A straight seam pipeline steel pipe and its manufacturing process

Abstract

This application relates to the field of steel pipe manufacturing technology, specifically disclosing a straight seam pipeline steel pipe and its manufacturing process. The straight seam pipeline steel pipe includes a steel pipe body and an anti-corrosion paint film covering the surface of the steel pipe body. The anti-corrosion paint film includes a primer layer, an intermediate paint layer, and a topcoat layer. The primer layer is obtained by curing a composite primer, the components of which include a water-based epoxy zinc-rich primer, silica sol, sodium polyaspartate, and cerium nitrate. The anti-corrosion paint film of this application has strong adhesion, therefore exhibiting strong resistance to external impacts and is not easily detached under impact, achieving a good anti-corrosion effect.

Description

Technical Field

[0001] This application relates to the field of steel pipe manufacturing technology, and more specifically, to a straight seam pipeline steel pipe and its manufacturing process. Background Technology

[0002] Currently, pipelines play a crucial role in the long-distance transportation of oil and natural gas. Since most long-distance pipelines operate outdoors, they require high corrosion resistance. A common corrosion protection method for pipelines is to cover their surface with an anti-corrosion paint film to isolate the steel pipe from the corrosive external environment. However, no matter how good the anti-corrosion paint film is, once it peels off, its protective effect is lost. Therefore, the anti-corrosion paint film needs to have good adhesion to the steel pipe.

[0003] Chinese patent CN101474644A discloses a straight seam pipeline steel pipe. By optimizing the welding process and operating parameters, the height of both the inner and outer weld seams can be made consistent with the base material pipe wall. This is beneficial for the anti-corrosion paint film to fully adhere to the base material pipe wall, making this type of steel pipe theoretically more suitable for transporting industrial raw materials such as oil, natural gas, and mineral powder compared to traditional straight seam pipeline steel pipes.

[0004] Regarding the aforementioned technologies, the inventors believe that even though straight seam pipeline steel pipes in the relevant technologies are conducive to the full adhesion of the anti-corrosion paint film to the base pipe wall, the adhesion of the current anti-corrosion paint film on the surface of the steel pipe is still relatively limited. Furthermore, the steel pipe will inevitably be subjected to external impacts during transportation and installation. When the impact force on the steel pipe is concentrated, the anti-corrosion paint film on the surface of the steel pipe is prone to local peeling off, affecting the service life of the steel pipe. Summary of the Invention

[0005] When the impact force on the steel pipe is concentrated, the anti-corrosion paint film coated on the surface of the steel pipe in related technologies is prone to local peeling, affecting the service life of the steel pipe. In order to improve this defect, this application provides a straight seam pipeline steel pipe and its manufacturing process.

[0006] In a first aspect, this application provides a straight seam pipeline steel pipe, which adopts the following technical solution:

[0007] A straight seam pipeline steel pipe, comprising a steel pipe body and an anti-corrosion paint film covering the surface of the steel pipe body, the anti-corrosion paint film comprising a primer layer, an intermediate paint layer and a topcoat layer, wherein the primer layer is obtained by curing a composite primer, the composite primer comprising the following components in parts by weight: 100-108 parts of water-based epoxy zinc-rich primer, 24-36 parts of silica sol, 1.4-1.8 parts of sodium polyaspartate, and 0.4-1.8 parts of cerium nitrate, wherein the weight average molecular weight of the sodium polyaspartate is 1800-5700.

[0008] By adopting the above technical solution, this application provides an improved composite primer formulation and uses this composite primer to prepare a primer layer. In the composite primer of this application, sodium polyaspartate, silica sol, and cerium nitrate have self-assembly properties, enabling them to assemble and form a hybrid film on the surface of the steel pipe. In the hybrid film, sodium polyaspartate can form coordination bonds with the metal on the surface of the steel pipe, thus achieving a good bonding effect between the hybrid film and the steel pipe. The sodium polyaspartate in the hybrid film contains a large number of amino groups, and the amino groups in the amino acid units can undergo curing and cross-linking with epoxy groups. Therefore, during the curing process of the composite primer of this application, the waterborne epoxy zinc-rich primer can cross-link with the hybrid film, thereby forming a primer layer with good adhesion. Based on the above primer layer, by sequentially forming an intermediate paint layer and a topcoat layer, a corrosion-resistant paint film with strong adhesion can be obtained. Because the anti-corrosion paint film of this application has strong adhesion, it has a strong resistance to external impact and is not easy to fall off when subjected to external impact. In addition, the formation of the hybrid film improves the isolation effect of the anti-corrosion paint film against external corrosive substances, so the straight seam pipeline steel pipe of this application has a good anti-corrosion effect.

