Surface corrosion-resistant pretreatment method

Abstract

The invention provides a surface corrosion-resistant pretreatment method, which is used for a wind power modular cabin and accessories thereof, and comprises the following steps: S1, environment and base material state control: placing a base material under an environmental condition with the relative humidity not higher than 70%, and enabling the surface temperature of the base material to be at least 3 DEG C higher than the dew point temperature of ambient air; s3, shot blasting treatment is conducted, specifically, the surface of the base material is subjected to shot blasting treatment; s5, spraying treatment is conducted, specifically, spraying treatment is conducted on the surface of the base material; wherein the step S5 is started within 4 hours after the step S1 is completed. According to the method, the base material has an ideal surface state through the step of controlling the environment and the state of the base material. And through shot blasting treatment, the rough surface of the base material is more beneficial to permeation and anchoring of the coating. And spraying treatment is started within 4 hours after the environment control step is completed, it is guaranteed that the surface of the base material is in the optimal state all the time, and therefore the spraying quality and the long-term stability of a coating are guaranteed, and the overall corrosion resistance of the base material can be effectively improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wind power modular nacelle and its accessory processing, more particularly to a surface corrosion-resistant pretreatment method. BACKGROUND

[0002] In the fields of industrial manufacturing, marine engineering, bridge construction, etc., metal structural parts are often exposed to harsh environments such as moisture, salt spray, and chemical corrosion, which can cause corrosion on the surface of the base material and seriously affect its mechanical properties and service life. To improve the corrosion resistance of metals, protective coatings are usually applied to their surfaces. In extreme corrosive environments, protective coatings are prone to fall off, ultimately affecting the strength and protection ability of metal structural parts.

[0003] Therefore, it is necessary to provide a surface corrosion-resistant pretreatment method to at least partially solve the above problems. SUMMARY

[0004] A series of simplified concepts are introduced in the summary section, which will be further described in detail in the detailed description section. The summary section of the present application does not mean to attempt to limit the key features and essential technical features of the claimed technical solutions, nor to determine the protection scope of the claimed technical solutions.

[0005] To at least partially solve the above problems, the present application provides a surface corrosion-resistant pretreatment method for wind power modular nacelle and its accessories, characterized in that it comprises the following steps:

[0006] S1, environmental and base material state control: placing the base material in an environment with a relative humidity of not more than 70%, and making the surface temperature of the base material at least 3℃ higher than the dew point temperature of the ambient air;

[0007] S3, shot blasting treatment: shot blasting treatment is performed on the surface of the base material;

[0008] S5, spraying treatment: spraying treatment is performed on the surface of the base material;

[0009] Wherein, the step S5 is started within 4 hours after the completion of the step S1.

[0010] According to the surface corrosion-resistant pretreatment method of the present application, through the environment and substrate state control steps, the substrate has an ideal surface state, which is beneficial to subsequent shot blasting treatment and spraying treatment. The shot blasting treatment makes the rough surface of the substrate more conducive to the penetration and anchoring of the coating, and enhances the mechanical interlocking effect between the coating and the substrate. The spraying treatment is started within 4 hours after the completion of the environment control step, which ensures that the surface of the substrate is always in the best state, thereby ensuring the spraying quality and the long-term stability of the coating. Through the organic combination of the above steps, not only the physical and chemical properties of the surface of the substrate are improved, but also the time of the spraying treatment is optimized, which ensures the good bonding between the coating and the substrate, thereby effectively improving the overall corrosion-resistant performance of the substrate and prolonging the service life. At the same time, the coating and the substrate are well bonded, reducing the number of rework and maintenance, reducing production costs, and improving economic benefits.

[0011] Optionally, in the step S3, an abrasive is used for the shot blasting treatment, wherein,

[0012] The abrasive is at least one of cast steel sand, quartz sand or ceramic sand; and / or

[0013] The particle size of the abrasive is 0.2mm-0.8mm.

[0014] Optionally, when the abrasive is cast steel sand, the cast steel sand is G25 grade;

[0015] When the abrasive is quartz sand, the particle size of the quartz sand is 0.3mm-0.8mm;

[0016] When the abrasive is ceramic sand, the particle size of the ceramic sand is 0.2mm-0.6mm.

