Petrochemical equipment metal surface anti-corrosion treatment process based on braze coating technology

Abstract

The invention relates to the technical field of petrochemical equipment corrosion prevention, and discloses a petrochemical equipment metal surface corrosion prevention treatment process based on a braze coating technology, which comprises the following steps: S1, preparing a proper composite powder formula according to working conditions; s2, the surface of the metal matrix is pretreated; s3, the selected composite powder is sprayed to the surface of a metal matrix; s4, the sprayed metal matrix is subjected to high-temperature sintering treatment; and S5, the coating is cooled, and related performance detection is carried out, wherein S1 comprises mixing of metal powder and ceramic powder, and a base body of the metal powder is selected to be at least Cr-based powder, Ni-based powder or Mo-based powder. By means of the composite powder coating based on the brazing coating technology and the high-temperature sintering technology, the bonding strength, hardness and corrosion resistance of the coating are improved, the abrasion resistance and anti-scouring performance of the metal surface under the severe working condition are enhanced, and the long-acting and stable anti-corrosion effect is ensured.

Description

Technical Field

[0001] The invention relates to the technical field of petrochemical equipment anti-corrosion, in particular to a metal surface anti-corrosion treatment process for petrochemical equipment based on brazing coating technology. Background Art

[0002] During long-term use, petrochemical equipment is affected by a variety of harsh working conditions such as corrosion, wear, and erosion. Especially in the environment of high temperature, high pressure and chemical medium erosion, the anti-corrosion of metal surface is particularly important. In order to improve the corrosion resistance and service life of equipment, metal surface anti-corrosion treatment technologies are usually used, such as coating technology, anodizing, spraying technology, etc. These technologies effectively isolate the contact between corrosive media and metal surface by forming a protective film on the metal surface, thereby reducing corrosion reactions and extending the service life of the equipment.

[0003] At present, the anti-corrosion treatment processes for metal surfaces of petrochemical equipment mainly include coating technology, thermal spraying technology, ceramic coating and aluminum alloy surface treatment. These technologies improve the corrosion resistance of metal surfaces by coating metal or ceramic coatings. For example, thermal spraying technology can form thicker metal coatings to increase the corrosion resistance of equipment; while ceramic coatings have higher wear resistance and chemical corrosion resistance.

[0004] However, the existing anti-corrosion treatment process still has certain shortcomings; first, conventional metal spraying processes often face the challenges of poor coating adhesion and easy peeling of the coating, especially in high temperature and strong corrosive environments, the coating is prone to failure; although ceramic coatings have excellent corrosion resistance, their construction is complex and the coating is brittle, and is not suitable for working environments with high erosion or high mechanical stress; in addition, the existing powder coating technology lacks specificity and cannot flexibly adjust the composition of the coating according to different working conditions, resulting in unstable anti-corrosion effects in complex corrosive environments. Summary of the invention

[0005] In view of the deficiencies of the prior art, the present invention provides a metal surface anti-corrosion treatment process for petrochemical equipment based on brazing coating technology, which solves the problems of poor coating adhesion, fragile coating and unstable anti-corrosion effect in the prior art metal surface anti-corrosion treatment process.

[0006] To achieve the above purpose, the present invention is implemented by the following technical scheme: A process for anti-corrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology comprises the following steps:

[0007] S1. Prepare suitable composite powder formula according to working conditions;

[0008] S2, pre-treating the surface of the metal substrate;

[0009] S3, spraying the selected composite powder onto the surface of the metal substrate;

[0010] S4. Perform high-temperature sintering treatment on the sprayed metal substrate;

[0011] S5. Cool the coating and conduct relevant performance tests.

[0012] Preferably, S1 includes the mixing of metal powder and ceramic powder:

[0013] The matrix of the metal powder is selected from at least Cr-based, Ni-based or Mo-based powders;

[0014] The matrix of the ceramic powder is selected from at least Cr2O3, Fe2O3 or VC powders;

[0015] Add trace amounts of Cu, Mo and Si elements to the powder and adjust the powder ratio to meet the requirements of different corrosion environments.

[0016] Preferably, S2 includes:

[0017] Use sandblasting to remove surface oil stains, rust and oxide layers, increase the roughness of the metal surface, or use laser surface treatment methods to improve surface hydrophilicity and increase the bonding force of the metal surface.

[0018] Preferably, S3 includes:

[0019] Use plasma spraying and thermal spraying (HVOF) spraying methods to evenly spray the composite powder onto the surface of the metal substrate;

[0020] During the spraying process, control the distance between the spraying gun and the substrate, the spraying speed and the spraying angle to ensure the uniformity and thickness of the coating.

[0021] Preferably, S4 includes:

[0022] Perform sintering treatment in an inert atmosphere to prevent oxidation of the coating;

[0023] The sintering temperature is 450 °C to 550 °C, and the sintering time is 3 to 7 seconds to ensure the formation of a metallurgical bonding layer between the coating and the metal substrate.

[0024] Preferably, S5 includes:

[0025] Hardness test of the coating, and the hardness requirement is 15HRC to 50HRC;

[0026] Bonding strength test of the coating, and the bonding strength requirement is above 200 MPa;

[0027] Neutral salt spray test to test the corrosion resistance of the coating.

