RESEARCH AND IMPROVEMENT OF MODES FOR BLOWING ELECTRIC RAIL STEEL MELT DURING PROCESSING ON THE LADLE-FURNACE UNIT

Using simulation of the melt purging process in a steel ladle, carried out in relation to the conditions of the electric steel melting shop of JSC EVRAZ ZSMK, the regularities of the influence of the intensity of purging on the parameters characterizing the intensity of metal mixing: mixing power and effective diffusion coefficient were determined. It is shown that an increase in the intensity of purging with an inert gas within a wide range of variation of this indicator increases the mixing power, regardless of the mode of outflow of gas jets and the direction of transfer. At the same time, the effect of the specific flow rate of the inert gas injected into the melt on the mixing intensity is more pronounced for the jet purge mode compared with the bubble mode, which makes it possible to determine the characteristics of the melt homogenization process when calculating the effective diffusion coefficient. Based on statistical studies, it was determined that in the conditions of the workshop under consideration, an increase in the duration of periods of purging of rail steel with an intensity of more than 1.1 m³/min. It has a significant effect on reducing rail rejection due to the presence of non-metallic inclusions. The obtained results of theoretical and analytical studies were the basis for the development of an improved mode of purging rail steel with inert gas during processing on the bucket furnace unit. A distinctive feature of the improved mode is the presence in the second half of the purge period with an increased to 1.2 – 1.6 m³/min intensity of inert gas supply with a duration of at least 10 minutes. Pilot testing of the developed inert gas purge mode has confirmed its effectiveness in terms of refining rail steel from non-metallic inclusions. In a series of 110 experimental smelters, a decrease in rail rejection due to the presence of non-metallic inclusions was recorded by 0.6 %.

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