Abstract: Based on the oxygen supply parameters of a 100 t converter, a secondary combustion oxygen lance nozzle was designed and the turbulent jet characteristics of the fluid inside the converter were described through  k-ε  model calculation. A secondary combustion oxygen lance nozzle with a diameter of 13.3 mm, a tilt angle of  38°, and 8 secondary holes was design. The nozzle was applied in industrial production under the condition of oxygen flow rate of  24 500-26 000 m³/h and working oxygen pressure of 0.85 MPa. Industrial tests showed that the secondary combustion oxygen lance nozzle could meet the normal requirements for converter slagging. Compared to conventional oxygen lance nozzles, the secondary combustion oxygen lance nozzle had better smelting effect at the upper limit of oxygen flow rate of 26 000 m³/h, which was beneficial for controlling converter splashing and slag overflow. The secondary combustion oxygen lance nozzle could exert the secondary combustion effect of CO in the furnace, increase the temperature of molten steel by 23.80 ℃, increase the scrap ratio by 1.48%, and achieve good application results.

Key words: combined blowing converter, secondary combustion nozzle, slagging, heat effect