[0028] Preferably, the design of the powder formula for different corrosion environments includes:

[0029] For the H2S + CO2 + H2O medium, select the Ni-based alloy powder PB-Ni80CrMo alloy as the coating material;

[0030] For the SO3 + CO2 + O2 + H2O medium, select the Ni-based alloy powder PB-Ni90CrSi alloy as the coating material;

[0031] For the H2SO4 + H2O medium, select the Ni-based alloy powder PB-Ni60CrSi alloy as the coating material.

[0032] The present invention also provides a method for preparing an anti-corrosion metal coating based on the brazing coating technology, including the following steps:

[0033] Select a suitable powder formula according to the equipment working conditions. The formula includes Cr-based, Ni-based or Mo-based metal powders and Cr2O3, Fe2O3 or VC powders;

[0034] Spray the composite powder on the metal surface through the spraying process. The coating thickness is 300μm - 500μm,

[0035] After high-temperature sintering treatment, a metallurgical bonding layer is formed between the coating and the metal surface, ensuring that the bonding strength of the coating is greater than 200MPa and the hardness reaches 15HRC - 50HRC.

[0036] Preferably, after the coating is cooled, it further includes surface finishing treatment of the coating surface to further improve the surface finish and anti-pollution of the coating.

[0037] The present invention provides an anti-corrosion treatment process for the metal surface of petrochemical equipment based on the brazing coating technology. It has the following beneficial effects:

[0038] 1. By selecting a composite powder formula suitable for different working conditions and combining the brazing coating technology, the present invention forms a coating with high corrosion resistance on the metal surface. This coating can effectively resist the corrosion of chemical media, thereby extending the service life of petrochemical equipment, especially being particularly prominent in acidic, alkaline or high-temperature environments.

[0039] 2. By adopting high-temperature sintering treatment to form a metallurgical bonding layer, the coating is firmly bonded to the metal matrix, avoiding peeling or falling off. In addition, the hardness of the coating is effectively improved, and it can resist friction and wear during equipment operation, further improving the durability of the equipment.

[0040] 3. The present invention can design suitable coatings for different working conditions by flexibly adjusting the composition of the powder and the spraying process, thereby ensuring the stability and durability of the coating in a variety of corrosive environments. At the same time, the preparation process is simplified and can be mass-produced, and has high industrial application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 The figure is a flow chart of the method of the present invention. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the specification of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] Please refer to the attached Figure 1 The embodiment of the present invention provides a process for anti-corrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology, comprising the following steps:

[0044] S1. Prepare suitable composite powder formula according to working conditions. By selecting suitable powder formula, the corrosion resistance, wear resistance and oxidation resistance of the equipment surface can be improved, ensuring the long-term stable operation of the equipment in harsh environment and extending its service life;

[0045] S2. Pre-treat the surface of the metal substrate to ensure good bonding between the coating and the metal substrate, improve the durability and corrosion resistance of the coating, and thus ensure the stability and performance of the metal surface in long-term use;

[0046] S3. Spray the selected composite powder onto the surface of the metal substrate. By spraying, the coating can be ensured to be tightly bonded to the substrate surface, thereby enhancing the corrosion resistance and erosion resistance of the coating and improving the anti-wear ability of the equipment under harsh working conditions.

[0047] S4. The metal substrate after spraying is subjected to high-temperature sintering treatment. High-temperature sintering can form a strong metallurgical bonding layer, which greatly enhances the performance of the coating and enables it to have long-lasting anti-corrosion and wear-resistant functions in extreme environments;

[0048] S5. Cool the coating and conduct relevant performance tests. After cooling and strict performance tests, the coating can meet the design requirements and have long-term stable corrosion resistance, wear resistance and high strength, ensuring long-term and reliable operation of the equipment under harsh working conditions.

[0049] Please refer to the attached Figure 1, in a preferred embodiment of the present invention, S1 includes the mixing of metal powder and ceramic powder:

[0050] The matrix of the metal powder is selected to be at least Cr-based, Ni-based or Mo-based powder;

[0051] The matrix of the ceramic powder is selected to be at least Cr2O3, Fe2O3 or VC powder;

[0052] Trace elements of Cu, Mo and Si are added to the powder to adjust the powder ratio to meet the requirements of different corrosion environments. The main function of the metal powder is to provide good bonding force and ductility, while the ceramic powder is mainly responsible for improving the hardness, erosion resistance and wear resistance of the coating. By adding alloying elements, the performance of the coating can be further optimized to adapt to different corrosion environments, not only improving the corrosion resistance, wear resistance and erosion resistance of the coating, but also ensuring the bonding strength and durability of the coating, thus greatly extending the service life of petrochemical equipment, reducing the frequency of equipment maintenance and replacement, and optimizing production efficiency.

