一、前 言 碳氮共渗工艺是目前广泛用于提高齿轮类零件的表面耐磨性能和接触疲劳抗力的一种热处理方法。由于碳、氮原子的同时渗入,碳氮共渗层,通常存有较多数量的残留奥氏体。 长期以来。人们认为残留奥氏体对渗层承载能力的提高是有害的。因此,在生产中通常采用高温回火(淬火前)、冷处理和重新加热至较低奥氏体化温度再次淬火等工艺 I. INTRODUCTION Carbonitriding is a kind of heat treatment method widely used to improve the surface wear resistance and contact fatigue resistance of gears. Due to the simultaneous infiltration of carbon and nitrogen atoms, the carbonitrided layer usually contains a larger amount of retained austenite. For a long time. It is considered that the retained austenite is detrimental to the increase of the bearing capacity of the coating. Therefore, in the production of high-temperature tempering is usually used (before quenching), cold treatment and re-heating to a lower austenization temperature and then quenching process