Prediction of Shrinkage Porosity and its Remedy by Numerical Simulation in a Conical Carbon Steel Casting

Casting simulation has been recognized as an efficient tool for analyzing mold filling behavior, solidification and cooling, and prediction of the position and type of internal defects. The main concern in the current study is to predict the occurrence of porosity defects with the current casting design of a conical part, and then presenting practical solutions to remove or reduce the defects. Niyama dimensionless criterion was used for precise quantification of micro-porosity. The results of the casting simulation with accordance to the current process parameters showed that the occurrence of shrinkage porosity defect took place considerably. In order to suggest a solution to decline the extent of porosity, the inclination of the part wall was utilized. The results indicated that with an increasing slope, the amount of porosity is successively reduced. Besides it was found that a slope in the order of 0.5° on the external wall would lead to a remarkable reduction in the shrinkage porosity by inducing the directional solidification. The effect of various designs of the casting including the positioning of the casting inside the mold on the extent of porosity is discussed.