Water-based coating for cast steel and method for preparing the same

Abstract

The application relates to the technical field of foundry coating, and discloses a water-based coating for cast steel and a preparation method thereof. The raw materials of the water-based coating for cast steel include the following components in parts by weight: refractory aggregate 100 parts, binder 2-6 parts, suspending agent 0.5-1 part, zirconium oxychloride octahydrate 0.3-0.4 part, sodium dihydrogen phosphate 0.3-0.4 part, defoaming agent 0.1-0.3 part, surfactant 0.2-0.4 part and water 50-55 parts. Through the technical scheme, the problem of poor suspending performance of the water-based coating for cast steel in the related art is solved.

Description

Technical Field

[0001] This application relates to the field of casting coating technology, specifically to a water-based coating for cast steel and its preparation method. Background Technology

[0002] Water-based coatings for cast steel are slurries made by dispersing refractory aggregates, binders, and various additives in water. Applied to the surface of the sand mold cavity, they dry and form a protective coating between the high-temperature molten steel and the sand mold, preventing defects such as sand adhesion and inclusion in the casting, thus resulting in a smooth-surfaced casting. Compared with alcohol-based coatings, water-based coatings have advantages such as lower cost, lower volatile matter content, and higher production safety, making them an important development direction for modern casting.

[0003] Suspension performance is an indicator of the quality of water-based coatings. Good suspension performance ensures that the composition of the water-based coating is uniform during storage and that a stable and continuous coating can be formed during application. However, water-based coatings generally suffer from poor suspension performance. This problem arises because the density of refractory aggregates is greater than that of water, and refractory aggregates tend to settle in coatings.

[0004] Currently, the industry mainly relies on suspending agents, such as attapulgite or carboxymethyl cellulose, to form a three-dimensional mesh structure to suppress the settling of refractory aggregates. However, the existing suspending agent mesh structure cannot stably support refractory aggregates after long-term standing, causing water-based coatings to easily form sediments that are difficult to re-stir, thus failing to adequately guarantee the suspension performance of the coatings. Summary of the Invention

[0005] This application proposes a water-based coating for cast steel and a method for preparing the same, in order to solve or alleviate at least one of the aforementioned problems.

[0006] The technical solution of this application is as follows:

[0007] This application proposes a water-based coating for cast steel, the raw materials of which include the following components in parts by weight: 100 parts of refractory aggregate, 2-6 parts of binder, 0.5-1 parts of suspending agent, 0.3-0.4 parts of zirconium oxychloride octahydrate, 0.3-0.4 parts of sodium dihydrogen phosphate, 0.1-0.3 parts of defoamer, 0.2-0.4 parts of surfactant, and 50-55 parts of water.

[0008] As a further technical solution, the refractory aggregate includes zircon powder and corundum powder in a mass ratio of 1 to 3:1.

[0009] As a further technical solution, the zircon powder is graded zircon powder, which is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 4wt%~6wt%, 15μm≤zircon powder<20μm 28wt%~32wt%, 20μm≤zircon powder<35μm 4wt%~6wt%, 35μm≤zircon powder<45μm 48wt%~52wt%, and 45μm≤zircon powder<50μm balance.

[0010] As a further technical solution, the corundum powder is graded corundum powder, which is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 6wt%~10wt%, 15μm≤corundum powder<20μm 10wt%~15wt%, 20μm≤corundum powder<35μm 45wt%~50wt%, 35μm≤corundum powder<45μm 18wt%~20wt%, and 45μm≤corundum powder<50μm balance.

[0011] As a further technical solution, the binder includes one or more of bentonite, water glass, acrylic latex, and phenolic resin.

[0012] As a further technical solution, the suspending agent includes one or more of attapulgite, carboxymethyl cellulose, and sepiolite powder.

[0013] As a further technical solution, the defoamer includes silicone defoamers and / or polyether defoamers.

[0014] As a further technical solution, the surfactant includes one or more of anionic surfactants, nonionic surfactants, and amphoteric surfactants.

