Flow and Dephosphorization Behavior During the Postblowing Stirring Stage in a 250 t Converter With a Single‐Flow Postcombustion Oxygen Lance

Numerical simulations and field tests on a 250 t converter studied how postblowing stirring time and bottom‐blowing flow rate affect steel flow and dephosphorization. This investigation compared the conventional and single‐flow postcombustion oxygen lances, highlighting the technology's key role in improving steel quality and productivity. The results show that increasing the postblowing stirring time or bottom‐blowing flow rate can increase the dephosphorization rate in the melt pool. When postblowing stirring was conducted for 60, 180, and 300 s, the dephosphorization rates of the conventional oxygen lance were 73.16%, 76.53%, and 79.39%, while those of the single‐flow postcombustion oxygen lance reached 79.90%, 82.35%, and 84.49%, respectively. Under different bottom‐blowing flow rates, compared with 1500 Nm 3 h −1 , when the flow rate was increased to 2400 Nm 3 h −1 , the dephosphorization rates of the conventional lance and the postcombustion lance were increased by 1.85% and 1.44%, respectively. Industrial trials demonstrated that the single‐flow postcombustion oxygen lance, compared to the conventional oxygen lance, reduced the iron content in final slag by 0.25%, decreased the phosphorus content by 0.0018%, and lowered the carbon‐oxygen concentration product from 0.00180 to 0.00167.