THE INFLUENCE OF THERMAL STRESSES AND STRAND BENDING ON SURF A CE DEFECTS FORMATION IN CONTINUOUSL Y CAST STRANDS

Improvement of slab surface quality is a very important goal in the continuous casting process of steel, closely coupled with casting line productivity and the tendency to increase casting speed. This study aims to analyze the impact of thermal stresses and strand bending on the formation of surface defects in continuously cast strands. A developed thermo-mechanical model combined with finite element software was utilized to determine the strain and stress fields within the continuously cast strand. Key parameters, such as the variation of selected criterion integrals, were calculated along the entire casting line from the solidification process in the mold to the cutting section. The steady solution to the heat transfer equation facilitated calculation of the strand temperature field, while the mould temperature was derived from a three-dimensional transient model. The finite element method allowed for the construction of both steady and transient heat transfer models, enhancing the finite element solution's accuracy regarding the temperature field. Additionally, a new algorithm for managing solidification heat was introduced to stabilize the steady solution to the heat transport equation, and the damageability of the strand was assessed based on four fracture criteria.