includes, in sequence, an adhesive layer composed of adhesive, a substrate layer composed of fiber composite material, and a protective layer composed of composite material containing fluorocarbon resin. The three layers are formed by hot pressing composite process. S2: Clean the surface of the offshore wind power foundation steel pile to be protected, transport the flexible composite sheet provided in step S1 for cutting, expose the adhesive layer, and directly stick it to the treated surface to be protected; S3: Roll the outer surface of the pasted flexible composite sheet to ensure it is fully bonded to the surface of the steel pile.

[0006] In conjunction with the first aspect, in step S1, the adhesive is a two-component adhesive, wherein component A contains a side-chain fluorinated polyurethane prepolymer, and component B of the adhesive contains a cyclic amine curing agent.

[0007] In conjunction with the first aspect, in step S1, the substrate layer is a core-sheath structure, the core layer is a carbon fiber bundle treated with plasma, and the sheath layer contains a thermoplastic polyurethane elastomer.

[0008] In conjunction with the first aspect, step S1 specifically includes: uniformly applying an adhesive to one side of the substrate layer to form an adhesive layer, pre-curing it, then uniformly applying a composite material to the other side to form a protective layer, and then combining the three-layer structure through gradient hot rolling, followed by quenching to form the flexible composite sheet.

[0009] In conjunction with the first aspect, the pre-curing is carried out in a hot air circulation environment with a wind speed of 1-3 m / s and a temperature of 60-80°C for 4-8 minutes, so that the solvent residue rate of the coating is less than 5% and the gel rate reaches 20%-50%.

[0010] In conjunction with the first aspect, the gradient hot rolling roll composite process sequentially includes: First stage: Pre-compression at 80-100℃ and 0.5-2MPa for 4-8 minutes; Second stage: Compact the material at 130-150℃ and 5-8MPa for 8-12 minutes; The third stage: final compounding at 160–190℃ and 10–15MPa for 10–15 minutes.

[0011] In conjunction with the first aspect, the quenching employs a three-stage gradient cooling method: First stage: Cooling from 160-190℃ to 90-100℃ at a cooling rate of 30-50℃ / s; The second stage: cooling from 90-100℃ to 60-70℃ at a cooling rate of 15-30℃ / s; The third stage: cooling from 60-70℃ to below 40℃ at a rate of less than 5℃ / s.

[0012] In conjunction with the first aspect, when pasting on curved surfaces and weld seams in step S2, a hot air gun is used to assist in heating the flexible composite sheet. The temperature of the auxiliary heating is controlled at 100-120°C, the distance between the hot air gun head and the flexible composite sheet is 10-20cm, and the heating is uniform in a circular motion at a speed of 60-80mm / s.

[0013] In conjunction with the first aspect, the cut size of the flexible composite sheet is 3 to 10 mm wider on one side than the area to be protected by the steel pile.

[0014] In conjunction with the first aspect, step S3 applies pressure using a mechanical gradient roller pressing and holding method, specifically including the following steps: A flexible pressure roller with a Shore A hardness of 50-60 is used to apply a pressure of 0.2-0.5 MPa, and the flexible composite sheet is rolled in a spiral pattern from the center to the edge 1-2 times. Using a rigid metal roller with a Shore A hardness of 80-90, apply a pressure of 0.8-1.5 MPa and perform multiple overlapping roller pressing 2-3 times in a single direction at a speed of 0.3-0.8 m / s; A constant-temperature heated steel roller with a Shore A hardness of 120-150 and a temperature of 60-80℃ is used to apply a pressure of 1.0-2.0MPa and perform a final slow rolling 2-3 times. Hold the pressure at 0.1–0.3 MPa for 15–30 minutes. When uniform and continuous micro-adhesive strips form at the edge of the adhesive layer and naturally cure to form an edge seal, terminate the pressure holding process to complete the mechanical gradient roller pressing and pressure holding process.

