METHOD FOR CONTINUOUS CASTING OF STEEL Russian patent published in 2004 - IPC

FIELD: ferrous metallurgy, namely continuous casting of steel to continuously cast slab cross-section ingots of steel kinds having trend for cracking and containing carbon, manganese, aluminum, sulfur, nitrogen, niobium, boron. SUBSTANCE: method of continuous casting of steel comprises steps of supplying steel to mold; drawing out of mold slab cross section ingot; feeding cooling agent onto surface of ingot in secondary cooling zone under mold; starting cooling agent supply onto surface of wide and narrow faces of slab in zone spaced from lower end of mold by distance determined according to expression M = [1 + (0.2C + 0.025 Mn + 1.1 Al + 1.7 S + 7.1 N + 2.0 Nb +25.0 B)]. In angular zones of slab along its wide and narrow faces and along the whole length of secondary cooling zone, cooling agent is not supplied along width determined according to expression: L = (0.4 - 0.6) M and Z = (0.2 - 0.5) M, where M - distance from lower end of mold until zone of starting cooling agent feed onto surface of slab along its wide and narrow faces, mm; V - speed of drawing slab out of mold, m/min; H - distance from steel meniscus in mold until its lower end, m; L - width of angular portions of surface of wide faces of slab onto which cooling agent is not fed, mm; Z - width of angular portions of surface of narrow faces of slab onto which cooling agent is not fed, mm; K - empiric coefficient equal to 33,1 - 231,5 mm•min^0,5. EFFECT: less number of rejected continuously cast slabs of steel kinds sensitive to surface and angular cracking. 2 tbl, 1 ex