METHOD OF MAKING LOW-ALLOYED PIPE STEEL Russian patent published in 2004 - IPC

FIELD: ferrous metallurgy; making quality steels; making steels in converter shops. SUBSTANCE: proposed method includes delivery of metal burden and slag-forming agents to converter, blowing with oxygen at amount of 70- 75% of its total amount, flushing oxidizing slag, delivery of manganese- containing oxide material in the amount sufficient for obtaining content of manganese in metal before tapping of 0.80-0.85 of content of manganese in finished metal together with slag-forming agents in the amount sufficient for obtaining basicity of 2.5-2.8 followed by blowing metal with remaining oxygen delivered in mixture with neutral gas at monotonic change of their ratio from (0.9-0.95): (0.005-0.10) to (0.005- 0.10): (0.9-0.95), respectively at simultaneous delivery of carbon- containing oxidant at flow rate of 0.12-0.15 of flow rate of manganese- containing oxide material whose delivery is terminated 2 to 3 minutes before termination of blowing. Then, metal is tapped to ladle, deoxidized and alloyed by delivery of vanadium-containing material in form of commercial vanadium pentoxide to ladle at specific flow rate of 2.6-3.0 kg/t of steel by filling ladle by 1.5 of its volume. Then, manganese- containing oxide material is fed to ladle together with aluminum at ratio of 1: (0.30-0.35) and slag-forming agents for obtaining basicity of slag of 2.5 to 2.8. EFFECT: enhanced efficiency. 2 cl, 1 ex