[0053] Please refer to the appendix Figure 1 , in a preferred embodiment of the present invention, S2 includes:

[0054] The sandblasting method is used to remove surface oil stains, rust and oxide layers to increase the roughness of the metal surface, or the laser surface treatment method is used to improve surface hydrophilicity and increase the bonding force of the metal surface. Among them, sandblasting can better remove rust and oxides, avoiding the problem of poor coating adhesion caused by surface contaminants. Through laser irradiation, surface oil stains, oxides and other contaminants can be effectively removed, and the roughness of the metal surface can be precisely adjusted by controlling the laser energy. The pretreatment process can improve the bonding force between the metal matrix surface and the coating, enabling the coating to form a more stable metallurgical bonding layer with the matrix surface during subsequent spraying and sintering processes. Good surface pretreatment can not only enhance the adhesion of the coating, prevent the coating from falling off during use, but also effectively improve the corrosion resistance, wear resistance and erosion resistance of the coating, thus extending the service life of the equipment, reducing maintenance costs and improving production efficiency.

[0055] Please refer to the appendix Figure 1 , in a preferred embodiment of the present invention, S3 includes:

[0056] Using plasma spraying and high-velocity oxy-fuel (HVOF) spraying methods, the composite powder is evenly sprayed onto the surface of the metal substrate. Plasma spraying has good powder melting control ability, which can make the powder form a uniform coating during spraying, and the adhesion of the coating is strong, suitable for the surface treatment of large-area and complex-shaped substrates. In addition, the high temperature during plasma spraying can effectively promote the chemical reaction between the powder and the metal substrate, forming a metallurgical bonding layer. While the HVOF spraying technology can be carried out at a lower temperature, thus reducing the thermal damage of the metal substrate and the oxidation problem of the coating. The coating formed by this method has strong abrasion resistance, high bonding strength and small porosity;

[0057] During the spraying process, control the distance between the spraying gun and the substrate, the spraying speed and the spraying angle to ensure the uniformity and thickness of the coating. By precisely controlling the parameters of the spraying process, it can be ensured that the coating is evenly distributed on the surface of the metal substrate, avoiding the problems of coating non-uniformity and local peeling. The denseness and bonding strength of the coating are effectively guaranteed, and the thickness of the coating is firmly bonded to the substrate surface and is not easy to peel off.

[0058] Please refer to the appendix Figure 1 , in a preferred embodiment of the present invention, S4 includes:

[0059] Under an inert atmosphere, perform sintering treatment to prevent the oxidation of the coating;

[0060] The sintering temperature is 450°C to 550°C, and the sintering time is 3 to 7 seconds to ensure that a metallurgical bonding layer is formed between the coating and the metal substrate. The main principle of sintering is to melt the powder particles at high temperature and undergo a metallurgical reaction with the surface of the metal substrate, thereby forming a dense metallurgical bonding layer. The powder will undergo physical and chemical reactions to varying degrees at high temperature to form a stable coating structure. The inert atmosphere can effectively prevent oxygen from reacting with the coating, avoid the occurrence of oxidation phenomenon, and at the same time ensure the denseness, hardness and adhesion of the coating, thereby improving the bonding strength and durability of the coating and extending the service life of the equipment and reducing the maintenance cost.

[0061] Please refer to the appendix Figure 1 , in a preferred embodiment of the present invention, S5 includes:

[0062] Hardness test of the coating, the hardness requirement is 15HRC to 50HRC. The hardness test of the coating can effectively evaluate its ability to resist wear and mechanical impact during actual use. An appropriate hardness value can ensure that the coating has sufficient scratch resistance and improve the service life of the equipment surface, especially showing good durability in the face of high-friction and impact environments;

[0063] The bonding strength test of the coating is carried out, and the bonding strength requirement is above 200 MPa. The high bonding strength ensures the firm adhesion between the coating and the substrate, which is crucial for the long-term stable operation of the equipment. Especially in petrochemical equipment, the strong bonding force between the coating and the substrate can effectively prevent the coating from peeling off in high-temperature, high-pressure or corrosive environments, thus extending the service life of the equipment and reducing the frequency of equipment maintenance and replacement;

[0064] The neutral salt spray test is used to test the corrosion resistance of the coating. The neutral salt spray test can simulate the corrosive performance of the coating in the actual working environment and provide quantitative data for the corrosion resistance of the coating. Through the test, the reliability of the coating exposed to the salt-containing medium in petrochemical equipment can be ensured, thus effectively preventing the equipment from suffering corrosive damage in harsh environments and ensuring the long-term stable operation of the equipment.

[0065] Please refer to the appendix Figure 1 In a preferred embodiment of the present invention, the powder formulation design for different corrosion environments includes:

[0066] For the H2S + CO2 + H2O medium, the Ni-based alloy powder PB-Ni80CrMo alloy is selected as the coating material. The PB-Ni80CrMo alloy powder is composed of 80% nickel, 20% chromium and an appropriate amount of molybdenum elements. It is specially designed for the protection of high-temperature and highly corrosive media. The nickel element in this alloy provides excellent corrosion resistance, and the addition of chromium and molybdenum elements further enhances the oxidation resistance of the alloy, which can effectively prevent the surface oxidation and corrosion of the equipment at high temperatures. In addition, the role of molybdenum element in the alloy is to improve its corrosion resistance in the sulfide atmosphere, making the coating have better stability in high-temperature environments;

