METHOD OF PRODUCING HOT-ROLLED SHEETS FROM LOW-ALLOYED TUBE STEEL OF K60 STRENGTH GRADE FOR LONGITUDINAL ELECTRIC-WELDED PIPES Russian patent published in 2017 - IPC C21D8/02 C22C38/38 B21B1/26 

FIELD: metallurgy.

SUBSTANCE: continuously cast steel ingots are produced containing, in wt %: 0.07-0.10 C, 0.20-0.35 Si, 1.60-1.75 Mn, not more than 0.10 of Cr, not more than 0.30 of Ni, not more than 0.20 of Cu, 0.010-0.025 Ti, 0.065-0.090 V, 0.040-0,060 Nb, not more than 0.5 of Mo, not more than 0.008 of N, 0.020-0.050 Al, not more than 0.004 of S, not more than 0.015 of P, Fe and inevitable impurities - the rest and having a total content of V+Ti+Nb not more than 0.15%, then the heating of the ingot to 1200±10°C, rough rolling with a regulated roll reduction in thickness, multiple of 4-5 thickness of the finished sheet, cooling down, finish rolling at the start temperature of 740-780°C and - and the finish temperature of 730-770°C, accelerated cooling to 580-680°C and air cooling are carried out to obtain a structure mainly consisting of bainite and ferrite.

EFFECT: ensuring of the given mechanical properties of the finished steel.

4 cl, 3 tbl