Alcohol-based casting coating for precoated sand moulds and method for preparing alcohol-based casting coating

Abstract

The invention discloses alcohol-based casting coating for precoated sand moulds and a method for preparing the alcohol-based casting coating, and belongs to the field of coating. The alcohol-based casting coating comprises, by weight, 63-67% of refractory powder with the size of 400-600 meshes, 1.0-1.4% of sodium bentonite, 1.6-2.3% of calcium bentonite, 1.2-1.8% of thermosetting phenolic resin, 0.6-0.9% of polyvinyl butyral and 28-31% of ethanol. The method includes proportionally mixing raw materials, except for the ethanol, with one another to obtain mixtures, adding the mixtures into a mixing mill, adding the ethanol with the mass accounting for 45-55% of the total mass of the ethanol into the mixing mill, and sufficiently mixing the mixtures and the ethanol to obtain paste coating; taking the paste coating out of the mixing mill, placing the paste coating in a stirring barrel, adding the remaining ethanol into the stirring barrel and uniformly stirring the paste coating and the remaining ethanol to obtain the finished alcohol-based casting coating. The method has the advantages that the alcohol-based casting coating is high in suspensibility and solid content, low in drying deformation, extremely high in covering power and excellent in brushing feeling and leveling property, coatings are smooth and clean and are good in breathability, and the surfaces of poured castings are smooth and clean.

Description

technical field [0001] The invention belongs to the field of coatings, in particular to an alcohol-based casting coating for coated sand molds and a preparation method thereof. Background technique [0002] Compared with the investment precision casting process, the coated sand casting process has a shorter production cycle and a simplified production process. Because the original sand grains used in the coated sand are good, the sand grains are finer, and the surface roughness of the sand mold is low, it is a precision or semi-precision casting. Forming methods, but the surface quality of castings is still not up to the level of traditional investment precision casting technology, producers hope that the use of coatings can improve the surface quality of castings. However, many commonly used resin sand or sodium silicate sand mold coatings on the market cannot meet this requirement. For example, ordinary coatings have coarse particles, poor brush feeling, heavy brush marks,...

AI Technical Summary

Problems solved by technology

[0002] Compared with the investment precision casting process, the coated sand casting process has a shorter production cycle and a simplified production process. Because the original sand grains used in the coated sand are good, the sand grains are finer, and the surface roughness of the sand mold is low, it is a precision or semi-precision casting. Forming method, but the surface quality of castings is still not up to the level of traditional investment casting process, producers hope that the use of coatings can improve the surface quality of castings

However, many commonly used resin sand or sodium silicate sand mold coatings on the market cannot meet this requirement. For example, ordinary coatings have coarse particles, poor brush feeling, heavy brush marks, and poor leveling. The effect of the surface finish of the casting, on the contrary, makes the original flat mold become rough and the surface of the casting is rougher, and the traditional coating has poor air permeability. The characteristics of coated sand are fine sand, large gas volume, and poor air permeability. Gas permeability, coated sand castings are prone to gas defects

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