High-carbon steel decarburization-resistant coating, preparation method and application thereof

Abstract

The present application relates to the technical field of anti-decarburization coating, and particularly relates to high-carbon steel anti-decarburization coating, a preparation method and application thereof. The coating comprises the following raw materials in parts by weight: 30-35 parts of SiO2, 4-6 parts of Al2O3, 0.5-1 part of talcum powder, 1-2 parts of gypsum powder, 1-5 parts of ZrO2, 1-3 parts of potassium feldspar powder, 1-3 parts of sodium feldspar powder, 5-10 parts of ZnO, 1-4 parts of Cr2O3, 5-8 parts of SiC, 5-9 parts of B2O3, 1-4 parts of graphite, and 30-40 parts of solvent; wherein, the Al / Si ratio is 1:6-8; the solvent is composed of 0.1-0.6% of methyl cellulose, 5-10% of sodium silicate / potassium silicate, 0.3-1% of polyethylene glycol, 0.01-0.03% of sodium hexadecyl sulfonate, and the rest of water. The coating has the advantages of rapid curing, low-temperature glazing, and simple phosphorus removal.

Description

Technical Field

[0001] The present invention relates to the technical field of anti-decarburization coatings, in particular to a high-carbon steel anti-decarburization coating and a preparation method and application thereof. Background Art

[0002] Decarburization is a common occurrence in hot working steel. In high temperatures exceeding 1000°C, the oxidizing atmosphere within the furnace continuously interacts with carbon in the surface layer of the metal matrix, reducing the carbon content in the outer layer of the steel. Diffusion of carbon from the inner layer of the steel billet causes the carbon content of the entire billet to decrease. This loss of carbon atoms leaves a decarburized layer with a distinct gradient microstructure. Correspondingly, mechanical properties exhibit a gradient within the decarburized layer: hardness is lowest at the topmost layer and increases with depth toward the matrix. Furthermore, surface decarburization can severely compromise the fatigue toughness of parts made from medium- and high-carbon steels directly after high-temperature heat treatment, reducing the fatigue limit by 50%. Furthermore, differences in expansion coefficients between different surface areas generate stresses during quenching, leading to microcracks in the transition zone between the decarburized and partially decarburized layers on the surface of medium- and high-carbon steels. This can exacerbate component failure and impact the steel's performance and service life.

[0003] To address this issue, CN117304722A designed a coating material using phosphate as a binder to protect against oxidation and decarburization during high-temperature treatment. However, this coating uses a large amount of aluminum polyphosphate, making it acidic. This coating can cause severe corrosion to metal bodies at high temperatures. Furthermore, the aluminum polyphosphate formed after dehydration at high temperatures cross-links with silicates, forming a compound that is difficult to descale, resulting in a large amount of residual oxides and reducing the surface quality of the material. The ingredients used in CN107500790B include 15-25% graphite and 15-35% silicon carbide. The carbon content in the ingredients is too high, and it is obvious that oxidation at high temperatures will produce carbon monoxide and carbon dioxide gases, which will also produce a large number of holes in the coating, causing the coating to lose its ability to isolate the air and inhibit oxidation and decarburization. CN117511260A uses water as a solvent, making it difficult to ensure a high curing speed. The coating in CN103757188A is composed of magnesium oxide, aluminum oxide, and calcium oxide. No substances that reduce the glazing temperature of the coating are used. The glazing temperature is above 800 degrees, but the steel billet begins to decarburize at 700 degrees during the heating process. The MG90T coating used on the market has a glazing temperature higher than 700 degrees, and it is difficult to provide protection during the heating process from 700°C to 1000°C. At the same time, the above-mentioned several existing anti-decarburization coatings cannot simply complete the dephosphorization process. Usually, they require high-pressure water gun flushing of more than 30MPa to complete the dephosphorization, which cannot meet the production conditions of some manufacturers and greatly limits the application and promotion of decarburization coatings. Therefore, the current existing technology cannot achieve the actual production needs of rapid curing, low-temperature glazing, and simple dephosphorization. Summary of the Invention

[0004] The purpose of the present invention is to address the above-mentioned deficiencies in the prior art and to provide a high-carbon steel anti-decarburization coating and a preparation method and application thereof.

