球铁驱动架铁型覆砂铸造工艺研究

Study on Iron Mould Overlying Sand Casting Process for Ductile Iron Driving Frame

针对某工程机械用球铁驱动架的结构特点及技术要求,进行了铁型覆砂铸造工艺设计。采用双工位覆砂造型机造型,中频感应炉熔炼进行了铸件生产。对铸件缩孔缺陷的原因进行了分析,通过对铸件热节部位增加铁型壁厚,减薄覆砂层厚度,改变凝固条件,同时利用铸型刚度大和球铁石墨化膨胀进行自补缩,解决了铸件内部缺陷。最终获得了金相组织、力学性能及内部质量满足技术要求的球铁驱动架铸件。

According to the structural characteristics and technical requirements of ductile iron driving frame for a construction machinery,the process of iron mold sand coating casting was designed.Casting production was carried out by using double station sand coating molding machine and intermediate frequency induction furnace melting.The causes of shrinkage cavity defects of castings were analyzed.By increasing the wall thickness of iron mold at the hot spot of the casting,thinning the thickness of sand coating and changing solidification conditions,the internal defects of castings were solved by self-compensate using the high stiffness of casting mold and graphitization expansion of ductile iron.Finally,the ductile iron driving frame castings with the microstructure,mechanical properties and internal quality meeting the technical requirements were obtained.