Surface corrosion-resistant treatment process for low-carbon steel

Abstract

The invention relates to the technical field of steel and discloses a surface corrosion-resistant treatment process for low-carbon steel. The method comprises the steps that S1, matrix steel is taken and cleaned, and a substrate layer is sprayed to the surface of the matrix steel through a plasma spraying method; the base layer comprises the following raw materials: Ni, Fe, Ti and TiO2 in a mass ratio of (70-80): (10-20): (3-8): (1-3); s2, a TiO2 layer is sprayed on the surface of the substrate layer through a plasma spraying method, and pretreated substrate steel is obtained; s3, the surface of the pretreated matrix steel is coated with a sealing coating, curing and drying are carried out, and low-carbon steel subjected to surface corrosion-resistant treatment is obtained; the sealing coating comprises the following raw materials in parts by mass: 100 parts of an organic silicon resin composition, 20-30 parts of modified titanium dioxide, 5-10 parts of composite modified silane and 20-30 parts of acetone.

Description

Technical Field

[0001] The invention relates to the technical field of steel and iron, and discloses a surface corrosion-resistant treatment process for low-carbon steel. Background Art

[0002] Low-carbon steel is widely used, and with the development of the times, the requirements for steel performance are becoming increasingly higher. Poor corrosion resistance of steel can seriously shorten the service life of steel, causing huge economic losses or casualties. Therefore, the surface of steel needs to be treated for corrosion resistance.

[0003] Plasma spraying technology is an effective method for surface alloying treatment and a research hotspot in the field of steel surface corrosion protection treatment. It has the advantages of simple operation, high flexibility and low cost. Plasma spraying titanium dioxide on the steel surface can significantly improve the corrosion resistance of the steel surface, but the titanium dioxide layer has poor bonding with the steel substrate and the coating has a high porosity, which affects its performance. In summary, it is of great significance to study a simple, easy-to-operate and effective surface corrosion resistance treatment process for low-carbon steel. Summary of the Invention

[0004] The purpose of the present invention is to provide a surface corrosion resistance treatment process for low carbon steel to solve the problems raised in the above background technology.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: A surface corrosion resistance treatment process for low carbon steel, comprising the following steps: S1: taking a base steel, cleaning it (using 280#, 400#, 600#, 1200#, and 2000# metallographic sandpaper to polish the surface, placing it in an acetone solution for ultrasonic cleaning, and drying it at 85°C), and spraying a base layer on the surface of the base steel by plasma spraying; the raw materials of the base layer include Ni, Fe, Ti, and TiO2 in a mass ratio of (70-80): (10-20): (3-8): (1-3);

[0006] S2: spraying a TiO2 layer on the surface of the base layer by plasma spraying to obtain a pretreated base steel;

[0007] S3: applying the sealing coating to the surface of the pre-treated base steel, curing and drying, and obtaining low-carbon steel with surface corrosion resistance treatment.

[0008] More optimally, Ni, Fe, Ti, and TiO2 in the base layer raw materials are at the micron level, with a particle size of 40 to 100 μm; the TiO2 used in the TiO2 layer is at the micron level, with a particle size of 40 to 100 μm.

[0009] More optimally, Ni, Fe, Ti, and TiO2 in the base layer raw materials are at the micron level, with a particle size of 80 μm; the TiO2 used in the TiO2 layer is at the micron level, with a particle size of 80 μm.

[0010] More optimally, the process conditions for spraying the base layer are: spraying voltage of 100-120V, spraying current of 350-400A, spraying distance of 100mm, powder feeding rate of 30-40g / min; the thickness of the base layer is 0.08-0.12mm;

[0011] The process conditions for spraying the TiO2 layer are as follows: spraying voltage of 120-150V, spraying current of 600-650A, spraying distance of 100mm, powder feeding rate of 45-50g / min, and TiO2 layer thickness of 0.25-0.3mm;

[0012] The coating thickness of the sealing coating is 0.4 to 1 μm.