[0005] A high carbon steel anti-decarburization coating of the present invention comprises the following raw materials in parts by weight:

[0006] SiO2 is 30-35 parts, Al2O3 is 4-6 parts, talc is 0.5-1 parts, gypsum powder is 1-2 parts, ZrO2 is 1-5 parts, potassium feldspar powder is 1-3 parts, sodium feldspar powder is 1-3 parts, ZnO is 5-10 parts, Cr2O3 is 1-4 parts, SiC is 5-8 parts, B2O3 is 5-9 parts, graphite is 1-4 parts, and the solvent is 30-40 parts;

[0007] Among them, the Al / Si ratio is 1:6-8;

[0008] The solvent consists of 0.1-0.6% methyl cellulose, 5-10% sodium silicate / potassium silicate, 0.3-1% polyethylene glycol, 0.01-0.03% sodium hexadecylsulfonate and the balance water.

[0009] Furthermore, the density of the coating is 2.8×10 3 kg / m 3 ~3.0×10 3 kg / m 3 , and\or, the solid content is 60% to 68%.

[0010] A method for preparing the high-carbon steel anti-decarburization coating as described above, comprising mixing the components according to the weight parts to obtain a powder, and stirring the powder and liquid until a suspension is formed to obtain the high-carbon steel anti-decarburization coating;

[0011] The preparation process of the liquid preparation is as follows: after heating water, methyl cellulose, sodium silicate, polyethylene glycol and sodium hexadecyl sulfonate are added in order, and stirred until no flocs remain.

[0012] An application of the above-mentioned high-carbon steel anti-decarburization coating comprises the following steps:

[0013] S1. A coating is atomized and sprayed on the surface of a high-carbon steel billet workpiece under a high-pressure air pump to form a coating;

[0014] S2. Place the sprayed and dried high-carbon steel billet into a heating furnace, slowly heat it to a preset temperature, and keep it warm for a period of time;

[0015] S3. After the heat preservation is completed, the high carbon steel billet workpiece is taken out for descaling.

[0016] Furthermore, in step S1, the thickness of the coating is 200um to 500um; or, the amount of the coating is 0.2kg / m 2 ~0.6kg / m 2 .

[0017] Furthermore, in step S1, the temperature of the surface of the high carbon steel billet workpiece is 10°C to 750°C; or, the temperature of the surface of the high carbon steel billet workpiece is 30°C to 300°C.

[0018] Furthermore, in step S2, the holding temperature is 1000-1300°C.

[0019] Furthermore, in step S2, in a heating furnace, the temperature is increased at a rate of 0.15-0.2°C / s to a preset temperature and then kept at that temperature for 1 hour.

[0020] Furthermore, in step S3, the specific operation of descaling is: using a high-pressure water gun to impact the steel billet with water for 3-5 minutes, the water pressure is 1-10 MPa, and then beating it to remove the coating material.

[0021] The high carbon steel anti-decarburization coating of the present invention pays attention to the relationship between the composition and performance of the protective coating, mainly considers the components around curing film formation, glaze protection and descaling, and achieves the purposes of rapid curing, low temperature glazing and simple phosphorus removal.

[0022] The mass of ZnO is controlled to be 5 to 10 parts. ZnO is a strong flux that can play a good fluxing role in a large range. At the same time, it can reduce the thermal expansion coefficient of the coating, resulting in a large difference in the thermal expansion coefficient between the coating and the steel. Moreover, as the temperature rises (the temperature reaches 1000°C), the 4-coordinated [ZnO4] is transformed into the 6-coordinated [ZnO6]. Due to the sparse octahedral structure of [ZnO6], the high-carbon steel billet coating provided in this application is easy to fall off under the impact of a water gun.

[0023] The SiO2 content is controlled at 30-35 parts per million, making up the majority of the coating. SiO2 forms a silicon-oxygen tetrahedral network structure. A suitable amount of SiO2 combines with K and Na ions to form NaSiO and KSiO, promoting film formation and imparting a certain gloss to the coating. However, excessive SiO2 can reduce the viscosity of the molten glass, causing coating loss at high temperatures.

[0024] The mass of Al2O3 is controlled at 4-6 parts. Al2O3 is an intermediate oxide that can combine with both SiO2 and alkaline oxides. During the glaze melting process, Al2O3 often captures free oxygen to form a four-coordinated structure, entering the silicon-oxygen network and strengthening the glass network structure. Due to its high stability and high melting point, Al2O3 can form a stable phase with other oxide components, and this stable phase reduces drastic changes in the melt. Rapid temperature changes during the film formation process can easily generate bubbles, but Al2O3 can promote a more stable temperature rise in the melt, thereby helping to better expel bubbles during firing. This makes the film formation process more stable. Therefore, Al2O3 not only improves the vitrification ability of the coating, but also inhibits bubble formation and promotes stable film formation.

