我公司加工的某系列行星齿轮,材料为20CrMo钢,形状如图1所示。热处理为渗碳淬火,有效硬化层深度1.0～1.3 mm,内孔及齿部硬度59～63 HRC,该系列行星齿轮热处理要求较高。某次由于设备故障造成两炉共840件零件表面硬度偏低,有效硬化层深度不合格(不足1.0 mm),需要返修。但通过试验直接补渗淬火后,内孔尺寸胀大,接近零件最终尺寸,后工 A series of planetary gears machined by our company, the material is 20CrMo steel, the shape is shown as in Fig. Heat treatment for carburizing and quenching, the effective depth of the hardened layer 1.0 ~ 1.3 mm, bore and tooth hardness 59 ~ 63 HRC, the series of planetary gear heat treatment requirements are higher. A certain time due to equipment failure caused a total of 840 parts of two furnaces surface hardness is low, the effective depth of hardened layer (less than 1.0 mm), the need for rework. However, after the test directly infiltration quenching, the hole size swollen, close to the final size of the parts, after work