Abstract: Sand castings are removed from their molds before cooling and reheated in a heat treating booster furnace. The castings are transferred from the booster furnace to a rotary drum filled with agitation media. As the castings pass through the media drum, they are simultaneously cleaned of sand particles and down-quenched by the agitation media. The system is particularly suited for austempering cast iron parts.

Abstract: A method for producing a selectively surface hardened cast iron part includes the steps of (a) heating the part to a desired austempering temperature of between about 450.degree. F. and about 800.degree. F. until the entire cast iron part possesses the desired austempering temperature substantially uniformly throughout it; (b) heating only the surface of the cast iron part to an austenitizing temperature of between about 1500.degree. F. and about 1800.degree. F. by immersing the cast iron part in a molten lead or tin bath until a desired thickness of an austenite layer is formed on the surface of the cast iron part, without substantial heating of the interior of the cast iron part; (c) quenching the surface-heated cast iron part in a non-liquid quenching bath atmosphere, i.e.

Abstract: A method for preparing an austempered cast iron which includes an ausferritic matrix, the cast iron having a silicon content of from about 1.6 to about 2.4 weight percent, and a carbon content of from about 1.6 to about 2.2 weight percent, such that the carbon equivalent of the cast iron is from about 2.1 to about 3.0 weight percent. The method includes (a) melting the cast iron composition; (b) pouring the melt into a mold to form a casting having eutectic carbide particles; (c) altering the temperature of the casting to about 1650.degree.-1900.degree. F. and maintaining the temperature of the casting at about 1650.degree.-1900.degree. F. until substantially all of the eutectic carbide particles convert to temper graphite nodules to form a temper graphite-containing casting; (d) cooling the temper graphite-containing casting to about 1500.degree.-1750.degree. F. and maintaining the temperature of the tempered graphite-containing casting at about 1500.degree.-1750.degree. F.

Abstract: A method for producing a selectively surface hardened cast iron part includes uniformly heating the surface of the part by immersion into a molten metallic bath until a desired thickness of surface austenite is produced, and thereafter quenching the heated cast iron part in a liquid quenching bath which is maintained at a temperature of between about 450.degree. to about 800.degree. F. for about 10 minutes to about 4 hours. The resultant selectively surface hardened cast iron part is surface hardened with the bulk of the body of the part remaining untempered. An apparatus for performing this process includes a molten metal bath chamber for containing the molten metal and a molten salt bath quenching chamber for quenching the cast iron parts with a conveyor means extending between the molten metal bath and the molten salt bath chambers. A second conveyor means removes the parts from the molten salt bath chamber.

Abstract: An austemperable cast iron which includes an ausferritic matrix, the cast iron having a silicon content of from about 1.6 to about 2.4 weight percent, and a carbon content of from about 1.6 to about 2.2 weight percent, such that the carbon equivalent of the cast iron is from about 2.1 to about 3.0 weight percent. The austempered cast iron is prepared by melting the cast iron composition; to about 1650.degree.-1900.degree. F. and maintaining the temperature of the casting at that temperature until substantially all of the eutectic carbide particles convert to temper graphite nodules to form a temper graphite-containing casting, then cooling the temper graphite-containing casting to about 1500.degree.-1750.degree. F. and maintaining the temperature of the tempered graphite-coating at about 1500.degree.-1750.degree. F. until a fully austenitic matrix is achieved, and then quenching and cooling the ausferritic matrix casting to room temperature before bainite is formed.