[0013] More optimally, the preparation of the sealing coating includes the following steps: Step 1: taking maleic anhydride, acetone, and KH550, stirring under nitrogen for 8 to 12 hours, adding sodium acetate and acetic anhydride, reflux for 10 to 15 hours, filtering to remove solids, and rotary evaporating to remove the solvent to obtain maleic anhydride-modified siloxane;

[0014] Step 2: Take maleic anhydride modified siloxane, 4-allylcatechol, acetone, and initiator BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 8-12 hours, and remove the solvent to obtain a composite modified siloxane;

[0015] Step 3: Take the organic silicone resin composition, modified titanium dioxide, composite modified silane, and acetone, mix them evenly, and obtain a sealing coating.

[0016] More optimally, the maleic anhydride-modified siloxane comprises the following raw materials, calculated by mass: 10-12 parts of maleic anhydride, 100-150 parts of acetone, 20-30 parts of KH550, 8-10 parts of sodium acetate, and 10-15 parts of acetic anhydride;

[0017] The composite modified siloxane comprises the following raw materials, calculated by mass: 15 to 20 parts of maleic anhydride modified siloxane, 20 to 30 parts of 4-allylcatechol, 50 to 200 parts of acetone, and 0.01 to 0.02 parts of initiator;

[0018] The sealing coating comprises the following raw materials, calculated by mass: 100 parts of an organic silicon resin composition, 20 to 30 parts of modified titanium dioxide, 5 to 10 parts of a composite modified silane, and 20 to 30 parts of acetone.

[0019] More optimally, the preparation of the modified titanium dioxide includes the following steps: taking nano-TiO2 and adding it to a mixed solution of water and ethanol to disperse it evenly, adding KH550, stirring at 50-60°C for 5-6 hours, filtering and drying to obtain amino-treated nano-TiO2; taking amino-treated nano-SiO2 and excess methyl acrylate, adding them to a methanol solvent at 25-30°C to react for 24-30 hours, filtering to obtain the solid, washing and purifying, mixing the obtained product with excess ethylenediamine and methanol solvent, and reacting at 25-30°C for 24-30 hours to obtain modified titanium dioxide.

[0020] More optimally, the particle size of nano-TiO2 is 40-100 nm.

[0021] More optimally, the particle size of nano-TiO2 is 60nm.

[0022] More optimally, the amino-treated nano-TiO2 comprises the following raw materials, calculated by weight: 10-15 parts of nano-TiO2, 40-50 parts of water, 50-60 parts of ethanol, and 2-3 parts of KH550;

[0023] The modified titanium dioxide comprises the following raw materials, calculated by mass: 10 to 15 parts of amino-treated nano-SiO2, 30 to 50 parts of methyl acrylate, and 30 to 50 parts of ethylenediamine.

[0024] More optimally, the silicone resin composition comprises a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:(0.5-0.8):(1-1.5).

[0025] More optimally, silicone transparent resin (SAR-2 silicone transparent resin from Shanghai Organic Resin Factory); amino silicone resin (CS-2020 amino silicone resin from Xiano New Materials); epoxy modified silicone resin (SH-023-7 epoxy modified silicone resin from Hubei Longsheng Sihai New Materials Co., Ltd.).

[0026] More optimally, the specific process of curing and drying is: curing at room temperature for 6 to 10 hours, curing at 60 to 80°C for 4 to 6 hours, and curing at 100 to 120°C for 2 to 3 hours.

[0027] More optimally, the chemical composition of the base steel is: C: 0.001-0.005%, Si: 0.01-0.03%, Mn: 0.1-0.2%, N: 0.001-0.004%, Al: 0.02-0.03%, Ti: 0.02-0.04%, and the rest is Fe and unavoidable impurities.

