HOT-ROLLED STEEL STOCK FOR HIGH-STRENGTH ELECTRIC WELDED TUBE EXCELLING IN TOUGHNESS AT LOW TEMPERATURE AT ELECTRIC WELD ZONE

摘要

PURPOSE:To manufacture the titled hot-rolled steel stork excelling in toughness at low temp. at the electric weld zone by incorporating specific percentage of C, Si, Mn, Ti, SolAl, P, S, O, N, V and Nb to Fe and by uniformly dispersing Ti oxides with specific grain size. CONSTITUTION:The hot-rolled steel stock for high-strength electric welded tubes consisting of, by weight, 0.03-0.15% C, 0.05-0.50% Si, 0.60-1.60% Mn, 0.005-0.060% Ti, =0.0150% SolAl, 0.001-0.020% P, 0.0003-0.030% S, 0.0005-0.0100% O, 0.0010-0.0120% N, uniformly dispersed Ti oxides with a size of 0.01-50mu, and the balance essentially Fe and further containing 0.005-0.300% V and/or 0.010-0.060% Nb is prepared. This hot-rolled steel stock has remarkably improved toughness at low temp. at the electric weld zone.