[0015] This application also proposes a method for preparing a water-based coating for cast steel, comprising the following steps:

[0016] S1. Prepare zirconium oxychloride solution and sodium dihydrogen phosphate solution separately. Add the sodium dihydrogen phosphate solution to the zirconium oxychloride solution, mix, adjust the pH value to 5-6, age, and obtain zirconium phosphate gel.

[0017] S2. Add refractory aggregate to the zirconium phosphate gel, mix, then add the remaining components, mix, degas, and obtain the water-based coating.

[0018] As a further technical solution, in step S1, the aging temperature is 40~45℃ and the time is 10~12h.

[0019] The beneficial effects of this application are:

[0020] Unlike existing technologies that rely solely on attapulgite or carboxymethyl cellulose to form a suspended mesh structure to suppress refractory aggregate settling, this application introduces zirconium oxychloride octahydrate and sodium dihydrogen phosphate into the water-based coating component. The resulting zirconium phosphate gel enhances the suspended mesh structure and improves the suspension performance of the water-based coating. Specifically:

[0021] (1) The zirconium phosphate gel formed by zirconium oxychloride octahydrate and sodium dihydrogen phosphate can fill the spaces between refractory aggregates to form a dense grid, which will have a steric hindrance effect on the refractory aggregates and increase the resistance to the sinking of the refractory aggregates, thereby effectively inhibiting the sinking tendency of the refractory aggregates.

[0022] (2) The zirconium phosphate gel formed by zirconium oxychloride octahydrate and sodium dihydrogen phosphate can be used as a reinforcing phase to fill around the suspended grid structure formed by the suspending agent, thereby strengthening the suspended grid structure and making the suspended grid structure more effective in resisting the settling of refractory aggregates. Detailed Implementation

[0023] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0024] It should be understood that, unless the context clearly indicates otherwise, the terms “comprising,” “including,” or “having” as used herein refer to the presence of an element, but do not exclude the presence or addition of one or more other elements. Furthermore, as used herein, “comprising” and / or “including” indicate the presence of shapes, numbers, steps, operations, members, elements, and / or combinations thereof, and do not exclude the presence or addition of one or more other shapes, numbers, operations, elements, and / or combinations thereof.

[0025] In this application, the numerical range indicated by "~" refers to the range of values ​​specified as the lower and upper limits, respectively, before or after the term. When multiple values ​​for the upper or lower limit of any numerical range are mentioned, the range disclosed herein can be understood as a range with any one of the mentioned upper limits as its upper limit and any one of the mentioned lower limits as its lower limit.

[0026] Abrasion resistance is another indicator of the quality of water-based coatings. During the handling and assembly of the coated mold, the coating surface will inevitably rub against the tooling and mold. If the abrasion resistance is insufficient, the coating is easily scratched or even partially peels off, compromising its integrity. These worn areas become weak points when pouring high-temperature molten steel, failing to effectively prevent molten metal penetration and leading to defects such as mechanical sand adhesion and scaling on the casting surface, affecting the dimensional accuracy and surface quality of the casting. Therefore, it is necessary to further improve the abrasion resistance of water-based coatings.

[0027] The following will describe in detail an embodiment of a water-based coating for cast steel and its preparation method.

[0028] According to one aspect of this application, a water-based coating for cast steel is provided, the raw materials comprising the following components in parts by weight: 100 parts refractory aggregate, 2-6 parts binder, 0.5-1 part suspending agent, 0.3-0.4 parts zirconium oxychloride octahydrate, 0.3-0.4 parts sodium dihydrogen phosphate, 0.1-0.3 parts defoamer, 0.2-0.4 parts surfactant, and 50-55 parts water.