[0028] Compared with the prior art, the beneficial effects achieved by the present invention are as follows: a TiO2 layer is sprayed on the surface of the base steel by a plasma spraying method. TiO2 has good corrosion resistance, but its bonding with the base steel is poor when directly sprayed. Therefore, a base layer made of Ni, Fe, Ti, and TiO2 is first sprayed. The base layer contains Ni and Fe, which has good bonding with the base steel. The Ti and TiO2 therein enhance the bonding strength between the base layer and the TiO2 layer, and finally a high-quality pretreated base steel is obtained. When performing the above steps, the plasma sprayed The process needs to be controlled: When spraying the base layer, a smaller voltage and current are used to reduce energy consumption and make it easier to control the thickness. The base layer is only used to improve the bonding strength of the TiO2 layer, so it does not need to be too thick. When spraying the TiO2 layer, a larger voltage and current are required to obtain a TiO2 layer with low porosity, high bonding strength, and good wear resistance. However, the current and voltage should not be too large, otherwise the powder may be over-melted or vaporized, which will affect the quality of the layer. The thickness of the TiO2 layer also needs to be controlled. If it is too low, the corrosion resistance will be poor, and if it is too high, the bonding strength between the layers will be reduced, affecting the wear resistance.

[0029] In order to further reduce the porosity of the TiO2 layer to improve corrosion resistance, the present invention applies a sealing coating on the outside of the TiO2 layer; the sealing coating is based on a silicone resin composition, and modified titanium dioxide and a composite modified silane are added; wherein amino silicone resin and epoxy modified silicone resin are added to the silicone resin composition in a certain proportion to promote curing and increase the degree of crosslinking, thereby increasing the interaction between the sealing coating layer and the TiO2 layer; the modified titanium dioxide is based on nano titanium dioxide as the core, and the nano titanium dioxide has a smaller particle size and can fill the gaps in the TiO2 layer. The tree-like multi-amino structure grafted on the outside can improve the mechanical properties of the silicone resin composition, increase the surface activity, and increase the adhesion to the TiO2 layer, wherein the amino group can also react with the epoxy modified The silicone resin produces cross-linking to promote curing, further enhancing the interaction between layers; the composite modified silane is a nitrogen-containing silane, which can effectively improve the bonding strength between the sealing coating and the pretreated substrate steel, wherein 4-allylcatechol is also grafted, and has excellent corrosion resistance and adhesion; in summary, after the silicone resin composition, modified titanium dioxide, and composite modified silane are mixed in a certain proportion, a sealing coating can be obtained, which can further enhance the corrosion resistance and wear resistance of the mild steel surface, and the coating has good bonding strength with the TiO2 layer; the present invention adopts a step-by-step curing process of curing at room temperature for 6 to 10 hours, curing at a temperature of 60 to 80°C for 4 to 6 hours, and curing at 100 to 120°C for 2 to 3 hours, which reduces internal stress, improves the surface quality of the coating, and further improves corrosion resistance. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] It should be noted that there are no special restrictions on the purchase manufacturers of all raw materials involved in the present invention, and illustratively include: ethanol (CAS: 64-17-5); nano titanium dioxide (item number 1227163995, 60 nm, anatase, Kramar); BPO (CAS: 94-36-0); KH550 (CAS: 919-30-2); methyl acrylate (CAS: 96-33-3); methanol (CAS: 67-56-1); ethylenediamine (CAS: 107-15-3); maleic anhydride (CAS: 108-31-6); acetone (CAS: 67-64-1); sodium acetate (CAS: 127-09-3); acetic anhydride (CAS: 108-24-7); 4-allylcatechol (CAS: 1126-61-0).

[0032] Unless otherwise specified, the following are parts by mass and mass ratios;

[0033] The chemical composition of the base steel is: C: 0.001%, Si: 0.02%, Mn: 0.15%, N: 0.003%, Al: 0.02%, Ti: 0.04%, and the rest is Fe and unavoidable impurities;

[0034] Example 1: S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was cleaned; and the base layer was sprayed on the surface of the base steel by plasma spraying at a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, and a powder feed rate of 35 g / min; the base layer thickness was 0.1 mm;

[0035] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.28 mm; thus obtaining a pretreated substrate steel;

[0036] S3: Take 12 parts of nano-TiO2 and add it to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse it evenly, add 2 parts of KH550, stir at 60℃ for 5 hours, filter and dry to obtain amino-type nano-TiO2; take 12 parts of amino-type nano-SiO2 and 50 parts of methyl acrylate, add them to 300 parts of methanol solvent and react at 25℃ for 24 hours, filter and collect the solid, wash and purify it, mix the obtained product with 50 parts of ethylenediamine and 300 parts of methanol, and react at 25℃ for 24 hours to obtain modified titanium dioxide;