[0015] Beneficial Effects: This disclosure provides a method for constructing an anti-corrosion coating for offshore wind turbine foundation steel piles. By employing a flexible composite sheet formed through a gradient hot-pressing process using an adhesive layer, a fiber reinforcement layer, and a fluorocarbon resin protective layer, the traditional complex multi-stage on-site coating process is simplified into a standardized installation procedure. This not only significantly improves construction efficiency and quality control, and shortens the offshore operation cycle, but also, thanks to the innovative composite structure of its coating material, achieves superior resistance to marine environmental corrosion, impact resistance, and durable adhesion. Therefore, it provides an efficient, reliable, and ultra-long-life anti-corrosion protection solution for offshore wind turbine steel piles, especially in splash zones and water-sensitive zones, effectively ensuring structural safety and reducing total life-cycle maintenance costs. Attached Figure Description

[0016] Figure 1 This is a schematic flowchart illustrating a method for constructing an anti-corrosion coating for offshore wind turbine foundation steel piles according to an embodiment of this disclosure. Detailed Implementation

[0017] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with those disclosed herein.

[0018] The terminology used in this disclosure is for the purpose of describing particular embodiments only and is not intended to be limiting of the present disclosure. The singular forms “a,” “the,” and “the” as used in this disclosure and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any and all possible combinations of one or more of the associated listed items.

[0019] Figure 1 This is a schematic flowchart illustrating a method for constructing an anti-corrosion coating on steel piles for offshore wind turbine foundations, according to an embodiment of this disclosure. The method includes the following steps: S1: Prefabricated flexible composite sheet, the structure of which includes, in sequence, an adhesive layer composed of adhesive, a substrate layer composed of fiber composite material, and a protective layer composed of composite material containing fluorocarbon resin. The three layers are formed by hot pressing composite process. S2: Clean the surface of the offshore wind power foundation steel pile to be protected, transport the flexible composite sheet provided in step S1 for cutting, expose the adhesive layer, and directly stick it to the treated surface to be protected; S3: Roll the outer surface of the pasted flexible composite sheet to ensure it is fully bonded to the surface of the steel pile.

[0020] In step S1, the adhesive is a two-component adhesive, wherein component A contains a side-chain fluorinated polyurethane prepolymer and component B contains a cyclic amine curing agent.

[0021] Specifically, the adhesive is a two-component reactive adhesive, comprising component A and component B, which are mixed in a weight ratio of A:B = 5:1. Component A, by weight, contains the following raw materials: 100 parts of side-chain fluorinated polyurethane prepolymer, 30 parts of polybutadiene rubber, 15 parts of polymethyl methacrylate, 10 parts of sheet-like nanofiller, and 6 parts of silane coupling agent. Component B contains the following raw materials: 40 parts of 1,3-cyclohexanedimethylamine, 60 parts of 4,4-diaminodicyclohexylmethane, and 4 parts of an amine compound.

[0022] The side-chain fluorinated polyurethane prepolymer is prepared by reacting polytetrahydrofuran ether diol with isophorone diisocyanate at 85°C for 2.5 h, then cooling to 60°C and adding a fluorinated alcohol end-capping agent. The fluorine content is 10%, and the reaction is carried out under inert gas protection. The core-shell toughening agent is an elastic microparticle with polybutadiene as the core and polymethyl methacrylate as the shell. The sheet-like nanofiller is a silane-modified nano-mica sheet with an aspect ratio greater than 100. The amine compound is m-phenylenediamine or isophorone diamine.

[0023] The substrate layer has a core-sheath structure, with the core layer being a carbon fiber bundle treated with plasma and the sheath layer containing thermoplastic polyurethane elastomer.

[0024] The sheath is made of the following raw materials by weight percentage: 100 parts thermoplastic polyurethane elastomer, 18 parts hydroxyl-terminated liquid nitrile rubber, 5 parts nano-organic montmorillonite, and 2 parts silane coupling agent; the core layer is a reinforcing skeleton composed of high-strength, high-modulus unidirectional fiber bundles, which are plasma-treated ultra-high molecular weight carbon fiber bundles with a fiber volume content of 70%.

