Abstract: This study aims to address the issues of coarse solidification microstructure and central segregation in Cr8Mo2SiV steel ingots by employing pulsed magneto-oscillation (PMO) technology to regulate the solidification process. Through microstructure characterization and elemental analysis, the effects of PMO peak currents (0, 1 000 $K_{\rm P}$, 1 500 $K_{\rm P}$, and 2 000$K_{\rm P}$ A) on the solidification structure and segregation behavior of Cr8Mo2SiV steel were systematically investigated. The results demonstrate that PMO treatment significantly refines the solidification structure. Under the 1 500$K_{\rm P}$ A parameter, the proportion of columnar crystal zones decreases from 30.8% in untreated samples to 8.07%, while that of the equiaxed crystal zone increases to 86.31%. Additionally, elemental segregation is markedly improved. The area of central segregation regions is reduced, and the enrichment of Cr, Mo, and other elements in interdendritic regions is diminished. The PMO mechanism promotes nucleation and internally generates electromagnetic forces that detach grains from the mold wall, thereby refining the grain structure. Furthermore, it induces a double recirculation flow within the melt, enhancing solute uniformity. This technology provides an effective solution for improving the solidification quality of Cr8Mo2SiV steel ingots.

Key words: pulsed magneto-oscillation (PMO), peak current, Cr8Mo2SiV steel, solidification structure, segregation