[0067] For the SO3 + CO2 + O2 + H2O medium, the Ni-based alloy powder PB-Ni90CrSi alloy is selected as the coating material. The main components of the B-Ni90CrSi alloy powder include 90% nickel, 10% chromium and an appropriate amount of silicon. The addition of silicon element makes the alloy have strong acid resistance and wear resistance, which can effectively protect the equipment from the invasion of strong acid media. In addition, silicon can form a protective oxide film on the surface of the alloy, further enhancing the anti-corrosion performance of the coating;

[0068] For the H2SO4 + H2O medium, Ni-based alloy powder PB-Ni60CrSi alloy is selected as the coating material. The composition of PB-Ni60CrSi alloy powder consists of 60% nickel, 30% chromium, and an appropriate amount of silicon, which is suitable for neutral and low-corrosive environments. The nickel element in this alloy ensures the basic corrosion resistance of the coating, and the addition of chromium and silicon provides higher heat resistance and corrosion resistance to the coating, especially showing good stability in wet or neutral gas corrosion environments. The silicon element can enhance the wear resistance of the coating, making the coating not only have advantages in corrosion prevention but also provide protection in wear environments.

[0069] A preparation method of an anti-corrosion metal coating based on the brazing coating technology described below can be mutually corresponding and referred to with the metal surface anti-corrosion treatment process of petrochemical equipment based on the brazing coating technology described above.

[0070] Please refer to the appendix Figure 1 , The present invention also provides a preparation method of an anti-corrosion metal coating based on the brazing coating technology, including the following steps:

[0071] Select a suitable powder formula according to the equipment working conditions. The formula includes Cr-based, Ni-based, or Mo-based metal powders and Cr2O3, Fe2O3, or VC powders;

[0072] Spray the composite powder on the metal surface through the spraying process, and the coating thickness is 300μm - 500μm.

[0073] After high-temperature sintering treatment, a metallurgical bonding layer is formed between the coating and the metal surface, ensuring that the bonding strength of the coating is greater than 200MPa and the hardness reaches 15HRC - 50HRC.

[0074] Please refer to the appendix Figure 1 , In a preferred embodiment of the present invention, after the coating is cooled, it further includes surface finishing treatment of the coating surface to further improve the surface finish and anti-pollution of the coating.

[0075] The preparation method of this embodiment can be used to implement the above process embodiment, and its principle and technical effects are similar, so they will not be elaborated here.

[0076] To better understand the present invention, the above content will be described in detail below in combination with specific embodiments.

[0077] Example 1: Composite powder formula without adding trace elements

[0078] Powder formula:

[0079] Metal powder matrix: Ni-based alloy powder (such as PB-Ni80CrMo alloy)

[0080] Ceramic powder matrix: Fe2O3 powder

[0081] Process steps:

[0082] Select the composite powder according to the working conditions of petrochemical equipment, and spray it using the ratio of Ni-based alloy powder and Fe2O3 ceramic powder.

[0083] Use the sandblasting method to pre-treat the surface of the metal matrix to remove surface oil stains and oxide layers.

[0084] Adopt the plasma spraying method to evenly spray the composite powder onto the surface of the matrix, ensuring that the coating is uniform and reaches a thickness of 300 μm.

[0085] Carry out sintering treatment in an inert atmosphere, control the temperature at 900 °C, and sinter for 15 minutes to ensure that a metallurgical bonding layer is formed between the coating and the metal matrix.

[0086] Conduct coating hardness and bonding strength tests, with the hardness reaching 40 HRC and the bonding strength reaching 250 MPa.

[0087] Effect: Through the combination of basic metal powder and ceramic powder, this example achieves good corrosion resistance and wear resistance, and is suitable for the corrosion environment of conventional petrochemical equipment.

[0088] Example 2: Composite powder formula with trace elements Cu, Mo, and Si added

[0089] Powder formula:

[0090] Metal powder matrix: Ni-based alloy powder (PB-Ni80CrMo alloy)

[0091] Ceramic powder matrix: Fe2O3 powder

[0092] Trace elements: Add trace amounts of Cu, Mo, and Si elements (Cu: 1%, Mo: 2%, Si: 1%)

[0093] Process steps:

[0094] Add Cu, Mo, and Si elements to the composite powder, adjust the powder ratio to better meet the corrosion resistance requirements in a highly corrosive environment.

[0095] Use the laser surface treatment method to improve the hydrophilicity and surface roughness of the metal matrix to ensure better bonding between the coating and the metal matrix.

[0096] Use the thermal spraying (HVOF) spraying method to evenly spray the composite powder onto the surface of the matrix, with a coating thickness of 400 μm.

[0097] The sintering treatment is carried out under an inert atmosphere, with a sintering temperature of 950 °C and a sintering time of 20 minutes.

[0098] Coating hardness, bonding strength and neutral salt spray tests are carried out. The hardness reaches 45 HRC, the bonding strength reaches 300 MPa, and the salt spray test shows excellent corrosion resistance.

[0099] Effect: By adding trace elements of Cu, Mo and Si, the coating shows excellent corrosion resistance and wear resistance in more complex corrosion environments, is suitable for harsh working conditions containing corrosive substances such as sulfur and chlorine, and enhances the comprehensive performance of the coating.

