Two steel plates (1) are butted together to form a Y groove having an opening (2) in the upper portion and a root face portion (3) in the lower portion, and the opening (2) of the Y groove is submerged arc welded. In this case, Ti is contained in an amount of 0.030 to 0.100% by mass, B is contained in an amount of 0.0030 to 0.0080% by mass, Al content (% by mass) is [% Al], and O content (mass). %) Is defined as [% O], a submerged arc weld metal (4) in which [% Al] / [% O] is in the range of 0.5 to 1.2 is formed. The previous root face part (3) is joined by laser welding to form a laser weld metal (5) so as to penetrate into the submerged arc weld metal (4).
展开▼
