Abstract：With the increase of phosphorus content in hot metal, it becomes more and more difficult to control the phosphorus content of pipeline steel in 250t combined blowing converter of the Hanbao steel-making plant. the thermodynamics and dynamics theory about dephosphorization of converter steelmaking process was analyzed, and the measures were introduced including remaining slag practice to raise the effect of dephosphorization, increasing the slag basicity, application of less slag when the phosphorus content of hot metal preponderate over 0.12%, control of lance movements of 200 mm higher than before, and the application of slag-stopping tapping by slide gate, etc. After application of these measures, the average w［P］ at blowing end-point reduced from 0.0122% to 0.0089%, and the w［P］ at ladle reduced from 0.0135% to 0.0096%. It has provided theoretical basis for Hanbao Steel to produce clean steels such as high-level pipeline steel.
2015, Vol. 25 
