In centrifugal casting, a permanent mold is rotated continuously about its axis at high speeds (300 to 3000 rpm) as the molten metal is poured. The molten metal is centrifugally thrown towards the inside mold wall, where it solidifies after cooling. The casting is usually a fine-grained casting with a very fine-grained outer diameter, owing to chilling against the mould surface. Impurities and inclusions are thrown to the surface of the inside diameter, which can be machined away. Cylinders and shapes with rotational symmetry are most commonly cast by this technique. Centrifugal casting is also applied to the casting of disk and cylindrical shaped objects such as railway carriage wheels or machine fittings where the grain, flow, and balance are important to the durability and utility of the finished product.
Typical materials that can be cast with this process are iron, steel, stainless steels, glass, and alloys of aluminum, copper and nickel. Two materials can be cast together by introducing a second material during the process. Typical parts made by this process are pipes, boilers, pressure vessels (see autofrettage), flywheels, cylinder liners and other parts that are axi-symmetric. It is notably used to cast cylinder liners and sleeve valves for piston engines, parts which could not be reliably manufactured otherwise.