A COUPLED FDM FEM MODEL FOR THE CONTINUOUS-CASTING PROCESS/

A coupled mathematical model has been developed to investigate the sol idification and further cooling, and the formation of thermal stresses , which cause quality defects like internal or surface cracks. The aim is to get a better understanding of the continuous casting process in order to contribute to an increase in productivity while keeping a re quired quality level, or improving product quality. For the simulation of mass transport, solidification and/or remelting, and heat transfer , a finite difference method is applied; for the calculation of the th ermo-mechanical stresses and strains the ADINA program is used. Becaus e the strand shrinkage within the mould determines the temperature fie ld via the cooling conditions, both thermal and stress analysis have t o be coupled to consider feedback. Emphasis is placed on the highly no nlinear material behaviour at temperatures near the solidification tem perature as well as on the three-dimensional and transient contact bet ween strand and mould. The reliability of the solutions depends on the discretization and element configuration chosen. Depending on the pro blem formulation a relatively simple plane strain formulation or a ful ly 3D stress formulation is used. The alternative possibilities of dif ferent grids and/or different material models are discussed with respe ct to accuracy and CPU-time.