High temperature resistance precoated sand

Abstract

The invention discloses high temperature resistance precoated sand, which comprises base sand, a binder, hexamethylenetetramine, a phenol formaldehyde resin, a silane coupling agent and an additive A, wherein the base sand comprises, by weight, 55-60 parts of iron ore sand, 60-70 parts of forsterite sand, and 7-10 parts of diatomite, a particle size of the base sand is 100-150 mesh, 3-5 parts by weight of boric acid, 1-2 parts by weight of water-soluble polymer glue powder, 3-5 parts by weight of starch, 0.5-0.8 part by weight of rosin, 4-5 parts by weight of dextrin and 4-6 parts by weight of water are subjected to a reaction and drying to obtain the binder, 4-6 parts by weight of a straw powder material, 2-4 parts by weight of sepiolite and 5-8 parts by weight of water are subjected to a mixing calcination treatment to obtain the additive A, a particle size of the straw powder material is 0.5-0.8 mm, and the obtained calcined product, 2-4 parts by weight of montmorillonite powder and 3-4 parts by weight of water glass are subjected to mixing granulation. The high temperature resistance precoated sand has the following characteristics that: moisture absorption resistance is good, roughness is low, high temperature resistance is provided, and sand sticking on a cast is not easily generated.

Description

Technical field [0001] The invention relates to a foundry sand, in particular to a high-temperature resistant coated sand, which is particularly suitable for the production of casting sand molds. Background technique [0002] Coated sand refers to molding sand or core sand covered with a solid resin film on the surface of sand grains before modeling. There are two coating processes: cold method and hot method: the cold method uses ethanol to dissolve the resin, and urotropine is added during the sand mixing process to coat the two on the surface of the sand grains, and the ethanol volatilizes to obtain coated sand; Method: Preheat the sand to a certain temperature, add resin to melt, stir to coat the surface of the sand, add urotropine aqueous solution and lubricant, cool, crush and sieving to obtain coated sand. Used for steel castings and iron castings. Since coated sand has the advantages of high strength, low gas evolution, high dimensional accuracy of production castings, ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the defects and problems of poor heat resistance, large roughness, and easy sand sticking on castings in the prior a