In permanent-mold casting (also called hard-mold casting), two halves of a mold are
made from materials with high resistance to erosion and thermal fatigue, such as cast
iron, steel, bronze, graphite, or refractory metal alloys. Typical parts made are automobile
pistons, cylinder heads, connecting rods, gear blanks for appliances, and
kitchenware. Parts that can be made economically generally weigh less than 25 kg, although
special castings weighing a few hundred kilograms have been made using this
process.