[0029] This application achieves a suspension rate of 99% after 6 hours and over 95% after 24 hours through the interaction of its components, meeting the suspension standard in JB / T 9226-2008 "Coatings for Sand Casting". Specifically:

[0030] Refractory aggregates, as a basic component of water-based coatings, ensure that the coating formed by the water-based coating maintains its structural integrity in high-temperature environments. This prevents direct contact between molten steel and the mold, avoids mold corrosion, and guarantees the dimensional accuracy and surface quality of the castings. Refractory aggregates can be zircon powder, corundum powder, magnesia powder, bauxite, etc. For example, for cast steel parts requiring high resistance to alkaline slag corrosion, magnesia powder can be selected as the refractory aggregate to prevent corrosion by alkaline substances.

[0031] Binders enable the components of water-based coatings to bond together and adhere the coatings to the mold surface. Binders can be inorganic, such as bentonite or water glass; or organic, such as acrylic latex or phenolic resin.

[0032] Suspension agents can increase the viscosity of water-based coating systems and form a three-dimensional suspended network structure within the coating, hindering the gravity settling of refractory aggregates and improving the suspension performance of the water-based coating. Suspension agents can be inorganic, such as attapulgite and sepiolite powder; or organic, such as carboxymethyl cellulose, xanthan gum, and sodium polyacrylate.

[0033] Zirconium oxychloride octahydrate and sodium dihydrogen phosphate can form zirconium phosphate gel. This gel can both fill the steric hindrance between aggregates and act as a reinforcing phase to strengthen the suspended network structure, increasing the settling resistance of refractory aggregates and improving the suspension performance of water-based coatings. Furthermore, this application uses the method of forming zirconium phosphate gel instead of directly adding zirconium phosphate powder, which avoids the powder particles, lacking a continuous structure, from weakening the suspension capacity of the water-based coating.

[0034] Defoamers eliminate air bubbles generated during the preparation process, such as those produced by stirring and pumping, preventing these bubbles from forming pores in the coating and affecting the surface quality of the casting. Defoamers can be silicone-based or polyether-based.

[0035] Surfactants can reduce the surface tension of water-based coatings, improve their wettability on the mold surface, and enable the coating to be evenly applied to the mold, thereby improving the quality of the casting. Surfactants can be anionic, such as sodium dodecylbenzene sulfonate and sodium dodecyl sulfate; nonionic, such as fatty alcohol polyoxyethylene ether and alkylphenol polyoxyethylene ether; or amphoteric, such as dodecyl dimethyl betaine and cocamidopropyl betaine.

[0036] In one embodiment of this application, the refractory aggregate includes zircon powder and corundum powder in a mass ratio of 1 to 3:1, such as 1:1, 2:1, 3:1, etc., but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] This application considers both aggregate performance and cost, combining thermally stable zircon powder with low-cost corundum powder. This approach satisfies the performance requirements of water-based coatings in the casting process while effectively reducing production costs. When the mass ratio of zircon powder to corundum powder is 1~3:1, it avoids excessive zircon powder leading to high costs for water-based coatings and excessive thermal expansion differences between the coating and the mold, which could cause coating cracking. Conversely, it avoids insufficient zircon powder, which would result in ineffective thermal shock resistance to molten steel, causing the coating to lose its protective function and leading to defects such as sand adhesion and inclusions in the casting.

[0038] In one embodiment of this application, the zircon powder is graded zircon powder, which is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 4wt%~6wt%, 15μm≤zircon powder<20μm 28wt%~32wt%, 20μm≤zircon powder<35μm 4wt%~6wt%, 35μm≤zircon powder<45μm 48wt%~52wt%, and 45μm≤zircon powder<50μm balance.

[0039] The corundum powder is graded corundum powder, which is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 6wt%~10wt%, 15μm≤corundum powder<20μm 10wt%~15wt%, 20μm≤corundum powder<35μm 45wt%~50wt%, 35μm≤corundum powder<45μm 18wt%~20wt%, 45μm≤corundum powder<50μm balance.

