METHOD OF REFINING OF STEEL IN LADLE-FURNACE Russian patent published in 2009 - IPC C21C7/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, namely to methods of secondary treatment of the rail steel in the ladle-furnace. The method involves electric heating of steel, gas blowing of the liquid steel through the porous bottom lances and steel treatment with slag. The electric heating of steel is performed with the rate of 0.07°C/min minimum under slag with basicity of 2.1-3.4 and initial content of ferric oxide 3% maximum, gas blowing of the liquid steel through the porous bottom lances is performed with both nitrogen and argon, and in the beginning nitrogen is blown with the flow rate of 0.08-0.25 m³/t of liquid steel and 5-40 m³/hr until the total amount of the nitrogen blown into the steel reaches 0.20 m³/t of liquid steel in which case agron blowing starts with the rate of 3-30 m³/hr.

EFFECT: reduced cost price of the manufactured steel, improved physical-mechanical properties of the steel, no nitrated ferroalloys are spent.