Welding flux for use in arc-welding of stainless steels, method of welding stainless steel members using the welding flux

A welding flux for use in welding stainless steel parts to increase welding penetration, consisting essentially a base material obtained from manganese peroxide (MnO2), and an activator selected from a material group that includes zinc oxide (ZnO), silicon dioxide (SiO2), chromium oxide (CrO2), titanium dioxide (TiO2), molybdenum dioxide (MoO2), and iron oxide (Fe2O2).