[0040] This application improves the wear resistance of water-based coatings by specifically designing the gradation of zircon powder and corundum powder, leveraging the synergistic effect of the two aggregates. Specifically, the zircon powder exhibits a bimodal particle size distribution, with the first peak located in the particle size range of ≥15μm and <20μm, and the second peak located in the particle size range of ≥35μm and <45μm. Zircon powder particles ≥15μm and <20μm effectively fill the pores within the water-based coating, making the coating structure denser; zircon powder particles ≥35μm and <45μm, with their larger particle size, provide good skeletal support for the water-based coating. Conversely, the corundum powder exhibits a unimodal particle size distribution, with the peak located in the particle size range of ≥20μm and <35μm. Corundum powder in this particle size range, with its high hardness, effectively resists wear damage. The gradation design of zircon powder and corundum powder can produce a synergistic effect. On the one hand, zircon powder and corundum powder with different particle size distributions can combine with each other to further achieve complementary spatial filling, promote the formation of a dense microstructure in water-based coatings, and improve wear resistance. On the other hand, unimodal corundum powder can be embedded in the dense skeleton of bimodal zircon powder, preventing the high-hardness corundum powder from peeling off under external force. This can give full play to the wear-resistant properties of corundum powder, thereby further improving the wear resistance of water-based coatings.

[0041] According to another aspect of this application, a method for preparing a water-based coating for cast steel is also provided, comprising the following steps:

[0042] S1. Prepare zirconium oxychloride solution and sodium dihydrogen phosphate solution separately. Add sodium dihydrogen phosphate solution to zirconium oxychloride solution, mix, adjust pH value to 5-6, age to obtain zirconium phosphate gel.

[0043] In this application, the mass ratio of zirconium oxychloride octahydrate to water in preparing the zirconium oxychloride solution is 0.3~0.4:10, and the mass ratio of sodium dihydrogen phosphate to water in preparing the sodium dihydrogen phosphate solution is 0.3~0.4:10. During the process of adding the sodium dihydrogen phosphate solution to the zirconium oxychloride solution, stirring is performed while adding. After the addition is complete, stirring continues for 30~40 minutes. Then, the pH value is adjusted to 5~6 using a pH adjuster. Finally, the solution is aged in a constant temperature water bath at 40~45℃ for 10~12 hours. During aging, the container is tightly sealed to prevent moisture evaporation. The setting of the aging temperature and time ensures the structural integrity of the zirconium phosphate gel, avoiding both rapid dehydration caused by high temperatures and insufficient cross-linking at low temperatures that would result in a loose gel.

[0044] S2. Add refractory aggregate to zirconium phosphate gel, mix, then add the remaining components, mix, degas, and obtain water-based coating.

[0045] In this application, refractory aggregate is added to the prepared zirconium phosphate gel and stirred at 300-350 rpm for 15-20 min. Then, binder, suspending agent, defoamer, surfactant and remaining water are added, and stirred at 400-500 rpm for 5-10 min. After mixing, the material is transferred to a vacuum degasser for degassing. During degassing, the vacuum degree is set to -0.08 to -0.1 MPa and the degassing time is 15-20 min. After degassing, a water-based coating is obtained.

[0046] The following will describe in detail, with reference to examples, a water-based coating for cast steel and its preparation method. The embodiments described below according to this application can be modified in various ways; therefore, the scope of this application should not be construed as limited to the embodiments described in detail below. The embodiments are provided to help those skilled in the art more easily understand this application.

[0047] Example 1

[0048] A water-based coating for cast steel comprises the following components in parts by weight: 50 parts zircon powder, 50 parts corundum powder, 2 parts bentonite, 0.5 parts attapulgite, 0.3 parts zirconium oxychloride octahydrate, 0.3 parts sodium dihydrogen phosphate, 0.1 parts FoamStar ST 2410 polyether defoamer, 0.2 parts sodium dodecylbenzene sulfonate, and 50 parts water;

[0049] The zircon powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an unclassified powder.

[0050] The corundum powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an ungraded powder.

