Flux for submerged arc welding, submerged arc welding method, and method for producing flux for submerged arc welding

摘要

Provided is a flux for submerged arc welding that is excellent in slag removability while suppressing the generation of iron grains and fork marks regardless of construction conditions. As a flux used for submerged arc welding, it contains a fluoride and an oxide, and the oxide is composed of a high-melting-point oxide having a melting point of 1800° C. or higher and a low-melting-point oxide having a melting point of less than 1800° C., Ca as the high melting point oxide The oxide containing the oxide and the oxide containing Mn as the low-melting-point oxide are included, and the content with respect to the total mass of the flux is 2 to 8% by mass of Mn in terms of MnO, and the above-mentioned MnO equivalent value, in terms of CaF 2 of F , CaO conversion value of Ca and CO 2 satisfy the relationship of 1.6≤{CaF 2 conversion value/(MnO conversion value + CaO conversion value + CO 2 )}, and the high melting point with respect to the total content of the oxides The flux for submerged arc welding, wherein the ratio of the total content of oxides (sum of high melting point oxides/sum of oxides) is 0.56 or more.