[0025] The Al / Si ratio in the coating is maintained at 1:6 to 8. Within this range, the aluminum oxide hexahedrons combine with silicon oxide tetrahedrons in the coating, reducing the expansion coefficient of the glaze layer and facilitating descaling. Excessive silicon oxide reacts with iron oxide to form ferric silicate and ferrous silicate compounds, which are difficult to remove under the impact of a water gun. Therefore, the amount of SiO2 needs to be controlled. An appropriate amount of SiO2 is conducive to film formation. However, excessive Al will cause the melting point of the coating material to rise, increasing the film-forming temperature of the coating, making it impossible to complete curing at low temperatures, thereby affecting the film-forming effect and anti-decarburization effect of the coating.

[0026] ZrO2, which has an extremely low coefficient of linear expansion, is present in 5-7 parts by weight of ZrO2's monoclinic phase. MgO provided by 0.5-1 parts by weight of talc and CaO provided by 1-2 parts by weight of gypsum powder are introduced through doping to form a solid solution of zirconium oxide, or microcrystalline zirconium silicate. This allows the ZrO2 to remain relatively stable after transitioning from a monoclinic to a tetragonal phase at 1170°C. Due to the phase transition between 1100°C and 1200°C, the volume of zirconium oxide expands, and its low coefficient of thermal expansion creates a gap between it and the steel substrate, allowing the coating to cool and self-scale off, achieving the purpose of descaling.

[0027] The mass of Cr2O3 is controlled to be 1 to 4 parts. The Cr element has a strong affinity for metals and can form chemical bonds or ionic bonds with the metal surface, which helps to improve the adhesion between the film layer and the substrate, ensures that the film and the metal matrix have a certain bonding strength, provides density of the film layer, reduces porosity and microcracks, prevents external media (such as water, oxygen, etc.) from penetrating into the coating, and further improves the performance of the film.

[0028] The mass of B2O3 is controlled to be 5 to 9 parts. B2O3 has the characteristic of forming a glassy structure at high temperature. Compared with other oxides, the boron-oxygen bond in the B2O3 molecule is relatively weak, making the molecular structure more flexible and able to form an amorphous structure with a low melting point, which makes its melting point relatively low. At the same time, it reduces the original tight lattice structure by coordinating with the metal ions in other oxides. After mixing with other high-melting-point oxides (such as SiO2, Al2O3, etc.), it can destroy the crystal structure of these oxides at a certain temperature, thereby lowering the melting point of the entire mixture. This allows the material to transition more easily from a solid state to a molten state at high temperatures, ultimately reducing the film-forming temperature and expanding the protection range of the coating.

[0029] The mass of SiC is 5 to 8 parts. SiC is a hard material that can improve the mechanical strength and wear resistance of the coating. In the process of transporting steel into the heating furnace, it can prevent the coating from being damaged due to vibration or other factors. At the same time, the surface reactivity of SiC is low and it is not easy to react directly with oxygen. It can effectively isolate the contact between oxygen and the steel surface, thereby enhancing its anti-decarburization effect. At high temperatures, SiC will undergo the following reactions: SiC+O2=SiO2+C, C+O2=CO2. These two reactions not only consume oxygen to achieve the purpose of anti-oxidation, but also generate SiO2, which promotes the formation of the film. The generated C has two ways of existence, one is to react with oxygen, and the other is to penetrate into the metal surface, which not only achieves the purpose of anti-oxidation, but also achieves the purpose of carbon supplementation.

[0030] Adding sodium silicate / potassium silicate water glass to the solvent allows for rapid crystallization in air, accelerating curing and reducing powdering. The weakly alkaline solvent also maintains coating viscosity, significantly improving spray application performance and shortening film formation time. However, excessive water glass content can introduce excessive potassium / sodium ions, which can cause chemical corrosion on the steel surface and compromise surface quality control.