[0051] The particle size of bentonite is 45~75μm;

[0052] The particle size of attapulgite is 45~75μm.

[0053] The preparation method of the above-mentioned water-based coating for cast steel includes the following steps:

[0054] S1. Dissolve zirconium oxychloride octahydrate and sodium dihydrogen phosphate separately in water (the mass ratio of zirconium oxychloride octahydrate to water is 0.3:10, and the mass ratio of sodium dihydrogen phosphate to water is 0.3:10) to obtain zirconium oxychloride solution and sodium dihydrogen phosphate solution. Add sodium dihydrogen phosphate solution to zirconium oxychloride solution while stirring at 500 rpm. After the addition is complete, continue stirring for 30 min. Then adjust the pH value to 5 with 0.1 mol / L sodium hydroxide solution. Finally, age in a constant temperature water bath at 40℃ for 12 h to obtain zirconium phosphate gel.

[0055] S2. Add zircon powder and corundum powder to the prepared zirconium phosphate gel and stir at 300 rpm for 20 min. Then add bentonite, attapulgite, FoamStar ST 2410 polyether defoamer, sodium dodecylbenzene sulfonate and the remaining water. Stir at 400 rpm for 10 min. After mixing, transfer to a vacuum degasser for degassing. During degassing, set the vacuum degree to -0.08 MPa and the degassing time to 20 min. After degassing, the water-based coating is obtained.

[0056] Example 2

[0057] A water-based coating for cast steel comprises the following components in parts by weight: 75 parts zircon powder, 25 parts corundum powder, 6 parts bentonite, 1 part attapulgite, 0.4 parts zirconium oxychloride octahydrate, 0.4 parts sodium dihydrogen phosphate, 0.3 parts FoamStar ST 2410 polyether defoamer, 0.4 parts sodium dodecylbenzene sulfonate, and 55 parts water.

[0058] The zircon powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an unclassified powder.

[0059] The corundum powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an ungraded powder.

[0060] The particle size of bentonite is 45~75μm;

[0061] The particle size of attapulgite is 45~75μm.

[0062] The preparation method of the above-mentioned water-based coating for cast steel includes the following steps:

[0063] S1. Dissolve zirconium oxychloride octahydrate and sodium dihydrogen phosphate separately in water (the mass ratio of zirconium oxychloride octahydrate to water is 0.4:10, and the mass ratio of sodium dihydrogen phosphate to water is 0.4:10) to obtain zirconium oxychloride solution and sodium dihydrogen phosphate solution. Add the sodium dihydrogen phosphate solution to the zirconium oxychloride solution while stirring at 450 rpm. After the addition is complete, continue stirring for 40 min. Then adjust the pH value to 6 with 0.1 mol / L sodium hydroxide solution. Finally, age in a constant temperature water bath at 45℃ for 10 h to obtain zirconium phosphate gel.

[0064] S2. Add zircon powder and corundum powder to the prepared zirconium phosphate gel and stir at 350 rpm for 15 min. Then add bentonite, attapulgite, FoamStar ST 2410 polyether defoamer, sodium dodecylbenzene sulfonate and the remaining water. Stir at 500 rpm for 5 min. After mixing, transfer to a vacuum degasser for degassing. During degassing, set the vacuum degree to -0.1 MPa and the degassing time to 15 min. After degassing, the water-based coating is obtained.

[0065] Example 3

[0066] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the zircon powder is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 4wt%, 15μm≤zircon powder<20μm 28wt%, 20μm≤zircon powder<35μm 4wt%, 35μm≤zircon powder<45μm 48wt%, and 45μm≤zircon powder<50μm balance.

[0067] Example 4

[0068] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the corundum powder is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 6wt%, 15μm≤corundum powder<20μm 10wt%, 20μm≤corundum powder<35μm 45wt%, 35μm≤corundum powder<45μm 18wt%, and 45μm≤corundum powder<50μm balance.

