Precoated sand for casting instruments

Abstract

Precoated sand for casting instruments comprises the following raw materials in parts by weight: 1-2 parts of matrix resin, 0.02-0.06 part of a coupling agent, 0.2-0.5 part of urotropine, 0.2-0.5 part of a curing agent, 0.5-1 part of sulfonated lignin fiber, 0.2-0.5 part of montmorillonite powder, 10-20 parts of electric fused zircon sand and 80-100 parts of magnesia. Compared with conventional precoated sand, the precoated sand for casting instruments has the performance of the conventional precoated sand, also has the performance of gas raising speed delay and nitrogen production inhibition, and can effectively reduce nitrogen porosity production so as to improve the rate of finished products of casted instruments, the universality of the precoated sand is increased, the precoated sand meets iron castings and steel castings, the product rate of castings is improved, molding material cost of casting enterprises is saved, and the precoated sand has excellent casting performance.

Description

technical field [0001] The invention relates to the technical field of casting, in particular to coated sand for instrument casting. Background technique [0002] Coated sand is molding sand or core sand whose surface is covered with a layer of solid resin film before molding. There are two coating processes for the preparation of coated sand: 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; the thermal method is to preheat the sand to a certain temperature, add resin to melt it, 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 for foundry is mainly used for steel castings and iron castings. [0003] With the continuous expansion of the application range of coated sand, diffe...

AI Technical Summary

Problems solved by technology

The coated sand used for instrument casting has high requirements on the performance of coated sand. When the existing coated sand is used for instrument casting, it is difficult to meet the requirements of actual casting performance.