PROCEDURE FOR PRODUCTION OF RAIL STEEL Russian patent published in 2011 - IPC C21C5/52 C21C7/00 

FIELD: metallurgy.

SUBSTANCE: procedure consists in charging metal scrape into furnace; as carburiser there is used hard iron at amount of 15-55 % of charge weight. Oxidising period is carried on till production of steel with contents of carbon reaches 0.15-0.65 %. Coke breeze is added into a ladle at amount of 0.1-0.8 % of liquid steel weight, also there is added lime at amount of 3-8 kg/t of steel and manganese alloys. At tapping steel from the furnace it is inert-gas flushed in the ladle through bottom tuyeres at consumption of 0.003-0.020 m³/ton of steel and intensity 3-20 m³/h. Further, steel is processed in the ladle-furnace installation to temperature 1590-1650°C and there is produced steel of chemical composition with required amounts of carbon, manganese, silicon and vanadium. During processing steel is inert-gas flushed in the ladle through bottom tuyeres at consumption of 6-25 m³/h, treated in a vacuum vessel of a chamber type at pressure below 0.3 torr. Also, steel is continuously flushed with nitrogen through bottom tuyeres at intensity 3-30 m³/h and consumption 0.01-0.35 m³/t of steel at total duration of processing for 10-65 min.

EFFECT: reduced concentration of oxygen in steel and impurity with non-metal inclusions; reduced consumption of ferro-alloys, upgraded complex of physical-mechanical properties of rail steel and reduced power consumption and duration of steel melting.