Macrosegregation under new flow pattern and temperature distribution induced by electromagnetic swirling flow in nozzle during continuous casting of square billet

Forced convection induced by mold electromagnetic stirrer (M-EMS) improves solidification structure in continuous casting of high carbon square billet, but vigorous stirring also causes macrosegregation. In this study, electromagnetic swirling flow in nozzle (EMSFN) was applied together with the M-EMS to optimize flow field and temperature distribution in the mold. The industrial test results showed that when the stirring directions of the two electromagnetic devices were opposite and the current parameter of the EMSFN device was SO Hz, 400 A, the equiaxed crystal ratio increased 15% compared with that by using the M-EMS only, and the macrosegregation of carbon was minimized simultaneously. The investigation on the growth direction of columnar crystal indicated that in the upper part of the mold the heat transfer in different directions and the weakened forced convection were the key factors to prevent the solute element from being depleted at the edge and to reduce the centerline positive segregation in the billet. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecomsnons.org/licenses/by-nc-nd/4.01)"