Abstract: This invention relates to a process for heat treating light-metal castings, particularly cylinder heads for piston engines, in which, after solidifying and removing the castings from the mold, they are solution treated with the residual casting heat at approximately 530.degree. C., are quenched, aged at approximately 170 to 210.degree. C. and are then cooled to room temperature. The castings are quenched individually with a mist-type fine mixture of air and water, which is nozzle sprayed on all sides by forced convection flow only to approximately 130 to 160.degree. C., and are charged at this temperature, while utilizing the residual heat, into an aging furnace. The evaporation heat of the water is utilized as latent cooling heat. The forming water vapor, carried away by the workpieces, is condensed and the condensed water is guided back to moisten the air/water mixture.