Numerical Modeling of Macrosegregation during the Direct-Chill Casting of an Al alloy Billet

ABSTRACT Macrosegregation has been received high attention in the solidification modeling studies. In the present work, a numerical model was developed to predict the macrosegregation during the DC Casting of an Al-۴.۵wt%Cu billet. The mathematical model developed in this study consists of mass, momentum, energy and species conservation equations for a two-phase mixture of liquid and solid in an axisymmetric coordinates. The solution methodology is based on a standard Finite Volume Method. A new scheme called Semi-Implicit Method for Thermodynamically-Linked Equations (SIMTLE) was employed to link energy and species equations with phase diagram of the alloying system. The model was tested by experimental data extracted from an industrial scale DC caster and a relatively good agreement was obtained. It was concluded that a proper macrosegregation model needs two key features: a precise flow description in the two-phase regions and a capable efficient numerical scheme