HIGH TOUGHNESS STEEL FOR HIGH STRENGTH WELDED STRUCTURE HAVING EXCELLENT BASE METAL TOUGHNESS AND ULTRAHIGH HEAT INPUT WELD ZONE HAZ TOUGHNESS, AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a high toughness steel for a high strength welded structure having excellent base metal toughness and ultrahigh heat input weld zone HAZ toughness.;SOLUTION: The high toughness steel for the high strength welded structure having excellent base metal toughness and ultrahigh heat input weld zone HAZ toughness has a composition containing, by weight, 0.01 to 0.20% C, 0.02 to 0.50% Si, 0.3 to 2.0% Mn, ≤0.03% P, 0.0001 to 0.030% S, 0.0005 to 0.050% Al, 0.003 to 0.050% Ti, 0.0001 to 0.005% Mg and 0.0001 to 0.005% Ca, and the balance iron with inevitable impurities, and further comprising one or more kinds selected from 0.005 to 0.30% Cr, 0.001 to 0.20% Nb and 0.005 to 0.30% Mo.;COPYRIGHT: (C)2006,JPO&NCIPI