船用低合金钢焊接件腐蚀行为研究

摘要

目的 研究船用低合金钢焊接件在海水中的腐蚀行为.方法 采用金相组织观察、极化曲线、电化学阻抗谱测试,以及扫描振动电极技术(SVET),对船用低合金钢焊接件在天然海水中的腐蚀行为进行研究.结果 船用低合金钢焊接件中热影响区与焊缝区及母材区金相组织发生明显分化,热影响区腐蚀倾向最大,耐蚀性最差,并且易与母材区形成电偶发生破坏.SVET测试结果表明,最大阳极电流出现在热影响区,随着浸泡时间的延长集中于靠近母材处.结论 焊接件各区域间组织存在较大差异,热影响区成为最易发生腐蚀破坏的区域,在海水中阳极反应发生在热影响区,随浸泡时间延长电流增大,腐蚀加重.%Objective To study corrosion behaviors of low-alloy hull steel in seawater.Methods Corrosion behaviors of low-alloy hull steel were studied by metallurgical structure observing, potentiodynamic scanning, electrochemical impedance spectroscopy (EIS), and scanning vibration electrode test.Results There was obvious difference among metallographic struc-tures in basement zone (BZ), heat-affected zone (HAZ) and weld zone (WZ). HAZ tended to have corrosion firstly, while the corrosion resistance of which was the lowest. And there was the probability of galvanic corrosion between HAZ and BZ. The result of SVET showed that the highest anodic current appeared in HAZ, and concentrated near BS as the time went on.Conclusion There are obvious differences among metallurgical structures in different zones, while HAZ turns out to be prior to cor-rode. Anodic reaction occurs at HAZ, and the max anodic current and corrosion increase with time.