Collapse-easy water glass core sand for casting train aluminum alloy castings and preparation method thereof

Abstract

The invention discloses collapse-easy water glass core sand for casting train aluminum alloy castings and a preparation method thereof. The collapse-easy water glass core sand is prepared by the following raw materials in parts by weight: 140-150 of olivine sand, 30-40 of garnet sand, 20-30 of allophane, 30-35 of siltstone, 15-20 of calcined kaolin, 8-10 of asbestos leftovers, 6-8 of beryllium oxide, 12-14 of boiling slag, 8-10 of water glass, 2-4 of sodium metaaluminate, 1-2 of cooked alum stone powder and the like. The core sand, prepared by such raw materials as olivine sand, garnet sand and siltstone enables such defect rates as sand bonding, air holes, cracks and looseness in casting of the aluminum alloy castings to be below 5%, largely improves the casting yield, and reduces the casting cost; the added sodium metaaluminate and cooked alum stone powder accelerate the hardening speed of the water glass, so that the core sand is high in strength and excellent in collapsibility, and the generation of harmful gas is reduced; and the added hydroxy propyl distarch phosphate, propylene glycol alginate and the like are attached on the surface of such raw sand as olivine sand, so that the interface strength is improved, and the green compression strength and the wet-heat tensile strength of the core sand are improved.

Description

field of invention [0001] The invention belongs to the field of foundry industry, and in particular relates to a collapsible water glass core sand used for casting train aluminum alloy castings and a preparation method thereof. Background technique [0002] Core sand is the material used to make cores in foundry production. It is generally made of casting sand, core sand binder and auxiliary additives and other molding materials mixed in a certain proportion. Generally, the requirements for molding sand are: high strength and thermal stability to 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 ability of molding sand to deform under the action of external force, and maintain the given shape when the external force is removed; better air permeability, that is, the ability of the pores of molding...

AI Technical Summary

Problems solved by technology

[0003] For aluminum alloy casting, the sand particle size in the traditional aluminum alloy casting sand formulation is too large or too small, and the sand material diameter is too large. Although the air permeability is good, the surface of the aluminum sand parts is relatively rough and the finish is not good. The diameter of the molding sand is too small, resulting in poor air permeability of the sand mold, and pores 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.

In addition, the traditional sand casting aluminum alloy products have a defect rate of more than 15% such as sand sticking, pores, and cracks, and the high rejection rate leads to a great increase in the cost of castings.

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