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The role of corn pregelatinized starch in casting
Jingrui Chemical Pregelatinized Starch manufacturer uses high-quality food grade starch and is processed by advanced production technology. It has high cohesive force and good dispersion. Non-toxic and environmentally friendly. It is an excellent adhesive for pellet casting, sand-mixing casting and gypsum board production. It can greatly improve the wet performance and dry strength of the casting model and improve the surface finish of the casting model. It is an indispensable adhesive additive in the foundry industry.
It can improve the hot wet tensile strength of the molding sand. The starch on the surface of the outer sand mold is burned by heat to create voids, which can buffer the thermal expansion of the silica sand. This greatly improves the sand inclusion resistance of the molding sand.
It can reduce the friction resistance between the molding sand and the pattern, improve the mold draftability of the molding sand, and reduce the mold waste rate due to poor mold drafting.
If the green sand mold is left for a period of time before closing, the surface of the molding sand will lose water, resulting in a decrease in surface strength and easy wear and tear, and it will be easily eroded when pouring molten metal. The problem is more serious when it is left for a long time or when the weather is dry. Adding starch to the molding sand can improve the air-drying resistance of the molding sand and reduce sand washing defects in castings.
Starch can significantly reduce the sensitivity of molding sand to moisture, reduce the moisture content of molding sand and improve the solidity rate of molding sand. If the moisture content of the molding sand is low during sand mixing, it will appear quite dry and hard and brittle. Add a small amount of this product to the molding sand, and the molding sand will immediately become pliable and easy to use for modeling. The effect will be more obvious when using higher degree of starch.
Reduces the high-temperature strength of the molding sand, thereby improving the shakeout performance of the molding sand.
pregelatinized starch