Easy-to-demould precoated sand and production process of easy-to-demould precoated sand

Abstract

The invention provides easy-to-demould precoated sand and a production process of the precoated sand, wherein the easy-to-demould precoated sand has the advantages that the qualified rate of sand core products can be ensured, the production efficiency is improved, and the production cost is reduced. The easy-to-demould precoated sand comprises the following ingredients in parts by weight: 100 parts of crude sand, 1 to 3 parts of phenolic resin, 0.1 to 0.5 parts of anti-mucosa liquid, 0.1 to 0.5 parts of flaky graphite powder, 0.47 to 4.0 parts of methenamine solution and 0.08 to 0.25 parts of calcium stearate. The production process of the easy-to-demould precoated sand comprises the following steps that (1) the crude sand is heated to 150 to 160 DEG C and is added into a sand mixing machine; (2) the anti-mucosa liquid is added into the crude sand, the materials are uniformly mixed, then, flaky graphite is added, the materials are uniformly mixed, phenolic resin is continuously added, and the materials are uniformly mixed; and (3) the crude sand is cooled, the methenamine solution is added to be uniformly mixed, the calcium stearate is continuously added and is uniformly mixed, finally, the cooling sand discharging is carried out, and the easy-to-demould precoated sand is prepared. The easy-to-demould precoated sand and the preparation method can be applied to the field of casting precoated sand core manufacture.

Description

technical field [0001] The invention relates to an easy-release coated sand and a production process of the easy-release coated sand. Background technique [0002] Coated sand refers to the molding sand or core sand that is covered with a layer of solid resin film and hexamethylenetetramine on the surface of the sand before molding. 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, 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. Coated sand is used for molding cores of steel castings, iron castings, and non-ferrous metal castings. [0003] Castings made of coated sand have the advantages of high dimensi...

AI Technical Summary

Problems solved by technology

However, when the complex sand core is demolded, the contact area between the sand core and the mold is large, or the mold design is defective, the frictional resistance between the mold and the sand core is relatively large, and it is easy to break the relatively small cross-section of the sand core, resulting in Scrap, reduce production efficiency, increase production cost

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