[0025] The protective layer comprises the following raw materials in parts by weight: 100 parts polymer matrix, 28 parts lamellar reinforcing filler, 1.5 parts nano silica, 4 parts organic modified montmorillonite, 3 parts anti-aging system, and 5 parts peroxide vulcanizing agent.

[0026] The polymer matrix is ​​a fluorocarbon resin and hydrogenated nitrile rubber in a mass ratio of 1:1; the layered reinforcing filler is mica powder, glass flakes, and graphene in a mass ratio of 1:1:1; the anti-aging system is rutile titanium dioxide, hindered amine light stabilizer, and phosphite in a mass ratio of 10:1:0.6; and the peroxide vulcanizing agent is a mixture of dicumyl peroxide and TAIC crosslinking agent in a mass ratio of 1:1.3.

[0027] Step S1 specifically includes: uniformly applying an adhesive to one side of the substrate layer to form an adhesive layer, pre-curing it, and then uniformly applying a composite material to the other side to form a protective layer. The three-layer structure is then laminated by gradient hot rolling, and after quenching, the flexible composite sheet is formed.

[0028] The pre-curing process involves treating the coating in a hot air circulation environment with a wind speed of 1–3 m / s and a temperature of 60–80°C for 4–8 minutes, so that the solvent residue rate of the coating is less than 5% and the gel rate reaches 20%–50%.

[0029] The gradient hot rolling roll composite process includes, in sequence: First stage: Pre-compression at 80-100℃ and 0.5-2MPa for 4-8 minutes; Second stage: Compact the material at 130-150℃ and 5-8MPa for 8-12 minutes; The third stage: final compounding at 160–190℃ and 10–15MPa for 10–15 minutes.

[0030] The quenching process employs a three-stage gradient cooling method: First stage: Cooling from 160-190℃ to 90-100℃ at a cooling rate of 30-50℃ / s; The second stage: cooling from 90-100℃ to 60-70℃ at a cooling rate of 15-30℃ / s; The third stage: cooling from 60-70℃ to below 40℃ at a rate of less than 5℃ / s.

[0031] In step S2, when pasting on curved surfaces and weld seams, a hot air gun is used to assist in heating the flexible composite sheet. The temperature of the auxiliary heating is controlled at 100-120°C, the distance between the hot air gun head and the flexible composite sheet is 10-20cm, and the heating is uniform in a circular motion at a speed of 60-80mm / s.

[0032] The cutting size of the flexible composite sheet is 3 to 10 mm wider on one side than the area of ​​the steel pile to be protected.

[0033] Step S3 applies pressure using a mechanical gradient roller pressing method, specifically including the following steps: A flexible pressure roller with a Shore A hardness of 50-60 is used to apply a pressure of 0.2-0.5 MPa, and the flexible composite sheet is rolled in a spiral pattern from the center to the edge 1-2 times. Using a rigid metal roller with a Shore A hardness of 80-90, apply a pressure of 0.8-1.5 MPa and perform multiple overlapping roller pressing 2-3 times in a single direction at a speed of 0.3-0.8 m / s; A constant-temperature heated steel roller with a Shore A hardness of 120-150 and a temperature of 60-80℃ is used to apply a pressure of 1.0-2.0MPa and perform a final slow rolling 2-3 times. Hold the pressure at 0.1–0.3 MPa for 15–30 minutes. When uniform and continuous micro-adhesive strips form at the edge of the adhesive layer and naturally cure to form an edge seal, terminate the pressure holding process to complete the mechanical gradient roller pressing and pressure holding process.

