Effects of Pulsed Magneto-Oscillation on the Homogeneity of Low Carbon Alloy Steel Continuous Casting Round Billet

Abstract

Pulsed Magneto-Oscillation (PMO) is a newly developed and effective homogenization technique, and has been successfully applied in rectangular continuous casting, but its processing parameters and effective stability in round billet continuous casting have not been investigated. In this paper, the effects of PMO on the solidification structure and the macrosegregation of Φ 178 mm continuous casting round billets for low carbon alloy steel were studied by industrial experiments. The results show that PMO can stably increase the equiaxed grain area, and reduce the macrosegregation of billets. Moreover, it has strong adaptability to steel grade and continuous casting process parameters. Compared with the billets without PMO treatment, for 93.8% of billets (15 billets) solidified with PMO, the equiaxed grain area ratio increased by an average of 5.8%, while for 87.5% of billets (14 billets), the carbon segregation index range decreased by an average of 0.06, though different steel grades, superheat and casting speed were used in the experiment. It is believed that convection caused by Lorentz force can accelerate the heat dissipation of steel liquid, and reduce the temperature of a liquid at the solidification front, while the magnetic oscillation effect is conducive to dendrite fragmentation. Both effects lead to refinement of the solidification structure and reduction of macrosegregation.