Enamel enamel and enamel for thick hot-rolled steel plates and method for producing the same

Abstract

The present application provides a kind of enamel enamel for thick hot-rolled steel plate and enamel and its preparation method.The chemical composition of the enamel enamel includes: SiO2 55%~58%, Al2O3 2.4%~3%, B2O3 11%~13%, CaO 1.5%~2.5%, SrO 0.5%~1.7%, CoO 1%~2%, NiO 0.5%~1%, Na2O 16%~19%, Li2O 1%~2%, K2O 1%~2% by weight content.The enamel enamel for thick hot-rolled steel plate provided by the present application can prepare 550MPa grade super-thick specification hot-rolled steel plate double-sided composite coating enamel with excellent performance, the coating has strong bonding force with steel plate, the adhesion strength is filamentous, resistant to citric acid A+ or above, the yield strength of enamel steel plate after enamel burning reaches 400~460MPa, and has very good anti-scaling performance.

Description

Technical Field

[0001] This invention relates to the field of enamel technology, and more particularly to an enamel glaze and enamel for thick hot-rolled steel plates, and a method for preparing the same. Background Technology

[0002] As the volume of enameled assembled tanks increases, the pressure they withstand also increases. Because the water pressure on the lower layer of the tank is greater than that on the upper layer, the strength of ordinary steel plates is no longer sufficient to meet the safety requirements after installation. The lower layer of the tank generally uses thicker steel plates, while the upper layer uses thinner steel plates. The yield strength of the lower layer of the enameled steel plates must meet the requirement of 400–460 MPa.

[0003] Using 550MPa grade thick steel plates can bring higher strength, but the defects after enamel firing increase, such as more bubbles and scorching. In order to fire the thick steel plates thoroughly and evenly, the firing time is longer than that of thin steel plates. As a result, the controllability of enamel color difference, firing time and scorching caused by the thickness of the enamel layer becomes increasingly worse.

[0004] The above are the shortcomings of existing technologies. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides an enamel glaze for thick hot-rolled steel plates, an enamel coating, and a method for preparing the same. The enamel glaze provided by this invention can effectively prepare double-sided enamel coatings for ultra-thick hot-rolled steel plates with a strength of 550 MPa. The prepared enamel coating exhibits strong adhesion to the steel plate, with a fibrous adhesion strength, and resistance to citric acid A+ or higher. The yield strength of the enamel-coated steel plate after firing reaches 400–460 MPa. It also possesses excellent anti-scaling properties and superior wear resistance, among other comprehensive properties.

[0006] In a first aspect, the present invention provides an enamel glaze for thick hot-rolled steel plates, wherein the chemical composition of the enamel glaze, by weight, comprises: SiO2 55%–58%, Al2O3 2.4%–3%, B2O3 11%–13%, CaO 1.5%–2.5%, SrO 0.5%–1.7%, CoO 1%–2%, NiO 0.5%–1%, Na2O 16%–19%, Li2O 1%–2%, and K2O 1%–2%.

[0007] Further preferably, the chemical composition of the enamel glaze, by weight, includes: SiO2 57%–58%, Al2O3 2.5%–2.7%, B2O3 12%–13%, CaO 2%–2.4%, SrO 1.2%–1.7%, CoO 1.3%–1.5%, NiO 0.85%–0.9%, Na2O 18%–19%, Li2O 1%–1.5%, and K2O 1.3%–1.5%.

[0008] Preferably, the raw materials for the enamel glaze include one or more of the following: quartz, feldspar, borax, calcium carbonate, strontium carbonate, cobalt oxide, nickel oxide, soda ash, and lithium carbonate.

[0009] In this invention, by using a reasonable ratio of quartz, feldspar, borax, strontium carbonate, lithium carbonate, and nickel oxide to control the content of specific chemical components in enamel glaze, the scaling and pinholes can be controlled better than expected.

