METHOD OF BLOWING HIGH-CHROMIUM STEELS Russian patent published in 2006 - IPC C21C5/35 

FIELD: ferrous metallurgy; methods of production of stainless steels; melting high-chromium (more than 9% of chromium) steels in converters at near-bottom or bottom blast (AOD, CLU,KCB-S processes).

SUBSTANCE: proposed method of blowing high-chromium steels in bottom-blown converters includes pouring high-chromium melt into bottom-blown converter, oxidizing blowing of the melt with oxygen and neutral gases through upper water-cooled lance and near-bottom lances, blowing with argon-oxygen mixture through near-bottom lances at content of carbon in metal from 0.15 to 0.20%. Then ratio of O₂ to inert gas is smoothly reduced from 6/1 at the beginning of oxidizing blowing to 1/6 at the end of blowing with argon-oxygen mixture. As soon as content of carbon in metal reaches 0.04-0.10%, melt is blown with argon only through near-bottom lances at intensity of 30-70 m³/min continued for 5-10 minutes, after which deoxidants and slag-forming materials are added.

EFFECT: reduced melting time; stable low content of carbon in metal ; reduced consumption of deoxidants, alloying agents and energy carriers; improved quality of metal.

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