Filler Metal Alloy B-3 is used for the gas metal arc (GMAW) of nickel-molybdenum alloy (ASTM B 333, B 335, B 366, B 564, B 616, B 622 and B 626 having UNS number N10675) including B-3® alloy to itself, for welding the clad side of joints in steel clad of nickel-molybdenum alloy, and for welding nickel-molybdenum alloys to steel and to other nickel base alloys. The alloy has outstanding resistance to hydrochloric and sulfuric acids in the as-welded condition and excellent thermal stability. Filler Metal Alloy B-3 is a great candidate for overlay and cladding where resistance to hydrochloric and sulfuric acids is needed.