[0010] Preferably, the raw materials used in the above-mentioned chemical composition of the enamel glaze are: SiO2 made of quartz and feldspar; Al2O3 made of feldspar; B2O3 made of borax; CaO made of calcium carbonate; SrO made of strontium carbonate; CoO made of cobalt oxide; NiO made of nickel oxide; Na2O made of borax and soda ash; and Li2O made of lithium carbonate. Preferably, the chemical composition of the feldspar contains 65%–75% SiO2, 12%–18% Al2O3, 2%–5% Na2O, and 5%–10% K2O. More preferably, the raw materials, by weight, include: 36–38 parts quartz, 12–16 parts feldspar, 21–23 parts borax, 2.3–3.5 parts calcium carbonate, 1–2 parts strontium carbonate, 1.5–1.7 parts cobalt oxide, 1–2 parts nickel oxide, 17–18 parts soda ash, and 2–3 parts lithium carbonate.

[0011] In the chemical composition of the enamel glaze of this invention, SiO2 is the main structural component forming the glaze and providing acid resistance. The SiO2 content is controlled at 55%–58% to suit the enamel firing temperature. Al2O3 in this glaze formulation mainly forms a stable glaze structure, maintaining a certain viscosity of the enamel layer at the set firing temperature to prevent scaling and bubble expansion. High Al2O3 content results in high viscosity and a tendency for scaling, while low Al2O3 content leads to low viscosity and bubble formation. Therefore, the Al2O3 content is controlled at 2.4%–3%. B2O3 in this glaze formulation mainly forms the main structure of the glaze and acts as a flux, improving the elasticity of the enamel layer and preventing cracking during bending. Excessive B2O3 content is detrimental to chemical stability. It also facilitates the bonding between the steel plate and the glaze layer during firing. Therefore, the B2O3 content is controlled at 11%–13%. CaO in this glaze formulation acts as a glassy auxiliary flux, adjusting the firing range of the enamel. In this porcelain enamel formulation system, SrO acts as a vitreous auxiliary agent. In this invention, SrO and Li2O assist in preventing enamel cracking and controlling pinholes. CoO in this porcelain enamel formulation system acts as an enamel adhesive; insufficient dosage will result in insufficient color saturation of the adhesive, causing color differences. NiO in this porcelain enamel formulation system acts as an enamel adhesive and also prevents enamel cracking. Na2O in this porcelain enamel formulation system acts as an enamel fluxing agent and also increases the coefficient of thermal expansion of the enamel, matching the coefficient of thermal expansion of the steel plate. Li2O in this porcelain enamel formulation system acts as an enamel fluxing agent, replacing part of the Na2O, increasing the chemical stability of the enamel layer and assisting in preventing enamel cracking. K2O in this porcelain enamel formulation system acts as an enamel fluxing agent, replacing part of the Na2O, improving the gloss and smoothness of the enamel surface. The calcined quartz and nickel oxide in the grinding raw materials of the enamel coating slurry of this invention help prevent enamel cracking. The calcined quartz in the grinding raw materials of the enamel coating slurry of this invention is beneficial to improving the wear resistance and acid resistance of the enamel surface. The synergistic formulation system of the above-mentioned chemical components at specific dosages significantly improves the overall performance of the enamel-lined steel sheet after firing.

[0012] Secondly, the method for preparing enamel glaze for thick hot-rolled steel plates provided by the present invention includes:

[0013] 1) The raw materials of the enamel glaze are mixed to obtain a mixture;

[0014] 2) Melt the mixture from step 1) at high temperature and then cool it with water to obtain enamel glaze.

[0015] Preferably, the high-temperature melting temperature is 1280–1300°C, and the melting time is 35–40 min.

[0016] Thirdly, the enamel for double-sided coating of thick hot-rolled steel plates provided by the present invention comprises the enamel glaze for thick hot-rolled steel plates.

[0017] Preferably, the raw materials include, by weight: 55%–69% of the enamel glaze, 10%–12% of calcined quartz, 3%–5% of clay suspending agent, 0.8%–1.3% of nickel oxide, 0.2%–0.5% of sodium nitrite, 0.2%–0.5% of borax, and 22%–25% of water.

