Modeling the continuous casting of steel

An axisymmetric and a three dimensional finite element model have been developed to compute the thermo-mechanical state of continuously cast steels in the casting mold. The model includes the mold in the analysis so that it fully accounts for the effects of mold distortion on the gap formed between the mold and the solidifying strand. It is solved iteratively so that the computed effect of the gap on heat transfer between the strand and the mold is consistent with the resultant thermal distortion of the strand and the mold.;The model is used to examine the effect of variations in steel carbon content and mold taper on heat transfer from the mold. It shows that the delta-gamma phase transformation of 0.1% carbon steel just below the melting point is responsible for the low average heat flux from that grade of steel and that the stress's induced by this transformation causes the grade's increased susceptibility to cracking. The model shows why the behavior of square and round billet casters are different. The heat flux from a round billet drops sharply below the meniscus and thereafter remains constant or may even increase towards the mold exit. The heat flux from a square caster drops almost linearly from the meniscus to the mold exit. The model shows that the gap between the mold and the solidifying strand widens rapidly just below the meniscus but then remains constant or narrows towards the mold exit in the round caster. The gap over much of the face of the square billet opens much more slowly.