The Effect Of Current On Inclusion And Bubble In Molten Steel

With the progress of society and the development of science and technology, the need for the property of steel material is increasingly higher, which means that some more advanced purification technology of molten steel should be proposed that based on original refining technology. The removal and control of bubble and inclusion in molten steel by applying electric field is a potential technology in metallurgy field, which has attracted much attention of metallurgists at home and abroad.This paper firstly summarizes the traditional technology of inclusion removal, then elaborates the technology of electromagnetic purification, the application of pulse current in metallurgy, the deoxidation of solid electrolyte and the purification of power ultrasonic. In order to research the effect of additional current on molten steel, this paper adopts upper energization method and upper and lower energization method to analyze the influences of energization, current voltage, electrode position and current waveform on the inclusion and bubble in molten steel by contrast experiment. Meanwhile, the mechanism is analyzed.The results obtained from primarily exploring experiments are as follows.(1) When direct current is applied in molten steel, the bubble in molten steel will move to the negative electrode under the force of electric field. The voltage strength has little influence on the bubble removal.(2) The inclusion which size is over5μm is hardly found in the middle and central area of steel sample after applying direct current in the upper part. When direct current voltage is5V, the cathode area exist some strip MgO inclusion which is packed with alloy of Mn-Mg. When direct voltage is10V, the central area of steel sample exist some filamentous pore which contains MgO inclusion(3) In pulse current electric filed, the size of inclusion in molten steel is decreased significantly. There is only MnS inclusion which size is less than5μm in the marginal area. Meanwhile, pulse current can decrease the bubble size and has higher efficiency of bubble removal.(4) When the molten steel adopts upper and lower energization method, some inclusions gather in the cathode area of steel sample, that mainly are Al2O3inclusion and metal inclusion. While, some pore with tiny MnS inclusion gather in the anode area of steel sample. It is hard to find MnS inclusion in other areas of steel sample.(5) Lots of experiments are needed to verify the effects of current on bubble and inclusion in molten steel. The mechanism remains to be further studied.