Founders embed these high-conductivity blocks into the mold wall adjacent to thick sections of a casting. By drawing heat away rapidly, they promote directional solidification and prevent shrinkage voids. They also refine the grain structure and can intentionally harden the surface of certain alloys, like cast iron, by producing white iron right at the contact point.
Place a steel chill right at the heavy junction of the flange so we don't get a hot tear when it shrinks.
Rookies often forget to clean or coat chills before use; a rusty or damp chill will cause massive gas blows in the casting.
Related terms
Hot tear
A crack that forms in a casting while the metal is still partially liquid and contracting.
Chvorinov's rule
A mathematical formula used to predict how long a metal casting will take to solidify based on its volume and surface area.
Dendrite
A branching, tree-like crystal structure that forms as molten metal solidifies.