[0017] Optionally, in the step S3, the process parameters of the shot blasting treatment meet at least one of the following conditions:

[0018] The compressed air pressure is 0.5MPa-0.7MPa;

[0019] The distance between the spray gun and the treated surface is 100mm-150mm;

[0020] The shot blasting angle is perpendicular to the surface and the deviation is not more than 15°.

[0021] Optionally, in the step S3, the shot blasting treatment is sequentially performed on the substrate in the order of from top to bottom and from inside to outside.

[0022] Optionally, in the step S3, ventilation treatment is performed at the same time as the shot blasting treatment.

[0023] Optionally, after the shot blasting treatment, the surface roughness of the substrate reaches the Sa2.5 grade standard.

[0024] Optionally, before the step S3, there is a surface defect checking step: confirming that the substrate is free of undercut, weld reinforcement, crater, spatter, porosity, slag inclusion, lack of fusion and lack of penetration defects, and all exposed corners are chamfered.

[0025] Optionally, before the step S5, there is a surface cleaning step: removing oil stains on the surface of the substrate, and blowing off floating dust on the surface of the substrate.

[0026] Optionally, in the step S5, paint or powder is used for spraying treatment. BRIEF DESCRIPTION OF DRAWINGS

[0027] The following drawings for the embodiments of the present application are hereby incorporated into this application as part of the present application for the purpose of understanding the present application. The embodiments of the present application and their description shown in the drawings are used to explain the principles of the present application. In the drawings,

[0028] Figure 1 Surface roughness of the substrate prepared for Example 1 of the present application;

[0029] Figure 2 Surface roughness of the substrate prepared for Comparative Example 4 of the present application;

[0030] Figure 3 Surface roughness of the substrate prepared for Comparative Example 4 of the present application;

[0031] Figure 4 Surface roughness of the substrate prepared for Comparative Example 2 of the present application;

[0032] Figure 5 Surface roughness of the substrate prepared for Comparative Example 3 of the present application;

[0033] Figure 6 Appearance of the substrate prepared for Example 1 of the present application within 4 hours;

[0034] Figure 7 Appearance of the substrate prepared for Comparative Example 4 of the present application within 10 hours;

[0035] Figure 8 Surface defect checking of the substrate prepared for Experimental Example 1 of the present application;

[0036] Figure 9 Surface defect checking of the substrate prepared for Experimental Example 1 of the present application;

[0037] Figure 10 Grid method diagram of the substrate prepared for Experimental Example 1 of the present application;

[0038] Figure 11 Thickness detection diagram of the substrate prepared for Experimental Example 1 of the present application;

[0039] Figure 12 Schematic diagram of grid method for the substrate prepared for Comparative Example 2 of the present application;

[0040] Figure 13 Schematic diagram of grid method coating detachment for the substrate prepared for Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0041] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without one or more of these specific details. In other instances, well-known features have not been described in detail to avoid obscuring aspects of the present application.

[0042] It is also to be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments consistent with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0043] In this document, ordinal numbers such as "first" and "second" cited in the present application are merely identifiers and have no other meaning, such as a particular order, etc. Also, for example, the term "first means" itself does not imply the existence of "second means", and the term "second means" itself does not imply the existence of "first means".

[0044] In this document, "upper", "lower", "front", "rear", "left", "right", and the like are used to indicate relative positional relationship between the relevant parts, not to limit the absolute position of the relevant parts.

[0045] In this document, "equal", "same", and the like are not strictly limited in the mathematical and / or geometric sense, but also include errors allowed in manufacturing or use that can be understood by those skilled in the art.

[0046] Unless otherwise indicated, numerical ranges herein are inclusive of the recited two endpoints in their entirety.

[0047] Now, example embodiments according to this application will be described in greater detail by referring to the drawings. These example embodiments can be implemented in various different forms, and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of these example embodiments to those skilled in the art.

[0048] At present, the application environment of offshore wind power modularization cabin is extremely harsh, which is in CX corrosion environment (extremely corrosive atmospheric corrosion environment). Carbon steel is often corroded due to its own characteristics, and it is difficult to ensure that the cabin design durability is more than 30 years, thereby causing early decay of the structural strength of the wind power modularization cabin, and thus causing more serious accidents such as loss of effective protection of the equipment in the cabin. Therefore, it is particularly important to treat the surface of the carbon steel to achieve corrosion resistance.

