A heavy-duty coating for petroleum pipes and a method for preparing the same

Abstract

This invention discloses a heavy-duty anti-corrosion coating for oil pipelines and its preparation method, belonging to the field of material surface treatment technology. The preparation method includes the following steps: pretreating the substrate, then performing laser modification treatment on the surface of the substrate to obtain a substrate with a surface-modified layer; applying a liquid primer to the substrate with the surface-modified layer using high-pressure airless spraying, followed by curing to obtain a substrate with both primer and surface-modified layer; when the surface temperature of the substrate with primer and surface-modified layer reaches a set temperature, applying a powder topcoat, followed by curing to obtain the heavy-duty anti-corrosion coating for oil pipelines.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of material surface treatment, and particularly relates to a heavy-duty corrosion-resistant coating for petroleum pipes and a preparation method thereof. BACKGROUND

[0002] With the continuous deepening of oil and gas field development, the corrosion environment faced by petroleum pipes and equipment is becoming more and more severe, and the corrosion problem is becoming more and more prominent. The traditional carbon steel material is also facing more and more severe tests. Especially when the natural gas contains not only H2S, CO2 and other corrosive gases, but also high-concentration Cl - underground, and high-temperature and high-pressure environments, the corrosion problem of this complex multi-phase medium system becomes extremely serious and complex, so failure accidents often occur, causing huge economic losses and safety hazards to the oil field.

[0003] Corrosion protection technology is a very effective and cost-effective method to solve the corrosion problem of carbon steel materials, and has been widely used. In the heavy-duty corrosion-resistant field, in order to make the coating have better corrosion protection effect and longer service life, a three-layer coating system of primer, intermediate paint and topcoat is usually used, for example, the patent “Heavy-duty corrosion-resistant coating system and preparation method thereof” (CN105081750A) uses a coating system of epoxy zinc-rich primer, epoxy iron oxide intermediate paint and acrylic topcoat, and the patent “Solvent-free heavy-duty corrosion-resistant coating system and use method thereof” (CN202011251897.7) uses a coating system of solvent-free epoxy zinc-rich primer, solvent-free epoxy iron oxide intermediate paint and solvent-free polyurethane topcoat. These coating systems are mostly suitable for the external corrosion protection of substrates such as offshore structures, power plants, petroleum and chemical environments and bridges, and do not consider the compatibility of the interface between the substrate and the primer and the interface between the coating layers. However, due to the characteristics of high temperature and high pressure, containing H2S / CO2 / Cl - in oil and gas fields, the corrosion environment shows strong particularity and complexity, and the application of the heavy-duty corrosion-resistant coating system is not mature at present. To improve the service performance of the coating system, material selection and interface compatibility are crucial factors. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the purpose of the present application is to provide a heavy-duty corrosion-resistant coating for petroleum pipes and a preparation method thereof, so as to improve the compatibility of the interfaces, improve the service performance of the coating system, and effectively prolong the service life of the petroleum pipes in harsh environments containing H2S / CO2 / Cl - .

[0005] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0006] The present application provides a preparation method of a heavy-duty corrosion-resistant coating for petroleum pipes, comprising the following steps:

[0007] S1: pretreating the substrate, then performing laser modification treatment on the surface of the substrate to obtain a substrate with a surface modification layer;

[0008] S2: spraying a liquid primer on the substrate with the surface modification layer by high-pressure airless spraying, and then curing to obtain a substrate with the primer and the surface modification layer;

[0009] S3: when the surface temperature of the substrate with the primer and the surface modification layer reaches a set temperature, performing powder topcoat spraying, and then curing to obtain a heavy-duty anti-corrosion coating for oil pipes.

[0010] Further, in S1, the pretreatment includes surface oil removal, rust removal, thermal cleaning and sand blasting treatment, and the surface roughness of the pretreated substrate is 40-80 μm.

[0011] Further, in S1, the thickness of the surface modification layer is 20-100 μm.

[0012] Further, in S2, the thickness of the dry film of the primer of the substrate with the primer and the surface modification layer is 20-50 μm; in S3, the total dry film thickness of the heavy-duty anti-corrosion coating for oil pipes is 200-400 μm; and in S3, the set temperature is 150-115 °C.

[0013] The application provides a heavy-duty anti-corrosion coating for oil pipes, which comprises, from bottom to top, a substrate surface modification layer, a silicone-modified epoxy phenolic liquid primer and a modified phenolic epoxy powder topcoat.

