Anti-carburizing coating for casting embedded steel parts

Abstract

The invention relates to the field of anti-carburizing coatings, in particular to an anti-carburizing coating applied to the outer wall of a cooling pipe in a cast embedded steel part before casting construction, and the anti-carburizing coating comprises the following raw materials in parts by weight: 1-5 parts of a reinforcing agent, 5-30 parts of a dispersing agent and 65-94 parts of a binder, the reinforcing agent is aluminum dihydrogen phosphate and sodium hexametaphosphate; the dispersing agent is cellulose, white corundum and aluminum oxide; the binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder; the anti-carburizing coating is an environment-friendly inorganic and organic mixture, has good manufacturability and convenient operability, is non-toxic and non-corrosive to steel parts, is low in cost, has good economic benefits and social benefits, and can realize the localization substitution of imported anti-carburizing coatings.

Description

Technical Field

[0001] The invention relates to a coating or covering material used for pre-embedded steel parts and related components in casting, and in particular to an anti-carburizing coating used on the outer wall of a cooling pipe in the pre-embedded steel parts in casting before casting construction. Background Art

[0002] Carburizing is a kind of metal surface treatment and a common heat treatment process for metal materials. It usually involves heating low-carbon steel in contact with a carbon-containing medium, so that the active carbon atoms produced by the decomposition of the carburizing medium penetrate into the surface of the steel part, and then undergo quenching and low-temperature tempering. It can make the surface of the carburized workpiece obtain a very high hardness, improve its wear resistance, and maintain the original toughness inside. However, carburizing will also make the structure brittle and easily cause fracture. However, in many cases, many steel parts do not need to be carburized, so it is necessary to solve the problem of anti-carburization on the surface of these steel parts. At present, there are several existing anti-carburization treatment methods: electrolytic copper plating method, plugging method, reserved machining allowance method and coating protection method. Electrolytic copper plating method refers to electroplating a layer of copper on the surface of steel parts. The process is relatively complicated, the cost is high, and there is toxicity and environmental pollution during the implementation process; the reserved machining allowance method will lead to material waste and increased machining costs, and this method cannot be used in the anti-carburization treatment of cast embedded steel parts. Summary of the invention

[0003] The purpose of the present invention is to provide a kind of anti-carburization coating which can be sprayed or coated on the surface of the steel parts after the casting embedded steel parts are preheated at 170℃-200℃ for 40 minutes, and the coating is evenly bonded, has a certain bonding strength, is not easy to fall off, has good hardness, corrosion resistance, wear resistance and impermeability after drying at 250℃-280℃ for 40 minutes, does not chemically react in the air during the drying process, does not crack or peel off, does not crack or fall off after complete cooling, and has an ideal anti-carburization effect on the casting embedded steel parts after casting; the present invention belongs to an environmentally friendly inorganic and organic mixture, has good processability and convenient operability, and has good economic and social benefits, and can be widely used in the anti-carburization protection of various casting embedded steel parts.

[0004] In order to achieve the above purpose, the technical solution adopted by the present invention is: an anti-carburizing coating for casting embedded steel parts, the original material is composed of 1-5 parts of reinforcing agent, 5-30 parts of dispersant, and 65-94 parts of binder in weight parts.

[0005] The reinforcing agent is aluminum dihydrogen phosphate and sodium hexametaphosphate, wherein the aluminum dihydrogen phosphate accounts for 20%-60% of the total weight of the reinforcing agent, and the sodium hexametaphosphate accounts for 40%-80% of the total weight of the reinforcing agent.

[0006] The dispersant is cellulose, white corundum and aluminum oxide, wherein cellulose accounts for 1%-10% of the total weight of the dispersant, white corundum accounts for 20%-60% of the total weight of the dispersant, and aluminum oxide accounts for 35%-79% of the total weight of the dispersant.

[0007] The particle sizes of white corundum and alumina are both less than 10 μm; the binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder, wherein the refractory clay accounts for 0.01%-2% of the total weight of the binder, the water glass and phenolic resin account for 2%-20% of the total weight of the binder, and the quartz powder accounts for 79%-96% of the total weight of the binder.

