The electrochemical corrosion behavior of Q235 welding joint in simulated groundwater water

The corrosion behavior of Q235 welding joint in simulating underground water solution was investigated by electrochemical technology. The open circuit potential, polarization curve and Electrochemical Impedance Spectroscopy (EIS) of three different welding joint areas (weld material, heat affected zone and the base metal) were measured. The changes of the potential and impedance of the three different areas, in 120 hours corrosion process under the steady state, was measured. The results indicated that the corrosion resistance of the heat affected zone is the most excellent and the weld zone is the worst, in the early corrosion period; the variation trend of potential and electrochemical impedance is consistent, the charge transfer resistance is increased, but the charge transfer resistance of the weld zone is still the lowest, corrosion resistance is still the worst. (authors)