[0018] Further preferably, the raw material composition, by weight, includes: 57%–58% porcelain enamel, 11%–12% calcined quartz, 4%–5% clay suspending agent, 0.8%–1% nickel oxide, 0.2%–0.3% sodium nitrite, 0.2%–0.3% borax, and 23%–25% water; more preferably, the grinding raw material composition of the enamel slurry, by weight percentage, is: 58% porcelain enamel, 11.5% calcined crystalline quartz, 4.4% clay suspending agent, 1.1% nickel oxide, 0.2% sodium nitrite, 0.2% borax, and 24.6% water.

[0019] In this invention, the preferred grinding raw materials, nickel oxide and calcined quartz, are combined to better utilize the acid resistance of calcined quartz. The optimal combination of calcined quartz and nickel oxide gives the enamel better anti-scalding properties. The grinding raw material, calcined quartz, interacts with a specific enamel glaze to further improve the firing range and reduce scorching defects in the enamel, resulting in a smoother enamel surface.

[0020] Preferably, the method for preparing the double-sided enamel coating for thick hot-rolled steel plates includes:

[0021] A) Mix and grind the raw materials according to the proportions, and sieve to obtain glaze slurry;

[0022] B) Spray the glaze obtained in step A) onto both the front and back surfaces of the steel plate and dry it;

[0023] C) The preform obtained by drying in step B) is fired to obtain enamel.

[0024] Preferably, in step A), the glaze slurry is obtained by passing it through an 80-100 mesh sieve; preferably, the sieve residue of the glaze slurry is 5-10 g / 100 mL; and / or, in step B), the drying temperature is 100-150°C; and / or, in step C), the firing temperature is 850-880°C, and the time is 10-30 min. In this invention, to avoid a decrease in yield strength after the steel plate is fired at high temperature, the enamel plate is fired at a temperature of 850-880°C. In this invention, the terms enamel, enamel plate, and enamel steel plate all refer to the enamel used for double-sided coating of the thick hot-rolled steel plate.

[0025] Further preferred, in step B), the thickness of the dried powder layer is 350–600 μm; and / or, in step C), the thickness of the enamel surface after firing is 250–480 μm.

[0026] In this invention, by controlling the firing temperature and the fineness of the glaze as the control points of the process, and by using the firing time as an auxiliary factor according to the thickness of the steel plate, a better performance improvement can be achieved under the above-mentioned preferred conditions.

[0027] Fourthly, the present invention provides the application of the enamel glaze for thick hot-rolled steel plates in the preparation of 550MPa grade ultra-thick hot-rolled steel plates with double-sided enamel coating for enamel-coated assembly tanks.

[0028] Preferably, the steel plate has a thickness of 10–14 mm and a yield strength of 460–550 MPa; the enamel has a filamentous adhesion strength and is resistant to citric acid A+; the enamel plate has a yield strength of 400–460 MPa; after standing for 15 days, there are no scale cracks on both sides, the wear resistance reaches Mohs 5, the color difference ΔE is less than 3%, the gloss is greater than 95%, the porcelain surface is soft, and there are no pinholes. The enamel process for 550 MPa-grade thick steel plates provided by this invention is more suitable for manufacturing thick steel plates for the lower layer of larger assembled tanks.

[0029] The enamel enamel for thick hot-rolled steel plates provided by this invention can be well used to prepare double-sided enamel-coated enamel plates for 550MPa grade ultra-thick hot-rolled steel plates used in enamel-coated assembly tanks. After firing, the enamel plate exhibits excellent adhesion, displaying a fibrous appearance. The enamel is resistant to citric acid A. + Grade A, with wear resistance reaching Mohs 5, color difference ΔE less than 3%, gloss greater than 95%, smooth porcelain surface, no pinholes, and good anti-scaling properties for steel plate enamel. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0031] Figure 1 This is a diagram showing the adhesion of enamel provided in Embodiment 1 of the present invention.

[0032] Figure 2 This is a diagram showing the adhesion of enamel provided in Embodiment 2 of the present invention.

[0033] Figure 3 This is a diagram showing the adhesion of enamel provided in Embodiment 3 of the present invention. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0035] Unless otherwise specified, the raw materials used in this invention are all conventionally available products on the market; unless otherwise specified, the methods used in this invention are all conventional methods in the field.