[0014] Further, the silicone-modified epoxy phenolic liquid primer comprises, by mass fraction, 24-30 parts of silicone-modified epoxy resin, 2-4 parts of t-butyl phenol formaldehyde resin, 5-8 parts of butanol etherified phenolic resin, 1-3 parts of titanium white, 5-8 parts of modified mica powder, 5-8 parts of barium sulfate, 2-4 parts of chromium oxide green, 1-3 parts of nano zinc oxide, 1-3 parts of glass flake, 0.2-0.1 parts of fumed silica, 0.5-1.2 parts of isocyanate silane coupling agent, 1.2-4 parts of auxiliary agent and 20-28 parts of solvent.

[0015] Further, the solvent in the silicone-modified epoxy phenolic liquid primer is one or a combination of several of toluene, xylene, butanone and cyclohexanone; and the auxiliary agent in the silicone-modified epoxy phenolic liquid primer includes leveling agent, wetting agent, defoaming agent and adhesion promoter.

[0016] Further, the epoxy equivalent of the silicone-modified epoxy resin in the silicone-modified epoxy phenolic liquid primer is 100-120 g / eq.

[0017] Further, the modified phenolic epoxy powder finish paint according to the present application comprises, in mass fraction, 30-38 parts of phenolic epoxy resin, 2-3.5 parts of butadiene-acrylonitrile rubber modified solid epoxy resin, 12-11 parts of amino-methyl phenyl silicone resin, 31-45 parts of pigment and filler, 2-5 parts of molybdenum disulfide, 0.5-1 part of fumed silica, and 1.5-3.1 parts of additives.

[0018] Further, the phenolic epoxy resin in the modified phenolic epoxy powder finish paint according to the present application has an epoxy equivalent of 590-130 g / eq, and the phenolic epoxy resin in the modified phenolic epoxy powder finish paint has a softening point of 87-93℃.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] The present application provides a preparation method of a heavy-duty anti-corrosion coating for petroleum pipes. The surface modification layer of the substrate obtained by modifying the substrate is beneficial to improve the adhesion of the coating to the substrate, mainly in the following aspects: the surface quality of the substrate can be effectively cleaned of residual grease, soluble salt and moisture; the contact area between the substrate and the coating is increased by cleaning the void impurities on the surface of the substrate, which is beneficial to the wetting and diffusion of the coating; the active points on the surface of the substrate are increased, and the primer promotes the adsorption of the coating on the surface of the substrate through bonding. The liquid primer on the substrate has good wettability and physical and chemical adsorption effect, and has good compatibility with the cross section of the substrate, which can effectively improve the adhesion of the coating. The powder finish paint has good high-temperature resistance, chemical medium resistance and corrosion resistance, and can adapt to harsh oil and gas field working conditions. At the same time, the powder finish paint and the liquid primer have good compatibility in material selection and preparation process, which ensures the good adhesion of the primer and the finish paint.

[0021] The adhesion of the heavy-duty anti-corrosion coating for petroleum pipes prepared by the present application to the substrate is up to 30 MPa or more, and the coating has stable performance and good corrosion resistance in an environment with a hydrogen sulfide partial pressure of less than 1.5 MPa, a CO2 partial pressure of less than 2.5 MPa, a Cl - concentration of less than 100 g / L, and a temperature of less than 150℃. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 Figure 2 is a picture of the appearance of the heavy-duty anti-corrosion coating for petroleum pipes prepared by the present application after high-temperature and high-pressure test. DETAILED DESCRIPTION

[0023] To enable persons skilled in the art to have a better understanding of the features and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used in the text are of the usual meaning understood by those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0024] Theories or mechanisms described and disclosed herein, whether or not correct, should not be construed as limiting the scope of the present application, i.e., the present application can be practiced without relying on any particular theory or mechanism.

[0025] Herein, all features defined in the form of numerical ranges or percentage ranges, such as numerical values, amounts, contents and concentrations, are for the sake of brevity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0026] Herein, unless otherwise specified, "comprise", "include", "contain", "have" or similar words encompass the meaning of "consist of" and "consist essentially of", e.g., "A comprises a" encompasses the meaning of "A comprises a and other" and "A comprises only a".

[0027] Herein, for the sake of brevity, all possible combinations of the various technical features in the various embodiments or examples are not described. Therefore, the various technical features in the various embodiments or examples can be combined in any manner as long as there is no contradiction, and all possible combinations should be considered to be within the scope of the present specification.

[0028] The present application provides a heavy-duty anticorrosive coating for petroleum pipes and a preparation method thereof.

