Magnetohydrodynamic Phenomena Fluid Cont

This study investigates magnetohydrodynamic flow phenomena and electromagnetic stirring (EMS) in billet casting to understand their effects on solidification microstructure and oscillation marks. The primary objective was to analyze the influence of EMS on central equiaxed zone formation and the fluid flow behavior during the casting process. Experimental methodologies included casting trials and computational modeling, with a focus on 40CrMo4 steel grade. Results indicated that EMS with a current of 310 A significantly increased the central equiaxed zone from 10-15% in unstirred billets to over 45% in stirred billets. The research also discovered that dendritic microstructures deflected downwards due to sustained upward flow, and unsteady flow phenomena were linked with changes in casting speed and EMS intensities. The computational model corroborated these findings, demonstrating a declining injected stream phenomenon from the Submerged Entry Nozzle (SEN) under specific stirring intensities, which affected the thermal distribution of the strand shell and overall casting quality. Additionally, the study underscored the advantages of ported SEN designs in promoting steel cleanliness, revealing that reduced casting speeds improved inclusion removal. The modeling results were validated through trials involving 65 bloom casting heats, showcasing a marked improvement in cleanliness using a 2-port SEN.