HIGH-STRENGTH STEEL PIPE AND HIGH-STRENGTH STEEL PLATE HAVING EXCELLENT DEFORMABILITY AND LOW TEMPERATURE IMPACT TOUGHNESS, AND METHOD OF MANUFACTURING OF STEEL PLATE Russian patent published in 2016 - IPC C21D8/10 C22C38/00 C21D8/02 

FIELD: metallurgy.

SUBSTANCE: steel pipe is manufactured by welding of the base steel plate formed as pipe, at that the base steel plate contains in wt %: C: from 0.010 to 0.080, Si: from 0.01 to 0.50, Mn: from 1.2 to 2.8, S: from 0.0001 to 0.0050, Ti: from 0.003 to 0.030, B: from 0.0003 to 0.005, N: from 0.0010 to 0.008, O: from 0.0001 to 0.0080, P 0.050 or below, Al 0.020 or below, Mo 0.03 or below, optionally one or several elements from Cr, Cu and Ni, Fe and accompanying admixtures - rest, at that Ceq calculated according to equation is from 0.30 to 0.53, and Pcm calculated according to equation is from 0.10 to 0.20, metal structure of the base steel plate contains from 27 to 90%, as recalculated per area, of polygonal ferrite and solid phase, comprising beinite and/or martensite, as its residues.

EFFECT: assurance of high strength, increased deformability and low temperature impact toughness.

21 cl, 6 tbl, 14 dwg