[0037] S4: Take 10 parts of maleic anhydride, 100 parts of acetone, and 25 parts of KH550, stir under nitrogen for 12 hours, add 8 parts of sodium acetate and 12 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0038] S5: Take 16 parts of maleic anhydride modified siloxane, 25 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0039] S6: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.6:1.2 to obtain a silicone composition; take 100 parts of the silicone resin composition, 25 parts of modified titanium dioxide, 8 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0040] S7: Apply the sealing coating to the surface of the pretreated base steel with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0041] Example 2: S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was taken and cleaned; and the base layer was sprayed on the surface of the base steel by plasma spraying at a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, and a powder feed rate of 35 g / min; the base layer thickness was 0.1 mm;

[0042] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.28 mm; thus obtaining a pretreated substrate steel;

[0043] S3: Take 12 parts of nano-TiO2 and add them to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse them evenly. Then add 2 parts of KH550 and stir at 60°C for 5 hours. Filter and dry to obtain amino-treated nano-TiO2. Take 10 parts of amino-treated nano-SiO2 and 50 parts of methyl acrylate and add them to 300 parts of methanol solvent and react at 25°C for 24 hours. Filter and collect the solid, wash and purify it. The obtained product is mixed with 50 parts of ethylenediamine and 300 parts of methanol and reacted at 25°C for 24 hours to obtain modified titanium dioxide.

[0044] S4: Take 10 parts of maleic anhydride, 100 parts of acetone, and 20 parts of KH550, stir under nitrogen for 12 hours, add 8 parts of sodium acetate and 10 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0045] S5: Take 15 parts of maleic anhydride modified siloxane, 20 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0046] S6: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.5:1 to obtain a silicone composition; take 100 parts of the silicone resin composition, 26 parts of modified titanium dioxide, 6 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0047] S7: Apply the sealing coating to the surface of the pretreated base steel with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0048] Example 3: S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was cleaned; and the base layer was sprayed on the surface of the base steel by plasma spraying at a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, and a powder feed rate of 35 g / min; the base layer thickness was 0.1 mm;

[0049] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.28 mm; thus obtaining a pretreated substrate steel;

[0050] S3: Take 12 parts of nano-TiO2 and add it to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse it evenly, add 2 parts of KH550, stir at 60℃ for 5 hours, filter and dry to obtain amino-modified nano-TiO2; take 15 parts of amino-modified nano-SiO2 and 50 parts of methyl acrylate, add them to 300 parts of methanol solvent and react at 25℃ for 24 hours, filter and collect the solid, wash and purify it, mix the obtained product with 50 parts of ethylenediamine and 300 parts of methanol, and react at 25℃ for 24 hours to obtain modified titanium dioxide;

[0051] S4: Take 12 parts of maleic anhydride, 100 parts of acetone, and 30 parts of KH550, stir under nitrogen for 12 hours, add 10 parts of sodium acetate and 15 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0052] S5: Take 20 parts of maleic anhydride modified siloxane, 30 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0053] S6: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.8:1.5 to obtain a silicone composition; take 100 parts of the silicone resin composition, 28 parts of modified titanium dioxide, 5 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0054] S7: Apply the sealing coating to the surface of the pretreated base steel with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0055] Comparative Example 1 (the preparation method of the sealing coating was changed, and the remaining steps were the same as those in Example 1): S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was taken and cleaned; and a base layer was sprayed on the surface of the base steel by plasma spraying. The spraying voltage was 120 V, the spraying current was 380 A, the spraying distance was 100 mm, and the powder feed rate was 35 g / min; the base layer thickness was 0.1 mm;

[0056] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.28 mm; thus obtaining a pretreated substrate steel;