[0008] The method of using this anti-carburizing coating for cast embedded steel parts is: Step 1: Mix the reinforcing agent, dispersant and binder according to the above proportions, add 20-40% of the total weight of the original material into hot water, mix to obtain the anti-carburizing coating for casting embedded steel parts, and put it into a spray pot; Step 2: Clean the surface of the steel parts and perform shot blasting, preheating at 170℃-200℃ for 30-50 minutes; Step 3: Use a spray pot to spray the anti-carburizing coating on the surface of the preheated steel part; the coating layer thickness is 0.3-0.7mm, and the coating surface is uniform without wrinkles or bulges; Step 4: After spraying, let it stand for 15-20 minutes, then dry it at 250℃-400℃ for 30-50 minutes to obtain the cast embedded steel parts.

[0009] In step 2, after the steel part is preheated at 170°C-200°C for 40 minutes, the temperature suddenly changes when the original material contacts the steel part body, making the viscosity stronger, the adhesion better, and not easy to peel off, thereby meeting the technical requirements of anti-carburization.

[0010] Therefore, the selected binder meets the technical requirements of high temperature resistance, stable chemical properties, good bonding performance, and good compatibility with other components of the coating; The present invention innovatively uses organic cellulose. In addition to having good wettability and dispersibility, more importantly, cellulose will pyrolyze to generate a variety of gaseous products and form micropores. Since the particle size of white corundum and alumina is less than 10μm, the particle size reaches the ultrafine powder level. These ultrafine powder particles penetrate into the gaps formed in the cured coating layer after the pyrolysis of cellulose, playing a secondary protective role.

[0011] Among the binder components, water glass is composed of sodium oxide and silicon dioxide in different proportions. It is a viscous liquid as the binder of refractory materials, and its viscosity can be adjusted according to the use requirements. Thermosetting phenolic resin is a commonly used binder in the production process of refractory materials. It is usually a viscous liquid, and the viscosity is adjusted according to different use requirements. The main component of refractory clay is aluminosilicate with a refractory temperature higher than 1580°C. It has plasticity when combined with water and becomes a dense block after drying and calcining. Quartz powder is silicon dioxide with a melting point of 1670°C-1710°C. It plays a bonding and densifying role in anti-carburization coatings.

[0012] To meet the technical requirements that the anti-carburizing coating can be sprayed or coated evenly and well on the surface of steel, and the coating layer has good hardness, corrosion resistance and wear resistance after spraying or coating, and after drying.

[0013] Among the reinforcing agent components, aluminum dihydrogen phosphate has good shock resistance, corrosion resistance and erosion resistance; among the reinforcing agent components, sodium hexametaphosphate, as a commonly used inorganic water reducer in refractory materials, has an auxiliary hardening effect on refractory materials at room temperature. It is characterized by fast hardening speed, high strength, and can also prevent refractory materials from shrinking and cracking; quartz powder and phenolic resin are mixed into a clay state, which can significantly improve the mechanical strength, heat resistance and wear resistance of the material. After spraying and curing, it has the characteristics of low porosity, good impermeability and strong corrosion resistance.

[0014] The beneficial effects of the present invention are: After the steel parts are preheated at 170℃-200℃ for 40 minutes, the coating can be sprayed or coated on the surface of the steel parts evenly and well, and the bonding effect is good and not easy to peel off; after the steel parts sprayed or coated with anti-carburizing coating are dried at 250℃-280℃ for 40 minutes, the anti-carburizing coating layer has good hardness, corrosion resistance and wear resistance, and no chemical reaction occurs in the air during the drying process, and no cracking or peeling occurs; The coating layer has good anti-carburization ability; it has a certain impact resistance and will not crack or peel off due to slight collision; it is harmless and non-corrosive to steel parts and castings as a whole; The invention is an environmentally friendly inorganic and organic mixture with good processability and convenient operability, is non-toxic and non-corrosive to steel parts, has low cost, has good economic and social benefits, and can realize the domestic substitution of imported anti-carburizing coatings. DETAILED DESCRIPTION

[0015] The following examples illustrate the implementation and features of the present invention, but the present invention is not limited to the following embodiments.