[0034] In the first embodiment provided in this disclosure, a protective material is uniformly coated on one side of the substrate layer to form a protective layer. This layer is then treated for 4 minutes in a hot air circulation environment with a wind speed controlled at 1 m / s and a temperature controlled at 60°C, resulting in a solvent residue rate of less than 5% and a gel rate of 20%. Next, an adhesive material is uniformly coated on the other side to form an adhesive layer. The three-layer structure is then laminated using gradient hot rollers. Specifically, the laminate is pre-pressed for 4 minutes at a temperature of 80°C and a pressure of 0.5 MPa to remove some air; then, it is compacted for 8 minutes at a temperature of 130°C and a pressure of 5 MPa to remove all air; finally, the laminate is melted, diffused, and laminated at the interfaces of each layer at a temperature of 160°C and a pressure of 10 MPa for 10 minutes. Next, a three-stage gradient curve is used for quenching. In the first stage, the cooling rate is controlled at 30℃ / s in the temperature range of 160℃ to 90℃. In the second stage, the cooling rate is controlled at 15℃ / s in the temperature range of 90℃ to 60℃. In the third stage, the cooling rate is controlled at less than 5℃ / s in the temperature range of 60℃ to below 40℃, so that the adhesive layer, reinforcing layer and protective layer form a flexible composite sheet.

[0035] The surface of the offshore wind power foundation steel piles to be protected is cleaned, that is, the steel pile surface is derusted and / or decontaminated, so that its surface cleanliness reaches St2 level or above.

[0036] The prepared flexible composite sheet is transported to the site and cut according to the shape of the area to be protected by the steel pile. The cut size is 3mm wider on each side of the area to be protected. The release film tightly adhering to the adhesive layer on the flexible composite sheet is peeled off. The flexible composite sheet is then directly pasted onto the prepared surface to be protected. When pasting on curved surfaces, welds, or complex areas to be protected, a hot air gun is used to assist in heating the flexible composite sheet. The temperature is controlled at 100℃, the distance between the hot air gun tip and the flexible composite sheet is 10cm, and the sheet is heated evenly in a circular motion at a speed of 60mm / s until the flexible composite sheet softens and exhibits a high-viscosity gloss. Then, the sheet is immediately pasted and pressed together. Mechanical gradient roller pressing is applied to the outer surface of the bonded flexible composite sheet to remove air between the adhesive layer and the steel pile surface, ensuring full adhesion between the flexible composite sheet and the steel pile surface, thus completing the anti-corrosion coating construction. The mechanical gradient roller pressing process specifically includes the following steps: A flexible pressure roller with a Shore A hardness of 50 is used to apply a pressure of 0.2 MPa and perform spiral rolling 1 to 2 times from the center of the flexible composite sheet to the edge. A rigid metal roller with a Shore A hardness of 80 is used, and a pressure of 0.8 MPa is applied. The roller is then subjected to multiple overlapping rolls twice in a single direction at a speed of 0.3 m / s. A constant-temperature heated steel roller with a Shore A hardness of 120 and a temperature of 60°C is used, and a pressure of 1.0 MPa is applied to perform two final slow rolling processes. Hold the pressure at 0.1 MPa for 15 minutes. When a uniform and continuous micro-adhesive strip forms at the edge of the adhesive layer and naturally cures to form an edge seal, stop the pressure holding process and complete the mechanical gradient roller pressing and pressure holding process.

[0037] In the second embodiment provided in this disclosure, a protective material is uniformly coated on one side of the substrate layer to form a protective layer. This layer is then treated for 8 minutes in a hot air circulation environment with a wind speed controlled at 3 m / s and a temperature controlled at 80°C, resulting in a solvent residue rate of less than 5% and a gel rate of 50%. Next, an adhesive material is uniformly coated on the other side to form an adhesive layer. The three-layer structure is then laminated using gradient hot rollers. First, the laminate is pre-pressed at 100°C and 2 MPa for 8 minutes to remove some air. Then, the laminate is compacted at 150°C and 8 MPa for 12 minutes to remove all air. Finally, the temperature is controlled at 190°C, the pressure at 15 MPa, and the time at 15 minutes to allow the interfaces of each material layer to melt, diffuse, and laminate. Next, a three-stage gradient curve is used for quenching. In the first stage, the cooling rate is controlled at 50℃ / s in the temperature range of 190℃ to 100℃. In the second stage, the cooling rate is controlled at 30℃ / s in the temperature range of 100℃ to 70℃. In the third stage, the cooling rate is controlled at less than 5℃ / s in the temperature range of 70℃ to below 40℃, so that the adhesive layer, reinforcing layer and protective layer form a flexible composite sheet.

