FLUX USED IN SUBMERGED ARC WELDING

摘要

PURPOSE: A flux used in a submerged arc welding is provided to improve an external appearance of a bead and to achieve superior impact toughness by controlling fluidity of slag when performing a welding process. CONSTITUTION: A flux used in a submerged arc welding includes 10 to 20 wt.% of SiO2, 20 to 35 wt.% of Al2O3, 20 to 30 wt.% of MgO, 10 to 25 wt.% of CaF2, 1 to 3 wt.% of CaO, 1.0 to 5.0 wt.% of FeO, 4.0 to 8.0 wt.% of MnO, 1.0 to 3.0 wt.% of Na2O+K2O. A ratio of MgO to SiO2+CaO is within a range of 1.00 to 2.20. Content of CO2 is under 1 wt.%. The amount of flux having a grain size larger than 1.7mm is less than 10 wt.%, and the amount of flux having a grain size less than 500 micrometer is less than 10 wt.%.