Depth of oscillation marks forming in continuous casting of steel

The surface of continuously cast slabs is characterized by the presence of oscillation marks. Direct linkage of the continuous casting process and hot rolling process requires that cast slabs should be free of surface defects. In the present work, a mechanical model has been developed for the prediction of the depth of oscillation marks of the depression type. It is based on the beam bending theory and on viscoplastic material behavior. The downward movement of the strand is taken correctly into account, which has not been done in previous models. Auxiliary parts of the model are the models for the determination of the temperature field and of the fluid flow and pressure in the meniscus region and in the gap between strand and mold. The deflection of the shell is computed as a function of time and distance from the shell tip. The retained deflection, which corresponds to the depth of oscillation marks observed on the slab surface, is determined for different values of stroke, frequency, and casting velocity. The theoretical data are compared with the measured data as available in the literature.