[0038] The surface of the offshore wind power foundation steel piles to be protected is cleaned, that is, the steel pile surface is derusted and / or decontaminated, so that its surface cleanliness reaches St2 level or above.

[0039] The flexible composite sheet is transported to the site and cut to the shape of the area to be protected by the steel pile. The cut size is 10mm wider on each side of the area to be protected. The release film tightly adhering to the adhesive layer on the flexible composite sheet is peeled off. The flexible composite sheet is then directly pasted onto the prepared surface to be protected. When pasting on curved surfaces, welds, or complex areas to be protected, a hot air gun is used to assist in heating the flexible composite sheet. The temperature is controlled at 120℃, and the distance between the hot air gun tip and the flexible composite sheet is 20cm. The sheet is heated evenly in a circular motion at a speed of 80mm / s until the flexible composite sheet softens and exhibits a high-adhesion gloss. Then, the sheet is immediately pasted and pressed together. Mechanical gradient roller pressing is applied to the outer surface of the bonded flexible composite sheet to remove air between the adhesive layer and the steel pile surface, ensuring full adhesion between the flexible composite sheet and the steel pile surface, thus completing the anti-corrosion coating construction. The mechanical gradient roller pressing process specifically includes the following steps: A flexible pressure roller with a Shore A hardness of 60 is used to apply a pressure of 0.5 MPa, and the flexible composite sheet is rolled in a spiral pattern twice from the center to the edge. A rigid metal roller with a Shore A hardness of 90 is used. A pressure of 1.5 MPa is applied, and the roller is repeatedly overlapped and pressed three times in a single direction at a speed of 0.8 m / s. A constant-temperature heated steel roller with a Shore A hardness of 150 and a temperature of 80°C is used, and a pressure of 2.0 MPa is applied to perform a final slow rolling process three times. Hold the pressure at 0.3 MPa for 30 minutes. When a uniform and continuous micro-adhesive strip forms at the edge of the adhesive layer and naturally cures to form an edge seal, stop the pressure holding process and complete the mechanical gradient roller pressing and pressure holding process.

[0040] In the third embodiment provided in this disclosure, a protective material is uniformly coated on one side of the substrate layer to form a protective layer. This layer is then treated for 5 minutes in a hot air circulation environment with a wind speed controlled at 1.5 m / s and a temperature controlled at 65°C, resulting in a solvent residue rate of less than 5% and a gel rate of 30%. Next, an adhesive material is uniformly coated on the other side to form an adhesive layer. The three-layer structure is then laminated using gradient hot rollers. First, the laminate is pre-pressed at 85°C and 1 MPa for 5 minutes to remove some air. Then, the laminate is compacted at 135°C and 6 MPa for 9 minutes to remove all air. Finally, the laminate is melted, diffused, and laminated at 170°C, 11 MPa, and for 11 minutes. Next, a three-stage gradient curve is used for quenching. In the first stage, the cooling rate is controlled at 35℃ / s in the temperature range of 170℃ to 92℃. In the second stage, the cooling rate is controlled at 20℃ / s in the temperature range of 90℃ to 100℃ to 63℃. In the third stage, the cooling rate is controlled at less than 5℃ / s in the temperature range of 62℃ to below 40℃, so that the adhesive layer, reinforcing layer and protective layer form a flexible composite sheet.

[0041] The surface of the offshore wind power foundation steel piles to be protected is cleaned, that is, the steel pile surface is derusted and / or decontaminated, so that its surface cleanliness reaches St2 level or above.