[0016] Embodiment 1:

[0017] The invention discloses an anti-carburizing coating for casting embedded steel parts. The raw materials are composed of 1 part of reinforcing agent, 5 parts of dispersing agent and 94 parts of bonding agent in weight parts.

[0018] The reinforcing agents are aluminum dihydrogen phosphate and sodium hexametaphosphate, the aluminum dihydrogen phosphate accounts for 20% of the total weight of the reinforcing agent, and the sodium hexametaphosphate accounts for 80% of the total weight of the reinforcing agent.

[0019] The dispersants are cellulose, white corundum and aluminum oxide, cellulose accounts for 1% of the total weight of the dispersant, white corundum accounts for 20% of the total weight of the dispersant, and aluminum oxide accounts for 79% of the total weight of the dispersant.

[0020] The binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder, the refractory clay accounts for 1% of the total weight of the binder, the water glass and phenolic resin account for 20% of the total weight of the binder, and the quartz powder accounts for 79% of the total weight of the binder; the particle sizes of white corundum and alumina are both less than 10 μm; The method of using this anti-carburizing coating for cast embedded steel parts is: Step 1: Mix the reinforcing agent, dispersant and binder according to the above proportions, add 20% hot water of the total weight of the original material, mix to obtain the anti-carburizing coating for casting embedded steel parts, and put it into a spray pot; Step 2: Clean the surface of the steel parts and perform shot blasting, and preheat at 170°C for 30 minutes; Step 3: Use a spray pot to spray the anti-carburizing coating on the surface of the preheated steel part; the coating layer thickness is 0.3mm, the coating surface is uniform, without wrinkles or bulges; Step 4: After spraying, let it stand for 15 minutes, then dry it at 250°C for 30 minutes to obtain the cast embedded steel parts.

[0021] Embodiment 2:

[0022] The invention discloses an anti-carburizing coating for casting embedded steel parts. The original materials include 5 parts of reinforcing agent, 30 parts of dispersing agent and 65 parts of bonding agent in weight parts.

[0023] The reinforcing agents are aluminum dihydrogen phosphate and sodium hexametaphosphate, wherein the aluminum dihydrogen phosphate accounts for 60% of the total weight of the reinforcing agent and the sodium hexametaphosphate accounts for 40% of the total weight of the reinforcing agent.

[0024] The dispersants are cellulose, white corundum and aluminum oxide, cellulose accounts for 10% of the total weight of the dispersant, white corundum accounts for 55% of the total weight of the dispersant, and aluminum oxide accounts for 35% of the total weight of the dispersant.

[0025] The binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder, the refractory clay accounts for 2% of the total weight of the binder, the water glass and phenolic resin account for 2% of the total weight of the binder, and the quartz powder accounts for 96% of the total weight of the binder; the particle sizes of white corundum and alumina are both less than 10 μm; The method of using this anti-carburizing coating for cast embedded steel parts is: Step 1: Mix the reinforcing agent, dispersant and binder according to the above proportions, add 30% hot water of the total weight of the original material, mix to obtain the anti-carburizing coating for casting embedded steel parts, and put it into a spray pot; Step 2: Clean the surface of the steel parts and perform shot blasting, and preheat at 185°C for 40 minutes; Step 3: Use a spray pot to spray the anti-carburizing coating on the surface of the preheated steel part; the coating layer thickness is 0.5mm, the coating surface is uniform, and there are no wrinkles or bulges; Step 4: After spraying, let it stand for 18 minutes, then dry it at 350°C for 40 minutes to obtain the cast embedded steel parts.

[0026] Embodiment 3:

[0027] The invention discloses an anti-carburizing coating for casting embedded steel parts. The original materials are composed of 3 parts of reinforcing agent, 7 parts of dispersing agent and 90 parts of bonding agent in weight parts.

