A Fully Coupled Analysis of Fluid Flow, Heat Transfer and Stress in Continuous Round Billet Casting

摘要

The thermal and vectorial fields in the strand and the temperature distribution in the mold were analyzed with a finite difference method (FDM) considering the effects of turbulence and natural convection of molten steel. The thermo-elasto-plastic behaviours of the strand and the mold were analyzed with a finite element method (FEM) taking into account the ferrostatic pressure due to the gravity force and the mechanical behaviors of the strand in liquid phase, mushy zone and δ/γ phase. The microsegregation of solute elements in steel was assessed to determine some characteristic temperature and solid, δ-Fe and γ-Fe fractions in the mushy zone. The heat transfer coefficient between the solidifying shell and the mold wall was iteratively determined with the coupled analysis of the fluid flow-heat transfer analysis by the FDM and the thermo-elasto-plastic stress analysis of the by FEM. With the above procedure, the mathematical model has been developed to predict the possibility of cracks in the strand, originated form the interdendritic liquid film in the mushy zone, through the fully coupled analysis　of fluid flow, heat transfer and stress in the continuously cast round billet. The calculated mold temperature and heat flux at various casting speeds show good agreements with the reported experimental observations.