[0057] S3: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.6:1.2 to obtain a silicone composition; take 100 parts of the silicone resin composition, 25 parts of nano-TiO2, 8 parts of KH550, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0058] S4: Apply the sealing coating to the pretreated base steel surface with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0059] Comparative Example 2 (using a transparent silicone resin instead of the silicone resin composition, and the remaining steps are the same as those in Example 1): S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was taken and cleaned; and the base layer was sprayed on the surface of the base steel by plasma spraying at a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, and a powder feed rate of 35 g / min; the base layer thickness was 0.1 mm;

[0060] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.28 mm; thus obtaining a pretreated substrate steel;

[0061] S3: Take 12 parts of nano-TiO2 and add it to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse it evenly, add 2 parts of KH550, stir at 60℃ for 5 hours, filter and dry to obtain amino-type nano-TiO2; take 12 parts of amino-type nano-SiO2 and 50 parts of methyl acrylate, add them to 300 parts of methanol solvent and react at 25℃ for 24 hours, filter and collect the solid, wash and purify it, mix the obtained product with 50 parts of ethylenediamine and 300 parts of methanol, and react at 25℃ for 24 hours to obtain modified titanium dioxide;

[0062] S4: Take 10 parts of maleic anhydride, 100 parts of acetone, and 25 parts of KH550, stir under nitrogen for 12 hours, add 8 parts of sodium acetate and 12 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0063] S5: Take 16 parts of maleic anhydride modified siloxane, 25 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0064] S6: Take 100 parts of organosilicon transparent resin, 25 parts of modified titanium dioxide, 8 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0065] S7: Apply the sealing coating to the surface of the pretreated base steel with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0066] Comparative Example 3 (the plasma spraying process was changed, and the remaining steps were the same as in Example 1): S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was taken and cleaned; and a base layer was sprayed on the surface of the base steel by plasma spraying at a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, and a powder feed rate of 50 g / min; the base layer thickness was 0.1 mm;

[0067] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, a powder feeding rate of 35 g / min, and a TiO2 layer thickness of 0.28 mm; a pretreated substrate steel was obtained;

[0068] S3: Take 12 parts of nano-TiO2 and add it to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse it evenly, add 2 parts of KH550, stir at 60℃ for 5 hours, filter and dry to obtain amino-type nano-TiO2; take 12 parts of amino-type nano-SiO2 and 50 parts of methyl acrylate, add them to 300 parts of methanol solvent and react at 25℃ for 24 hours, filter and collect the solid, wash and purify it, mix the obtained product with 50 parts of ethylenediamine and 300 parts of methanol, and react at 25℃ for 24 hours to obtain modified titanium dioxide;

[0069] S4: Take 10 parts of maleic anhydride, 100 parts of acetone, and 25 parts of KH550, stir under nitrogen for 12 hours, add 8 parts of sodium acetate and 12 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0070] S5: Take 16 parts of maleic anhydride modified siloxane, 25 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0071] S6: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.6:1.2 to obtain a silicone composition; take 100 parts of the silicone resin composition, 25 parts of modified titanium dioxide, 8 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0072] S7: Apply the sealing coating to the surface of the pretreated base steel with a thickness of 0.8 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0073] Comparative Example 4 (the thickness of the base layer, TiO2 layer, and sealant coating was changed, and the remaining steps were consistent with Example 1): S1: 75 parts of Ni, 15 parts of Fe, 5 parts of Ti, and 1 part of TiO2 were mixed uniformly to obtain a base layer raw material; a base steel was taken and cleaned; the base layer was sprayed on the surface of the base steel by plasma spraying, with a spraying voltage of 120 V, a spraying current of 380 A, a spraying distance of 100 mm, and a powder feed rate of 35 g / min; the base layer thickness was 0.05 mm;

[0074] S2: A TiO2 layer was sprayed on the surface of the substrate layer by plasma spraying with a spraying voltage of 150 V, a spraying current of 650 A, a spraying distance of 100 mm, a powder feeding rate of 50 g / min, and a TiO2 layer thickness of 0.4 mm; a pretreated substrate steel was obtained;

