| 摘要 |
PROBLEM TO BE SOLVED: To provide a flux for submerged arc welding which achieves an excellent welding work efficiency and enables diffusible hydrogen amount in a weld metal to be reduced even in any of an AC type and a DC type welding power source.SOLUTION: The flux for submerged arc welding has a composition which contains AlO: 15 -35 mass%, SiO: 10 -30 mass%, MgO : 10 - 25 mass%, F (in terms of CaFconversion value) : 10 - 25 mass%, Mn (in terms of MnO conversion value) : 3 - 20 mass%, Na (in terms of Naconversion value) and/or K (in terms of KO conversion value) : 0.5 - 4.5 mass% in total, Fe (in terms of Fe conversion value) : 0.5 - 8 mass% in total, and CaO : regulated to 6 mass% or less and water soluble SiO: regulated to less than 1 mass%, and satisfies the following numerical expression (1). |