[0049] The application provides a surface corrosion-resistant pretreatment method for a wind power modularization cabin and accessories thereof.

[0050] A surface corrosion-resistant pretreatment method comprises the following steps:

[0051] S1, environment and substrate state control: placing the substrate in an environment condition with a relative humidity of not higher than 70%, and making the surface temperature of the substrate higher than the dew point temperature of the ambient air by at least 3℃;

[0052] S3, shot blasting treatment: performing shot blasting treatment on the surface of the substrate;

[0053] S5, spraying treatment: performing spraying treatment on the surface of the substrate;

[0054] Wherein, step S5 is started within 4 hours after step S1 is completed.

[0055] In the environment and substrate state control step, by placing the substrate in an environment condition with a relative humidity of not higher than 70%, the formation of water film adsorbed on the surface of the substrate is effectively inhibited, and the oxidation of metal swarf generated by subsequent shot blasting into loose rust layer due to the humid environment is avoided, so as to ensure the exposure of active metal on the surface after shot blasting. By ensuring that the surface temperature of the substrate is higher than the dew point temperature of the ambient air by at least 3℃, condensation is fundamentally prevented. Through the environment and substrate state control step, the substrate has an ideal surface state, which is convenient for subsequent shot blasting treatment and spraying treatment.

[0056] In the shot blasting step, the surface of the substrate is subjected to shot blasting treatment, which can completely remove rust, scale, oil stains and other impurities on the surface, while introducing a certain surface roughness. This treatment makes the rough surface of the substrate more conducive to the penetration and anchoring of the coating, enhancing the mechanical interlocking effect between the coating and the substrate. It creates favorable conditions for subsequent paint spraying or powder spraying, ensuring paint adhesion and corrosion protection effect.

[0057] In the spraying step, the substrate surface is prevented from rusting again through spraying treatment.

[0058] The spraying treatment is started within 4 hours after the completion of the environmental control step, effectively preventing the substrate surface from being contaminated or corroded again during the waiting period for spraying due to exposure to air. This timeliness ensures that the substrate surface is always in the best condition, thereby ensuring the quality of the spraying and the long-term stability of the coating.

[0059] Through the organic combination of the above steps, not only the physical and chemical properties of the substrate surface are improved, but also the time of the spraying treatment is optimized to ensure good bonding between the coating and the substrate, thereby effectively improving the overall corrosion resistance of the substrate, prolonging the service life, and reducing the number of rework and maintenance, reducing production costs and improving economic benefits.

[0060] The substrate treated by the pretreatment method has sufficient adhesion of paint or powder coating to the substrate of the wind power modularization cabin and its accessories, which is strong enough to resist the corrosion of the marine atmospheric environment, thereby ensuring that the design durability of the wind power modularization cabin and its accessories reaches more than 30 years at the source of the corrosion prevention process design, greatly reducing the frequency of intermediate maintenance, saving operation and maintenance costs, and ensuring the long-term stable operation of the equipment. It is especially suitable for extreme corrosive environments (such as CX corrosion environment), and can meet the stringent requirements of wind power modularization cabins and other special fields for the corrosion resistance of the substrate.

[0061] Optionally, in step S3, abrasive is used for shot blasting treatment. Optionally, the abrasive is at least one of cast steel sand, quartz sand or ceramic sand. Cast steel sand, quartz sand and ceramic sand have high hardness and are not easy to break, and can be reused multiple times, thereby reducing dust generation and waste, meeting the requirements of energy saving and environmental protection.

[0062] Optionally, the abrasive has a particle size range of 0.2mm-0.8mm. The particle size range of the abrasive can be, but is not limited to, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm. Too small particle size (e.g. less than 0.2mm) results in a smoother surface, but lower cleaning efficiency. Too large particle size (e.g. greater than 0.8mm) results in a faster cleaning speed, but may damage the substrate or cause uneven surface. The force defined by this range takes into account the cleaning efficiency and surface quality, avoiding the adhesion decline or substrate damage caused by too coarse or too fine abrasive.

[0063] Optionally, when the abrasive is cast steel sand, the cast steel sand is G25 grade. Cast steel sand has high hardness, HRC is 40-50, and strong wear resistance, which can be used for high-strength substrates (such as carbon steel).

