METHOD FOR PRODUCTION OF HOT-ROLLED HIGH-STRENGTH ROLLED METAL Russian patent published in 2019 - IPC C21D8/02 C22C38/20 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, more specifically to rolling, and can be used for production of rolled stock for production of tubing string. Method comprises melting steel containing, wt. %: carbon 0.21–0.29, silicon 0.30–0.80, manganese 1.0–1.60, sulfur not more than 0.005, phosphorus not more than 0.015, chrome 0.10–0.40, nickel 0.10–0.40, copper 0.10–0.40, aluminum 0.02–0.07, nitrogen not more than 0.01, niobium not more than 0.01, titanium not more than 0.03, vanadium not more than 0.01, molybdenum not more than 0.01, calcium not more than 0.02, iron and unavoidable impurities – the rest, continuous casting into slabs, heating of slabs, hot rolling at finish rolling finish temperature in range T_nr+20 °C÷A_r3+50 °C, where T_nr – temperature of recrystallisation stopping, °C, cooling of rolled stock after finish rolling for first 10–15 s in air, and then with water with cooling rate of not more than 9 °C/s at the first section and not more than 5 °C/s at second, strip coiling in range of 580÷640 °C with ferrite-pearlite structure with ferrite content of 40–70 % in which there are no elements of quenching type structure.

EFFECT: improving strength properties and corrosion resistance of rolled stock.

1 cl, 3 tbl