[0031] Controlling the content of sodium hexadecyl sulfonate in the solvent, this surfactant can remove the surface tension of water and activate the powder particles, thereby eliminating bubbles in the coating, improving the coating quality and shortening the film-forming time.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. The coating has excellent curing properties. After spraying, it forms a glossy coating on the surface of the high-carbon steel billet. The coating is firmly bonded to the surface of the high-carbon steel billet without powder loss or cracking, and has a strong bonding force. At the same time, the curing speed after bonding is excellent, and it can be completed within 3 to 5 minutes to begin protecting the steel billet surface.

[0034] 2. Compared with traditional anti-decarburization coatings, the high-carbon steel anti-decarburization coating of the present invention has a wider range of protection. Specifically, it can provide effective protection effects up to 1300 degrees after glazing at a low temperature of 700 degrees.

[0035] 3. After the high-temperature heat treatment is completed and the steel billet is taken out of the furnace, the bonding force between the coating and the surface of the high-carbon steel billet workpiece is weakened. No high-pressure water gun is required. The descaling rate of more than 95% can still be achieved at a descaling water pressure of 10MPa. Compared with the anti-decarburization products on the market, the descaling effect is obvious and the descaling effect is better.

[0036] 4. The coating has good suspension performance, long storage time, simple process and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Surface images of the high-carbon steel anti-decarburization coating provided in the embodiments of the present application and the MG90T high-carbon steel coating on the market sprayed on 60Si-Cr high-carbon steel before heat treatment;

[0038] Figure 2 Surface images of the high-carbon steel anti-decarburization coating provided in the embodiment of the present application and the MG90T high-carbon steel coating on the market sprayed on 60Si-Cr high-carbon steel after heat treatment and final descaling under 10 MPa water pressure;

[0039] Figure 3 The metallographic cross-sections under optical microscope are respectively the high carbon steel billet workpiece after treatment in Example 1, the high carbon steel without coating after dephosphorization after heat treatment, and the high carbon steel billet workpiece after treatment in Comparative Example 3. DETAILED DESCRIPTION

[0040] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solutions of the present invention, but the present invention is not limited to these embodiments.

[0041] Example 1

[0042] The application of high carbon steel anti-decarburization coating on high carbon steel billet workpiece (60Si-Cr) is as follows:

[0043] S1. Surface pretreatment of high carbon steel billet workpiece.

[0044] Use sandpaper to polish the surface of the high-carbon steel billet to remove the oxide layer on the surface of the high-carbon steel billet. After the surface of the high-carbon steel billet is polished smooth, ultrasonic cleaning is performed on the high-carbon steel. Keep the surface of the high-carbon steel free of oil stains.

[0045] S2. Spray the surface of the high carbon steel billet and allow it to dry naturally.

[0046] After the coating is mixed evenly and made viscous, it is atomized and sprayed onto the surface of the high-carbon steel workpiece using a high-pressure spray gun. The viscosity is controlled between 100 and 150 mPa·s before spraying onto the high-carbon steel surface. After spraying, the high-carbon steel workpiece is allowed to dry at room temperature.

[0047] S3. Complete heat treatment

[0048] Place the sprayed and dried high-carbon steel billet into a heating furnace and slowly heat it to the desired temperature at a rate of 0.15-0.2°C / s. Heat to a holding temperature of 1080°C and hold for 1 hour. Remove the high-carbon steel billet and perform descaling.

[0049] S4. Descaling of high carbon steel billet workpiece

[0050] After the sample is taken out of the heating furnace, the steel billet is subjected to water impact for 3-5 minutes. After the water impact, the coating material is removed by beating. Finally, the high carbon steel billet workpiece is cleaned and dried.

[0051] Among them, the mass percentage of the coating is 30 parts of SiO2, 5 parts of Al2O3, 1 part of talc, 1 part of gypsum powder, 1.5 parts of ZrO2, 2 parts of albite, 3 parts of potassium feldspar, 6 parts of ZnO, 1 part of Cr2O3, 7 parts of SiC, 7 parts of B2O3, 4 parts of graphite, and 35 parts of solvent.

[0052] The film formation is completed in 3 minutes, with good film formation effect and gloss. The glazing temperature is 658 degrees. The descaling effect is excellent under 10MPa water pressure, with a descaling rate of 96% and no decarburization on the surface.

[0053] Example 2

[0054] The coating composition is different from that of Example 1, and the rest is the same as that of Example 1.