[0009] Preferably, the composite primer comprises the following components in parts by weight: 104-108 parts of waterborne epoxy zinc-rich primer, 30-36 parts of silica sol, 1.6-1.8 parts of sodium polyaspartate, and 1.2-1.8 parts of cerium nitrate.

[0010] By adopting the above technical solution, this application optimizes the raw material ratio of the composite primer, enhances the adhesion of the anti-corrosion paint film, improves the protective effect of the anti-corrosion paint film on the straight seam pipeline steel pipe, and helps to extend the service life of the straight seam pipeline steel pipe.

[0011] Preferably, the weight-average molecular weight of the polyaspartic acid sodium salt is 3600-5700.

[0012] By adopting the above technical solution, this application optimizes the weight-average molecular weight of polyaspartic acid, enhances the adhesion of the anti-corrosion paint film, improves the protective effect of the anti-corrosion paint film on straight seam pipeline steel pipe, and helps to extend the service life of straight seam pipeline steel pipe.

[0013] Preferably, the silica sol has a silica mass fraction of 34-40%.

[0014] By adopting the above technical solution, this application optimizes the silica mass fraction of the silica sol, enhances the adhesion of the anti-corrosion paint film, improves the protective effect of the anti-corrosion paint film on the straight seam pipeline steel pipe, and helps to extend the service life of the straight seam pipeline steel pipe.

[0015] Preferably, the composite primer further includes a silane coupling agent, wherein the silane coupling agent contains an amino group in its molecule, and the amount of the silane coupling agent is 0.2-1.4% of the weight of the silica sol.

[0016] By adopting the above technical solution, this application adds a silane coupling agent with an amino group in the molecule to the composite primer. The silanol group produced after the hydrolysis of the silane coupling agent can undergo dehydration condensation with the silanol group in the silica sol. The amino group in the silane coupling agent molecule can participate in the curing reaction of the waterborne epoxy zinc-rich primer, thereby improving the crosslinking effect between the waterborne epoxy zinc-rich primer and the hybrid film, and helping to enhance the adhesion of the anti-corrosion paint film.

[0017] Preferably, the amount of the silane coupling agent is 0.6-1.4% of the weight of the silica sol.

[0018] By adopting the above technical solution, the dosage of silane coupling agent was optimized, the crosslinking effect between waterborne epoxy zinc-rich primer and hybrid film was improved, and the adhesion of anti-corrosion paint film was enhanced.

[0019] Preferably, the composite primer comprises sulfonated graphene, and the amount of sulfonated graphene is 0.1-0.2% of the weight of the waterborne epoxy zinc-rich primer.

[0020] By adopting the above technical solution, this application has optimized the composition of the composite primer by adding sulfonated graphene. The addition of sulfonated graphene can enhance the conductivity of the primer layer, help improve the cathodic protection of the primer layer, and alleviate the electrochemical corrosion of the steel pipe body.

[0021] Preferably, the sulfonated graphene is prepared according to the following method:

[0022] Graphite was oxidized to obtain graphite oxide; graphite oxide was reduced using a reducing agent to obtain pre-reduced graphite oxide; the pre-reduced graphite oxide was prepared into a suspension, the suspension was added to a diazonium salt solution of p-aminobenzenesulfonic acid, stirred under ice bath conditions, then ultrasonically dispersed and washed with deionized water until neutral, the washing product was reduced a second time with hydrazine hydrate, and dried to obtain sulfonated graphene.

[0023] By adopting the above technical solution, this application adds the treatment of diazonium aminobenzenesulfonic acid salt in the process of preparing graphene, and obtains graphene with sulfonic acid groups loaded on the surface, namely sulfonated graphene.

[0024] Preferably, the amount of sulfonated graphene used is 0.15-0.2% of the weight of the waterborne epoxy zinc-rich primer.

[0025] By adopting the above technical solution, this application optimizes the amount of sulfonated graphene, improves the cathodic protection effect of the primer layer, and alleviates the electrochemical corrosion of the steel pipe body.

