Thermal Stress Analysis of Bulging with Roll Misalignment for Various Slab Cooling Intensities

Temperature, displacement, strain and stress fields in the solidifying strand of continuous steel slab casters were numerically investigated to understand bulging phenomena between support rolls. The thermal model accounted for heat transfer variations at the strand surface between rolls in the spray zones, including roll contact, direct spray impingement, convection, and radiation. Shell temperatures were calculated for different spray zone cooling designs and were validated with experimental measurements from thermocouples embedded in the solidifying steel shell. The results were further investigated with an elastic-plastic thermal-stress model. Roll misalignment was found to be a dominant factor in determining shell bulging. Moreover, the maximum bulging strain across the solidification front was found to correlate to about 2.4 times the ratio of maximum bulging displacement to roll pitch.