Study and control of factors influencing casting shrinkage using DOE and numerical simulation

Abstract

Abstract The purpose of this study is to predict the effect of various factors like alloying elements, Inoculation and Carbon Equivalent (CEV) on green sand casting shrinkage defect in gearbox housing, without changing the casting methoding system. Foundries are prone to have defects related to feeding and gating system, sand and process parameters. In some engineering applications, it is very difficult to alter methoding system due to specific casting geometry requirements. If not controlled during development stage, the rejections may seriously affect the productivity. This research work involves the optimization of various factors by DoE and numerical simulation to reduce the shrinkage defect. Unlike the prototype or sample lot trial, mass production of gearbox housing castings has been done in a foundry to achieve the research purpose. Effect of these factors on final casting hardness and tensile strength has also been studied and found to be on positive side, as these parameters are important for satisfactory performance under dynamic loading. Outcome was the reduction in shrinkage porosity from 10.9% to 3.2% with overall saving of 41k USD over the period of 4.5 months. Implication of this study involves standardization of optimum range of alloy elements and inoculation for different grades of grey cast iron.