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采用动电位极化和电化学阻抗技术研究了电化学充氢后X80钢母材和焊缝在近中性p H值溶液中的电化学行为,并结合光学显微镜对试样充氢前后的形貌进行了观察,测量了母材和焊缝的放氢量。结果表明,电化学充氢并没有改变钢的组织结构;相同电化学充氢条件下,焊缝比母材吸收更多的氢。在近中性p H值溶液中,未充氢时母材比焊缝有更好的耐蚀性能。充氢促进母材和焊缝在近中性p H值溶液中的阳极溶解。随充氢时间增加,母材和焊缝的自腐蚀电位负移,腐蚀电流增大,腐蚀产物膜电阻和极化电阻减小,母材与焊缝电化学腐蚀行为均加剧。充氢后焊缝中位错缺陷浓度高,对氢起钉扎作用的,使焊缝的耐蚀性大于母材。
The electrochemical behavior of X80 steel base metal and weld seam in near-neutral p H solution after electrochemical hydrogen charging was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. Combined with optical microscopy, The appearance was observed and the amount of hydrogen released from the base metal and weld measured. The results show that the electrochemical charging of hydrogen does not change the microstructure of the steel. Under the same electrochemical hydrogenation, the weld absorbs more hydrogen than the base metal. In the near-neutral p H solution, the base metal has better corrosion resistance than the weld without hydrogen charging. Hydrogen charging promotes anodic dissolution of base metal and weld in near-neutral p H solution. With the increase of hydrogen charging time, the self-corrosion potential of the base metal and the weld negatively shifts, the corrosion current increases, the membrane resistance and polarization resistance of the corrosion products decrease, and the electrochemical corrosion behavior of the base metal and the weld seam aggravates. After hydrogen charging, the concentration of dislocation defects in the weld is high, and the pinning effect on the hydrogen causes the corrosion resistance of the weld to be greater than the base metal.