STEEL ALLOY FOR LOW-ALLOYED STEEL FOR PRODUCTION OF HIGH-STRENGTH SEAMLESS STEEL PIPES Russian patent published in 2013 - IPC C22C38/38 C22C38/24 

FIELD: metallurgy.

SUBSTANCE: steel has the following chemical composition, wt %: 0.15 - 0.18 C, 0.20 -0.40 Si, 1.40 - 1.60 Mn, not more than 0.05 P, not more than 0.01 S, not more than 0.50 to 0.90 Cr, from more than 0.50 to 0.80 Mo, from more than 0.10 to 0.15 V, 0.60 - 1.00 W, 0.0130 - 0.0220 N, iron, and admixtures from melting - balance. The ratio V/N makes from 4 to 12, and steel may additionally contain one or several elements from: Al not more than 0.03, Ni not more than 0.40, Nb not more than 0.04, Ti not more than 0.04.

EFFECT: pipes have required strength characteristics, proper general welding characteristics and required quality of surface during hot rolling.

6 cl, 1 tbl