METHOD OF PRODUCTION OF ROLLED STRIPS FROM SUPER LOW-CARBON STEEL FOR SUBSEQUENT STAMPING Russian patent published in 2003 - IPC

FIELD: metallurgy; production of strips from super low-carbon steel (IF steel) for subsequent stamping; manufacture of automobiles. SUBSTANCE: proposed method includes process of making steel containing the following components, mass-%: carbon, less than 0.01; silicon, less than 0.01; manganese, 0.1-0.15; sulfur, less than 0.008; phosphorus, less than 0.008; chromium, less than 0.003; nickel, less than 0.003; copper, less than 0.004; nitrogen, less than 0.006; titanium, 0.015-0.035; niobium, 0.03-0.065; iron and unavoidable admixtures being the remainder; steel is teemed in slabs which are heated to temperature of 1100-1200 C; then, hot rolling is performed at temperature of termination of process of 890- 910 C, after which strips are wound in rolls at temperature dictated by the following dependence : T_wind = -0,19k²-, where T_wind is temperature of winding, C; k is coefficient characterizing degree of steel stabilization which is equal to: k = (Nb+1.9375(Ti-3.43N-1.5S) C, where Nb, Ti, N, S and C show content of niobium, titanium, nitrogen, sulfur and carbon, mass-%; then, strips are subjected to pickling, cold rolling, continuous annealing and skin rolling at cogging lesser than 1%. EFFECT: enhanced smoothness of mechanical properties over length of strip; improved quality of surface.