| 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.
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