Precoated sand with sand adhesion prevention characteristic and used for high manganese steel and preparation method and application thereof

Abstract

The invention relates to precoated sand with a sand adhesion prevention characteristic and used for high manganese steel and a preparation method and application thereof. The precoated sand with the sand adhesion prevention characteristic and used for the high manganese steel comprises base aggregate, first reinforcement aggregate, second reinforcement aggregate, binder, a curing agent and lubricant. The base aggregate is silica sand. The first reinforcement aggregate comprises ferroferric oxide or / and chromite sand. The second reinforcement aggregate is magnesia. The precoated sand has good high temperature resistant strength and chilling performance, a sand core does not need to be coated with paint, and in this way, the precoated sand has a sand adhesion prevention function when used for a high manganese steel casting. The casting cast in the sand core prepared by the preparation method does not need polishing after casting, unstable factors in the production process are reduced greatly, the yield of castings is increased greatly, cost of a casting enterprise can be lowered, production efficiency of the casting enterprise can be improved, and the precoated sand can be used in the foundry industry on a large scale.

Description

technical field [0001] The invention relates to the technical field of casting materials, in particular to a coated sand for high manganese steel with anti-sticking sand properties, a preparation method and application thereof. Background technique [0002] Coated sand refers to the molding sand whose surface is covered with a layer of solid resin film before molding and core making. The process is to use materials such as thermoplastic phenolic resin plus latent curing agent (urotropine) and lubricant (calcium stearate) to prepare coated sand through a certain coating process. Since the main component of sand is silica, after the existing coated sand is made into a sand core, the silica on the surface of the coated sand core is likely to react with the manganese oxide and iron oxide in the high manganese steel during the high temperature casting process , to produce manganese silicate and fayalite, so that non-metallic impurities are formed on the contact surface between t...

AI Technical Summary

Problems solved by technology

Since the main component of sand is silica, after the existing coated sand is made into a sand core, the silica on the surface of the coated sand core is likely to react with the manganese oxide and iron oxide in the high manganese steel during the high temperature casting process , to produce manganese silicate and fayalite, so that non-metallic impurities are formed on the contact surface between the sand core and the high manganese steel melt, which reduces the high temperature resistance of the surface of the coated sand core and makes the high manganese steel melt infiltrate Sand core, resulting in sticky sand phenomenon

[0003] Whether it is precision casting or sand casting, the phenomenon of sand sticking is a very common casting defect. Once this problem occurs, it will greatly increase the cost of later machining, and if it is serious, it will form a large number of waste products, causing enterprises to suffer from human and financial resources. Losses in various aspects such as material resources

At present, the only way to solve the problem of sand sticking in the industry is to apply paint to the parts of the sand core that are prone to stick to sand. However, although the method of manual coating can improve the sand sticking situation, it will bring other derivative problems: (1) Manual coating , adding a process, time-consuming and labor-intensive, increasing production costs, and affecting output; (2) The coating needs to be manually stirred and applied, and there are too many unstable factors, such as the thickness of the coating cannot be controlled, and if the coating is too thin, the sand sticking situation cannot be improved; If the coating is too thick, it will easily affect the size of the sand core, making the casting lack of meat, and directly lead to the scrapping of the casting; (3) When using it, there is no special instrument for testing, so it is impossible to determine whether the coating itself can withstand the high temperature of molten steel

However, since high manganese steel contains manganese oxide and iron oxide, it is easy to react with silica on the surface of the sand core made of coated sand to produce manganese silicate (melting point 1280-1360°C) and fayalite (melting point 1000°C). ) and other low-melting-point substances, thereby reducing the high-temperature resistance strength of the surface of the sand core, which can easily cause chemical sticking of sand, which directly affects the surface roughness of the casting

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