[en] It is possible that the corrosion resistance at the overpack welds is different from that at base metal due to the differences of material properties. In this study, corrosion behavior of welded joint for carbon steel was compared with base metal using the specimens taken from welded joint model fabricated by TIG (Tungsten Arc Welding, GTAW), MAG (Gas Metal Arc Welding, GMAW) and EBW (Electron Beam Welding) respectively. The corrosion tests were performed for following three items. Propagation of general corrosion, pitting corrosion and crevice corrosion under aerobic condition. Stress corrosion cracking susceptibility. Propagation of general corrosion and hydrogen embrittlement under anaerobic condition. The results of these corrosion tests indicated that the corrosion resistance to general corrosion, pitting corrosion and crevice corrosion at welded metal of TIG and MAG was inferior to base metal. It is possible that the filler materials used for welding and the microstructures of weld metal affected the corrosion resistance. No deterioration of corrosion resistance was observed in any corrosion modes for EBW, which does not need filler material. Neither the base metals nor the welds is not susceptible to SCC under the carbonate concentration near that of the disposal environment. (author)