First, it can improve the hot and wet tensile strength of the molding sand to increase the toughness of the molding sand and the surface finish of the casting model, and the α starch on the surface of the molding sand will generate a void after being heated and burned, which can buffer the thermal expansion of the silica sand. Thus, the anti-clamping ability of molding sand is greatly improved.
Second, it can reduce the friction resistance between the mold sand and the pattern, improve the molding of the mold sand, reduce the type waste rate due to poor molding, and effectively reduce the defect problem of the casting.
Third, if the wet sand is placed for a period of time before the mold is combined, the surface of the sand will lose water and the surface strength will be reduced and easy to wear, and it will be easily eroded when pouring metal liquid. The problem is more serious when it is left for a long time or when the weather is dry. Adding Longxiang α starch to mold sand can improve the ability of mold sand to resist air drying and reduce sand washing defects.
Advantages of A-starch in molding sand
α starch can significantly reduce the sensitivity of molding sand to water, reduce the water content of molding sand and improve the firmness of molding sand. When mixing sand, if the water content of molding sand is low, it will appear rather dry and hard and brittle. When a small amount of this product is added to the molding sand, the molding sand immediately becomes flexible and easy to shape and use.
The high temperature strength of molding sand is increased, and the knock-out performance of molding sand is improved.
Water content is less than 8%, water solubility is more than 90%, ash content is less than 0.5%, particle size (100 mesh pass rate) is more than 95%