[0069] Example 5

[0070] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the zircon powder is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 6wt%, 15μm≤zircon powder<20μm 10wt%, 20μm≤zircon powder<35μm 45wt%, 35μm≤zircon powder<45μm 18wt%, 45μm≤zircon powder<50μm balance;

[0071] The corundum powder is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 4wt%, 15μm≤corundum powder<20μm 28wt%, 20μm≤corundum powder<35μm 4wt%, 35μm≤corundum powder<45μm 48wt%, and 45μm≤corundum powder<50μm balance.

[0072] Example 6

[0073] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the zircon powder is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 4wt%, 15μm≤zircon powder<20μm 28wt%, 20μm≤zircon powder<35μm 4wt%, 35μm≤zircon powder<45μm 48wt%, and 45μm≤zircon powder<50μm balance.

[0074] The corundum powder is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 6wt%, 15μm≤corundum powder<20μm 10wt%, 20μm≤corundum powder<35μm 45wt%, 35μm≤corundum powder<45μm 18wt%, 45μm≤corundum powder<50μm balance.

[0075] Example 7

[0076] The only difference between this embodiment and Embodiment 2 is that, in this embodiment, the zircon powder is composed of zircon powder with the following particle sizes: 10μm≤zircon powder<15μm 6wt%, 15μm≤zircon powder<20μm 32wt%, 20μm≤zircon powder<35μm 6wt%, 35μm≤zircon powder<45μm 52wt%, 45μm≤zircon powder<50μm balance;

[0077] The corundum powder is composed of corundum powder with the following particle sizes: 10μm≤corundum powder<15μm 10wt%, 15μm≤corundum powder<20μm 15wt%, 20μm≤corundum powder<35μm 50wt%, 35μm≤corundum powder<45μm 20wt%, 45μm≤corundum powder<50μm balance.

[0078] Comparative Example 1

[0079] A water-based coating for cast steel, the raw materials of which include the following components in parts by weight: 50 parts zircon powder, 50 parts corundum powder, 2 parts bentonite, 0.5 parts attapulgite, 0.1 parts FoamStar ST 2410 polyether defoamer, 0.2 parts sodium dodecylbenzene sulfonate, and 50 parts water.

[0080] The zircon powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an unclassified powder.

[0081] The corundum powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an ungraded powder.

[0082] The particle size of bentonite is 45~75μm;

[0083] The particle size of attapulgite is 45~75μm.

[0084] The above-mentioned method for preparing water-based coatings for cast steel includes the following steps: adding each component, stirring at 400 rpm for 10 min, after mixing, transferring to a vacuum degassing machine for degassing treatment, during degassing treatment, setting the vacuum degree to -0.08 MPa, the degassing time to 20 min, and after degassing, obtaining the water-based coating.

[0085] Comparative Example 2

[0086] A water-based coating for cast steel, the raw materials of which include the following components in parts by weight: 50 parts zircon powder, 50 parts corundum powder, 2 parts bentonite, 0.5 parts attapulgite, 0.5 parts zirconium phosphate, 0.1 parts FoamStar ST 2410 polyether defoamer, 0.2 parts sodium dodecylbenzene sulfonate, and 50 parts water.

[0087] The zircon powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an unclassified powder.

[0088] The corundum powder has a D50 particle size of 35μm, a D10 particle size of 10μm, and a D90 particle size of 75μm; it is an ungraded powder.

[0089] The particle size of bentonite is 45~75μm;

[0090] The particle size of attapulgite is 45~75μm.

[0091] The above-mentioned method for preparing water-based coatings for cast steel includes the following steps: adding each component, stirring at 400 rpm for 10 min, after mixing, transferring to a vacuum degassing machine for degassing treatment, during degassing treatment, setting the vacuum degree to -0.08 MPa, the degassing time to 20 min, and after degassing, obtaining the water-based coating.