[0036] In this invention, the clay suspending agent used is Suzhou kaolin, and the steel plate used is Shougang SRT550.

[0037] Example 1

[0038] This embodiment provides an enamel glaze for a high-strength steel plate. The raw material composition (the chemical composition of feldspar contains 71.6% SiO2, 15% Al2O3, 2.1% Na2O, and 8% K2O) and the chemical composition by weight percentage are shown in Tables 1 and 2.

[0039] Table 1. Raw material composition of enamel glaze in Examples 1-3 and Comparative Example 1, wt.%

[0040] raw material quartz Feldspar Borax Calcium carbonate Strontium carbonate cobalt oxide Nickel oxide soda ash lithium carbonate Example 1 37 14 22 3 1.5 1.5 1 17 3 Example 2 36 15 21 3.5 2 1.5 1 18 2 Example 3 38 12 23 2.3 1 1.7 1 18 3 Comparative Example 1 37 14 22 3 1.5 1.5 1 17 3

[0041] Table 2. Chemical composition of enamel glaze in Examples 1-3 and Comparative Example 1, wt.%

[0042] chemical composition <![CDATA[SiO2]]> <![CDATA[Al2O3]]> <![CDATA[B2O3]]> CaO SrO CoO NiO <![CDATA[Na2O]]> <![CDATA[Li2O]]> <![CDATA[K2O]]> Example 1 57.70 2.58 12.91 2.06 1.29 1.33 0.88 18.32 1.49 1.38 Example 2 57.29 2.7 12.31 2.4 1.7 1.32 0.88 18.79 1 1.47 Example 3 57.70 2.58 12.91 2.06 1.29 1.33 0.88 18.32 1.49 1.38 Comparative Example 1 56.2 3.15 12.84 2.05 1.29 1.32 0.88 18.9 1.48 1.86

[0043] This embodiment also provides a method for preparing the above-mentioned enamel glaze, which adopts the following steps:

[0044] Step 1: Mix the raw materials according to the above formula, and mix for a certain period of time. Once mixed evenly, set aside.

[0045] Step 2: The raw material mixture is added to the porcelain glaze melting furnace and melted at a temperature of 1300℃ for 38 minutes.

[0046] Step 3: Pour the molten liquid into water to cool;

[0047] Step 4, Enamel Drying: Drain the water and dry the porcelain to obtain enamel.

[0048] This embodiment also provides a method for preparing enamel, using the porcelain glaze prepared in step 4, as follows:

[0049] Step 5, the glaze slurry is prepared by the following steps: by weight fraction, 58% porcelain glaze, 11.5% calcined quartz, 4.4% clay suspending agent, 1.1% nickel oxide, 0.2% sodium nitrite, 0.2% borax, and 24.6% water are ball-milled and mixed, and then passed through an 80-mesh sieve to obtain the glaze slurry;

[0050] Step 6: Sift 5-10 grams of glaze slurry per 100 ml to obtain usable glaze slurry;

[0051] Step 7: Spray the glaze obtained in step 6 onto the front and back surfaces of the steel plate (the steel plate thickness is 11mm and the yield strength is 550MPa), and dry it at a temperature of 100℃ to 150℃ with heated air.

[0052] Step 8: After drying, the powder layer thickness is 350μm to 600μm;

[0053] Step 9: The firing temperature of the enamel plate is 850℃~880℃, and the firing time is 20 minutes.

[0054] Step 10: After firing, the thickness of the porcelain surface is between 250μm and 480μm.

