Numerical simulation of macrosegregation in continuously cast gear steel 20CrMnTi with final electromagnetic stirring

A 3D/2D hybrid multi-physical-field mathematical model, which takes into consideration the thermosolutal buoyance, was developed to predict the macrosegregation of gear steel 20CrMnTi continuously cast by a curved billet caster with size of 160 mm × 160 mm, and investigated the effect of final electromagnetic stirring (F-EMS) on the fluid flow, heat transfer and solute distribution in the liquid core of continuously cast steel. The results show that the application of F-EMS eliminates the effect of thermosolutal buoyancy on the asymmetric distribution of carbon concentration in the cross section of billet and accelerates the final solidification of resident molten steel in the liquid core of strand, but promotes the negative carbon segregation near the billet center. When the gear steel 20CrMnTi is cast at the temperature of 1803 K and speed of 1.7 m/min, the solidification end advances forward from 9.84 to 9.72 m, and center carbon segregation ratio of billet decreases from 1.24 to 1.17 with the increase in current density of F-EMS from 0 to 350 A.