[0042] The flexible composite sheet is transported to the site and cut to the shape of the area to be protected by the steel pile. The cut size is 4mm wider on each side of the area to be protected. The release film tightly adhering to the adhesive layer on the flexible composite sheet is peeled off. The flexible composite sheet is then directly pasted onto the prepared surface to be protected. When pasting on curved surfaces, welds, or complex areas to be protected, a hot air gun is used to assist in heating the flexible composite sheet. The temperature is controlled at 105℃, and the distance between the hot air gun tip and the flexible composite sheet is 12cm. The sheet is heated evenly in a circular motion at a speed of 65mm / s until the flexible composite sheet softens and exhibits a high-adhesion gloss. Then, it is immediately pasted and pressed together. Mechanical gradient roller pressing is applied to the outer surface of the bonded flexible composite sheet to remove air between the adhesive layer and the steel pile surface, ensuring full adhesion between the flexible composite sheet and the steel pile surface, thus completing the anti-corrosion coating construction. The mechanical gradient roller pressing process specifically includes the following steps: A flexible pressure roller with a Shore A hardness of 53 is used to apply a pressure of 0.3 MPa and perform spiral rolling 1 to 2 times from the center to the edge of the flexible composite sheet. A rigid metal roller with a Shore A hardness of 82 is used. A pressure of 1 MPa is applied, and the roller is repeatedly overlapped twice in one direction at a speed of 0.4 m / s. A constant-temperature heated steel roller with a Shore A hardness of 130 and a temperature of 65°C is used, and a pressure of 1.2MPa is applied to perform two final slow rolling processes. Hold the pressure at 0.15 MPa for 20 minutes. When a uniform and continuous micro-adhesive strip forms at the edge of the adhesive layer and naturally cures to form an edge seal, stop the pressure holding process and complete the mechanical gradient roller pressing and pressure holding process.

[0043] In the fourth embodiment provided in this disclosure, a protective material is uniformly coated on one side of the substrate layer to form a protective layer. This layer is then treated for 7 minutes in a hot air circulation environment with a wind speed controlled at 2.5 m / s and a temperature controlled at 75°C, resulting in a solvent residue rate of less than 5% and a gelation rate of 40%. Next, an adhesive material is uniformly coated on the other side to form an adhesive layer. The three-layer structure is then laminated using gradient hot rollers. First, the laminate is pre-pressed at 95°C and 1.5 MPa for 7 minutes to remove some air. Then, the laminate is compacted at 145°C and 7 MPa for 11 minutes to remove all air. Finally, the laminate is melted, diffused, and laminated at 180°C, 14 MPa, and for 14 minutes. Next, a three-stage gradient curve is used for quenching. In the first stage, the cooling rate is controlled at 45℃ / s in the temperature range of 180℃ to 98℃. In the second stage, the cooling rate is controlled at 25℃ / s in the temperature range of 98℃ to 68℃. In the third stage, the cooling rate is controlled at less than 5℃ / s in the temperature range of 68℃ to below 40℃, so that the adhesive layer, reinforcing layer and protective layer form a flexible composite sheet.

[0044] The surface of the offshore wind power foundation steel piles to be protected is cleaned, that is, the steel pile surface is derusted and / or decontaminated, so that its surface cleanliness reaches St2 level or above.

[0045] The flexible composite sheet is transported to the site and cut to the shape of the area to be protected by the steel pile. The cut size is 9mm wider on each side of the area to be protected. The release film tightly adhering to the adhesive layer on the flexible composite sheet is peeled off. The flexible composite sheet is then directly pasted onto the prepared surface to be protected. When pasting on curved surfaces, welds, or complex areas to be protected, a hot air gun is used to assist in heating the flexible composite sheet. The temperature is controlled at 115℃, and the distance between the hot air gun tip and the flexible composite sheet is 18cm. The sheet is heated evenly in a circular motion at a speed of 75mm / s until the flexible composite sheet softens and exhibits a high-viscosity gloss. Then, it is immediately pasted and pressed together. Mechanical gradient roller pressing is applied to the outer surface of the bonded flexible composite sheet to remove air between the adhesive layer and the steel pile surface, ensuring full adhesion between the flexible composite sheet and the steel pile surface, thus completing the anti-corrosion coating construction. The mechanical gradient roller pressing process specifically includes the following steps: A flexible pressure roller with a Shore A hardness of 58 is used to apply a pressure of 0.4 MPa, and the flexible composite sheet is rolled twice in a spiral pattern from the center to the edge. A rigid metal roller with a Shore A hardness of 88 is used, and a pressure of 1.3 MPa is applied. The roller is then subjected to multiple overlapping rolls three times in a single direction at a speed of 0.7 m / s. A constant-temperature heated steel roller with a Shore A hardness of 140 and a temperature of 75°C is used, and a pressure of 1.8MPa is applied to perform a final slow rolling process three times. Hold the pressure at 0.25 MPa for 25 minutes. When a uniform and continuous micro-adhesive strip forms at the edge of the adhesive layer and naturally cures to form an edge seal, stop the pressure holding process and complete the mechanical gradient roller pressing and pressure holding process.

