Effects of pulse magneto-oscillation on GCr15 bearing steel continuous casting billet

Pulse magneto-oscillation (PMO) added during solidification could affect the solidification structure and macrosegregation. A modified thermal simulation equipment was applied to prepare GCr15 bearing steel continuous casting billets with different PMO peak currents. Then, metallographic analysis, component analysis and numerical simulation were adopted to study the influence of PMO peak current and its mechanism. The sample with 150 KIA PMO peak current treatment has little difference with the samples without PMO treatment on solidification structure and macrosegregation. As the peak currents are 250 and 350 KIA, the columnar zone increases and macrosegregation aggravated. When 450 KIA peak current is selected, the equiaxed grain ratio is enlarged, and the dendritic grains are refined, and the macrosegregation of C, Cr, Si and Mn is decreased significantly. By analyzing, different convections induced by PMO with various peak currents are the key factor to change the solidification structure and macrosegregation.