FLUX FOR SUBMERGED ARC WELDING

摘要

Provided is a flux for submerged arc welding that has good welding workability and can reduce the diffusion hydrogen content in a weld metal in the use of either an AC or a DC welding power source. The flux for submerged arc welding includes Al 2 O 3 : 15 to 35% by mass; SiO 2 : 10 to 30% by mass; MgO: 10 to 25% by mass; F (in terms of CaF 2 ): 10 to 25% by mass; Mn (in terms of MnO): 3 to 20% by mass; Na (in terms of Na 2 O) and/or K (in terms of K 2 O) : 0.5 to 4.5% by mass in total; and Fe (in terms of FeO): 0.5 to 8% by mass, in which a CaO content is restricted to 6% by mass or less, a water-soluble SiO 2 is restricted to less than 1% by mass, and the flux has a composition that satisfies the following formula (I):0.2‰¤[MgO ([Al 2 O 3 ]/+[MnO])‰¤0.8(I).