[0029] The present application will be further described in conjunction with specific examples. It should be understood that these examples are only used to illustrate the present application and not intended to limit the scope of the present application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the content taught by the present application, and these equivalent forms should also fall within the scope of the claims attached herewith.

[0030] In the following examples, the instruments and equipment of the art are used. In the following examples, the experimental methods not specified for specific conditions are usually carried out according to the conventional conditions or according to the conditions recommended by the manufacturers. In the following examples, various raw materials are used, unless otherwise specified, and the conventional commercially available products are used, which are of the conventional specifications in the art. In the specification of the present application and in the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0031] The present application provides a heavy-duty anti-corrosion coating for petroleum pipes, comprising a substrate surface modification layer, a liquid primer of silicone-modified epoxy phenolic resin, and a modified phenolic epoxy powder topcoat.

[0032] The substrate surface modification layer is obtained by irradiating the pipe surface with a laser, and has a thickness of 20-100 microns. The liquid primer comprises, by mass fraction: silicone-modified epoxy resin 24-30 parts, t-butyl phenol formaldehyde resin 2-4 parts, butanol etherified phenolic resin 5-8 parts, titanium white 1-3 parts, modified mica powder 5-8 parts, barium sulfate 5-8 parts, chromium oxide green 2-4 parts, nano-zinc oxide 1-3 parts, glass flake 1-3 parts, fumed silica 0.2-0.1 parts, isocyanate silane coupling agent 0.5-1.2 parts, auxiliary agent 1.2-4 parts, and solvent 20-28 parts.

[0033] The solvent in the primer is one or a combination of several of toluene, xylene, butanone, and cyclohexanone; the auxiliary agent in the primer includes leveling agent, wetting agent, defoaming agent, and adhesion promoter. The silicone-modified epoxy resin in the primer has an epoxy equivalent weight of 100-120 g / eq.

[0034] The powder topcoat comprises, by mass fraction: phenolic epoxy resin 30-38 parts, butacryl rubber-modified solid epoxy resin 2-3.5 parts, amino-methyl phenyl silicone resin 12-11 parts, pigment and filler 31-45 parts, molybdenum disulfide 2-5 parts, fumed silica 0.5-1 parts, and auxiliary agent 1.5-3.1 parts.

[0035] The phenolic epoxy resin in the powder topcoat has an epoxy equivalent weight of 590-130 g / eq and a softening point of 87-93℃. The auxiliary agent in the powder topcoat includes curing accelerator, leveling agent, and defoaming agent.

[0036] The powder coating is prepared by mixing the components in the prescribed proportions, melting and extruding through a screw extruder, tabletting, crushing, grinding, and sieving.

[0037] A method for preparing a heavy-duty anti-corrosion coating for petroleum pipes, comprising the following steps:

[0038] (1) Surface oil removal, rust removal, thermal cleaning, and sandblasting treatment are performed on the substrate to make the substrate surface free of scale, oil stains, water, burrs, and spiral scratches, and the surface roughness reaches 40-80 microns.

[0039] (2) Laser modification treatment is performed on the substrate surface using a CO2 laser, with a laser power of 0.8 KW, a laser track pitch of 5-8 mm, and a scanning speed of 30-35 mm / s.

[0040] (3) liquid primer spraying is carried out by high-pressure airless spraying, one spraying is carried out, and then curing is carried out at 180-200 DEG C for 55-70 min, the dry film thickness of the cured primer is controlled to be 20-50 mu m.

[0041] (4) after the primer is cured, when the surface temperature of the base reaches 150-115 DEG C, powder topcoat spraying is carried out, one spraying is carried out, and then curing is carried out at 200-215 DEG C for 110-120 min, the total dry film thickness of the cured coating is controlled to be 200-400 mu m.

[0042] Example 1

[0043] The liquid primer coating formula is as follows by weight: silicone modified epoxy resin 30 parts, t-butyl phenol formaldehyde resin 4 parts, butanol etherified phenolic resin 8 parts, titanium white 2 parts, modified mica powder 1 part, barium sulfate 1 part, chromium oxide green 3 parts, nano zinc oxide 2, glass flake 2 parts, fumed silica 0.5 parts, isocyanate silane coupling agent 1 part, auxiliary agent 4 parts, toluene 5 parts, xylene 5 parts, cyclohexanone solvent 15 parts.

