METHOD OF PRODUCING EXTREMELY LOW-CARBON STEEL Russian patent published in 2019 - IPC C21C7/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of ferrous metallurgy, in particular to the production of extremely low-carbon steels with secondary treatment and casting in continuous casting plants. In the method, liquid iron with a mass fraction of sulfur of not more than 0.005 % is used, during the production of steel in the steel-ladle, flux is added in the amount of 0.5–3.0 kg/t of steel containing 0.1–15.0 % CaO, not less than 60.0 % of Al₂O₃ and no more than 15 % MgO, vacuum decarburization of steel is carried out at a pressure in the vacuum chamber of less than 25 kPa for 10–25 minutes. After the end of vacuum decarburization, aluminum and lime are introduced into the steel bucket to obtain the ratio (CaO)/(Al₂O₃) less than 1.0, alloying materials are introduced, when steel is doped with titanium-containing materials, they are introduced not earlier than 2 minutes after the addition of the last portion of the mentioned alloying materials, after which steel-ladle is fed for casting.

EFFECT: invention makes it possible to stabilize the carbon content in steel less than 0,0045 %, to increase the purity of steel from non-metallic inclusions and to reduce the number of surface defects.

5 cl, 2 tbl