Brittle fracture characteristics to excellent under-matching for welding metal

摘要

PROBLEM TO BE SOLVED: To provide weld metal which has high strength and with which sufficient fracture toughness can be assured even if the hardness of the weld metal in a welded joint part is below ≤210 in welding of a thick steel plate having a plate thickness exceeding 50 mm.;SOLUTION: The weld metal for under matching having the excellent brittle fracture resistance growth characteristic is a metallic structure of ≤210 in hardness (Hv) of the weld metal in the welded joint of a welded structure, ≤8 μm in the diameter of the equivalent circle in the crystal particle diameter of the weld metal, ≤10% in the area rate of the island-shaped martensite of the weld metal and ≤40% in the area rate of the ferrite of a length ≥30 μm and a width ≥10 μm.;COPYRIGHT: (C)2006,JPO&NCIPI