What is the role of starch in Dongguan casting?

What is the role of starch in Dongguan casting?

1. It can improve the thermal humidity and tensile strength of the molding sand. A kind of starch on the surface of the sand mold creates gaps after heating and burning, which can buffer the heating and expansion of the silica sand. This greatly improves the sand resistance of the molding sand.

2. It can reduce the friction resistance between the molding sand and the molding sand, improve the mold ejection properties of the molding sand, and reduce the mold waste rate caused by poor mold ejection.

3. If the green sand mold is left for a period of time before synthesis, the surface of the molding sand will lose water, resulting in reduced surface strength, easy wear, and easy erosion when pouring molten metal. The problem is more serious when it is left for a long time or the weather is dry. In the molding sand Adding starch can improve the wind drying resistance of the molding sand and reduce sand washing defects in castings.

4. Starch can significantly reduce the sensitivity of the molding sand to moisture, reduce the moisture content of the molding sand, and improve the solidity of the molding sand. When mixing sand, if the moisture content of the molding sand is low, it will appear quite dry, scattered, hard, and brittle. In the molding sand By adding a small amount of this product to the molding sand, the molding sand immediately becomes flexible and easy to model. Using highly refined starch will have a more obvious effect.

5. Reduce the high-temperature strength of the molding sand, thereby improving the shakeout performance of the molding sand.