[0064] Optionally, when the abrasive is quartz sand, the particle size of the quartz sand is 0.3mm-0.8mm. It has low cost, wide source and low hardness characteristics, so slightly larger particle size is used. In the cost limited scene, acceptable surface roughness and cleaning effect are achieved by optimizing the particle size.

[0065] Optionally, when the abrasive is ceramic sand, the particle size of the ceramic sand is 0.2mm-0.6mm. The regular shape of ceramic sand can reduce dust with fine particle size, while maintaining sufficient impact force. Optionally, ceramic sand is suitable for precision surface treatment (such as weak substrate parts), reducing substrate deformation.

[0066] Optionally, the compressed air pressure of the shot blasting treatment is 0.5MPa-0.7MPa. The compressed air pressure can be, but is not limited to, 0.5MPa, 0.55MPa, 0.6MPa, 0.65MPa, 0.7MPa. Too low pressure (e.g. less than 0.5MPa) results in insufficient kinetic energy of the abrasive, incomplete cleaning. Too high pressure (e.g. greater than 0.7MPa) may damage the substrate or waste energy. The pressure of the compressed air defined by this range optimizes the impact force of the abrasive to remove rust and dirt on the surface, while removing stress on the surface of the steel, improving surface quality. Ensure that the substrate surface is thoroughly cleaned and the substrate is not damaged, while controlling energy consumption and equipment wear.

[0067] Optionally, the distance between the shot blasting treatment gun and the treatment surface is 100mm-150mm. The distance between the shot blasting treatment gun and the treatment surface includes, but is not limited to, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm. Too close (e.g. less than 100mm) may result in local over-cleaning or abrasive rebound. Too far (e.g. greater than 150mm) reduces the impact force of the abrasive. By limiting the distance within this range, it ensures uniform distribution of the abrasive at the outlet of the gun, avoids uneven surface or cleaning blind area, and improves processing efficiency.

[0068] Optionally, the shot blasting angle is perpendicular to the surface with a deviation of no more than 15°. The shot blasting angle includes but is not limited to 75°, 80°, 85°, 90°, 95°, 100°, 105°. The perpendicular angle (90°) can maximize the abrasive impact force. A too large deviation (e.g. less than 75° or more than 105°) can result in a decrease in cleaning efficiency or produce surface diagonal lines. By limiting the range, the abrasive can effectively act on the surface of the substrate, ensuring that the surface roughness of the shot blasted substrate is uniform, and avoiding differences in coating adhesion caused by angle deviation.

[0069] Optionally, the shot blasting sequence is from top to bottom and from inside to outside. From top to bottom avoids abrasive accumulation in low places; from inside to outside prevents edge area omission, thereby achieving full coverage, reducing repeated processing, and improving surface consistency. Optionally, for the wind power modular cabin and its accessories, the top structure of the cabin is processed first, and then gradually processed towards the bottom; for accessories, a similar sequence should also be followed to ensure that each part can be uniformly shot blasted. During shot blasting, the spray gun is moved constantly to avoid local over-shot blasting caused by long-time spraying at the same position.

[0070] Optionally, the shot blasting is sequentially processed according to the sequence from top to bottom and from inside to outside.

[0071] Optionally, ventilation is performed simultaneously with shot blasting. This improves the working environment, protects the health of the operators, and at the same time avoids dust adhering to the surface of the substrate affecting the quality of the coating. During the implementation of shot blasting, efficient ventilation systems and dust removal equipment are used to effectively reduce the generation and diffusion of dust, protecting the health of the operators and the safety of the environment.

[0072] Optionally, professional monitors should be arranged in the shot blasting operation area to ensure that unrelated personnel do not enter the operation site. The operator needs to wear a shot blasting work suit with an air distributor, including a helmet, gloves made of rubber or artificial leather, and protective glasses and dust masks.

[0073] Optionally, after shot blasting, the surface roughness of the substrate reaches the Sa2.5 level standard. When the roughness reaches the Sa2.5 level, the mechanical interlocking force between the coating and the substrate is high, prolonging the corrosion protection life.

[0074] Optionally, before step S3, there is also a surface defect inspection step S2: confirming that the substrate has no undercut, weld bead, crater, spatter, porosity, slag inclusion, incomplete penetration, and incomplete fusion defects, and all exposed corners are treated with a chamfer. Avoiding defects as corrosion starting points, chamfering reduces stress concentration and improves the overall protective performance of the coating.

