Rocker arm shell is an important component of shearer with multistage wall thickness,variable cross-section and other heterogeneous features.Aiming to improve the casting quality of shearer rocker arm shell and resolve defects such as shrinkage porosity and shrinkage cavity caused by immature casting processes,the rocker arm shell of MG325 shearer was taken as the research object.Two casting process schemes,top-injection and bottom-injection,were designed and ProCAST software was used to investigate the filling and solidification process of shearer rocker arm shell castings under different pouring schemes.Meanwhile,the temperature field and solidification field as well as the position of shrinkage porosity and shrinkage cavity defects were analyzed.Based on Niyama criterion and stress field distribution,the bottom-injection casting process was optimized.The results show that the shearer rocker arm shell castings in the solidification and cooling process maintain an incremental temperature gradient after optimization,effectively promoting the castings to achieve sequential solidification.The defect rate of rocker arm shell castings is significantly reduced and the filling effect is improved after optimization.The shrinkage hole volume only accounts for 0.004 9％of the rocker arm shell volume.The stress optimization at the thin-wall end face of the motor hole is 38.47％,while the stress optimization at the output port reaches 91.08％.The research results provide a theoretical basis and data support for the casting technology of shearer rocker arm shell.
关键词
采煤机/摇臂壳体/铸造缺陷/工艺优化/残余应力
Key words
shearer/rocker arm shell/casting defect/process optimization/residual stress
维普
万方数据