UNBENDING OF CONTINUOUSLY CAST SLABS WITH LIQUID-CORE

A finite element model for the straightening process of continuously c ast slabs with liquid core is presented. The passage of a strand secti on through the straightening zone is simulated in three-dimensional ge ometry with a time dependent load procedure. The model accounts for vi scoelastoplastic material properties. Since ferrostatic pressure is in cluded, bulging and unbending deformations are obtained simultaneously . Contact boundary conditions are prescribed at the rollers. Temperatu re profiles in the shell are considered in an approximation. The secti on of computation is long enough to capture the entire unbending defor mation, Features of pure one point unbending are deduced from computat ions where bulging is suppressed with a continuous strand guide. The f ollowing unbending systems are studied: one point straightening, five point straightening without intermediate rollers, four point straighte ning with intermediate rollers, and continuous straightening. The resu lts are interpreted in terms of elementary bending modes. Conclusions for the design of unbending systems are derived.