Graphite chills have developed rapidly due to their advantages of low density, high thermal conductivity, strong heat storage capacity, and reusability. An increasing number of foundries are promoting this new casting process, which uses graphite as a chilling material to replace metallic materials.
Comparison of Physical Properties Between Cast Iron Chills and Graphite Chills

Indicator	Cast Iron Chill	Graphite Chill
Density / (g/cm³)	7.5	1.65 ～ 1.85
Thermal Conductivity / (W/m·℃)	48	115 ～ 129
Specific Heat Capacity / (J/kg·℃)	444	710 ～ 1510
Melting Point / ℃	1535	3850
Thermal Expansion Coefficient (10⁻⁶/℃)	10	＜ 6

Placing formed graphite chills at the hot spot areas of castings that require chilling can make the metallographic structure of the castings consist of fine flake pearlite accounting for over 95%. The number of eutectic cells can reach 450-550 per cm, and the hardness of the castings can increase by 20-50 HB, which can improve the surface finish and wear resistance of the castings. When using graphite chills, graphite coating or talc powder coating can be applied on them, and their service life is 5-10 times longer than that of metallic chills.
Therefore, using graphite chills as chillers to replace metallic chills can better solve the problems of porosity and shrinkage cavity in castings such as cast steel, cast copper, and cast aluminum. It can also effectively address casting defects like white cast iron and blowholes caused by the use of metallic chills. Castings using graphite chills have a smooth surface, easy sand cleaning, few defects, and no sand adhesion.