On The Importance of Modeling 3D Shrinkage Cavities for the Prediction of Macrosegregation in Steel Ingots

With this work an existing 3-phase mixed columnar-equiaxed solidification model is extend to treat the formation of shrinkage cavity by including an additional phase. In the previous model a mixed columnar and equiaxed solidification approach that considers the multiphase transport phe- nomena (mass, momentum, species and enthalpy) is proposed to calculate the as-cast structure including columnar-to-equiaxed transition (CET) and formation of macrosegregation. In order to incorporate the formation of shrinkage cavity, a supplementary phase, i.e. gas phase or covering liquid slag phase, is considered in addition to the previously introduced 3 phases (parent melt, solidifying columnar dendrite trunks and equiaxed grains). No mass and species transfer between the new phase and the other 3 phases is necessary, but momentum and energy transfer is of critical importance for the formation of the shrinkage cavity and with that the flow and formation of mac- rosegregation would be influenced. Some modelling approaches for the momentum and energy transfer are suggested and tested.