Effect of mold electromagnetic stirring on solidification structure and solute segregation in continuous casting bloom

The effect of mold electromagnetic stirring (M-EMS) on the solidification structure and solute segregation in the continuous casting bloom of U78CrV steel is investigated. The solute distribution in the macroscale is analyzed using a carbon–sulfur analyzer and that in the microscale is measured with an electron probe microanalyzer. The Image-J software is applied to analyze the number density and area ratio of segregation spots. The results show that the segregation spots are mainly located in the columnar to equiaxed transition zone and the equiaxed zone, which are enriched with C, Cr, and Mn elements. With the M-EMS applied, the columnar grain inclines to the upstream side. As the current intensity increases, the deflecting angle of columnar grain rises, especially with the current intensity larger than 300 A. Besides, the center segregation shows a declining trend and the area fraction of the equiaxed zone rises clearly. Moreover, it is found that the area ratio and number density of segregation spots increase with the higher current intensity of M-EMS.