[0055] The enamel produced by the method provided in this embodiment exhibits filamentous adhesion strength, as shown in the figure. Figure 1 The enamel plate provided in this embodiment, after firing, exhibits a fine and uniform bubble structure under a microscope, making it less prone to scaling (too large bubbles will prevent the electric spark from passing through, while the absence or excessively small bubbles will easily cause scaling). The specific parameters and results of the enamel plate obtained by the above method are as follows: the total enamel layer thickness is 250–480 μm; after standing for 15 days, the surface condition of both sides of the enamel-coated steel plate is observed; both sides are free of scaling, the wear resistance reaches Mohs 5, the color difference ΔE is less than 3%, the gloss is greater than 95%, the porcelain surface is smooth, and there are no pinholes, demonstrating excellent anti-scaling properties; the yield strength of the enamel plate obtained after enamel coating is 440 MPa, and the tensile strength is 607 MPa. This meets the usage requirements of enamel-coated assembled tanks.

[0056] Example 2

[0057] This embodiment provides an enamel for a high-strength steel plate. The raw material composition (the chemical composition of feldspar contains 71.6% SiO2, 15% Al2O3, 2.1% Na2O, and 8% K2O) and the chemical composition by weight percentage are shown in Tables 1 and 2.

[0058] This embodiment also provides a method for preparing the above-mentioned enamel, which adopts the following steps:

[0059] Step 1: Mix the raw materials according to the formula, and after mixing for a certain period of time and until evenly mixed, set aside.

[0060] Step 2: The raw material mixture is added to the porcelain glaze melting furnace and melted at a temperature of 1300℃ for 38 minutes.

[0061] Step 3: Pour the molten liquid into water to cool;

[0062] Step 4, Enamel Drying: Drain the water and dry the porcelain to obtain enamel.

[0063] This embodiment also provides a method for preparing enamel, using the porcelain glaze prepared in step 4, as follows:

[0064] Step 5, the glaze slurry is prepared by the following steps: by weight fraction, 58% enamel glaze, 11.5% calcined quartz, 4.4% clay suspending agent, 1.1% nickel oxide, 0.2% sodium nitrite, 0.2% borax, and 24.6% water are ball-milled and mixed, and then passed through an 80-mesh sieve to obtain the glaze slurry;

[0065] Step 6: Sift 5-10 grams of glaze slurry per 100 ml to obtain usable glaze slurry;

[0066] Step 7: Spray the glaze obtained in step 6 onto the front and back surfaces of the steel plate (the steel plate thickness is 13mm and the yield strength is 550MPa), and dry it at a temperature of 100℃ to 150℃ with heated air.

[0067] Step 8: After drying, the powder layer thickness is 350μm to 600μm;

[0068] Step 9: The firing temperature of the enamel plate is 850℃~880℃, and the firing time is 23 minutes.

[0069] Step 10: After firing, the thickness of the porcelain surface is between 250μm and 480μm.

[0070] The enamel produced by the method provided in this embodiment exhibits filamentous adhesion strength, as shown in the figure. Figure 2 It is resistant to citric acid A+. Microscopic observation after enameling of the enamel plate provided in this embodiment shows that the bubble structure is small and uniform, and it is not prone to scaling. The specific parameters and results of the enamel plate prepared by the above method are as follows: the total enamel thickness is 300-350 μm; after standing for 15 days, the surface condition of both sides of the enameled steel plate is observed; there is no scaling on either side, the wear resistance reaches Mohs 5, the color difference ΔE is less than 3%, the gloss is greater than 95%, the porcelain surface is soft, there are no pinholes, and it has good anti-scaling performance; the yield strength of the enamel plate after enameling is 407 MPa, and the tensile strength is 581 MPa. It meets the usage requirements of enameled assembled tanks.

[0071] Example 3

[0072] This embodiment provides an enamel glaze for a high-strength steel plate. The raw material composition (the chemical composition of feldspar includes 71.6% SiO2, 15% Al2O3, 2.1% Na2O, and 8% K2O) and chemical composition by weight percentage are shown in Tables 1 and 2. A 14mm thick steel plate was used for the enamel firing test.

[0073] This embodiment also provides a method for preparing the above-mentioned enamel glaze, which adopts the following steps:

[0074] Step 1: Mix the raw materials according to the formula, and after mixing for a certain period of time and until evenly mixed, set aside.

[0075] Step 2: The raw material mixture is added to the porcelain glaze melting furnace and melted at a temperature of 1300℃ for 38 minutes.