[0075] Optionally, before step S5, there is a surface cleaning step S4: removing oil stains on the surface of the substrate, and blowing off floating dust on the surface of the substrate. Optionally, use organic solvents (such as acetone) for wiping and cleaning, to ensure that the surface is free of grease residues. For the dust, loose rust layer and other surface defects, use compressed air for blowing, to remove the floating dust on the surface. Through the cleaning step, prevent oil stains from hindering the curing of the coating, and prevent floating dust from causing pinholes in the coating, to ensure that the coating is in direct contact with the substrate.

[0076] Optionally, in step S5, use paint or powder for spraying treatment. During the waiting period for spraying, use clean compressed air to blow the surface, to keep the surface clean, dry and free of contaminants.

[0077] Experimental Example 1

[0078] (1) Environmental and substrate state control: spraying environment temperature and humidity: dry temperature 27℃, humidity 70%, dew point 22℃, substrate temperature 32.2℃, the difference between the substrate temperature and the dew point temperature difference > 3℃.

[0079] (2) Abrasive selection: use G25 cast steel sand as abrasive, particle size between 0.2-0.8mm.

[0080] (3) Configuration of shot blasting equipment: use special shot blasting equipment to ensure efficiency and safety during shot blasting. The configuration of the equipment should include an efficient ventilation system, in order to avoid the wind flow disorder and dust flying caused by the pressure-in type ventilation, use the extraction type ventilation to keep the shot blasting environment clean and the line of sight clear.

[0081] (4) Safety preparation for shot blasting operation: professional monitors should be arranged in the shot blasting operation area to ensure that unrelated personnel do not enter the operation site. The operator needs to wear a shot blasting work clothes with an air distributor, including a helmet, gloves made of rubber or artificial leather, and protective glasses and dust masks.

[0082] (5) Safety and environmental protection measures: ventilation system: ensure that the ventilation system of the shot blasting workshop is running effectively, to avoid the health impact of dust on the operator. Equipment inspection: regularly inspect and maintain the gas storage tank, pressure gauge and safety valve to ensure the safe operation of the equipment. Dust control: effective measures should be taken to reduce the spread of dust during shot blasting, such as using a closed shot blasting chamber or setting up dust removal equipment.

[0083] (6) Surface defect inspection step: the inspector and the shot blasting worker jointly confirm that the shot blasting structure has no undercut, weld bead, crater, spatter, porosity, slag inclusion, incomplete penetration, incomplete fusion, and all exposed corners are well treated to ensure that there are no sharp corners.

[0084] (7) Shot blasting: G25 steel sand is loaded into the shot blasting equipment, and high-speed jetting is performed on the surface of the steel material to remove rust and dirt on the surface, and at the same time, to remove the stress on the surface of the steel material and improve the surface quality.

[0085] (8) Shot blasting parameter setting: The compressed air pressure is controlled between 0.5-0.7 MPa. This pressure range can ensure that the abrasive has enough impact force to remove surface impurities, and at the same time, will not cause excessive damage to the surface of the carbon steel. The distance between the spray gun and the treated surface is kept at about 100-150 mm to ensure uniform shot blasting. The shot blasting angle should be perpendicular to the treated surface as much as possible, with a deviation of not more than 15°, to ensure that the abrasive can effectively act on each part of the surface.

[0086] (9) Shot blasting operation implementation sequence: The shot blasting operation is performed in the order of from top to bottom and from inside to outside. The top structure of the cabin is treated first, and then gradually towards the bottom. For accessories, a similar sequence should also be followed to ensure that each part can be uniformly treated by shot blasting. During the shot blasting process, the spray gun should be moved constantly to avoid long-time spraying at the same position, which may cause local excessive shot blasting.

[0087] (10) Surface roughness detection: The surface roughness after shot blasting is detected using a roughness meter, and the requirement is to reach the Sa2.5 level (near white level) standard. That is, the surface should be free of visible grease, dirt, scale, rust, and paint or powder coating, and any remaining traces should only be point-like or stripe-like light stains. If the roughness does not meet the requirements, the local area should be treated again by shot blasting.

[0088] (11) Surface cleaning: First, the oil stains on the surface of the carbon steel cabin and its accessories are thoroughly removed. Organic solvents (such as acetone) can be used for wiping and cleaning to ensure that the surface is free of grease residues. For dust, loose rust layer, etc. on the surface, compressed air is used for blowing to remove the floating dust on the surface.

