HOT-ROLLED SHEET FROM LOW-ALLOY STEEL FOR HIGH-PRESSURE VESSELS AND METHOD OF ITS PRODUCTION Russian patent published in 2025 - IPC C21D8/02 C21D9/46 B21B1/38 C22C38/42 C22C38/44 C22C38/46 C22C38/48 C22C38/50 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, namely to the production of sheets on reversing mills used for the production of vessels operating under pressure. Hot-rolled sheet of low-alloy steel for high-pressure vessels is made of steel containing, wt.%: carbon 0.08-0.13, silicon from 0.10 to less than 0.50, manganese 0.9-1.3, sulphur is not more than 0.010, phosphorus not more than 0.020, chrome 0.05-0.30, nickel 0.01-0.30, copper 0.05-0.30, aluminium 0.01-0.08, niobium not more than 0.06, vanadium not more than 0.06, titanium 0.005-0.050, molybdenum not more than 0.05, arsenic not more than 0.10, nitrogen not more than 0.008, tin not more than 0.010, boron not more than 0.008, calcium not more than 0.005, iron – the rest, wherein carbon equivalent of steel C_e≤0.43%. Method of producing a hot-rolled sheet from low-alloy steel for high-pressure vessels includes steel melting, its out-of-furnace treatment, steel casting into continuously cast billets, performing their austenisation in a furnace, tempering, rough rolling, finishing rolling, which is started at temperature of 890-970 °C and terminated at temperature of 840-900 °C, after which the sheets are cooled in air.

EFFECT: sheet has a ferrite-pearlite structure, with a ferrite grain size of not more than 10 points, a score of non-metallic inclusions of not more than 2.5 points on the average, yield point is not less than 220 MPa, ultimate strength is 410-560 MPa, relative elongation is not less than 21%, impact viscosity KCV_-46 is not less than 34 J/cm².

8 cl, 3 tbl, 1 ex