Abstract: In order to achieve the BOF end-point direct-tapping without pouring slag, the key is to control the foaming slag degree for the BOF single slag process. In this paper, on the base of theoretical analysis of the influencing factors for the slag foaming degree, the effects of charging sequence and oxygen supply system on the slag foaming degree in 180 t BOF were studied by production trial, the conclusions are as follows: improving the adding methods of lime, dolomite and coolant, at the same time controlling the oxygen supply based on the TSC measuring information can reduce the final slag foaming degree greatly. After taking the above three measures, the average deslagging angle of the 180 t BOF is increased from 84 ° to 90.3 °, the BOF direct-tapping rate without pouring slag at the blowing end-point is increased from 10 % to 50 %, and the tapping tem perature loss is reduced by 6 ℃to10 ℃ compared with the conventional tapping process.

Key words: BOF, direct-tapping, foaming slag, charging sequence, oxygen supply system