By the use of protective atmosphere heating alternative to oxidizing atmosphere heating to the precise control of carbon potential, nitrogen potential of the controllable atmosphere heating, heat treatment after the performance of parts improved heat treatment defects such as decarburization, cracks and other greatly reduced, heat treatment after the reduction of finishing , Improve the utilization of materials and machining efficiency. Vacuum heating gas quenching, vacuum or low pressure carburizing, nitriding, nitrocarburizing and boronizing can significantly improve the quality, reduce distortion and improve life.