[0026] Secondly, this application provides a manufacturing process for straight seam pipeline steel pipes, which adopts the following technical solution.

[0027] A manufacturing process for a straight seam pipeline steel pipe includes the following steps:

[0028] (1) In the straight seam welded pipe production line, steel pipe body is obtained by processing and finishing plate coils as raw materials.

[0029] (2) The above-mentioned composite primer is sprayed onto the surface of the steel pipe body and baked and cured to obtain the primer layer; epoxy glass flake paint is sprayed onto the surface of the primer layer and waited for the epoxy glass flake paint to cure to obtain the intermediate paint layer; aliphatic polyurethane topcoat is sprayed onto the surface of the intermediate paint layer and waited for the aliphatic polyurethane topcoat to cure into the topcoat layer to obtain an anti-corrosion paint film composed of primer layer, intermediate paint layer and topcoat layer, thus completing the preparation of straight seam pipeline steel pipe.

[0030] By adopting the above technical solution, this application first produced the steel pipe body, and then sequentially applied a primer layer, an intermediate paint layer and a topcoat layer to the surface of the steel pipe body to obtain an anti-corrosion paint film, thus completing the preparation of the straight seam pipeline steel pipe.

[0031] In summary, this application has the following beneficial effects:

[0032] 1. The anti-corrosion paint film of this application has strong adhesion, so the anti-corrosion paint film has a strong resistance to external impact and is not easy to fall off when subjected to external impact. In addition, the formation of the hybrid film improves the isolation effect of the anti-corrosion paint film against external corrosive substances, so the straight seam pipeline steel pipe of this application has a good anti-corrosion effect.

[0033] 2. This application has been optimized by adding sulfonated graphene to the components of the composite primer. The addition of sulfonated graphene can enhance the conductivity of the primer layer, help improve the cathodic protection of the primer layer, and alleviate the electrochemical corrosion of the steel pipe body. Detailed Implementation

[0034] The present application will be further described in detail below with reference to the embodiments, preparation examples and comparative examples. The raw materials involved in the present application can all be obtained commercially.

[0035] Preparation example of sulfonated graphene

[0036] The following explanation uses Preparation Example 1 as an example.

[0037] Preparation Example 1

[0038] In this preparation example, sulfonated graphene was prepared according to the following method:

[0039] (1) Dissolve potassium persulfate and phosphorus pentoxide in concentrated sulfuric acid, add graphite, heat in a water bath at 80°C, stir mechanically for 4.5 h, cool to room temperature (20°C), then dilute and filter, wash and dry, mix the remaining solid with concentrated sulfuric acid evenly, heat to 0°C in an ice bath, add potassium permanganate powder (control the reaction temperature not to exceed 5°C), then oxidize for 2 h under heating in a water bath at 35°C and mechanical stirring, dilute with deionized water equivalent to 5 times the volume of the mixture, add hydrogen peroxide until a yellow precipitate is formed, then filter while hot, wash the product with 3.4% (mass fraction) hydrochloric acid solution, wash with deionized water and dry to obtain graphite oxide;

[0040] (2) Graphite oxide was reduced with sodium borohydride in a water bath at 70°C to obtain pre-reduced graphite oxide; a 1 mg / mL pre-reduced graphite oxide suspension was prepared, and a diazonium salt solution of p-aminobenzenesulfonic acid (1.35 g, 10 mL) was added to the suspension. The suspension was stirred in an ice bath for 6 h, then sonicated for 30 min, and washed with deionized water until pH = 7. Then it was reduced again with hydrazine hydrate (the weight ratio of hydrazine hydrate to pre-reduced graphite oxide was 1:1). After drying, sulfonated graphene was obtained.

[0041] Example

[0042] Examples 1-5

[0043] The following description uses Example 1 as an example.

[0044] Example 1

[0045] In this embodiment, the waterborne epoxy zinc-rich primer used is Barrier 80WF 6DY, the epoxy glass flake paint is Penguard Pro GF, and the aliphatic polyurethane topcoat is Hardtop AX.

[0046] The composite primer used in this embodiment includes the following components: 100 kg of waterborne epoxy zinc-rich primer, 24 kg of silica sol, 1.4 kg of sodium polyaspartate, and 0.4 kg of cerium nitrate; the weight-average molecular weight of sodium polyaspartate is 1800, and the silica sol has a silica mass fraction of 28%.

