METHOD OF OPEN HEARTH MAKING OF LOW-HARDENABILITY STRUCTURAL STEEL Russian patent published in 2001 - IPC

FIELD: metallurgy, particularly, making of structural steels with low hardenability in open-hearth furnaces. SUBSTANCE: method of production of carbon steel with low hardenability includes charging into open-hearth furnace of metallic charge from iron-carbon alloy and scrap with content in them of Cr, Ni and Cu ensuring their content after melting in melt within 0.10%; introduction of slag-forming materials; heating and melting of burden; slag skimming; bath heating up to temperature of beginning of melt finishing; melt finishing to obtain the required composition and temperature during periods of shaping-up and lime boiling; correction of slag composition during shaping-up and lime boiling by skimming from furnace of a part of slag and periodic additions of slag-forming materials to ensure content of Mn in melt tapping not more 0.10%. Metal is deoxidized in furnace and during tapping into ladle or in ladle with Al and Ti alloys which are introduced with consumption value ensuring in finished metal of Al in amount of 0.03-0.10% and Ti in amount of 0.06-0.12%. Si and its alloys are introduced into melt after its deoxidation with Al and Ti. Iron-carbon alloy is used in the form of semiproduct obtained after devanadization of vanadium iron or blast-furnace conversion pig iron with Mn content of not more 0.5. Si and its alloys are introduced into ladle in deoxidized steel after introduction into melt of 100% of Al and at least 50% of required amount of Ti during filling of ladle with melt up to its 2/3 volume. EFFECT: higher strength and service properties of steel produced by proposed method. 4 cl, 1 ex