[0076] Step 3: Pour the molten liquid into water to cool;

[0077] Step 4, Enamel Drying: Drain the water and dry the porcelain to obtain enamel.

[0078] This embodiment also provides a method for preparing enamel, using the porcelain glaze prepared in step 4, as follows:

[0079] Step 5, the preparation method of the glaze slurry adopts the following steps: by weight fraction, 58% porcelain glaze, 11.5% calcined quartz, 4.4% clay suspending agent, 1.1% nickel oxide, 0.2% sodium nitrite, 0.2% borax and 24.6% water are ball-milled and mixed, and passed through an 80-mesh sieve to obtain the glaze slurry;

[0080] Step 6: Sift 5-10 grams of glaze slurry per 100 ml to obtain usable glaze slurry;

[0081] Step 7: Spray the glaze obtained in step 6 onto the front and back surfaces of the steel plate (the steel plate thickness is 14mm and the yield strength is 550MPa), and dry it at a temperature of 100℃ to 150℃ with heated air.

[0082] Step 8: After drying, the powder layer thickness is 350μm to 600μm;

[0083] Step 9: The firing temperature of the enamel plate is 850℃~880℃, and the firing time is 24 minutes.

[0084] Step 10: After firing, the thickness of the porcelain surface is between 250μm and 480μm.

[0085] The enamel produced by the method provided in this embodiment exhibits filamentous adhesion strength, as shown in the figure. Figure 3It is resistant to citric acid A+. Microscopic observation after enameling of the enamel plate provided in this embodiment shows that the bubble structure is small and uniform, and it is not prone to scaling. The specific parameters and results of the enamel plate prepared by the above method are as follows: the total enamel thickness is 250-480μm; after standing for 15 days, the surface condition of both sides of the enameled steel plate was observed; there was no scaling on either side, the wear resistance reached Mohs 5, the color difference ΔE was less than 3%, the gloss was greater than 95%, the porcelain surface was soft, without pinholes, and it had good anti-scaling performance; the yield strength of the enamel plate after enameling is 410MPa, and the tensile strength is 571MPa. It meets the usage requirements of enameled assembled tanks.

[0086] Comparative Example 1

[0087] This comparative example provides an enamel coating for a high-strength steel plate, the raw material composition of which (the chemical composition of feldspar contains 64.7% SiO2, 18.4% Al2O3, and 6% Na2O)

[0088] The K2O content is 10.9% and the chemical composition by weight percentage is shown in Tables 1 and 2.

[0089] The method for preparing the enamel provided in this comparative example adopts the following steps:

[0090] Step 1: Mix the raw materials according to the formula, and after mixing for a certain period of time and until evenly mixed, set aside.

[0091] Step 2: The raw material mixture is added to the porcelain glaze melting furnace and melted at a temperature of 1300℃ for 38 minutes.

[0092] Step 3: Pour the molten liquid into water to cool;

[0093] Step 4, Enamel Drying: Drain the water and dry the porcelain to obtain enamel.

[0094] The enamel preparation method provided in this comparative example uses the enamel prepared in step 4, and the method is as follows:

[0095] Step 5, the glaze slurry is prepared by the following steps: by weight fraction, 58% enamel glaze, 11.5% calcined quartz, 4.4% clay suspending agent, 1.1% nickel oxide and 24.6% water are ball-milled and mixed, and then passed through an 80-mesh sieve to obtain the glaze slurry;

[0096] Step 6: Sift 5-10 grams of glaze slurry per 100 ml to obtain usable glaze slurry;

[0097] Step 7: Spray the glaze obtained in step 6 onto the front and back surfaces of the steel plate (the steel plate thickness is 13mm and the yield strength is 550MPa), and dry it at a temperature of 100℃ to 150℃ with heated air.

[0098] Step 8: After drying, the powder layer thickness is 350μm to 600μm;

[0099] Step 9: The firing temperature of the enamel plate is 850℃~880℃, and the firing time is 23 minutes.

[0100] Step 10: After firing, the thickness of the porcelain surface is between 250μm and 480μm.

