COLD-ROLLED AND ANNEALED STEEL SHEET, METHOD OF ITS PRODUCTION AND USE IN PRODUCTION OF AUTOMOTIVE PARTS Russian patent published in 2020 - IPC C22C38/58 C22C38/38 C22C38/06 C21D8/04 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to cold-rolled and annealed steel sheet used for production of vehicle parts. Sheet has chemical composition, containing, wt %: 0.6≤C≤1.3, 15.0≤Mn≤35, 5≤Al≤15, Si≤2.40, S≤0.03 %, P≤0.1 %, N≤0.1, optionally, at least one of Ni, Cr and Cu in amount of up to 4.0 %, 3.0 % and up to 3.0 %, and optionally at least one of B, Ta, Zr, Nb, V, Ti, Mo and W in total amount up to 2.0 %, balance—iron and unavoidable impurities. Microstructure of said sheet is austenite and contains up to 3 % of kappa-carbides and, if necessary, up to 5 % of granular ferrite. Average grain size and average austenite grain aspect ratio are less than 6 mcm and 1.5–6, respectively, and average grain size and average ratio of ferrite sides, in case of its presence, respectively less than 5 mcm and less than 3.0.

EFFECT: obtaining sheet with required mechanical properties.

15 cl, 4 tbl