Monitoring and evaluation of temperature distribution in continuous steel casting coupled with optimal temperature intervals providing no defects can be used for the prediction of crack formation in the cast strand. Crack locations can be further specified with the use of mechanical stress-strain distribution model. These crack locations are strongly dependent on the zero ductility temperature (ZDT) and the liquid impenetrable temperature (LIT). To avoid the excessive stress and strain distribution in the steel, parts of the strand where bending and unbending take place should not be in ZDT and LIT intervals. Thus, the casting speed and water flow rates through cooling nozzles have to be modified to avoid these crack sensitive temperature intervals where the stress exceeds its maximum allowable value determined from the crack criteria. In this paper, the thermal solidification and mechanical stress-strain distribution models of billets with sharp and rounded corners for structural steel grades S355 are presented and the results are compared. Further, the idea of coupling between thermal and mechanical models is presented, which serves as a base for a crack predictive model assessing the quality of cast semi-products.