Core sand for automobile engine casting and preparation method of core sand

Abstract

The invention discloses a core sand for automobile engine casting and a preparation method of the core sand. The core sand is prepared from the following raw materials in parts by weight: 170-180 parts of forsterite sand, 40-55 parts of graphite sand, 35-40 parts of high-magnesium phosphate tailing slag, 40-60 parts of skarn, 25-30 parts of waste foam concrete, 40-50 parts of knar clay, 15-18 parts of coal powder, 16-20 parts of coconut coir, 14-16 parts of blast furnace gas ash, 8-12 parts of high-aluminum fine powder, 10-15 parts of calcium zirconate, 15-17 parts of hollow silica nanospheres, 2-3 parts of sodium silicate, 3-5 parts of aluminum silicate, 3-4 parts of ammonium alginate, 4-6 parts of hydroxyethyl cellulose, 4-7 parts of beta-cyclodextrin and a proper amount of water. The core sand disclosed by the invention is good in performance; in the casting process, the amount of gas evolution is small, the drying time is short, the gas permeability is good, and the wet tensile strength is high; meanwhile, the demolding property of a sand mold can be improved, the sensibility to water during pouring can be lowered, and gas holes in a casting can be prevented; and bentonite and sodium water glass are adopted as binders, so that the mold drawing strength and the collapsibility of the core sand can be improved.

Description

Invention field [0001] The invention belongs to the field of foundry industry, and specifically relates to a core sand for automobile engine foundry and a preparation method thereof. Background technique [0002] The cylinder block material of automobile engine should have sufficient strength, good castability and machinability, and the price should be low. Therefore, the commonly used cylinder block materials are cast iron and alloy cast iron. However, the use of aluminum alloy cylinders is more and more common, because aluminum alloy cylinders are light in weight, have good thermal conductivity, and the capacity of the coolant can be reduced. After starting, the cylinder body quickly reaches the working temperature, and the thermal expansion coefficient is exactly the same as that of the aluminum piston. The gap change after heating is small, which can reduce impact noise and oil consumption. Moreover, the thermal expansion is the same as the aluminum alloy cylinder head, and ...

AI Technical Summary

Problems solved by technology

In the usual core sand formula for casting aluminum, the particle size of the core sand is too large or too small, and the diameter of the core sand is too large. Although the air permeability is good, the surface of the aluminum sand parts is rough and the finish is not good. Small, resulting in poor air permeability of the sand mold, and the aluminum castings have good pores

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