Core composition for casting, and method for preparing core for casting using the same

Abstract

Disclosed are a core composition for casting and a method for preparing a core for casting using the composition. The core composition for casting includes: molding sand; a binder that includes a water glass-based binder and an oxide film inhibitor; and an additive, thereby improving a sand removing property without releasing harmful gases.

Description

TECHNICAL FIELD[0001]The present invention relates to a core for casting that may improve a sand removing property without releasing harmful gases. Further, the present invention relates to a method for preparing a core for casting using the composition.BACKGROUND[0002]Generally, when a casting having a hole such as a cylinder is made by a casting work, a mold having a shape corresponding to the hole is referred to as a core. In other words, when performing a casting process of a casting having a hole or a hollow casting, a molten casting material is injected into a mold after a core is placed inside the mold, and when the casting is hardened, the casting and the core are removed from the mold, and then the core is removed from the casting.[0003]Meanwhile, as a method for preparing the core, molding sand and a shape binder are introduced to a mold, and the shape binder is cured and formed to a prescribed shape. The molding sand may be common sand, and an organic binder is typically ...

AI Technical Summary

Benefits of technology

The invention provides a core composition for casting with improved sand removing properties. The water glass-based binder is combined with an additive for sand removal such as zinc oxide, which reduces flexure strength at high temperatures. The core composition can rapidly become less flexible when left unattended and is exposed at high temperatures, making it easier to remove sand. The use of an inorganic binder also prevents the release of harmful gases during casting and is environmentally friendly. These technical effects result in cost savings and improved efficiency in the casting process.

Problems solved by technology

The organic hinder has advantages such as a fast curing rate, however, harmful influences may occur in casting environment, for example, the life span of a casting mold may be reduced by the harmful gases, and condensates and the like may occur during casting.

However, when the water glass-based binder is used, flexure strength is reduced compared to organic binders, and the strength is rapidly reduced due to a weakening bonding power caused by a hygroscopic property of water glass depending on the time left unattended.

In addition, the water glass-based binder may be vitrified at a high temperature of about 540° C. or greater, and when sand is removed after casting using the water glass-based binder, the molding sand may adhere to the surface of a casting product such that post treatments may be complicated.

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