[0047] In this embodiment, the straight seam pipeline steel pipe is prepared according to the following steps:

[0048] (1) The following steps are performed sequentially: plate and coil preparation, feeding, uncoiling, leveling, cutting, shearing and welding, loop storage, edge milling, scrap collection, steel plate flaw detection, forming, steel pipe welding, scrap collection, removal of internal and external burrs, No. 1 pull-out frame, online ultrasonic testing of steel pipe, weld annealing treatment, No. 2 pull-out frame, air cooling, water cooling, sizing and straightening, marking, length cutting, steel pipe output. After output, one path of the steel pipe is sent to the sampling / cutting machine via the unloading platform to cut samples or cut defective pipe sections, and the other path is sent by the chain conveyor for appearance and dimensional inspection. Then, the pipe is flushed with water to remove internal burrs. The process involves flattening and chamfering, hydrostatic testing, ultrasonic testing of the pipe body and ends, visual inspection, weighing and length measurement, final inspection, and warehousing. Steel pipes with visual defects are re-inspected, ground / cut, and returned to the flattening and chamfering stage to obtain the steel pipe body. The steel pipe body in this step has a specification of X65 and a chemical composition of: carbon 0.03%, silicon 0.17%, manganese 1.51%, phosphorus 0.024%, sulfur 0.005%, nickel 0.17%, copper 0.04%, molybdenum 0.16%, nitrogen 0.006%, niobium 0.06%, aluminum 0.02%, titanium 0.01%, and the remainder being iron.

[0049] (2) The composite primer is sprayed onto the surface of the steel pipe body and cured by baking to obtain the primer layer; the epoxy glass flake paint is sprayed onto the surface of the primer layer and the intermediate paint layer is obtained after the epoxy glass flake paint is cured; the aliphatic polyurethane topcoat is sprayed onto the surface of the intermediate paint layer and the aliphatic polyurethane topcoat is cured to form the topcoat layer, thus obtaining an anti-corrosion paint film composed of primer layer, intermediate paint layer and topcoat layer, which completes the preparation of straight seam pipeline steel pipe; in this step, the spray gun pressure is 0.45MPa, the spray distance is 250mm, and the thickness of each spray is controlled at 200μm.

[0050] As shown in Table 1, the main difference between Examples 1-5 lies in the different raw material ratios of the composite primer.

[0051] Table 1 Raw material ratio of composite primer

[0052] sample Waterborne epoxy zinc-rich primer / kg silica sol / kg Sodium polyaspartate / kg Cerium nitrate / kg Example 1 100 24 1.4 0.4 Example 2 102 26 1.5 0.7 Example 3 104 28 1.6 1.0 Example 4 106 30 1.7 1.4 Example 5 108 32 1.8 1.8

[0053] Examples 6-9

[0054] As shown in Table 2, the difference between Examples 6-9 and Example 5 is that the weight-average molecular weight of sodium polyaspartate is different.

[0055] Table 2. Weight-average molecular weight of sodium polyaspartate

[0056] sample Example 5 Example 6 Example 7 Example 8 Example 9 weight average molecular weight 1800 2700 3600 4400 5700

[0057] Examples 10-13

[0058] As shown in Table 3, the difference between Examples 10-13 and Example 9 is that the mass fraction of silica in the silica sol is different.

[0059] Table 3. Mass fraction of silica in silica sol

[0060] sample Example 9 Example 10 Example 11 Example 12 Example 13 Silica mass fraction / % 28 31 34 37 40

[0061] Example 14

[0062] The difference between this embodiment and Embodiment 13 is that the composite primer also includes a silane coupling agent. The silane coupling agent is methyltriethoxysilane, and the amount of silane coupling agent is 0.2% of the weight of the silica sol.

[0063] Example 15

[0064] The difference between this embodiment and Example 14 is that the silane coupling agent used is γ-aminopropyltriethoxysilane.

[0065] As shown in Table 4, the difference between Examples 15-19 is that the percentage of silane coupling agent used in the weight of the silica sol (hereinafter referred to as silane percentage) is different.

[0066] Table 4. Silane content

[0067] sample Example 15 Example 16 Example 17 Example 18 Example 19 Silane percentage 0.2 0.4 0.6 1.1 1.4

[0068] Example 20

[0069] The difference between this embodiment and Example 19 is that the composite primer includes sulfonated graphene, which is prepared according to the method of Preparation Example 1, and the amount of sulfonated graphene is 0.1% of the weight of the waterborne epoxy zinc-rich primer.

