重型变速箱光孔渗碳齿轮热处理返工工艺研究

对重型变速箱光孔渗碳齿轮由于热处理设备发生异常情况或故障停机时造成的不合格品制定的返工工艺进行了分析研究。改进了常规直接补渗碳淬火工艺，在最终淬火工艺前增加退火缓冷工艺，将一次淬火马氏体进行马氏体-奥氏体一珠光体转变，避免连续淬火导致零件内孔涨大报废。经过改进后的退火缓冷及补渗碳和淬火返工，其零件内孔平均磨削余量能够满足磨削齿轮内孔余量的加工需求。

Study on Heat Treatment Rework Process for the Light Hole Carburized Gear of Heavy-duty Gearbox

The heat treatment rework process about the light hole carburized gear of heavy-duty gearbox analysed and researched, which treat with disqualification due to abnormal or downtime of heat treatment equipment. We improved the conventional direct reinforcing carburizing and quenching process, and in- creased the annealing and slow cooling process before the final quenching process. The quenching martens- ite had been transformed to martensite-austenite-pearlite, in order to avoid continuous quenching to make inner bore of part up big, and to be declared worthless. After improving annealing and slow cooling, sup- plemented carburizing and quenching rework process, the average grinding allowance of inner bore of part can meet the processing needs of grinding gear inner hole margin.