[0092] Experiment Example 1: Suspension Performance Test

[0093] The suspension rates of the water-based coatings prepared in Examples 1-2 and Comparative Examples 1-2 were tested according to JB / T 9226-2008 "Coatings for Sand Casting" after 6 hours and 24 hours of standing. The test results are shown in Table 1 below.

[0094] Table 1 Suspension performance test results

[0095]

[0096] The comparison between Examples 1-2 and Comparative Examples 1-2 shows that by introducing zirconium oxychloride octahydrate and sodium dihydrogen phosphate to form zirconium phosphate gel in the water-based coating components, this application can enhance the suspended mesh structure and improve the suspension performance of the water-based coating, so that the suspension rate of the water-based coating reaches 99% after 6 hours of standing and more than 95% after 24 hours of standing.

[0097] Experimental Example 2: Coating Abrasion Resistance Test

[0098] The wear resistance of the water-based coatings prepared in Examples 2 to 7 were tested in accordance with JB / T 9226-2008 "Coatings for Sand Casting". The test results are shown in Table 2 below.

[0099] Table 2 Abrasion resistance test results

[0100]

[0101] The comparison between Examples 6-7 and Examples 2-5 shows that, through the synergistic effect between bimodal zircon powder and unimodal corundum powder, this application can further achieve complementary spatial filling, promote the formation of a dense microstructure in water-based coatings, and improve wear resistance. It can also fully utilize the wear-resistant properties of corundum powder to further improve the wear resistance of water-based coatings.

[0102] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A water-based paint for cast steel, characterized by, The raw materials include the following components by weight: 100 parts of refractory aggregate, 2-6 parts of binder, 0.5-1 part of suspending agent, 0.3-0.4 part of zirconium oxychloride octahydrate, 0.3-0.4 part of sodium dihydrogen phosphate, 0.1-0.3 part of defoaming agent, 0.2-0.4 part of surfactant, and 50-55 parts of water; The refractory aggregate includes zirconium powder and corundum powder in a mass ratio of 1-3:1; The zirconium powder is graded zirconium powder, which is composed of zirconium powder with the following particle sizes: 10 μm≤zirconium powder<15 μm 4wt%-6wt%, 15 μm≤zirconium powder<20 μm 28wt%-32wt%, 20 μm≤zirconium powder<35 μm 4wt%-6wt%, 35 μm≤zirconium powder<45 μm 48wt%-52wt%, and 45 μm≤zirconium powder<50 μm the balance; The corundum powder is graded corundum powder, which is composed of corundum powder with the following particle sizes: 10 μm≤corundum powder<15 μm 6wt%-10wt%, 15 μm≤corundum powder<20 μm 10wt%-15wt%, 20 μm≤corundum powder<35 μm 45wt%-50wt%, 35 μm≤corundum powder<45 μm 18wt%-20wt%, and 45 μm≤corundum powder<50 μm the balance.

2. The water-based paint for cast steel according to claim 1, characterized by The binder includes one or more of bentonite, water glass, acrylic latex, and phenolic resin.

3. The water-based paint for steel casting according to claim 1, characterized by The suspending agent includes one or more of attapulgite, carboxymethyl cellulose, and sepiolite powder.

4. The water-based paint for steel casting according to claim 1, characterized by The defoaming agent includes silicone defoaming agent and / or polyether defoaming agent.

5. The water-based paint for steel casting according to claim 1, characterized by The surfactant includes one or more of anionic surfactant, nonionic surfactant, and amphoteric surfactant.

6. A method for preparing a water-based paint for cast steel, for preparing the water-based paint according to claim 1, characterized by, The method includes the following steps: S1, respectively prepare a zirconium oxychloride solution and a sodium dihydrogen phosphate solution, add the sodium dihydrogen phosphate solution to the zirconium oxychloride solution, mix, adjust the pH value to 5-6, age, obtain a zirconium phosphate gel, and the aging temperature is 40-45°C and the aging time is 10-12h; S2, add the refractory aggregate to the zirconium phosphate gel, mix, add the remaining components, mix, and degas to obtain the water-based coating.

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