[0044] The powder topcoat coating formula is as follows: phenolic epoxy resin 32 parts, butacryl rubber modified solid epoxy resin 2 parts, amino methyl phenyl silicone resin 12 parts, pigment and filler 40 parts, molybdenum disulfide 4 parts, fumed silica 0.5 parts, auxiliary agent 2 parts.

[0045] The preparation steps of the petroleum pipe heavy-duty corrosion-resistant coating matching system are as follows:

[0046] (1) the surface of the base material is subjected to oil removal, rust removal, thermal cleaning and sand blasting treatment, so that the surface of the base material is free of oxide skin, oil stain, water, burr and spiral scratch, and the surface roughness reaches 40 mu m.

[0047] (2) the surface of the base material is subjected to laser modification treatment by using a CO2 laser, the laser power is 0.8 KW, the laser track pitch is 5 mm, and the scanning speed is 32 mm / s.

[0048] (3) liquid primer spraying is carried out by high-pressure airless spraying, one spraying is carried out, and then curing is carried out at 180 DEG C for 10 min, the dry film thickness of the cured primer is 20 mu m.

[0049] (4) after the primer is cured, when the surface temperature of the base reaches 110 DEG C, powder topcoat spraying is carried out, one spraying is carried out, and then curing is carried out at 215 DEG C for 120 min, the total dry film thickness of the cured coating is 200 mu m.

[0050] Example 2

[0051] The liquid primer coating formula is as follows in terms of weight: 24 parts of silicone modified epoxy resin, 2 parts of t-butyl phenol formaldehyde resin, 5 parts of butanol etherified phenolic resin, 1 part of titanium white, 5 parts of modified mica powder, 5 parts of barium sulfate, 2 parts of chromium oxide green, 1 part of nano zinc oxide, 1 part of glass flake, 0.2 part of fumed silica, 0.5 part of isocyanate silane coupling agent, 1.2 parts of auxiliary agent, 5 parts of toluene, 8 parts of dimethylbenzene, and 15 parts of cyclohexanone solvent.

[0052] The powder topcoat coating formula is as follows: 30 parts of phenolic epoxy resin, 2 parts of butacryl rubber modified solid epoxy resin, 12 parts of amino methyl phenyl silicone resin containing, 31 parts of pigment and filler, 2 parts of molybdenum disulfide, 0.5 part of fumed silica, and 1.5 parts of auxiliary agent.

[0053] The preparation steps of the petroleum pipe heavy-duty corrosion-resistant coating matching system are as follows:

[0054] (1) The surface of the base material is subjected to oil removal, rust removal, thermal cleaning and sand blasting treatment, so that the surface of the base material is free of oxide skin, oil stain, water, burr and spiral scratch, and the surface roughness reaches 80 μm.

[0055] (2) The surface of the base material is subjected to laser modification treatment by using a CO2 laser, the laser power is 0.8 KW, the laser track pitch is 8 mm, and the scanning speed is 35 mm / s.

[0056] (3) The liquid primer is sprayed by using high-pressure airless spraying, one pass is sprayed, and then the primer is cured at 200 ℃ for 10 min, and the dry film thickness of the cured primer is 50 μm.

[0057] (4) After the primer is cured, when the surface temperature of the base material reaches 115 ℃, the powder topcoat is sprayed, one pass is sprayed, and then the coating is cured at 200 ℃ for 110 min, and the total dry film thickness of the coating after curing is 400 μm.

[0058] Example 3

[0059] The liquid primer coating formula is as follows in terms of weight: 21 parts of silicone modified epoxy resin, 3 parts of t-butyl phenol formaldehyde resin, 1 part of butanol etherified phenolic resin, 3 parts of titanium white, 8 parts of modified mica powder, 8 parts of barium sulfate, 4 parts of chromium oxide green, 3 parts of nano zinc oxide, 3 parts of glass flake, 0.1 part of fumed silica, 1.2 parts of isocyanate silane coupling agent, 4 parts of auxiliary agent, 1 part of toluene, 4 parts of dimethylbenzene, and 15 parts of cyclohexanone solvent.

[0060] The powder topcoat coating formula is as follows: 38 parts of phenolic epoxy resin, 3.5 parts of butacryl rubber modified solid epoxy resin, 11 parts of amino methyl phenyl silicone resin containing, 45 parts of pigment and filler, 5 parts of molybdenum disulfide, 1 part of fumed silica, and 3.1 parts of auxiliary agent.

[0061] The preparation steps of the heavy-duty anti-corrosion coating system for petroleum pipes of the present application are as follows:

[0062] (1) The surface of the substrate is subjected to oil removal, rust removal, thermal cleaning and sand blasting treatment, so that the surface of the substrate is free of oxide scale, oil stains, water, burrs and spiral scratches, and the surface roughness reaches 10 μm.

