Molding sand for aluminum casting and preparation technology thereof

Abstract

The invention belongs to the field of foundry industry, in particular relates to molding sand for aluminum casting and a preparation technology thereof. The molding sand for the aluminum casting comprises the following constituents: old sand, new sand, bentonite and water. The preparation technology of the molding sand for the aluminum casting comprises a sand-mixing method: weighting the old sand, the new sand and the bentonite according to a proportion, firstly mixing the same for 10 to 20 seconds, adding water to mix for 80 to 100 seconds and standing the mixed material for 20 seconds after the mixed material is well mixed. The invention has the advantages that the particle sizes of the sand are strictly controlled, the sand with the particle size of 200 / 100 meshes is selected, and the proportion of the sand failing to pass 200 meshes is larger than 50 percent so that both the surface smoothness of aloxite parts and the air permeability of the molding sand are favorable.

Description

technical field [0001] The invention belongs to the field of foundry industry, and in particular relates to a molding sand used for casting aluminum and a preparation process thereof. Background technique [0002] Molding sand is a material used for molding in sand casting. Molding sand is generally made of molding materials such as foundry sand, molding sand binder and auxiliary additives mixed in a certain proportion, and natural silica sand containing clay can also be used. The role of molding sand in the casting process is extremely important. The casting waste caused by poor quality of molding sand accounts for about 30-50% of the total casting waste. Usually, the requirements for molding sand are: high strength and thermal stability. Withstand various external forces and high temperatures; good fluidity, that is, the ability of the molding sand to move between sand particles under the action of external force or its own gravity; certain plasticity, that is, the deforma...

AI Technical Summary

Problems solved by technology

The defect is: the particle size of the molding sand in the usual casting aluminum sand formulation is either too large or too small: the particle size of the molding sand is too large, although the air permeability is good, but the surface of the aluminum sand piece is rough and the finish is not good; the particle size of the molding sand If it is too small, the air permeability of the sand mold is not good, and the aluminum casting has pores.