[0055] The mass percentage of the coating is 30 parts of SiO2, 5 parts of Al2O3, 0.5 parts of talc, 2 parts of gypsum powder, 1 part of ZrO2, 2 parts of Na feldspar, 3 parts of K feldspar, 7 parts of ZnO, 1 part of Cr2O3, 6.5 parts of SiC, 9 parts of B2O3, 2 parts of graphite, and 35 parts of solvent.

[0056] The film formation is completed in 4 minutes with good film forming effect. The glazing temperature is 665 degrees. The descaling effect is excellent under 8MPa water pressure, the descaling rate is 92%, and there is no obvious decarburization on the surface.

[0057] Example 3

[0058] The coating composition is different from that of Example 1, and the rest is the same as that of Example 1.

[0059] The mass percentage of the coating is 35 parts of SiO2, 5 parts of Al2O3, 1 part of talc, 2 parts of gypsum powder, 3 parts of ZrO2, 1 part of Na feldspar, 1 part of K feldspar, 9 parts of ZnO, 1 part of Cr2O3, 5 parts of SiC, 7 parts of B2O3, 1 part of graphite, and 37 parts of solvent.

[0060] The film formation is completed in 3 minutes with good film forming effect. The glazing temperature is 675 degrees. The descaling effect is excellent under 5MPa water pressure, the descaling rate is 91%, and there is no obvious decarburization on the surface.

[0061] Comparative Example 1

[0062] The coating composition is different from that of Example 1, and the rest is the same as that of Example 1.

[0063] The mass percentage of the coating is 30 parts of SiO2, 8 parts of Al2O3, 1 part of talc, 1 part of gypsum powder, 1.5 parts of ZrO2, 2 parts of albite, 3 parts of potassium feldspar, 2 parts of ZnO, 1 part of Cr2O3, 7 parts of SiC, 7 parts of B2O3, 4 parts of graphite, and 35 parts of solvent.

[0064] Film formation was completed in 8 minutes, with a glazing temperature of 750°C. Under a water pressure of 10 MPa, descaling was moderate, with a descaling rate of 80%, and no noticeable surface decarburization. This was due to the excessively high aluminum oxide content, which significantly increased the glazing temperature and slowed film formation. Furthermore, due to the significant reduction in zinc oxide content, descaling was moderate.

[0065] Comparative Example 2

[0066] The coating composition is different from that of Example 1, and the rest is the same as that of Example 1.

[0067] The mass percentage of the coating is 45 parts of SiO2, 5 parts of Al2O3, 0.5 parts of talc, 2 parts of gypsum powder, 1 part of ZrO2, 2 parts of albite, 3 parts of potassium feldspar, 7 parts of ZnO, 6 parts of Cr2O3, 6.5 parts of SiC, 2 parts of graphite, and 40 parts of solvent.

[0068] Film formation was complete in 10 minutes, with average results. Glazing temperature was 770°C, and descaling was average at 10 MPa water pressure, with a descaling rate of 85%. A fully decarburized layer was present on the surface. This was due to the high silica content and an alumina to silica ratio below 1:8, resulting in average descaling. Furthermore, the coating had low viscosity, which compromised its protective properties. Furthermore, the high chromium oxide content and the absence of boron slowed film formation, all of which affected the descaling performance of the coating.

[0069] Comparative Example 3

[0070] The coating composition is different from that of Example 1, and MG90T coating on the market is used. Other components are the same as those of Example 1.

[0071] Film formation was completed in 10 minutes, with average film formation results. Glazing temperature was 720°C, and descaling was average at 20 MPa water pressure, with a descaling rate of 82%. No noticeable decarburization was observed on the surface. Because the commercially available MG90T coating has an excessively high aluminum oxide to silicon oxide ratio of 1:2, the coating cures at too high a temperature, preventing film formation at room temperature. Furthermore, MG90T coating has a high SiC content and contains no boron, resulting in slow film formation and average descaling results.

[0072] Figure 1 This is a surface image of the high-carbon steel anti-decarburization coating provided in the embodiment of the present application and the MG90T high-carbon steel coating on the market sprayed on 60Si-Cr high-carbon steel before heat treatment; it can be seen from the figure that the film formed by the high-carbon steel anti-decarburization coating provided in the embodiment of the present application has a certain gloss and a fast film-forming rate, while the film formed by the MG90T high-carbon steel coating has no gloss, a relatively slow film-forming rate, and a certain roughness.