[0075] S3: Take 12 parts of nano-TiO2 and add it to a mixed solution of 40 parts of water and 60 parts of ethanol and disperse it evenly, add 2 parts of KH550, stir at 60℃ for 5 hours, filter and dry to obtain amino-type nano-TiO2; take 12 parts of amino-type nano-SiO2 and 50 parts of methyl acrylate, add them to 300 parts of methanol solvent and react at 25℃ for 24 hours, filter and collect the solid, wash and purify it, mix the obtained product with 50 parts of ethylenediamine and 300 parts of methanol, and react at 25℃ for 24 hours to obtain modified titanium dioxide;

[0076] S4: Take 10 parts of maleic anhydride, 100 parts of acetone, and 25 parts of KH550, stir under nitrogen for 12 hours, add 8 parts of sodium acetate and 12 parts of acetic anhydride, reflux for 12 hours, remove the solid by suction filtration, and remove the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane;

[0077] S5: Take 16 parts of maleic anhydride modified siloxane, 25 parts of 4-allylcatechol, 100 parts of acetone, and 0.01 parts of BPO, heat and pressurize to 80°C under nitrogen protection, stir and react for 12 hours, and remove the solvent to obtain a composite modified siloxane;

[0078] S6: Take a transparent silicone resin, an amino silicone resin, and an epoxy-modified silicone resin in a mass ratio of 8:0.6:1.2 to obtain a silicone composition; take 100 parts of the silicone resin composition, 25 parts of modified titanium dioxide, 8 parts of composite modified silane, and 25 parts of acetone, mix them evenly, and obtain a sealing coating;

[0079] S7: Apply the sealing coating to the pretreated base steel surface with a thickness of 1.3 μm, cure at room temperature for 6 hours, heat to 70° C. for 5 hours, and cure at 120° C. for 2 hours to obtain low-carbon steel with surface corrosion resistance treatment.

[0080] Performance test: The low carbon steels prepared in Examples 1 to 3 and Comparative Examples 1 to 4 and subjected to surface corrosion resistance treatment were tested for (1) corrosion current density to assess corrosion resistance; and (2) wear resistance. The grinding element was a Cr15 grinding ball with a diameter of 3.5 mm, a load of 200 N, a time of 20 min, and a motor speed of 560 r / min. See Table 1 for details.

[0081] Table 1:

[0082]

[0083] Conclusion: In comparative example 1, the preparation method of the sealing coating is changed. The raw materials of the sealing coating are silicone resin composition, nano-TiO2, KH550, and acetone solvent, and the performance is significantly reduced; in comparative example 2, the silicone resin composition is replaced by silicone transparent resin. Due to changes in the degree of cross-linking, etc., the performance is not as good as that of the embodiment; in comparative example 3, the plasma spraying process is changed, resulting in a significant decrease in wear resistance, from which it can be seen that the importance of plasma spraying process conditions is important; in comparative example 4, the thickness of the base layer, TiO2 layer, and sealing coating is changed, and the performance is reduced, from which it can be seen that controlling the thickness is of great significance; in summary, the low-carbon steel prepared by the present invention with surface corrosion resistance treatment has good bonding between layers, high surface quality, and good wear resistance.

[0084] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A surface corrosion resistance treatment process for low carbon steel, characterized by: The following steps are involved: S1: taking a base steel, cleaning it, and spraying a base layer on the surface of the base steel by plasma spraying; the raw materials of the base layer include Ni, Fe, Ti, and TiO2 in a mass ratio of (70-80): (10-20): (3-8): (1-3); S2: spraying a TiO2 layer on the surface of the base layer by plasma spraying to obtain a pretreated base steel; S3: applying the sealing coating to the pre-treated base steel surface, curing and drying, and obtaining low-carbon steel with surface corrosion resistance treatment.

2. The surface corrosion resistance treatment process for low carbon steel according to claim 1, characterized in that: The process conditions for spraying the base layer are as follows: spraying voltage of 100-120V, spraying current of 350-400A, spraying distance of 100mm, powder feeding rate of 30-40g / min; base layer thickness of 0.08-0.12mm; The process conditions for spraying the TiO2 layer are as follows: spraying voltage of 120-150V, spraying current of 600-650A, spraying distance of 100mm, powder feeding rate of 45-50g / min, and TiO2 layer thickness of 0.25-0.3mm; The coating thickness of the sealing coating is 0.4 to 1 μm.

