Influence of Pulse Current on Inclusion Properties of Alumina in Molten Steel

Abstract

In the process of metal purification, the study of controlling the morphology and size distribution of non-metallic inclusions in steel based on electric fields has attracted extensive attention. However, the action mechanism of electric fields on inclusions in liquid steel has not been clearly identified. In this paper, the influence of pulse current on the quantity, size, and distribution of alumina inclusions in liquid steel was explored through a high-temperature energization experiment, and the action mechanism of pulse current was expounded based on the angle of interface free energy. The results show that the number of small alumina inclusions in the steel after electric pulse treatment (the pulse current density was 0.1–3 A/cm2, the frequency was 100 Hz, and the pulse waveform was a square wave) was significantly increased compared with the sample without electric pulse treatment, and the particle size was concentrated at 2–5 μm, and the inclusions were concentrated in the upper and lower parts of the sample. However, in the samples without electrification treatment, the large particles of inclusions are the majority, the particle size was concentrated at about 10 μm, and the inclusions were concentrated in the upper and middle parts of the samples. When the pulse current was applied to the molten steel, the interfacial free energy of the internal system of liquid steel alumina inclusion was reduced, the nucleation of alumina inclusion was promoted, the aggregation growth between alumina particles was inhibited, and then the migration and distribution of inclusions were also affected. The experimental results could provide technical support for high-quality steel smelting production to a certain extent.