[0070] As shown in Table 5, the difference between Examples 20-24 is that the percentage of sulfonated graphene used in the waterborne epoxy zinc-rich primer (hereinafter referred to as the percentage of sulfonated graphene) is different.

[0071] Table 5. Percentage of sulfonated graphene

[0072] sample Example 20 Example 21 Example 22 Example 23 Example 24 Sulfonated graphene percentage 0.1 0.12 0.15 0.18 0.2

[0073] Comparative Example

[0074] Comparative Example 1

[0075] The difference between this comparative example and Example 1 is that only water-based epoxy zinc-rich primer was used to prepare the primer layer, without adding silica sol, sodium polyaspartate, and cerium nitrate.

[0076] Comparative Example 2

[0077] The difference between this comparative example and Example 1 is that the composite primer does not contain cerium nitrate.

[0078] Comparative Example 3

[0079] The difference between this comparative example and Example 1 is that the composite primer does not include silica sol.

[0080] Comparative Example 4

[0081] The difference between this comparative example and Example 1 is that the composite primer does not include sodium polyaspartate.

[0082] Performance testing methods

[0083] I. Adhesion

[0084] Using a PATM01 hydraulic instrument, the adhesion of coatings was tested by the pull-off method according to ISO4624-2002 "Paints and varnishes - tests for adhesion". Then, with Comparative Example 1 as the benchmark, the ratio of the coating adhesion of each embodiment and the comparative example to the coating adhesion of Comparative Example 1 was calculated. This ratio was recorded as the relative adhesion. The results are shown in Table 6.

[0085] II. Corrosion Resistance

[0086] A steel sheet measuring 10mm × 10mm × 2mm, made of X65 steel used in the embodiments of this application, was selected and polished to a bright mirror finish with 1200 grit sandpaper. It was then cleaned with acetone and deionized water and dried. Following the method described in the embodiments, an anti-corrosion paint film was applied to the surface of the steel sheet to obtain a sample. Using a CH1600E electrochemical workstation and a three-electrode system, the corrosion current density of the sample was determined using the Tafel tangential epitaxy method. The corrosive medium was a 3.5% sodium chloride solution. The reference electrode was a silver / silver chloride electrode, and the control electrode was a graphite electrode. Based on Comparative Example 1, the ratio between the corrosion current density of each embodiment and the corrosion current density of Comparative Example 1 was calculated. This ratio was recorded as the relative corrosion current density, and the calculation results of the relative corrosion current density are shown in Table 6.

[0087] Table 6 Relative Adhesion and Relative Corrosion Current Density

[0088]

[0089]

[0090] Combining Examples 1-5 and Comparative Example 1 with Table 6, it can be seen that the relative adhesion measured in Examples 1-5 is greater than that in Comparative Example 1, and the relative corrosion current density is lower than that in Comparative Example 1. This indicates that the anti-corrosion paint film of this application has strong adhesion and strong resistance to external impact, making it less prone to peeling off under external impact. Simultaneously, the formation of the hybrid film improves the isolation effect of the anti-corrosion paint film against external corrosive substances, resulting in better anti-corrosion performance of the straight seam pipeline steel pipe of this application. In Examples 1-5, the relative adhesion measured in Examples 3-5 is lower, while the relative corrosion current density is higher, indicating that the composite primer prepared according to the proportions of Examples 3-5 helps improve the adhesion of the anti-corrosion paint film and the corrosion resistance of the straight seam pipeline steel pipe.

[0091] Combining Example 1 and Comparative Examples 2-4 with Table 6, it can be seen that the relative adhesion measured in Comparative Examples 2-4 is less than that in Example 1, indicating that when silica sol, sodium polyaspartate and cerium nitrate are not used together, the adhesion of the anti-corrosion paint film on the surface of the steel pipe is poor.

[0092] As can be seen from Examples 5-9 and Table 6, when the weight-average molecular weight of sodium polyaspartate is 3600-5700, the adhesion of the anti-corrosion paint film is stronger, which improves the protective effect of the anti-corrosion paint film on the straight seam pipeline steel pipe and helps to extend the service life of the straight seam pipeline steel pipe.

