Geometry-Driven Criterion Function for Predicting Shrinkage Porosity in Stainless Steel Castings with T-Junction

Abstract

Metal castings with the presence of shrinkage porosity are often recycled or rejected and in turn reduce productivity of the process as well as increase energy cost involved in the process. This can be overcome by prevention of its occurrence using a suitable prediction technique. A detailed study of literature reveals that several Criterion Functions (an empirical model that connects solidification phenomena with formation of shrinkage porosity) have been employed to predict the location of shrinkage porosity in castings manufactured using particular process-alloy combination by values of process parameters (mostly thermal gradient, cooling rate, and velocity of molten metal). However, criterion function considering the effect of geometric variation in stainless steel castings on an extent of shrinkage porosity need to be established. In the present work, a benchmark casting, a combination of three T junctions, has been cast and used for the development of geometry-driven criterion function for stainless steel castings. Real experimental results with the presence of shrinkage porosity were used for superimposing on virtual experimental results (simulated results) for establishment of local simulation conditions. These conditions are further used in extrapolating results using casting simulation. The developed geometry-driven criterion function was further validated and found to be effective in prediction of shrinkage porosity.