METHOD OF PRODUCING HOT-ROLLED SHEETS FROM LOW-ALLOY STEEL Russian patent published in 2024 - IPC C21D8/02 C21D9/46 B21B1/38 C22C38/42 C22C38/44 C22C38/48 C22C38/50 C22C38/54 

FIELD: metallurgy.

SUBSTANCE: invention relates to metallurgy, particularly, to production of hot-rolled sheets at reversing mills with application of controlled rolling. Method of producing hot-rolled sheets from low-alloyed steel involves heating of continuously cast billets for austenisation, rough rolling, finish rolling, and cooling of sheets. Continuously cast billets are made from low-alloy steel containing components at the following ratio, wt.%: carbon 0.08–0.13, silicon 0.5–0.9, manganese 1.3–1.7, sulphur not more than 0.010, phosphorus not more than 0.020, chromium is not more than 0.10, nickel is not more than 0.10, copper not more than 0.10, aluminium 0.01–0.08, niobium not more than 0.05, vanadium not more than 0.05, titanium not more than 0.05, molybdenum not more than 0.05, arsenic not more than 0.10, nitrogen not more than 0.010, tin not more than 0.010, boron not more than 0.008, calcium not more than 0.005, iron – balance, wherein carbon equivalent of steel C_e≤0.43. Heating of continuously cast billets for austenitizing is carried out at temperature of 1,150–1,250 °C, finish rolling is started at temperature of Ar3+(70÷170) °C and terminated at temperature Ar3+(10÷50) °C, then the sheets are cooled at rate of 3–15 °C/s to temperature of 600–750°C, after which they are cooled in air. Carbon equivalent C_e is calculated by formula: C_e=C+Mn/6+Si/24+Cr/5+Ni/40+Cu/13+V/14+P/2, where C, Mn, Si, Cr, Ni, Cu, V, P – content of corresponding components, wt.%.

EFFECT: sheets have high mechanical properties, including impact strength with a V-shaped concentrator, as well as satisfactory flatness.

6 cl, 3 tbl, 1 ex