3. The surface corrosion resistance treatment process for low carbon steel according to claim 1, characterized in that: The preparation of the sealing coating comprises the following steps: Step 1: taking maleic anhydride, acetone, and KH550, stirring under nitrogen for 8 to 12 hours, adding sodium acetate and acetic anhydride, refluxing for 10 to 15 hours, removing the solid by suction filtration, and removing the solvent by rotary evaporation to obtain maleic anhydride-modified siloxane; Step 2: Take maleic anhydride modified siloxane, 4-allylcatechol, acetone, and an initiator, heat and pressurize to 80°C under nitrogen protection, stir and react for 8-12 hours, and remove the solvent to obtain a composite modified siloxane; Step 3: Take the organic silicone resin composition, modified titanium dioxide, composite modified silane, and acetone, mix them evenly, and obtain a sealing coating.

4. The surface corrosion resistance treatment process for low carbon steel according to claim 3, characterized in that: The maleic anhydride modified siloxane comprises the following raw materials, calculated by mass: 10 to 12 parts of maleic anhydride, 100 to 150 parts of acetone, 20 to 30 parts of KH550, 8 to 10 parts of sodium acetate, and 10 to 15 parts of acetic anhydride; The composite modified siloxane comprises the following raw materials, calculated by mass: 15 to 20 parts of maleic anhydride modified siloxane, 20 to 30 parts of 4-allylcatechol, 50 to 200 parts of acetone, and 0.01 to 0.02 parts of initiator; The sealing coating comprises the following raw materials, calculated by mass: 100 parts of an organic silicon resin composition, 20 to 30 parts of modified titanium dioxide, 5 to 10 parts of a composite modified silane, and 20 to 30 parts of acetone.

5. The surface corrosion resistance treatment process for low carbon steel according to claim 3, characterized in that: The preparation of the modified titanium dioxide comprises the following steps: Take nano-TiO2 and add it to a mixed solution of water and ethanol and disperse it evenly, add KH550, stir at 50-60℃ for 5-6h, filter and dry to obtain amino-type nano-TiO2; take amino-type nano-SiO2 and methyl acrylate, add them to methanol solvent and react at 25-30℃ for 24-30h, filter and obtain the solid, wash and purify it, mix the obtained product with ethylenediamine and methanol, and react at 25-30℃ for 24-30h to obtain modified titanium dioxide.

6. The surface corrosion resistance treatment process for low carbon steel according to claim 5, characterized in that: The amino-treated nano-TiO2 comprises the following raw materials, calculated by mass: 10 to 15 parts of nano-TiO2, 40 to 50 parts of water, 50 to 60 parts of ethanol, and 2 to 3 parts of KH550; The modified titanium dioxide comprises the following raw materials, calculated by mass: 10 to 15 parts of amino-treated nano-SiO2, 30 to 50 parts of methyl acrylate, and 30 to 50 parts of ethylenediamine.

7. The surface corrosion resistance treatment process for low carbon steel according to claim 3, characterized in that: The organic silicon resin composition comprises organic silicon transparent resin, amino organic silicon resin and epoxy modified organic silicon resin in a mass ratio of 8:(0.5-0.8):(1-1.5).

8. The surface corrosion resistance treatment process for low carbon steel according to claim 1, characterized in that: The specific process of curing and drying is: curing at room temperature for 6 to 10 hours, curing at 60 to 80°C for 4 to 6 hours, and curing at 100 to 120°C for 2 to 3 hours.

9. The surface corrosion resistance treatment process for low carbon steel according to claim 1, characterized in that: The chemical composition of the base steel is: C: 0.001-0.005%, Si: 0.01-0.03%, Mn: 0.1-0.2%, N: 0.001-0.004%, Al: 0.02-0.03%, Ti: 0.02-0.04%, and the rest is Fe and unavoidable impurities.

10. Low-carbon steel with surface corrosion resistance treatment obtained by the surface corrosion resistance treatment process for low-carbon steel according to any one of claims 1 to 9.

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