[0063] (2) The surface of the substrate is subjected to laser modification treatment by using a CO2 laser, the laser power is 0.8 KW, the laser track pitch is 7 mm, and the scanning speed is 30 mm / s.

[0064] (3) The liquid primer is sprayed by using high-pressure airless spraying, one pass is sprayed, and then cured at 195 ℃ for 55 min, the dry film thickness of the cured primer is 40 μm.

[0065] (4) After the primer is cured, when the surface temperature of the substrate reaches 110 ℃, the powder topcoat is sprayed, one pass is sprayed, and then cured at 210 ℃ for 120 min, the total dry film thickness of the coating after curing is 300 μm.

[0066] Example 4

[0067] The liquid primer coating formula is as follows by weight: silicone-modified epoxy resin 28 parts, t-butyl phenol formaldehyde resin 3 parts, butanol etherified phenolic resin 7 parts, titanium white 3 parts, modified mica powder 8 parts, barium sulfate 8 parts, chromium oxide green 3 parts, nano zinc oxide 2 parts, glass flake 3 parts, fumed silica 0.3 parts, isocyanate silane coupling agent 0.8 parts, auxiliary agent 3 parts, toluene 1 part, xylene 4 parts, cyclohexanone solvent 15 parts.

[0068] The powder topcoat coating formula is as follows: phenolic epoxy resin 31 parts, butacryl rubber modified solid epoxy resin 3 parts, amino methyl phenyl silicone resin 15 parts, pigment and filler 40 parts, molybdenum disulfide 4 parts, fumed silica 0.8 parts, auxiliary agent 2.5 parts.

[0069] The preparation steps of the heavy-duty anti-corrosion coating system for petroleum pipes of the present application are as follows:

[0070] (1) The surface of the substrate is subjected to oil removal, rust removal, thermal cleaning and sand blasting treatment, so that the surface of the substrate is free of oxide scale, oil stains, water, burrs and spiral scratches, and the surface roughness reaches 70 μm.

[0071] (2) The surface of the substrate is subjected to laser modification treatment by using a CO2 laser, the laser power is 0.8 KW, the laser track pitch is 7 mm, and the scanning speed is 32 mm / s.

[0072] (3) The liquid primer is sprayed by using high-pressure airless spraying, one pass is sprayed, and then cured at 200 ℃ for 10 min, the dry film thickness of the cured primer is 30 μm.

[0073] (4) After the primer is cured, when the temperature of the surface of the base reaches 114℃, a powder topcoat is sprayed, one pass, and then cured at 210℃ for 120 min, after which the total dry film thickness of the coating is 250 μm.

[0074] As shown in Figure 1 The coating prepared by the present application has good adhesion, compatibility and corrosion resistance. The adhesion of the coating to the base material is 33.51 MPa, and after 15 days of test under high temperature and high pressure conditions of hydrogen sulfide partial pressure of 1.5 MPa, CO2 partial pressure of 2.5 MPa, Cl - concentration of 100 g / L and temperature of 150℃, the coating is intact, and no failure phenomena such as bubbling, discoloration, cracking, peeling and the like occur.

[0075] The above content only illustrates the technical idea of the present application, and cannot limit the protection scope of the present application. Any modification made according to the technical idea of the present application on the basis of the technical scheme falls within the protection scope of the claims of the present application.