[0089] (12) Spraying treatment: After shot blasting, paint or powder spraying should be performed as soon as possible to avoid re-rusting of the carbon steel surface. Among them, it is required to start spraying within 4 hours after step (1) is completed. During the waiting period for spraying, clean compressed air can be used to blow the surface to keep it clean, dry, and free of contaminants.

[0090] Referring to Figure 1 and Figure 3 , the surface roughness of the substrate prepared in Experimental Example 1 reaches the Sa2.5 level standard (Ra≤2.5 μm).

[0091] Referring to Figure 6 , the appearance quality of the substrate prepared in Experimental Example 1 is very good within 4 hours.

[0092] Referring to Figure 8 andFigure 9 The surface of the substrate prepared in Experimental Example 1 was uniform and free of defects.

[0093] Referring to Figure 10 The substrate prepared in Example 1 was subjected to regular cleaning but was not sufficiently dried, leaving partial traces of water spots on the surface. According to the ISO 2409:2020 standard (crosshatch method), the adhesion grade was 1. Referring to Figure 11 The coating thickness was 259 pm.

[0094] Comparative Example 2

[0095] Step (1) Environment and substrate state control: The substrate was placed in an environment with a relative humidity of 80%, and the surface temperature of the substrate was made to be 5°C higher than the dew point temperature of the air in the environment.

[0096] Steps (2)-(12) were the same as in Experimental Example 1.

[0097] Referring to Table 1, Figure 4 (a) and Figure 4 (b), the surface roughness of the substrate prepared in Comparative Example 2 reached the Ra 3.1-3.5 pm standard. The abrasive in Comparative Example 2 adhered unevenly due to high humidity.

[0098] Referring to Figure 12 and Figure 13 The substrate prepared in Comparative Example 2 was subjected to regular cleaning but was not sufficiently dried, leaving partial traces of water spots on the surface. According to the ISO 2409:2020 standard (crosshatch method), the adhesion grade was 2. Specifically, partial peeling of the coating was observed at the intersection of the cut grid and / or along the edge of the cut line. According to the evaluation, the area of the affected intersection cut area accounted for about 5% to 15% of the total test area.

[0099] Comparative Example 3

[0100] Step (1) Environment and substrate state control: The substrate was placed in an environment with a relative humidity of 60%, and the surface temperature of the substrate was made to be 1°C higher than the dew point temperature of the air in the environment.

[0101] Steps (2)-(12) were the same as in Experimental Example 1.

[0102] Referring to Figure 5 The surface roughness of the substrate prepared in Comparative Example 3 reached the Ra 2.75 pm standard. The shot blasting in Comparative Example 3 was not complete due to insufficient temperature difference.

[0103] Comparative Example 4

[0104] Steps (1)-(11) were the same as in Experimental Example 1.

[0105] Step (12) Spray treatment: The spray treatment was started 10 hours after the completion of step (1).

[0106] Reference Figure 2 and Figure 3 The surface roughness of the substrate prepared in Comparative Example 4 reached the Sa2.5 level standard (Ra≤2.5 μm).

[0107] Reference Figure 7 The longer the delay time between sanding and spray coating within 10 hours, the more serious the rust degree of the substrate prepared in Comparative Example 4.

[0108] According to the ISO 2409:2020 standard (cross-cut method), the adhesion grade was 2. The specific performance was that partial peeling of the coating was observed at the intersection of the cut grid and / or along the edge of the cut line. After evaluation, the affected cross-cut area accounted for about 5% to 15% of the total test area. See Figure 13 .

[0109] Comparison table of experimental example 1, comparative example 2, comparative example 3, comparative example 4 experimental data

[0110]

[0111] From Table 1, we can conclude that:

[0112] 1. Surface roughness: combined Figures 1-5 Experimental Example 1 and Comparative Example 4 both reached the Sa2.5 level standard (Ra≤2.5 μm), but Comparative Example 2 caused uneven abrasive adhesion due to high humidity, and Comparative Example 3 caused incomplete shot blasting due to insufficient temperature difference.

[0113] 2. Secondary rust rate: combined Figure 6 and Figure 7 The spray delay time significantly affected the rust rate, and the rust rate increased exponentially with the delay time (Comparative Example 4 had a rust rate of 30% due to a delay of 10 hours).

