METHOD OF PRODUCING ESPECIALLY-LOW-CARBON STEEL Russian patent published in 2014 - IPC C21C7/00 

FIELD: metallurgy.

SUBSTANCE: process comprises metal tapping in steel ladle at metal oxidation not over 950 ppm. Equalising blowing with inert gas is conducted for 2-60 minutes at slag residual depth of 2-150 mm to start vacuum decarburisation at metal oxygenation of 350-600 ppm and 1610-1650°C. After vacuum decarburisation aluminium and lime are added to obtain (CaO)/(Al₂O₃) ratio in cover slag of 1.0-1.7. The slag is deoxidised to (FeO)≤1.5 wt %. Ferroalloys are added to blow the melt with inert gas. At blowing, calcium-bearing agent is introduced in melt depth in amount of 0.15-0.5 kg of calcium per ton of steel. Now, ladle steel is fed for casting.

EFFECT: ruled out non-metallic inclusions, higher yield of commercial metal.

2 cl, 2 tbl