STEEL WIRE FOR LARGE HEAT INPUT SUBMERGED ARC WELDING AND METHOD OF MANUFACTURING SUBMERGED ARC WELDED JOINT AS WELL AS SUBMERGED ARC WELDED JOINT

摘要

PROBLEM TO BE SOLVED: To provide a steel wire for large heat input submerged arc welding which makes it possible to obtain weld metal having excellent toughness and a method of manufacturing a welded joint as well as the welded joint.;SOLUTION: The steel wire containing 0.03 to 0.10% C, ≤0.0035% N, ≤0.40% Si, 1.0 to 2.5% Mn and ≥0.003% Ti and satisfying Ti/N: 15 to 50 is used as the welding wire in welding steel products having a base metal composition of ≤0.006 mass% Ti and ≤0.012% Nb by large heat input submerged arc welding of heat input ≥159 kJ/cm. The steel wire may further contain one or ≥2 kinds among Mo, Nb, B and Ni. A flux containing boron oxide or further ≤0.0030 mass% N of iron powder is preferably used. As a result, the weld metal has a structure of ≤15 area% in grain boundary ferrite quantity and has high toughness.;COPYRIGHT: (C)2002,JPO