[0114] 3. Adhesion: High humidity (Comparative Example 2) caused the coating to lose adhesion to the substrate.

[0115] Based on the comparison of the experimental results of the above examples and comparative examples, the following observations can be made:

[0116] When the relative humidity of the environment does not exceed 70%, the difference between the surface temperature of the substrate and the ambient temperature is at least 3°C, and the shot blasting is performed, and the rust-proof coating spray is implemented within 4 hours after the cleaning is completed (Specific embodiment 1), the comprehensive performance of the obtained coating system is the best.

[0117] When surface cleaning and spraying are performed when the relative humidity of the environment is higher than 70% or the temperature difference between the substrate surface and the ambient temperature is less than 3°C (Comparative Examples 2-3), tests and observations show that the surface cleaning effect is incomplete and / or the risk of subsequent corrosion of the substrate is increased.

[0118] If the anti-rust coating is applied after more than 4 hours following the completion of surface cleaning (Comparative Example 4), the substrate is prone to secondary corrosion during the delay period, according to tests and observations.

[0119] The above comparison results show that controlling the relative humidity of the environment to ≤70%, the temperature difference to ≥3℃, and completing the spraying within 4 hours after cleaning are crucial for obtaining a coating system with excellent comprehensive performance, avoiding incomplete surface cleaning, and preventing (including initial and secondary) rust risks.

[0120] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for descriptive purposes only and is not intended to limit the scope of this application. Terms such as “setup” appearing herein can refer to either a component being directly attached to another component or a component being attached to another component via an intermediary. A feature described in one embodiment herein may be applied, alone or in combination with other features, to another embodiment, unless that feature is not applicable in that other embodiment or is otherwise stated.

[0121] This application has been described through the above embodiments; however, it should be understood that the above embodiments are for illustrative purposes only and are not intended to limit this application to the described embodiments. Those skilled in the art will understand that many more variations and modifications can be made based on the teachings of this application, and all such variations and modifications fall within the scope of protection claimed in this application.

Claims

1. A surface corrosion-resistant pretreatment method for wind turbine modular nacelles and their accessories, characterized in that, Includes the following steps: S1. Environmental and substrate condition control: The substrate is placed in an environment with a relative humidity of not more than 70%, and the surface temperature of the substrate is at least 3°C ​​higher than the dew point temperature of the ambient air. S3. Shot blasting: The surface of the substrate is shot blasted. S5. Spray coating treatment: Spray coating treatment is performed on the surface of the substrate; Specifically, step S5 shall begin within 4 hours after step S1 is completed.

2. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, In step S3, shot blasting is performed using abrasive materials. The abrasive is at least one of cast steel sand, quartz sand, or ceramic sand; and / or The abrasive particle size is 0.2mm-0.8mm.

3. The surface corrosion-resistant pretreatment method according to claim 2, characterized in that, When the abrasive is cast steel sand, the cast steel sand is grade G25; When the abrasive is quartz sand, the particle size of the quartz sand is 0.3mm-0.8mm; When the abrasive is ceramic sand, the particle size of the ceramic sand is 0.2mm-0.6mm.

4. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, In step S3, the process parameters for shot blasting must satisfy at least one of the following conditions: The compressed air pressure is 0.5MPa-0.7MPa; The distance between the spray gun and the surface to be treated should be 100mm-150mm; The shot blasting angle is perpendicular to the surface and the deviation does not exceed 15°.

5. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, In step S3, the shot peening process is performed on the substrate in a top-to-bottom and inside-to-outside order.

6. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, In step S3, ventilation is performed simultaneously with the shot blasting process.

7. The surface corrosion-resistant pretreatment method according to any one of claims 1 to 6, characterized in that, After shot blasting, the surface roughness of the substrate reaches the Sa2.5 standard.

8. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, Before step S3, a surface defect inspection step is also included: confirming that the substrate is free from defects such as undercut, weld beads, arc craters, spatter, porosity, slag inclusions, incomplete penetration, and incomplete fusion, and that all exposed edges and corners are blunted.

9. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, Before step S5, a surface cleaning step is also included: removing oil stains from the surface of the substrate and blowing away floating dust from the surface of the substrate.

10. The surface corrosion-resistant pretreatment method according to claim 1, characterized in that, In step S5, paint or powder is used for spraying.

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