低合金渗碳钢是拖拉机底盘齿轮的常用材料。其传统工艺路线是锻造→正火→机加工→渗碳淬火→回火。近年来,我厂在生产20CrMnMo 钢齿轮的过程中发现,由于冶金因素或其它原因,有时会出现与一般正常组织(片状珠光体+等轴或网状铁素体)不同的非正常组织。具有一定数量异常组织的齿轮坯,其机械加工性能变坏,既严重损耗刀具,又影响了零件质量和生产效率,甚至 Low alloy carburized steel is a commonly used material for tractor chassis gears. Its traditional process route is forging → normalizing → machining → carburizing and quenching → tempering. In recent years, during the process of producing 20CrMnMo steel gears, our factory found that, due to metallurgical factors or other reasons, abnormal tissues other than normal tissues (lamellar pearlite, equiaxed or reticular ferrite) sometimes appear. Gear blanks with a certain number of anomalous structures deteriorate the machinability of the workpieces, both seriously damaging the tool, affecting the quality and productivity of the parts and even