High-temperature stable precoated sand

Abstract

The invention discloses high-temperature stable precoated sand, and belongs to the field of casting materials. Polylactic acid, lanthanum stearate and the like are used as raw materials, and are combined with subsequent nanoparticle effects for mutual connection to form space netty structures with nanometer microholes so as to improve the forming effect of the precoated sand. Three types of nanoparticles are used as nanomaterials for ultrasonic dispersion and acid mixing effects to improve the dispersion effect; and through adding of nanometer TiO2, a lot of plastic deformation energy can be absorbed when the external pressure effect is suffered, so that the softness of the prepared precoated sand is improved, the shell mold flexibility is improved, and the high-temperature pressure strength is improved. In the mixing process, through coaction between inorganic-organic components, compact air separation layers are formed in the precoated sand, and the influence on the internal of the precoated sand can be reduced when high-temperature effect is suffered. The high-temperature stable precoated sand solves the problems of easy unshelling and agglomeration of traditional precoated sandin the preparation process due to lower high-temperature pressure strength of the traditional precoated sand.

Description

technical field [0001] The invention belongs to the field of casting materials, and in particular relates to a high-temperature stable 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 on the surface of the sand grains before molding. The commonly used laminating process has two processes: cold method and thermal method. The cold method is to dissolve the resin with ethanol, add the raw sand for mixing and grinding, and the ethanol volatilizes during the sand mixing process, and then add the curing agent hexamethylenetetramine to coat the two on the surface of the sand grains to obtain coated sand. Due to the extremely low production efficiency of the cold film coating process, the thermal method is widely used at present. The key point of the process is that in the sand mixer, the raw sand preheated to a certain temperature is contacted with thermoplastic phenolic resin to melt it...

AI Technical Summary

Problems solved by technology

[0008] The technical problem to be solved by the present invention is to provide a kind of high-temperature stable coated sand in view of the low high-temperature compressive strength of the commonly used coated sand and the problems that the coated sand is prone to shelling and agglomeration during the preparation process.