METHOD OF MAKING SHEET STEEL Russian patent published in 2003 - IPC

FIELD: metallurgy; production of hot-rolled and cold-rolled steel sheets at high drawing properties for cold stamping. SUBSTANCE: steel containing the following components, mass-%: C, 0.002-0.007; Si, 0.005-0,050; Mn, 0.08-0.16; Al, 0.01-0.05; Ti 0,05-0.12; P≤, 0.015; S≤, 0.010; Cr≤, 0.04; Ni≤, 0.04; Cu≤, 004; N≤, 0/06 and Fe being the remainder is subjected to continuous teeming at rate of 0.4-1.6 m/min and temperature of 1500 to 1580 C in slabs which are heated to temperature of 1150-1240 C and are kept for 2.5-4 hours, after which they are rolled in strips at temperature of end of rolling process not below 870 C. Hot-rolled strips are cooled with water to temperature of 550 to 730 C and are rolled in rolls. After etching, strips are subjected to cold rolling at total cogging of no less than 70% and annealing at temperature of 700 to 750 C keeping them at this temperature for 11-34 h. Then, strips are subjected to skin-rolling at cogging of 0.4-1.2% at surface roughness of 2-4 mkm Ra and density of peaks of 60 to 120 l/cm. Provision is made for version according to which hot-rolled strips are subjected to annealing at temperature of 660-680 C followed by keeping them for 10-18 h. EFFECT: improved drawing properties; increased yield of sheet steel. 6 cl, 6 dwg, 1 ex