Abstract: Susceptibility to intergranular corrosion of HR3C steel welded joint was investigated by doubleloop electrochemical potentiokinetic reactivation (DL-EPR) method. The microstructure of HR3C steel welded joint was examined with optical microscopy, X-ray diffractometer, scanning electron microscopy and energy dispersive spectrometer. The results show that the weld metal and heataffected zone of HR3C steel joint consisted of γ-phase and precipitates. The welded joint exhibited low susceptibility to intergranular corrosion. Intergranular corrsion resistance of the weld metal was improved due to the high content of Cr and Nb in the weld metal and the segragation of Nb and Cr near the grain and dendrite boundaries. However, the heat-affected zone was susceptible to intergranular corrosion owing to the depletion of Cr near the region of grain boundaries where M23C6 precipitates formed during welding.