Fe 3 C和珠光体对低碳铁素体钢腐蚀电化学行为的影响

The microstructure of X80 pipeline steel welding joint, consisted of Fe3C and de- generated pearlite, was simulated by carburizing treatment. The effects of Fe3C and pearlite on the electrochemical properties of bainitic ferrite steel and localized corrosion occurrence regularity in Ying- tan soil simulation solution were investigated by scanning Kelvin probe (SKP), scanning vibrating probe (SVP) and local electrochemical impedance spectroscopy (LEIS), combined with immersion test. It is demonstrated that the corrosion potential of degenerated pearlite is lower than bainitic ferrite, and decreases with increasing Fe3C content. Localized corrosion occurs on the surface of the carburized sample in Yingtan soil simulation solution. The anodic oxidation process is observed to be initiated on the carburized degenerated pearlite, whereas the cathodic reaction involving dissolved H + is on bainitic ferrite, and the anodic current density increases with increasing Fe3C concentration. As the ion contents of the soil simulation solution doubled, the anodic dissolution of degenerated pearlite increases, and the local impedance of the electrode decreases.