METHOD OF STEEL MICROALLOYING Russian patent published in 1999 - IPC

FIELD: ferrous metallurgy, particularly, production of steel of high strength. SUBSTANCE: method includes determination of content of chromium, nickel and copper before deoxidation of steel; deoxidation; alloying and microalloying of melt. Amount of microalloying element introduced into steel is calculated by formula: E=D/K+L(A-Cr)+M(B- Ni)+N(C-Cu), where E is amount of microalloying element introduced into steel, %; D is medium grade content of microalloying element, %; K is coefficient of assimilation of microalloying element by steel; L,M,N are proportionality factors; A,B,C are mean contents in steel of chromium, nickel and copper, respectively, %; Cr,Ni,Cu are contents of these element in metal before deoxidation, respectively, %. If microalloying element is used in form of niobium, proportionality factors L, M and N in said formula equal 0.015, 0.005 and 0.025, respectively. In case of use of vanadium as microalloying element, these factor are equal to 0.035, 0.020 and 0.045, respectively. EFFECT: stable level of steel mechanical properties in various heats. 2 cl, 2 tbl