Gray Cast Iron Coating For Casting Applications With High Refractoriness And Excellent Surface Finish

Gray Cast Iron Coating

The gray cast iron coating is a functional material applied to the surface of the sand mold cavity. Its primary function is to isolate molten metal from the mold, thereby improving casting surface quality and dimensional accuracy. It is a key auxiliary material in gray cast iron casting processes. The coating mainly consists of refractory aggregates, binders, suspending agents, and functional additives.

Features:

1.Pouring Compatibility and Anti-Burn-On Performance

With a refractoriness of 1500–1600 °C, the coating is well matched to the pouring temperature of gray cast iron (1350–1420 °C). Common aggregates include quartz powder and bentonite, which effectively prevent sand adhesion while maintaining normal graphite formation.

2.Low Gas Generation to Reduce Casting Defects

The binder system (e.g., CMC combined with bentonite) features low moisture absorption and minimal gas evolution after drying. With permeability optimized for foam pattern degassing, the coating helps reduce gas-related defects such as porosity and pinholes.

3.Strong Adhesion with Easy Cleaning

The coating exhibits excellent hang-on performance and remains crack-free and firmly bonded after drying. After pouring, it peels off in a shell-like form, leaving a smooth casting surface and allowing for efficient post-casting cleaning.

4.Flexible Processing and Cost Efficiency

Recommended water-to-powder ratio: approximately 1:0.6–0.7. The coating can be applied by dipping, pouring, or brushing, with a coating thickness of 0.8–1.2 mm. The dry powder offers a long shelf life and can be easily prepared by adding water, making it suitable for batch production of gray iron castings such as engine blocks and machine tool beds.