METHOD OF MANUFACTURING CONSTRUCTION ROLLED PRODUCT FROM LOW-ALLOY STEEL Russian patent published in 2019 - IPC C21D8/02 C22C38/04 C21D1/28 

FIELD: metallurgy.

SUBSTANCE: method of producing corrosion-resistant rolled products from steel with a thickness of 4–10 mm includes heating, rough rolling, finishing rolling, the steel has the following ratio of components, wt. %: carbon 0.16–0.22, manganese 1.40–1.65, silicon 0.25–0.55, chrome 0.10–0.40, nickel 0.03–0.40, copper 0.05–0.40, niobium 0.01–0.06, vanadium 0.10–0.16, phosphorus not more than 0.020, sulfur not more than 0.006, aluminum 0.01-0.06, oxygen not more than 0.003, iron and inevitable impurities are the rest; finish rolling is completed at 870–940 °C with subsequent cooling to a coiling temperature in two stages: first stage with a speed of 15÷50 °C/s up to 550÷650 °C, the second stage with a speed of 6÷15°C/s up to 450÷550°C, followed by double heating of the rolled product: first up to As₃+(20÷40) °C followed by air cooling, then to As₁±30 °C followed by air cooling.

EFFECT: obtained rolled product has the following strength characteristics: σt≥490 MPa σat≥570 MPa, with a KCU-40 impact strength of at least 40 J/cm², and with the exception of the formation of end cracks in the manufacture of parts operation of cutting.

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