[0101] The enamel plate prepared in this comparative example has a total enamel layer thickness of 300-350 μm. After standing for 15 days, the surface condition of the steel plate after enamelizing was observed on both sides. One side showed scaling, the enamel surface was smooth, there were no pinholes, and the anti-scaling performance was poor. The yield strength of the enamel plate prepared after enamelizing was 415 MPa and the tensile strength was 580 MPa. The neutralization performance of the enamel plate in this comparative example was worse than that of Examples 1-3.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An enamel for thick hot-rolled steel plates, characterized in that, It includes the following raw materials by weight: 55%~69% enamel glaze, 10%~12% calcined quartz, 3%~5% clay suspending agent, 0.8%~1.3% nickel oxide, 0.2%~0.5% sodium nitrite, 0.2%~0.5% borax, and 22%~25% water; The chemical composition of the enamel glaze, by weight, includes: SiO2 57%~58%, Al2O3 2.5%~2.7%, B2O3 12%~13%, CaO 2%~2.4%, SrO 1.2%~1.7%, CoO 1.3%~1.5%, NiO 0.85%~0.9%, Na2O 18%~19%, Li2O 1%~1.5%, and K2O 1.3%~1.5%. The thick hot-rolled steel plate is a 550MPa grade ultra-thick hot-rolled steel plate with a thickness of 10~14mm.

2. The enamel for thick hot-rolled steel plates according to claim 1, characterized in that, The raw materials for the enamel glaze include quartz, feldspar, borax, calcium carbonate, strontium carbonate, cobalt oxide, nickel oxide, soda ash, and lithium carbonate.

3. The enamel for thick hot-rolled steel plates according to claim 2, characterized in that, The raw materials of the enamel glaze, by weight, include: 36-38 parts quartz, 12-16 parts feldspar, 21-23 parts borax, 2.3-3.5 parts calcium carbonate, 1-2 parts strontium carbonate, 1.5-1.7 parts cobalt oxide, 1-2 parts nickel oxide, 17-18 parts soda ash, and 2-3 parts lithium carbonate.

4. The enamel for thick hot-rolled steel plates according to any one of claims 1-3, characterized in that, The method for preparing the enamel glaze includes: 1) The raw materials of the enamel glaze are mixed to obtain a mixture; 2) Melt the mixture from step 1) at high temperature and then cool it with water to obtain enamel glaze.

5. The enamel for thick hot-rolled steel plates according to claim 4, characterized in that, The high-temperature melting temperature is 1280~1300 ℃; the time is 35~40 min.

6. The method for preparing enamel for thick hot-rolled steel plates according to any one of claims 1-5, characterized in that, Includes the following steps: A) Mix and grind the raw materials according to the proportions, and sieve to obtain glaze slurry; B) Spray the glaze obtained in step A) onto both the front and back surfaces of the steel plate and dry it; C) The preform obtained by drying in step B) is fired to obtain enamel.

7. The method for preparing enamel for thick hot-rolled steel plates according to claim 6, characterized in that, In step A), the glaze slurry is obtained by passing it through an 80-100 mesh sieve; and / or, in step B), the drying temperature is 100-150℃; and / or, in step B), the thickness of the dried powder layer is 350-600μm; and / or, in step C), the thickness of the enamel surface after firing is 250-480μm; and / or, in step C), the firing temperature is 850-880℃ and the firing time is 10-30min.

8. The method for preparing enamel for thick hot-rolled steel plates according to claim 7, characterized in that, In step A), the coarseness of the glaze slurry is 5~10 g / 100 mL.

9. The application of the enamel for thick hot-rolled steel plates according to any one of claims 1-5 or the enamel for thick hot-rolled steel plates prepared by the preparation method of any one of claims 6-8 in the preparation of double-sided enamel-coated 550MPa grade ultra-thick hot-rolled steel plates for enamel-coated assembly tanks.

10. The application according to claim 9, characterized in that, The steel plate has a thickness of 10~14mm and a yield strength of 460~550MPa; the enamel has a filamentous adhesion strength and is resistant to citric acid A+; the enamel plate has a yield strength of 400~460MPa. Double-sided, scaleless burst.

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