Hot-rolled strip having a dual-phase structure

Abstract

The invention relates to a method of producing hot-rolled strip having a dual-phase structure from a slab previously produced by ingot casting or continuous casting. The slab contains carbon, manganese, silicon and chromium as essential constituents in addition to iron. The slab is heated up to the rolling temperature, hot-rolled at a temperature above A.sub.r3, rapidly cooled from the rolling temperature and coiled at a relative low temperature. The characterizing features of the invention are that the hot-rolled strip (a) is produced from a steel which, in addition to 0.05 to 0.16% of C, 0.5 to 1.0% of Si, 0.3 to 1.5% of Cr, .ltoreq.0.025% of P, .ltoreq.0.015% of S, 0.02 to 0.10% of Al and .ltoreq.0.011% of N, contains 0.2 to 0.4% of Mn, the remainder being iron and usual impurities, (b) is rapidly cooled, immediately after finish-rolling, from final rolling temperature down to the coiling temperature at a mean rate in the range from 30.degree. to 70.degree. C./s and without interruptions, and (c) is then coiled at a temperature in the range from 350.degree. to 190.degree. C.

Dependencies are inferred from the claim text.