Numerical Modelling of Continuous Casting of Steel Accounting for Dendrite Growth Phenomena

摘要

The general aim of this work is to calculate the extent of the equiaxed zone in continuously cast steel products. It is known that free equiaxed grains can grow only in undercooled liquid zones. Undercooling of the bulk liquid occurs because the columnar dendrite tips, growing from the mold, reject solutes into the liquid. The temperature front is then lower than the equilibrium liquidus temperature. The specific aim of this contribution is to calculate the thermal and physical state of continuously cast steel long products assuming a columnar solidification mode, but taking into account the tip undercooling at the solidification front. A 2-D heat transfer model has been developed, where a columnar solidification mode is assumed and calculation of the dendrite tip undercooling is coupled with heat transfer. Dendrite arm spacings are calculated in the case of standard and sharp cooling conditions respectively. Numerical results agree with the tendencies observed in earlier experimental works.