Controlling the spatial distribution and alignment of inclusions in sulfur containing steel by pulsed electric current

Driving the separation of inclusions is crucial for purifying molten steel and avoiding nozzle clogging. However, small sized inclusions with the density close to that of molten steel are difficult to be driven. In other words, the method to separate inclusions in molten steel based on Stokes' law has certain limitations. This study investigates the spatial distribution and alignment behavior of sulfide inclusions in sulfur containing steel. It proposes an innovative approach to separate inclusions in molten steel by utilizing the difference in electrical properties between inclusions and the matrix. The influence of frequency and current intensity on the purification effect of inclusions was studied. It was found that under the action of pulsed electric current, inclusions would move away from the electrode area, forming purification zone. The removal effect of inclusions in the molten steel increases with the increase of frequency and current intensity. At the parameters of 5000 Hz and 250 A, the removal rate of inclusions reached 52%. Amazingly, inclusions also tend to align along the direction of the current line. Combining numerical calculations, it was found that under the action of pulsed electric current, inclusions tend to migrate from high current density regions to low current density regions in order to achieve the lowest system energy. This study provides an effective solution for the purification of sulfur containing steel and the inhibition of nozzle clogging. At the same time, it also provides a new path for improving the clean and purified smelting of other metal materials.