[0093] As can be seen from Examples 9-13 and Table 6, when the silica mass fraction of the silica sol is 34-40%, the adhesion of the anti-corrosion paint film is stronger, which improves the protective effect of the anti-corrosion paint film on the straight seam pipeline steel pipe and helps to extend the service life of the straight seam pipeline steel pipe.

[0094] As can be seen from Examples 13 and 14 and Table 6, the amino-free silane coupling agent has a limited effect on improving the adhesion of the anti-corrosion paint film.

[0095] Based on Examples 14, 15-19 and Table 6, it can be seen that the relative adhesion measured in Examples 15-19 is greater than that in Example 14. This indicates that the amino groups in the silane coupling agent molecule improve the crosslinking effect between the waterborne epoxy zinc-rich primer and the hybrid film by participating in the curing reaction of the waterborne epoxy zinc-rich primer, thereby enhancing the adhesion of the anti-corrosion coating film.

[0096] Based on Examples 19 and 20-24 and Table 6, it can be seen that the relative adhesion measured in Examples 20-24 is greater than that in Example 19, and the relative corrosion current density is much lower than that in Example 19. This indicates that the addition of sulfonated graphene helps to improve the adhesion of the anti-corrosion paint film and enhance the corrosion resistance of the straight seam pipeline steel pipe.

[0097] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A straight-seam pipeline steel pipe characterized by, The straight seam pipeline steel pipe comprises a steel pipe body and an anticorrosive paint film covering the surface of the steel pipe body, the anticorrosive paint film comprising a primer layer, an intermediate paint layer and a topcoat layer, the primer layer being obtained after curing of a composite primer, the composite primer comprising the following components in parts by weight: 104-108 parts of a water-based epoxy zinc-rich primer, 30-36 parts of silica sol, 1.6-1.8 parts of polyaspartic acid sodium, 1.2-1.8 parts of cerous nitrate, the polyaspartic acid sodium having a weight-average molecular weight of 1800-5700; the silica sol having a mass fraction of silicon dioxide of 34-40%; the components of the composite primer further comprising a silane coupling agent, the silane coupling agent having an amino group in the molecule, the silane coupling agent being used in an amount of 0.2-1.4% by weight of the silica sol; the components of the composite primer comprising sulfonated graphene, the sulfonated graphene being used in an amount of 0.1-0.2% by weight of the water-based epoxy zinc-rich primer.

2. The straight-seam line pipe steel pipe according to claim 1, characterized by The polyaspartic acid sodium has a weight-average molecular weight of 3600-5700.

3. The straight-seam line pipe steel pipe according to claim 1, characterized by, The silane coupling agent is used in an amount of 0.6-1.4% by weight of the silica sol.

4. The straight-seam line pipe steel pipe according to claim 1, characterized by, The sulfonated graphene is prepared by the following method: Graphite is oxidized to obtain oxidized graphite; the oxidized graphite is reduced using a reducing agent to obtain pre-reduced oxidized graphite; the pre-reduced oxidized graphite is prepared into a suspension, the suspension is added into a p-aminobenzenesulfonic acid diazonium salt solution, stirred under ice bath conditions, then dispersed by ultrasonic and washed with deionized water until neutral, the washed product is subjected to secondary reduction using hydrazine hydrate, and dried to obtain sulfonated graphene.

5. The straight-seam line pipe steel pipe according to claim 1, characterized by The sulfonated graphene is used in an amount of 0.15-0.2% by weight of the water-based epoxy zinc-rich primer.

6. A process for the production of a straight-seam pipeline steel pipe, characterized by, The method comprises the following steps: (1) a steel pipe body is obtained by processing and finishing a plate coil as a raw material in a straight seam pipe production line; (2) the composite primer of any one of claims 1-5 is sprayed onto the surface of the steel pipe body, and a primer layer is obtained after baking and curing; an epoxy glass flake paint is sprayed onto the surface of the primer layer, and an intermediate paint layer is obtained after curing of the epoxy glass flake paint; an aliphatic polyurethane topcoat is sprayed onto the surface of the intermediate paint layer, and an anticorrosive paint film composed of the primer layer, the intermediate paint layer and the topcoat layer is obtained after curing of the aliphatic polyurethane topcoat as a topcoat layer, and the preparation of the straight seam pipeline steel pipe is completed.

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