METHOD FOR PRODUCING WILD-ROLLED HIGH-STRENGTH SHEETS FROM LOW-ALLOY STEEL Russian patent published in 2021 - IPC C21D8/02 C21D9/48 C22C38/06 C22C38/12 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely the production of cold-rolled high-strength rolled products from low-alloy steels, which can be used in the automotive industry. The method includes steel smelting, casting, hot rolling, water cooling, coiling of strips into coils, cold rolling, recrystallization annealing. Smelt steel containing, wt. %: C - 0.05-0.07, Mn - 0.35-0.60, Si 0.02-0.07, Al - 0.03-0.06, N - no more than 0.007, Nb - 0.025 -0.035, Fe and inevitable impurities - the rest. The temperature of the end of hot rolling and the temperature of recrystallization annealing are calculated according to the dependencies, and the temperature of the coiling of hot-rolled strips is maintained in the range of 560-620°C. Recrystallization annealing is carried out when processing cold-rolled steel in a continuous annealing unit, in which the end of accelerated cooling and the beginning of over-aging for rolled products with a minimum yield strength of 300 MPa and 340 MPa is carried out at a temperature in the range of 360-380°C, and for rolled products with a minimum the value of the yield point of 380 MPa - in the range of 400-420°С.

EFFECT: increased ductility and expanded technological capabilities by obtaining from steel the same chemical composition of rolled products of different strength classes, i.e. creation of cassette technology.

1 cl, 2 tbl