[0073] Figure 2 Surface images of the high-carbon steel anti-decarburization coating provided in the embodiment of the present application and other high-carbon steel coatings on the market after spraying on 60Si-Cr high-carbon steel after heat treatment and final descaling under 10 MPa water pressure; it can be seen from the figure that the high-carbon steel anti-decarburization coating provided in the embodiment of the present application basically all falls off under the impact of water flow, and the descaling effect is significant, while the descaling effect of MG90T coating is average under the impact of water flow of the same size.

[0074] Figure 3The metallographic section photos of the high-carbon steel blank workpiece after the treatment of Example 1, the high-carbon steel blank workpiece after the treatment of Comparative Example 3 and the high-carbon steel after the heat treatment without coating are shown in the figure, and the depth of the decarburization layer of each can be seen. The decarburization layer of the high-carbon steel anti-decarburization coating provided by the present application is about 100 um, while the decarburization layer of Comparative Example 3 reaches about 400 um, and the decarburization layer without coating reaches 500 um. It is shown that the high-carbon steel anti-decarburization coating provided by the present application has certain anti-decarburization performance.

[0075] The above is not involved in the prior art.

[0076] Although some specific embodiments of the present application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, not for limiting the scope of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, but will not deviate from the direction of the present application or exceed the scope defined by the appended claims. Those skilled in the art should understand that any modification, equivalent replacement, improvement, etc. made according to the technical essence of the present application to the above embodiments shall be included in the protection scope of the present application.

Claims

1. A high carbon steel anti-decarburization coating, characterized in that: The coating comprises the following raw materials in parts by weight: SiO2 is 30-35 parts, Al2O3 is 4-6 parts, talc is 0.5-1 parts, gypsum powder is 1-2 parts, ZrO2 is 1-5 parts, potassium feldspar powder is 1-3 parts, sodium feldspar powder is 1-3 parts, ZnO is 5-10 parts, Cr2O3 is 1-4 parts, SiC is 5-8 parts, B2O3 is 5-9 parts, graphite is 1-4 parts, and the solvent is 30-40 parts; Among them, the Al / Si ratio is 1:6-8; The solvent is composed of 0.1-0.6% methylcellulose, 5-10% sodium silicate / potassium silicate, 0.3-1% polyethylene glycol, 0.01-0.03% sodium hexadecyl sulfate and the balance water; The application of high carbon steel anti-decarburization coating includes the following steps: S1. A coating is atomized and sprayed on the surface of a high-carbon steel billet workpiece under a high-pressure air pump to form a coating; S2. Place the sprayed and dried high-carbon steel billet into a heating furnace, slowly heat it to a preset temperature, and keep it warm for a period of time; S3. After the heat preservation is completed, the high carbon steel billet workpiece is taken out for descaling; In step S2, the holding temperature is a temperature within the range of 1000-1300°C.

2. The high carbon steel anti-decarburization coating according to claim 1, characterized in that The density of the coating is 2.8×10 3 kg / m 3 ~3.0×10 3 kg / m 3 , and\or, the solid content is 60% to 68%.

3. The high carbon steel anti-decarburization coating according to claim 1, wherein: In step S1, the thickness of the coating is 200um to 500um; or, the amount of the coating is 0.2kg / m 2 ~0.6kg / m 2 .

4. The high carbon steel anti-decarburization coating according to claim 1, wherein: In step S1, the temperature of the surface of the high carbon steel billet workpiece is 10°C to 750°C; or, the temperature of the surface of the high carbon steel billet workpiece is 30°C to 300°C.

5. The high carbon steel anti-decarburization coating according to claim 1, characterized in that: In step S2, in a heating furnace, the temperature is increased at a rate of 0.15-0.2°C / s to the holding temperature and then kept at this temperature for 1 hour.

6. The high carbon steel anti-decarburization coating according to claim 1, characterized in that: In step S3, the specific operation of descaling is: using a high-pressure water gun to impact the steel billet with water for 3-5 minutes, the water pressure is 1-10 MPa, and then beating it to remove the coating material.

7. A method for preparing a high carbon steel anti-decarburization coating according to any one of claims 1 to 6, characterized in that: Mixing the components according to the weight parts to obtain a powder, and stirring the powder and the liquid to form a suspension to obtain the high carbon steel anti-decarburization coating; The preparation process of the liquid is as follows: after heating water, methyl cellulose, sodium silicate / potassium silicate, polyethylene glycol and sodium hexadecyl sulfonate are added in sequence, and stirred until no flocs remain.

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