Bonded flux for submerged arc welding and welded metal

The invention provides a bonding flux for submerged arc welding of high-Cr ferritic heat-resistant steel, which can obtain welding metal with excellent tensile strength and toughness after PWHT. A bonded flux for submerged arc welding of high-Cr ferritic heat-resistant steel contains, in mass% with respect to the total mass of the flux, 25.0% to 36.0% of MgO, 7.0% to 18.0% of Ca, 4.5% to 12.0% of F, 9.5% to 21.7% of Al2O3, 8.0% to 20.0% of SiO2, 1.0% to 8.0% of CO2, 0.5% to 4.0% of Na, 4.0% or less of ZrO2, 0.80% or less of Al, and 0.12% or less of C. When the contents of MgO, F, and CO2 in the flux are [MgO], [F], and [CO2], respectively, the value obtained by formula (1): [MgO] + 2.055 * [F]/([CO2]) is 6.0 to 45.0. 提供一种高Cr铁素体系耐热钢的埋弧焊用粘结焊剂，能够得到在PWHT后具有优异抗拉强度和韧性的焊接金属。高Cr铁素体系耐热钢的埋弧焊用粘结焊剂，以相对于焊剂总质量的质量％计，含有MgO：25.0％～36.0％、Ca：7.0％～18.0％、F：4.5％～12.0％、Al2O3：9.5％～21.7％、SiO2：8.0％～20.0％、CO2：1.0％～8.0％、Na：0.5％～4.0％，并且ZrO2：4.0％以下、Al：0.80％以下、C：0.12％以下，将焊剂中的MgO、F、CO2的含量分别设为[MgO]、[F]、[CO2]时，由式(1)：([MgO]+2.055×[F])/([CO2])得到