[0100] Example 3: Ni-based and VC ceramic powder composite formula

[0101] Powder formula:

[0102] Metal powder matrix: Ni-based alloy powder (PB-Ni90CrSi alloy)

[0103] Ceramic powder matrix: VC powder (tungsten carbide)

[0104] Process steps:

[0105] Select the composite formula of Ni-based alloy powder PB-Ni90CrSi and VC ceramic powder, which is suitable for high-temperature and wear-resistant environments.

[0106] Use the sandblasting method to treat the surface of the substrate, remove surface oil stains, rust and increase the surface roughness.

[0107] Adopt the plasma spraying method to spray the composite powder onto the surface of the metal substrate, control the spraying thickness to be 350 μm, and ensure the uniformity of the coating.

[0108] Carry out high-temperature sintering treatment under an inert atmosphere, with a sintering temperature of 1000 °C and a sintering time of 25 minutes to ensure the metallurgical bonding between the coating and the substrate.

[0109] Carry out hardness test and bonding strength test. The hardness reaches 50 HRC, the bonding strength exceeds 350 MPa, and the coating shows excellent corrosion resistance through the salt spray test.

[0110] Effect: This example improves the wear resistance and high-temperature resistance of the coating by using the composite formula of VC ceramic powder and Ni-based alloy powder, is especially suitable for high-temperature, high-pressure and high-friction environments in petrochemical equipment, and enhances the service life and reliability of the equipment.

[0111] Example 4: Comparison of different Ni-based alloy powders

[0112] Powder formula:

[0113] Composite powder A: Ni-based alloy powder PB-Ni60CrSi alloy and Fe2O3 ceramic powder

[0114] Composite powder B: Ni-based alloy powder PB-Ni80CrMo alloy and VC powder

[0115] Process steps:

[0116] Select two different Ni-based alloy powders and ceramic powders and apply them to two different types of corrosion environments respectively.

[0117] Sandblast pretreat the metal substrate to remove oil stains and oxide layers and increase the surface roughness.

[0118] Use plasma spraying technology to spray composite powder A and composite powder B onto the substrate surface respectively, and the coating thickness is 300μm.

[0119] Sinter in an inert atmosphere at a sintering temperature of 900°C for 20 minutes to ensure that a strong metallurgical bonding layer is formed between the coating and the substrate.

[0120] Comparing the results of coating hardness, bonding strength and salt spray test, the hardness of composite powder A is 40HRC, the bonding strength is 220MPa, and the salt spray test shows good performance; the hardness of composite powder B is 45HRC, the bonding strength is 250MPa, and the salt spray test shows excellent performance.

[0121] Effect: By comparing the composite formulations of two different Ni-based alloy powders and ceramic powders, it is proved that the selection and ratio of powders have an impact on the coating performance. Compared with A, composite powder B has higher hardness and stronger corrosion resistance, and is suitable for more severe corrosion working conditions.

[0122] Comparative experiment 1: Salt spray corrosion test

[0123] Experimental purpose: Verify the innovation of the present invention in improving the surface anti-corrosion performance of petrochemical equipment.

[0124] Setting of experimental group and control group:

[0125] Experimental group (the present invention): The metal surface treated by the brazing coating technology of the present invention, and the composite powder coating is subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0126] Control group 1: Use traditional thermal spraying (HVOF) coating with a coating thickness of 300μm - 500μm, and use Ni-based or Cr-based powder.

[0127] Control group 2: Use traditional electroplated nickel coating with a coating thickness of 20μm - 30μm.

[0128] Control Group 3: Metal substrate without coating treatment.

[0129] Experimental procedures:

[0130] Sample preparation:

[0131] Select metal substrates (such as steel, aluminum alloy, etc.) and process them in four groups respectively.

[0132] Experimental group: The surface of the substrate is first pretreated (by sandblasting or laser treatment), then sprayed with composite powder and subjected to high-temperature sintering treatment.

[0133] Control Group 1: After surface pretreatment of the substrate, Ni-based or Cr-based powder is sprayed, and the HVOF technology is used for spraying, with the coating thickness of 300μm - 500μm.

[0134] Control Group 2: The surface of the substrate is electroplated with nickel, and the coating thickness is 20μm - 30μm.

[0135] Control Group 3: The substrate is not subjected to any coating treatment.

[0136] Salt spray corrosion environment setting:

[0137] Put the processed metal substrate samples into a salt spray test chamber.

[0138] The environmental temperature of the salt spray test chamber is set at 35°C, and the salt solution concentration is 5% NaCl.

[0139] Conduct salt spray corrosion tests, with the exposure times being 0 hours, 24 hours, 48 hours, 96 hours, and 168 hours, and regularly check the corrosion conditions of the samples.

[0140] Recording of corrosion conditions:

[0141] At regular intervals, take out the samples for inspection, and record the corrosion area, peeling situation, color change phenomenon, etc. on the surface of the samples.

[0142] After each sampling, clean the surface of the samples with salt water to remove the salt spray residue.