[0046] In the fifth embodiment provided in this disclosure, a protective material is uniformly coated on one side of the substrate layer to form a protective layer. This layer is then treated for 6 minutes in a hot air circulation environment with a wind speed controlled at 2 m / s and a temperature controlled at 70°C, resulting in a solvent residue rate of less than 5% and a gel rate of 35%. Next, an adhesive material is uniformly coated on the other side to form an adhesive layer. The three-layer structure is then laminated using gradient hot rollers. First, the laminate is pre-pressed at 90°C and 1.3 MPa for 6 minutes to remove some air. Then, the laminate is compacted at 140°C and 6.5 MPa for 10 minutes to remove all air. Finally, the laminate is melted, diffused, and laminated at 175°C, 13 MPa, and for 12 minutes. Next, a three-stage gradient curve is used for quenching. In the first stage, the cooling rate is controlled at 40℃ / s in the temperature range of 175℃ to 90℃ to 100℃. In the second stage, the cooling rate is controlled at 22℃ / s in the temperature range of 95℃ to 65℃. In the third stage, the cooling rate is controlled at less than 5℃ / s in the temperature range of 65℃ to below 40℃, so that the adhesive layer, reinforcing layer and protective layer form a flexible composite sheet.

[0047] The surface of the offshore wind power foundation steel piles to be protected is cleaned, that is, the steel pile surface is derusted and / or cleaned to make its surface cleanliness reach St2 level or above. The flexible composite sheet is transported to the site and cut to the shape of the area to be protected by the steel pile. The cut size is 6mm wider on each side of the area to be protected. The release film tightly adhering to the adhesive layer on the flexible composite sheet is peeled off. The flexible composite sheet is then directly pasted onto the prepared surface to be protected. When pasting on curved surfaces, welds, or complex areas to be protected, a hot air gun is used to assist in heating the flexible composite sheet. The temperature is controlled at 110℃, and the distance between the hot air gun tip and the flexible composite sheet is 15cm. The sheet is heated evenly in a circular motion at a speed of 70mm / s until the flexible composite sheet softens and exhibits a high-viscosity gloss. Then, it is immediately pasted and pressed together. Mechanical gradient roller pressing is applied to the outer surface of the bonded flexible composite sheet to remove air between the adhesive layer and the steel pile surface, ensuring full adhesion between the flexible composite sheet and the steel pile surface, thus completing the anti-corrosion coating construction. The mechanical gradient roller pressing process specifically includes the following steps: A flexible pressure roller with a Shore A hardness of 55 is used to apply a pressure of 0.35 MPa and perform a spiral roller press once from the center of the flexible composite sheet to the edge. A rigid metal roller with a Shore A hardness of 85 is used, and a pressure of 1.1 MPa is applied. The roller is then subjected to multiple overlapping rolls twice in a single direction at a speed of 0.6 m / s. A constant-temperature heated steel roller with a Shore A hardness of 135 and a temperature of 70°C is used, and a pressure of 1.5MPa is applied to perform a final slow rolling process three times. Hold the pressure at 0.2 MPa for 23 minutes. When a uniform and continuous micro-adhesive strip forms at the edge of the adhesive layer and naturally cures to form an edge seal, stop the pressure holding process and complete the mechanical gradient roller pressing and pressure holding process.

[0048] The above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit it. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure, and should all be included within the protection scope of this disclosure.

