STEEL MAKING METHOD Russian patent published in 2013 - IPC C21C7/04 C21C7/10 

FIELD: metallurgy.

SUBSTANCE: method involves melting in an arc furnace of a semi-finished product, pouring of molten metal into a ladle, feeding of solid slag mixture and alloying additives, treatment of molten metal with the main slag, balancing argon blowdown, control of molten metal oxidation, aluminum deoxidation, vacuum slag treatment and vacuum casting; with that, pouring of molten metal into the ladle is performed without slag cutoff, and treatment of molten metal in the ladle is performed using slag with basicity of (CaO+Al₂O₃)SiO₂, which is equal to 4, 5…16. With that, vacuum slag treatment is performed for two times provided that the first vacuum slag treatment is started at oxygen activity in molten metal of 0.01…0.05 wt % and total content in the slag of iron and manganese oxides in the range of 15…25 wt %, and the second vacuum slag treatment is performed at oxygen activity in the molten metal of not more than 0.01 wt % and total content in the slag of iron and manganese oxides of not more than 5 wt %, and addition of slag forming and alloying components is performed prior to the second vacuum slag treatment.

EFFECT: invention allows creating an economical steel making technology providing low content of hydrogen and sulphur in steel, and increasing viscosity and ductility of steel.

4 cl, 3 tbl