METHOD TO PRODUCE THICK-SHEET STRIP OF LOW-ALLOY STEEL Russian patent published in 2017 - IPC C21D8/02 B21B1/26 C22C38/00 

FIELD: metallurgy.

SUBSTANCE: to obtain strip of 365 Mpa strength class and higher with a guarantee of toughness at temperatures to -60°C and of viscous component ration in fracture of samples determined by falling weight test in temperature range to -20°C is at least 60% at minimum cost for alloying, continuous cast blank of steel is obtained with the following ratio of elements, wt %: Σ (C+Si)=0.54-0.82, Mn (1.894÷3.24)×(C+Si), Σ (Cr+Ni+Cu) not more than 0.15, Σ (V+Nb+Ti) no more than 0.02, N no more than 0.008, Al 0.02-0.05, S not more than 0.010, P is not more than 0.018, iron and unavoidable impurities are the rest, C_e= 0.37-0.43%, blank is subjected to rough rolling with relative reductions of at least 8% per pass, except for passes of achieving width and up to thickness of rolled piece not less than 3 thicknesses of finished sheet, to cooling and finish rolling of rolled piece at start temperature of 810-850°C and completion of 720-760°C with production of ferrite-pearlite structure with grain size not more than 9 points, which is deformed in rolling direction in ratio of at least 2:1 with respect to direction of rolled stock thickness and strip roughness of not more than 3 points. The ratio of volume fraction of ferrite to pearlite fraction is not less than 4:1.

EFFECT: production of thick sheet steel strip of low alloy steel thickness from 10 to 15 mm.

3 cl, 3 tbl