Claims

1. A method for preparing a heavy-duty coating for petroleum pipes, characterized by, The method comprises the following steps: S1: pretreating the substrate, and then performing laser modification treatment on the surface of the substrate to obtain a substrate with a surface modification layer; a CO2 laser is used to perform laser modification treatment on the surface of the substrate, the laser power is 0.8 kW, the laser track pitch is 5-8 mm, and the scanning speed is 30-35 mm / s; in the step S1, the thickness of the surface modification layer is 20 μm-100 μm; S2: spraying an organic silicon modified epoxy phenolic liquid primer on the substrate with the surface modification layer by using high-pressure airless spraying, and then curing after spraying to obtain a substrate with a primer and a surface modification layer; S3: when the surface temperature of the substrate with the primer and the surface modification layer reaches a set temperature, performing modified phenolic epoxy powder topcoat spraying, and then curing after spraying to obtain a heavy-duty anti-corrosion coating for oil pipes; According to mass fractions, the composition of the organic silicon modified epoxy phenolic liquid primer comprises: 24-30 parts of organic silicon modified epoxy resin, 2-4 parts of t-butyl phenol formaldehyde resin, 5-8 parts of butanol etherified phenolic resin, 1-3 parts of titanium white, 5-8 parts of modified mica powder, 5-8 parts of barium sulfate, 2-4 parts of chromium oxide green, 1-3 parts of nano zinc oxide, 1-3 parts of glass flake, 0.2-0.6 parts of fumed silica, 0.5-1.2 parts of isocyanate silane coupling agent, 1.2-4 parts of additives, and 20-28 parts of solvent; The composition of the modified phenolic epoxy powder topcoat comprises: 30-38 parts of phenolic epoxy resin, 2-3.5 parts of butacryl rubber modified solid epoxy resin, 12-16 parts of amino methyl phenyl silicone resin, 36-45 parts of pigment and filler, 2-5 parts of molybdenum disulfide, 0.5-1 part of fumed silica, and 1.5-3.6 parts of additives; the additives in the modified phenolic epoxy powder topcoat comprise a curing accelerator, a leveling agent and a defoaming agent.

2. The method of claim 1, wherein the petroleum pipe anticorrosive coating is prepared by the steps of: In the step S1, the pretreatment comprises surface oil removal, rust removal, thermal cleaning and sand blasting treatment, and the surface roughness of the pretreated substrate is 40-80 μm.

3. The method of claim 1, wherein the petroleum pipe anticorrosive coating is prepared by the steps of: In the step S2, the thickness of the dry film of the primer of the substrate with the primer and the surface modification layer is 20-50 μm; in the step S3, the total dry film thickness of the heavy-duty anti-corrosion coating for oil pipes is 200-400 μm; and in the step S3, the set temperature is 150-165 ℃.

4. An oil pipe heavy-duty coating characterized by, The heavy-duty anti-corrosion coating for oil pipes comprises, from bottom to top, a substrate surface modification layer, an organic silicon modified epoxy phenolic liquid primer and a modified phenolic epoxy powder topcoat; According to mass fractions, the composition of the organic silicon modified epoxy phenolic liquid primer comprises: 24-30 parts of organic silicon modified epoxy resin, 2-4 parts of t-butyl phenol formaldehyde resin, 5-8 parts of butanol etherified phenolic resin, 1-3 parts of titanium white, 5-8 parts of modified mica powder, 5-8 parts of barium sulfate, 2-4 parts of chromium oxide green, 1-3 parts of nano zinc oxide, 1-3 parts of glass flake, 0.2-0.6 parts of fumed silica, 0.5-1.2 parts of isocyanate silane coupling agent, 1.2-4 parts of additives, and 20-28 parts of solvent; The composition of the modified phenolic epoxy powder finish paint comprises: phenolic epoxy resin 30-38 parts, butyronitrile rubber modified solid epoxy resin 2-3.5 parts, amino methyl phenyl silicone resin 12-16 parts, pigment and filler 36-45 parts, molybdenum disulfide 2-5 parts, fumed silica 0.5-1 part, and auxiliary agent 1.5-3.6 parts; the auxiliary agent in the modified phenolic epoxy powder finish paint comprises a curing accelerator, a leveling agent and a defoaming agent. The preparation process of the substrate surface modification layer is as follows: The substrate surface is subjected to laser modification treatment by using a CO2 laser, the laser power is 0.8 kW, the laser track pitch is 5-8 mm, and the scanning speed is 30-35 mm / s; the thickness of the surface modification layer is 20 μm-100 μm.

5. The heavy-duty coating for petroleum pipes according to claim 4, characterized in that, The solvent in the organic silicon modified epoxy phenolic liquid primer is one or a combination of several of toluene, xylene, butanone and cyclohexanone; the auxiliary agent in the organic silicon modified epoxy phenolic liquid primer comprises a leveling agent, a wetting agent, a defoaming agent and an adhesion promoter.

6. The heavy-duty coating for petroleum pipes according to claim 4, characterized in that, The epoxy equivalent weight of the organic silicon modified epoxy resin in the organic silicon modified epoxy phenolic liquid primer is 100-120 g / eq.

7. The heavy-duty coating for petroleum pipes according to claim 4, characterized in that, The epoxy equivalent weight of the phenolic epoxy resin in the modified phenolic epoxy powder finish paint is 590-630 g / eq, and the softening point of the phenolic epoxy resin in the modified phenolic epoxy powder finish paint is 87-93℃.

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