HOT-ROLLED STEEL SHEET AND METHOD OF ITS PRODUCTION Russian patent published in 2015 - IPC C21D8/02 B21B3/02 C22C38/06 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of the hot-rolled steel sheets. The hot-rolled sheet is made out of steel containing in wt %: C from 0.01 to 0.4, Si from 0.001 to 2.5, Mn from 0.001 to 4.0, Al from 0.001 to 2.0, P 0.15 or below, S 0.03 or below, N 0.01 or below, O 0.0 or below, Fe and inevitable admixtures - rest. Average pole density of the orientation group from {100}<011> to {223}<110> is equal to arithmetic average of the pole densities of each orientation of the crystals {100}<011>, {116}<110>, {114}<110>, {112}<110> and {223}<110>, that is from 1.0 to 5.0, and pole density of the orientation of the crystal {332}<113> is from 1.0 to 4.0 at central area of thickness from 5/8 to 3/8 of steel sheet surface. The metallographic structure of the steel sheet includes multiple grains, in % over area: from 30 to 99 of ferrite and beinite, and from 1% to 70% of martensite, at that dia ≤ 13 where dia is average size of martensite grains, micron, TS/fM×dis/dia ≥ 500, where TS is tensile strength of the steel sheet, MPa, fM is portion of martensite area, in % of area, dis is average distance between martensite grains, micron. During the sheet manufacturing the hot rolling is performed by several runs with temperature determined by the reduction ratio and cooling rate.

EFFECT: production of the hot sheet with high strength, uniform deformability, in particular local deformability.

21 cl, 2 dwg, 22 tbl