Foundry sand for high-precision castings and preparation method thereof

Abstract

The invention discloses casting molding sand for a high-precision casting. The casting molding sand is prepared from the following raw materials in parts by weight: 160-180 parts of chromite sand, 20-30 parts of medical stone, 15-20 parts of iron red powder, 1-2 parts of superfine barium sulfate, 3-4 parts of carboxymethyl cellulose, 25-30 parts of aluminum ammonium sulfate, 2-3 parts of sodium tripolyphosphate, 2-3 parts of dodecylbenzenesulphonic acid, 2-3 parts of pine tar, 1-2 parts of lactose, 2-4 parts of silica sol, 7-9 parts of furan resin, 2-4 parts of polyoxyethylene lauryl ether, 8-10 parts of pea starch, 100-130 parts of quartz sand and an appropriate amount of water. The casting molding sand is smooth, high in adhesion, high in plasticity, high in thermal stability, high in air permeability, good in thermal stability and low in shrinkage rate, and the size of the casting is stable; by virtue of superfine barium sulfate, the fluidity and the dispersity of the molding sand are improved, and the collapsibility at high temperature is improved; the casting molding sand is easy to mold, a core is easy to manufacture, the phenomena of shrinkage cavities and shrinkage porosity infrequently occur, the casting yield is improved, and the casting molding sand is applicable to manufacturing of castings with high precision requirement.

Description

Technical field [0001] The invention relates to the field of casting, in particular to a casting sand for high-precision castings and a preparation method thereof. Background technique [0002] Molding sand is a material used for molding in casting. Molding sand is generally made by mixing molding materials such as raw sand for foundry, molding sand binder, and auxiliary additives in a certain proportion. Natural clay-containing silica sand can also be used. The usual molding sand formulations for aluminum casting have too large a particle size or Too small, the diameter of the molding sand is too large, although the air permeability is good, the surface of the aluminum sand is relatively rough, the smoothness is not good, and the diameter of the molding sand is too small, resulting in poor air permeability of the sand, and pores in the aluminum casting. The pulverized clay green sand, which is widely used at home and abroad, is generally made by mixing raw sand, binders, pulver...

AI Technical Summary

Problems solved by technology

Molding sand is generally made by mixing molding materials such as raw sand for casting, molding sand binder and auxiliary additives in a certain proportion. Natural silica sand containing clay can also be used. In the usual molding sand formula for aluminum casting, the particle size of the molding sand is too large or If it is too small, the diameter of the sand material is too large. Although the air permeability is good, the surface of the aluminum sand parts is rough and the finish is not good. The diameter of the sand material is too small, resulting in poor air permeability of the sand mold and air holes in the aluminum casting

Coal powder clay green sand, which is widely used at home and abroad, is generally made of raw sand, binders, coal powder additives, etc. and water. It has a certain anti-sticking sand effect, low material cost, and high production efficiency. However, its consumption is large, the emission is serious, and the coal powder is burned and decomposed in the casting process to produce toxic gas pollution.