Optimization of the blowing sequence in a top and bottom blowing converter containing pretreated hot metal

Experimental and theoretical studies have been carried out to clarify metallurgical reactions in combined blowing converters affected by the oxygen flow rates from the top and the bottom of the furnace. The 5t combined blowing converter showed a decrease in oxygen content in the bath with in increase in the oxygen flow rate from the bottom, while the 5t bottom blowing converter showed a decrease in oxygen content with a decrease in the oxygen flow rate. These experimental results are interpreted in terms of an index, I, related to the inverse of the oxygen efficiency used for decarburization. Oxygen content in the steel melt and (T.Fe) in slag decrease with the decrease in the I value from LD to Q-BOP, which indicates that I is suitable for characterizing metallurgical reactions. The metallurgical reactions at blow end can be controlled by changing the oxygen flow rates of top and bottom blowing, based on the aimed I value.