重卡后桥主减壳铸件组织异常的防止措施

Preventive Measures for Abnormal Structure of Heavy Truck Rear Axle Main Reducer Shell Casting

介绍了重卡后桥主减壳铸件的结构及技术要求,针对采用原生产工艺进行试生产过程中在铸件轴承档部位出现珠光体体积分数超标以及出现莱氏体的问题,利用能谱分析仪对试块进行能谱分析,发现该区域铁液成分存在严重偏析,铸件此处的铁液冷却快,导致白口倾向加重。通过增加原铁液和浇注铁液的w(Si)量,并用碳化硅对原铁液进行预处理,控制w(Mn)量不超过0.5%,解决了轴承挡部位组织异常问题,且力学性能符合技术要求。

The structure and technical requirements of the main reducer shell casting of the rear axle of the heavy truck were introduced.In view of the problem that the volume fraction of pearlite exceeded the standard and ledeburite in the bearing gear part of the casting during the trial production using original process,by analyzing with Energy Spectrum Analyzer,it was found that there was serious segregation of the molten iron in this area,and the molten iron in the casting cooled quickly,resulting in aggravated white iron tendency.By increasing the amount of w(Si)in the original molten iron and casting molten iron,pretreating the original molten iron with silicon carbide,and controlling the amount of w(Mn)within 0.5%,the problem of abnormal organization in bearing block part was solved,and the mechanical properties meet the technical requirements.