[0028] The reinforcing agents are aluminum dihydrogen phosphate and sodium hexametaphosphate, wherein the aluminum dihydrogen phosphate accounts for 30% of the total weight of the reinforcing agent and the sodium hexametaphosphate accounts for 70% of the total weight of the reinforcing agent.

[0029] The dispersant is cellulose, white corundum and aluminum oxide, wherein the cellulose accounts for 10% of the total weight of the dispersant, the white corundum accounts for 50% of the total weight of the dispersant, and the aluminum oxide accounts for 40% of the total weight of the dispersant.

[0030] The binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder, the refractory clay accounts for 1% of the total weight of the binder, the water glass and phenolic resin account for 20% of the total weight of the binder, and the quartz powder accounts for 69% of the total weight of the binder; the particle sizes of white corundum and alumina are both less than 10 μm; The method of using this anti-carburizing coating for cast embedded steel parts is: Step 1: Mix the reinforcing agent, dispersant and binder according to the above proportions, add 40% hot water of the total weight of the original material, mix to obtain the anti-carburizing coating for casting embedded steel parts, and put it into a spray pot; Step 2: Clean the surface of the steel parts and perform shot blasting, and preheat at 200°C for 50 minutes; Step 3: Use a spray pot to spray the anti-carburizing coating on the surface of the preheated steel part; the coating layer thickness is 0.7mm, the coating surface is uniform, and there are no wrinkles or bulges; Step 4: After spraying, let it stand for 20 minutes, then dry it at 400°C for 50 minutes to obtain the cast embedded steel parts.

Claims

1. An anti-carburizing coating for casting embedded steel parts, characterized in that: The raw materials are composed of 1-5 parts of reinforcing agent, 5-30 parts of dispersing agent and 65-94 parts of binder in weight proportions.

2. The anti-carburizing coating for casting embedded steel parts according to claim 1, characterized in that: The reinforcing agent is aluminum dihydrogen phosphate and sodium hexametaphosphate, wherein the aluminum dihydrogen phosphate accounts for 20%-60% of the total weight of the reinforcing agent, and the sodium hexametaphosphate accounts for 40%-80% of the total weight of the reinforcing agent.

3. The anti-carburizing coating for casting embedded steel parts according to claim 1, characterized in that: The dispersant is cellulose, white corundum and aluminum oxide, wherein the cellulose accounts for 1%-10% of the total weight of the dispersant, the white corundum accounts for 20%-60% of the total weight of the dispersant, and the aluminum oxide accounts for 35%-79% of the total weight of the dispersant.

4. The anti-carburizing coating for casting embedded steel parts according to claim 3, characterized in that: The particle size of white corundum and alumina is less than 10μm.

5. The anti-carburizing coating for casting embedded steel parts according to claim 1, characterized in that: The binder is water glass, thermosetting phenolic resin, refractory clay and quartz powder, wherein the refractory clay accounts for 1%-2% of the total weight of the binder, the water glass and phenolic resin account for 2%-20% of the total weight of the binder, and the quartz powder accounts for 79%-96% of the total weight of the binder.

6. The anti-carburizing coating for casting embedded steel parts according to claim 1, characterized in that: The method of using this anti-carburizing coating for cast embedded steel parts is: Step 1: Mix the reinforcing agent, dispersant and binder according to the above proportions, add 20-40% of the total weight of the original material into hot water, mix to obtain the anti-carburizing coating for casting embedded steel parts, and put it into a spray pot; Step 2: Clean the surface of the steel parts and perform shot blasting, preheating at 170℃-200℃ for 30-50 minutes; Step 3: Use a spray pot to spray the anti-carburizing coating on the surface of the preheated steel part; the coating layer thickness is 0.3-0.7mm, and the coating surface is uniform without wrinkles or bulges; Step 4: After spraying, let it stand for 15-20 minutes, then dry it at 250℃-400℃ for 30-50 minutes to obtain the cast embedded steel parts.