Apparatus and method for sand core debonding and heat treating metal castings

A continuous process for the removal of sand cores from the internal passages and cavities of a plurality of metal castings formed by the sand cores, said sand cores being comprised of sand and a binder to maintain a required form and hardness of the sand core, said binder being thermally decomposed at an elevated temperature, which comprises;

• providing a fluidized bed furnace, having a bed formed of fluidized sand maintained at a temperature sufficient to thermally decompose the binder and a freeboard space above the bed;
• continuously passing in sequence through the furnace, submerged in the fluidized sand, a series of individual and separate metal castings containing the sand cores, said passing being at a speed to maintain individual castings in the series submerged for a period of time sufficient to thermally decompose the binder;
• whereby sand from the cores, free of binder, flows freely from the individual casting to assimilate with the fluidized sand in the furnace bed.