Method of metal processing using cryogenic cooling

A method for processing a metal part in a continuous furnace, the method comprising:

• providing the furnace wherein the metal part is passed therethrough on a conveyor belt and comprises a hot zone and a cooling zone wherein the cooling zone has a first temperature;
• circulating a feed gas through the cooling zone using a convective cooling system;
• introducing a cryogenic fluid at a pressure from 15 to 500 psig into the cooling zone where the cryogenic fluid reduces the temperature of the cooling zone to a second temperature, wherein at least a portion of the cryogenic fluid provides a vapor within the cooling zone and cools the metal parts passing therethrough, wherein the cryogenic fluid is introduced into the cooling zone by spraying directly onto the metal part;
• and
• providing one or more temperature sensors located within the furnace,
• wherein the furnace further comprises one or more curtains having an actuator to open and close the one or more curtains and wherein at least one of the temperature sensors is in electrical communication with the actuator and a programmable logic controller (PLC);
• and wherein the PLC controls the temperature of the metal part by directing the actuator to open or close one or more of the curtains based upon information obtained by the PLC from the one or more temperature sensors.