Method for manufacturing flat steel products from boron microalloyed multi-phase steel

摘要

A method, which allows high-tensile flat steel products to be manufactured with less effort includes a steel that forms a multi-phase microstructure and contains (in wt. %) 0.08-0.12% C, 1.70-2.00% Mn, up to 0.030% P, up to 0.004% S, up to 0.20% Si, 0.01-0.06% Al, up to 0.0060% N, 0.20-0.50% Cr, 0.010-0.050% Ti, 0.0010-0.0045% B, remainder iron and unavoidable impurities, being cast into a cast strip having a thickness of 1-4 mm. The cast strip is hot-rolled in-line into a hot-rolled strip having a thickness of 0.5-3.2 mm in a continuous process at a final hot-rolling temperature ranging from 800 to 1100° .C, the deformation degree being greater than 20%. The hot-rolled strip is coiled at a coiling temperature ranging from 250 to 570° C., so as to obtain a hot-rolled strip, which has a minimum tensile strength R_m of 800 MPa at a minimum breaking elongation A₈₀ of 5%.