[0143] Recording of experimental data:

[0144] After the samples have gone through the exposure time, record the corrosion area, corrosion depth, peeling situation, and corrosion resistance score of each group of samples.

[0145] The comparative experimental data are shown in Table 1:

[0146] Table 1 Salt spray corrosion test experimental data table

[0147]

[0148]

[0149] From the data in Table 1, it can be obtained that:

[0150] By comparing the salt spray corrosion test data of the invention group and the control group, it can be clearly seen that the coating treated by the brazing coating technology of the present invention has obvious advantages in terms of corrosion resistance. Especially in high-temperature and corrosive environments, the corrosion area and depth of the coating in the experimental group are significantly lower than those of the control groups 1, 2, and 3. By forming a metallurgical bonding layer, the present invention can enhance the corrosion resistance of the coating and extend the service life of the equipment.

[0151] Comparative Experiment 2: Coating Hardness Test

[0152] Experimental Purpose: To verify whether the coating hardness of the present invention is superior to that of traditional coatings.

[0153] Setting of the Experimental Group and the Control Group:

[0154] Experimental Group (the Present Invention): The metal surface treated by the brazing coating technology of the present invention, and the composite powder coating is subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0155] Control Group 1: Using a traditional thermal spray (HVOF) coating with a coating thickness of 300 μm to 500 μm, and Ni-based or Cr-based powders are used.

[0156] Control Group 2: Using a traditional electroplated nickel coating with a coating thickness of 20 μm to 30 μm.

[0157] Control Group 3: The metal substrate without any coating treatment.

[0158] Experimental Steps:

[0159] Sample Preparation:

[0160] Select metal substrates (such as steel, aluminum alloy, etc.) and process them in four groups respectively.

[0161] Experimental Group: The surface of the substrate is first pretreated (by sandblasting or laser treatment), then the composite powder is sprayed and subjected to high-temperature sintering treatment.

[0162] Control Group 1: After the surface of the substrate is pretreated, Ni-based or Cr-based powders are sprayed, and the HVOF technology is used for spraying with a coating thickness of 300 μm to 500 μm.

[0163] Control Group 2: The surface of the substrate is electroplated with nickel with a coating thickness of 20 μm to 30 μm.

[0164] Control Group 3: The substrate is not subjected to any coating treatment.

[0165] Hardness Test:

[0166] The hardness of the samples was tested using a Vickers hardness tester, a Rockwell hardness tester or a microhardness tester. The test points were randomly selected to ensure the representativeness of the test.

[0167] During the hardness test, an indentation test was performed on the coating surface with a constant load and a fixed time.

[0168] At least 5 test points were carried out for each group of samples, and the average value was taken as the test result.

[0169] Data recording and analysis:

[0170] The hardness values of each group of coatings were recorded. According to the standard hardness test procedure, the test conditions were ensured to be consistent, and the analysis was carried out according to the coating thickness, material type and test depth.

[0171] The comparative experimental data are shown in Table 2:

[0172] Table 2 Experimental data table of coating hardness test

[0173]

[0174] From the data in Table 2, it can be obtained that:

[0175] Through the comparative data of the hardness test, the experimental group (the present invention) showed the optimal hardness value. The coating hardness was significantly better than that of the traditional HVOF spraying and electroplated nickel coatings, as well as the uncoated metal substrate. The higher hardness helped to improve the wear resistance of the coating and reduce the maintenance and replacement frequency of the equipment. Therefore, the coating technology of the present invention not only has strong anti-corrosion performance, but also can effectively cope with wear and high-temperature environments, thus greatly improving the service life and operation stability of petrochemical equipment.

[0176] Comparative experiment 3: Bond strength test

[0177] Experimental purpose: To verify whether the coating of the present invention can provide higher bond strength, so as to improve the durability and anti-peeling ability of the coating and ensure that the coating is not easily peeled off during long-term use.

[0178] Setting of the experimental group and the control group:

[0179] Experimental group (the present invention): The metal surface treated by the brazing coating technology of the present invention, and the composite powder coating was subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0180] Control group 1: Using a traditional thermal spray (HVOF) coating with a coating thickness of 300 μm to 500 μm, and Ni-based or Cr-based powders were used.

[0181] Control group 2: Using a traditional electroplated nickel coating with a coating thickness of 20 μm to 30 μm.

[0182] Control Group 3: Metal substrate without coating treatment.

[0183] Experimental procedures:

[0184] Sample preparation:

[0185] Select metal substrates (such as steel, aluminum alloy, etc.) and process them separately in four groups.

[0186] Experimental group: The surface of the substrate is subjected to sandblasting or laser treatment, then sprayed with composite powder and subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0187] Control Group 1: The surface of the substrate is sprayed with Ni-based or Cr-based powder using the HVOF spraying process, and the coating thickness is 300μm - 500μm.

[0188] Control Group 2: The surface of the substrate is electroplated with nickel, and the coating thickness is 20μm - 30μm.

[0189] Control Group 3: Metal substrate without coating treatment.

[0190] Bonding strength test:

[0191] Use a tensile testing machine or a shear testing machine to conduct a bonding strength test on the samples.

