HIGH-TENSILE STRENGTH STEEL WELD JOINT HAVING EXCELLENT RESISTIVITY TO GENERATION OF DUCTILE CRACK FROM WELD ZONE, AND METHOD FOR PRODUCING THE SAME

摘要

PROBLEM TO BE SOLVED: To provide a high-tensile strength steel weld joint having excellent resistivity to the generation of ductile cracks from a weld zone, particularly, from a weld toe, and suitably used for the field of ground structures such as bridges and buildings subjected to an earthquake load.;SOLUTION: The high-tensile strength steel weld zone having excellent resistivity to the generation of ductile cracks from a weld zone is obtained by subjecting a steel member having a composition comprising 0.01 to 0.12% C, 0.01 to 0.5% Si, 0.4 to 2% Mn, ≤0.05% P, ≤0.003% S, 0.002 to 0.05% Al and 0.0030 to 0.01% N, and the balance Fe with impurities, and satisfying 0.05≤(Si/30)+(Mn/20)+(Cu/20)+(Ni/60)+(Cr/20)+(Mo/15)+(V/10)≤0.15 as a base material to arc welding, and, in the microstructure on the side of the heat-affected zone in a weld toe, the fractions of ferrite and bainite are 10 to 40% and ≥50%, respectively.;COPYRIGHT: (C)2009,JPO&INPIT