HIGH-STRENGTH COLD-ROLLED SHEET STEEL CHARACTERIZED BY HIGH FORMABILITY AND METHOD FOR MANUFACTURE THEREOF Russian patent published in 2021 - IPC C22C38/38 C22C38/28 C22C38/26 C22C38/24 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: invention relates to the area of metallurgy, namely to cold-rolled sheet steel used in manufacture of vehicle parts. The steel has a chemical composition containing, % wt.: 0.19 ≤ carbon ≤ 0.24, 1.9 ≤ manganese ≤ 2.2, 1.4 ≤ silicon ≤ 1.6, 0.01 ≤ aluminium ≤ 0.06 , 0.2 ≤ chromium ≤ 0.5, phosphorus ≤ 0.02, sulfur ≤ 0.03, if necessary, at least one element from: niobium ≤ 0.06, titanium ≤ 0.08, vanadium ≤ 0.1 and calcium ≤ 0.005, the rest is iron and inevitable impurities. The steel has a microstructure including 5 to 15% tempered martensite, 10 to 15% residual austenite and optionally up to 5% ferrite expressed as surface area fractions, wherein the residue constitutes bainite, wherein the content of bainite is no less than 70%.

EFFECT: steel exhibits the required high strength and formability.

15 cl, 4 tbl