Claims

1. A method for constructing an anti-corrosion coating for steel piles used in offshore wind turbine foundations, characterized in that, Includes the following steps: S1: Prefabricated flexible composite sheet, the structure of which includes, in sequence, an adhesive layer composed of adhesive, a substrate layer composed of fiber composite material, and a protective layer composed of composite material containing fluorocarbon resin. The three layers are formed by hot pressing composite process. S2: Clean the surface of the offshore wind power foundation steel pile to be protected, transport the flexible composite sheet provided in step S1 for cutting, expose the adhesive layer, and directly stick it to the treated surface to be protected; S3: Roll the outer surface of the pasted flexible composite sheet to ensure it is fully bonded to the surface of the steel pile.

2. The construction method according to claim 1, characterized in that, In step S1, the adhesive is a two-component adhesive, wherein component A contains a side-chain fluorinated polyurethane prepolymer, and component B contains a cyclic amine curing agent.

3. The construction method according to claim 1, characterized in that, In step S1, the substrate layer is a core-sheath structure, the core layer is a carbon fiber bundle treated with plasma, and the sheath layer contains thermoplastic polyurethane elastomer.

4. The construction method according to claim 1, characterized in that, Step S1 specifically includes: uniformly applying an adhesive to one side of the substrate layer to form an adhesive layer, pre-curing it, and then uniformly applying a composite material to the other side to form a protective layer. The three-layer structure is then laminated by gradient hot rolling, and after quenching, the flexible composite sheet is formed.

5. The construction method according to claim 4, characterized in that, The pre-curing process involves treating the coating in a hot air circulation environment with a wind speed of 1–3 m / s and a temperature of 60–80°C for 4–8 minutes, so that the solvent residue rate of the coating is less than 5% and the gel rate reaches 20%–50%.

6. The construction method according to claim 5, characterized in that, The gradient hot rolling roll composite process includes, in sequence: First stage: Pre-compression at 80-100℃ and 0.5-2MPa for 4-8 minutes; Second stage: Compact the material at 130-150℃ and 5-8MPa for 8-12 minutes; The third stage: final compounding at 160–190℃ and 10–15MPa for 10–15 minutes.

7. The construction method according to claim 6, characterized in that, The quenching process employs a three-stage gradient cooling method: First stage: Cooling from 160-190℃ to 90-100℃ at a cooling rate of 30-50℃ / s; The second stage: cooling from 90-100℃ to 60-70℃ at a cooling rate of 15-30℃ / s; The third stage: cooling from 60-70℃ to below 40℃ at a rate of less than 5℃ / s.

8. The construction method according to claim 1, characterized in that, In step S2, when pasting on curved surfaces and weld seams, a hot air gun is used to assist in heating the flexible composite sheet. The temperature of the auxiliary heating is controlled at 100-120°C, the distance between the hot air gun head and the flexible composite sheet is 10-20cm, and the heating is uniform in a circular motion at a speed of 60-80mm / s.

9. The construction method according to claim 8, characterized in that, The cutting size of the flexible composite sheet is 3 to 10 mm wider on one side than the area of ​​the steel pile to be protected.

10. The construction method according to claim 1, characterized in that, Step S3 applies pressure using a mechanical gradient roller pressing method, specifically including the following steps: A flexible pressure roller with a Shore A hardness of 50-60 is used to apply a pressure of 0.2-0.5 MPa, and the flexible composite sheet is rolled in a spiral pattern from the center to the edge 1-2 times. Using a rigid metal roller with a Shore A hardness of 80-90, apply a pressure of 0.8-1.5 MPa and perform multiple overlapping roller pressing 2-3 times in a single direction at a speed of 0.3-0.8 m / s; A constant-temperature heated steel roller with a Shore A hardness of 120-150 and a temperature of 60-80℃ is used to apply a pressure of 1.0-2.0MPa and perform a final slow rolling 2-3 times. Hold the pressure at 0.1–0.3 MPa for 15–30 minutes. When uniform and continuous micro-adhesive strips form at the edge of the adhesive layer and naturally cure to form an edge seal, terminate the pressure holding process to complete the mechanical gradient roller pressing and pressure holding process.

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