High-strength, deformation-resisting and collapsible precoated sand and preparation technology thereof

Abstract

The invention belongs to the field of casting, and particularly relates to high-strength, deformation-resisting and collapsible precoated sand and a preparation technology thereof. The precoated sand and the preparation technology aim to solve the technical problem that a sand core made of precoated sand according to a ratio is low in strength and prone to deformation. The high-strength, deformation-resisting and collapsible precoated sand is composed of crude sand, phenolic resin, curing agents, lubricants and disperser, wherein the crude sand is composed of 20%-30% of nice foundry sand and 70%-80% of quartz sand, the addition quantity of the phenolic resin is 0.9%-1.2% of the mass of the crude sand, the addition quantity of the curing agents is 9%-13% that of the phenolic resin, the addition quantity of the lubricants is 0.1%-0.15% of the mass of the crude sand, and the addition quantity of the disperser is 0.05%-0.4% of the mass of the crude sand. The invention further provides the preparation technology of the precoated sand. The precoated sand has the advantages of high temperature and normal temperature strength, high deformation resistance, good formability, easy collapsibility, good mobility and low gas-forming amount, and completely meets the production technology requirements of an engine with complex structure and high performance.

Description

technical field [0001] The invention belongs to the field of casting, and in particular relates to a high-strength, deformation-resistant, easy-to-collapse coated sand and a preparation process thereof. Background technique [0002] Coated sand, the surface of the sand particles is covered with a layer of solid resin film before molding or core sand. There are two coating processes: cold method and hot method: the cold method dissolves the resin with ethanol, and adds urotropine during the sand mixing process, so that the two are coated on the surface of the sand grains, and the ethanol volatilizes to obtain coated sand; Preheat the sand to a certain temperature, add resin to melt, stir to coat the resin on the surface of the sand, add urotropine aqueous solution and lubricant, cool, crush, and sieve to obtain coated sand. It is mainly used in the production of various complex castings such as automobile cylinder blocks, cylinder heads, intake manifolds, various pipe fittin...

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Problems solved by technology

[0003] With the development of automobile engines in the direction of miniaturization, high performance, and complex structure, the coated sand should have the advantages of high strength, high fluidity, deformation resistance, easy collapse, and small gas generation. However, the existing coated sand It is difficult to meet the above requirements at the same time

For example, the patent of patent publication number CN102921878A discloses a kind of coated sand and its preparation method, and the patent publication number of CN103658506B discloses a kind of easy-filling coated sand and its preparation process. Compared with the manufactured sand core, it is difficult to have the advantages of high strength, good fluidity, easy collapse, low gas generation and high deformation resistance at the same time, and cannot meet the manufacturing needs of sand cores with complex structures and large differences in wall thickness

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