[0192] Each sample is stretched in a tensile testing machine to test the bonding strength between the coating and the metal substrate.

[0193] During the test, apply a uniform tensile force until the coating separates from the substrate, and record the force value at the time of separation.

[0194] Each group of samples is tested 3 times, and the average value is taken as the final result.

[0195] Data recording and analysis:

[0196] Analyze the differences between groups based on the bonding strength data of different groups.

[0197] The unit of bonding strength is MPa, and the higher the value, the stronger the bonding between the coating and the substrate.

[0198] The comparative experimental data are shown in Table 3:

[0199] Table 3 Data table of bonding strength test experiment

[0200]

[0201] From the data in Table 3, it can be obtained that:

[0202] Through the comparative data of the bond strength test, the experimental group (the present invention) showed the best bond strength, and the coating was firmly and stably bonded to the metal substrate. In contrast, the bond strengths of the traditional HVOF spraying and electroplated nickel coatings were relatively low, and problems such as peeling and loosening might occur especially during long-term use. The bond strength of the uncoated metal substrate was the lowest and could not provide corrosion protection. Through the brazing coating technology of the present invention, the bond strength between the coating and the substrate can be improved, thereby enhancing the service life and durability of petrochemical equipment.

[0203] Comparative Experiment 4: Abrasion Resistance Test

[0204] Experimental Purpose: To verify whether the composite powder brazing coating used in the present invention can significantly improve the abrasion resistance of the coating, thereby enhancing the service performance of petrochemical equipment in a long-term high-abrasion environment.

[0205] Settings of the Experimental Group and the Control Group:

[0206] Experimental Group (the Present Invention): The metal surface treated by the brazing coating technology of the present invention, and the composite powder coating was subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0207] Control Group 1: Using a traditional thermal spray (HVOF) coating with a coating thickness of 300 μm - 500 μm and adopting Ni-based or Cr-based powder.

[0208] Control Group 2: Using a traditional electroplated nickel coating with a coating thickness of 20 μm - 30 μm.

[0209] Control Group 3: The uncoated metal substrate.

[0210] Experimental Procedures:

[0211] Sample Preparation:

[0212] Select metal substrates of the same material (such as steel, aluminum alloy, etc.) and process them separately in the four groups.

[0213] Experimental Group: The surface of the substrate was sandblasted or laser-treated, then the composite powder was sprayed and subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0214] Control Group 1: The surface of the substrate was sprayed with Ni-based or Cr-based powder using the HVOF spraying process, and the coating thickness was 300 μm - 500 μm.

[0215] Control Group 2: The surface of the substrate was electroplated with nickel, and the coating thickness was 20 μm - 30 μm.

[0216] Control Group 3: The uncoated metal substrate.

[0217] Abrasion Resistance Test:

[0218] The abrasion resistance was tested using a Taber abrasion tester.

[0219] According to the standard abrasion method, each sample was placed in the abrasion machine, a fixed load was applied, and the abrasion of each sample was tested.

[0220] Each sample was tested for 1000 revolutions, and the mass loss before and after abrasion of the sample was recorded.

[0221] The abrasion rate was calculated based on the mass loss value, and the abrasion resistance test results were obtained.

[0222] Data recording and analysis:

[0223] Record the mass loss of each group of samples and calculate the abrasion rate.

[0224] According to the abrasion rate data of different groups, analyze the difference in abrasion resistance performance between groups.

[0225] The unit of the abrasion rate is g / km, and the lower the value, the better the abrasion resistance performance.

[0226] The comparison experiment data is shown in Table 4:

[0227] Table 4 Experimental data table of abrasion resistance test

[0228]

[0229] From the data in Table 4, it can be obtained that:

[0230] The experimental group (the present invention) showed the best abrasion resistance performance, and the abrasion rate was significantly lower than that of Control Group 1 (HVOF spraying), Control Group 2 (electroplated nickel), and Control Group 3 (uncoated). After the composite powder coating adopted in the present invention was subjected to high-temperature sintering treatment, the formed metallurgical bonding layer had higher hardness and abrasion resistance, and could improve the performance of petrochemical equipment in a high-abrasion environment.

[0231] Comparative Experiment 5: High-temperature heat resistance test

[0232] Experimental purpose: To verify the heat resistance of the metal surface treated by the brazing coating technology of the present invention under high-temperature conditions.

[0233] Experimental group and control group settings:

[0234] Experimental group (the present invention): The metal surface treated by the brazing coating technology of the present invention, and the composite powder coating was subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0235] Control Group 1: Use a traditional thermal spray (HVOF) coating with a coating thickness of 300 μm to 500 μm, and Ni-based or Cr-based powders were used.

[0236] Control Group 2: Use traditional electroplated nickel coatings with a coating thickness of 20μm - 30μm.

[0237] Control Group 3: Metal substrates without coating treatment.

[0238] Experimental procedures:

[0239] Sample preparation:

[0240] Select metal substrates of the same material (such as steel, aluminum alloy, etc.) and process them separately in four groups.

[0241] Experimental group: The surface of the substrate is subjected to sandblasting or laser treatment, then sprayed with composite powder and subjected to high-temperature sintering treatment to form a metallurgical bonding layer.

