| 摘要 |
PROBLEM TO BE SOLVED: To provide fused flux which can achieve low oxygenation and low hydrogenation of weld metal and further has satisfactory welding work efficiency (that is removality of slag, bead shape, etc.) in submerged arc welding for forming weld metal such as a line pipe for which high toughness is required.SOLUTION: The fused flux for submerged arc welding contains: SiOof 10 to 27 mass%; MnO of 2 to 10 mass%; TiOof 2 to 6 mass%; CaO of 10 to 25 mass%; CaFof 15 to 40 mass%; AlOof 5 to 30 mass%; MgO of 2 to 10 mass%; FeO of 0.3 to 3 mass%; BOof 0.6 mass% or less; and the balance consisting of inevitable impurities. A BI value calculated by using the following formula (1) with the above contents satisfies 1.3 or more, and [%CaF]/[%CaO] satisfies 1 or more. (1) BI=(0.5[%MnO]+[%CaO]+[%MgO]+[%CaF])÷([%SiO]+0.5([%TiO]+[%AlO])) |