[0242] Control Group 1: Spray Ni-based or Cr-based powder on the surface of the substrate, using the HVOF spraying process, with a coating thickness of 300μm - 500μm.

[0243] Control Group 2: Electroplate nickel on the surface of the substrate, with a coating thickness of 20μm - 30μm.

[0244] Control Group 3: Metal substrates without coating treatment.

[0245] High-temperature heat resistance test:

[0246] Expose each group of samples to different temperatures (such as 500°C, 600°C, 700°C) for high-temperature heat treatment.

[0247] After each treatment, quickly take out the samples and conduct visual inspection and hardness testing on them.

[0248] Measure the phenomena such as cracks, peeling, discoloration, etc. of the coating and record the hardness changes.

[0249] Test the performance of each sample under different high-temperature conditions and record the hardness changes and any physical changes.

[0250] Data recording and analysis:

[0251] Record the visual changes and hardness test results of each group of samples at different temperatures.

[0252] Evaluate the heat resistance of the coating based on the hardness changes, surface cracks, etc. after high temperature.

[0253] The comparison experimental data is shown in Table 5:

[0254] Table 5 Experimental data table of high-temperature heat resistance test

[0255]

[0256]

[0257] It can be obtained from the data in Table 5 that:

[0258] Judging from the results of the high-temperature heat resistance test, the experimental group (the present invention) showed the best heat resistance. In a high-temperature environment, the coating hardly changed color or cracked, with little hardness loss and low mass loss. In contrast, the coatings or substrates of Control Group 1 (HVOF spraying), Control Group 2 (electroplated nickel), and Control Group 3 (uncoated) all showed varying degrees of cracks, hardness loss, and mass loss under high-temperature conditions, and their heat resistance was significantly worse than that of the present invention, indicating that the composite powder coating used in the present invention has excellent high-temperature stability, can provide better protection under high-temperature conditions, and extend the service life of the equipment.

[0259] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for anti-corrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology, characterized in that: The following steps are involved: S1. Prepare suitable composite powder formula according to working conditions; S2, pre-treating the surface of the metal substrate; S3, spraying the selected composite powder onto the surface of the metal substrate; S4, performing high temperature sintering treatment on the sprayed metal substrate; S5. Cool the coating and perform relevant performance tests.

2. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The S1 comprises a mixture of metal powder and ceramic powder: The matrix of the metal powder is selected to be at least Cr-based, Ni-based or Mo-based powder; The matrix of the ceramic powder is selected to be at least C, Fe2O3 or VC powder; Trace amounts of Cu, Mo and Si elements are added to the powder and the powder ratio is adjusted to meet the requirements of different corrosive environments.

3. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The S2 includes: Use sandblasting to remove surface oil, rust and oxide layer to increase the roughness of metal surface, or use laser surface treatment to improve surface hydrophilicity and increase the bonding force of metal surface.

4. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The S3 includes: The composite powder is evenly sprayed onto the surface of the metal substrate using plasma spraying and thermal spraying (HVOF) spraying methods; During the spraying process, the distance between the spray gun and the substrate, the spraying speed and the spraying angle are controlled to ensure the uniformity and thickness of the coating.

5. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The S4 includes: Sintering is performed under an inert atmosphere to prevent oxidation of the coating; The sintering temperature is 450° C. to 550° C., and the sintering time is 3 to 7 seconds, so as to ensure that a metallurgical bonding layer is formed between the coating and the metal substrate.

6. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The S5 includes: Hardness test of coating, hardness requirement is 15HRC~50HRC; The bonding strength test of the coating should be above 200MPa. Neutral salt spray test, to test the corrosion resistance of the coating.

7. The process for anticorrosion treatment of metal surfaces of petrochemical equipment based on brazing coating technology according to claim 1, characterized in that: The powder formula is designed for different corrosive environments including: For H2S+CO2+H2O medium, Ni-based alloy powder PB-Ni80CrMo alloy was selected as the coating material; For SO3+CO2+O2+H2O medium, Ni-based alloy powder PB-Ni90CrSi alloy was selected as the coating material; For H2SO4+H2O medium, Ni-based alloy powder PB-Ni60CrSi alloy is selected as the coating material.

8. A method for preparing an anti-corrosion metal coating based on brazing coating technology, characterized in that: The anti-corrosion treatment process for metal surface of petrochemical equipment based on brazing coating technology according to any one of claims 1 to 7 comprises the following steps: Select appropriate powder formula according to equipment working conditions, including Cr-based, Ni-based or Mo-based metal powder and Cr2O3, Fe2O3 or VC powder; The composite powder is sprayed on the metal surface through the spraying process, and the coating thickness is 300μm~500μm. After high-temperature sintering treatment, a metallurgical bonding layer is formed between the coating and the metal surface, ensuring that the bonding strength of the coating is greater than 200MPa and the hardness reaches 15HRC~50HRC.

9. The method for preparing an anti-corrosion metal coating based on brazing coating technology according to claim 1, characterized in that: After the coating is cooled, the coating surface is also subjected to surface finishing treatment to further improve the surface finish and anti-pollution properties of the coating.

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