NaCl浓度对X80管线钢母材和焊缝区电化学腐蚀行为的研究  

Study on the Influence of Sodium Chloride Concentration on the Electrochemical Corrosion Behavior of X80 Pipeline Steel Base Material and Weld Zone

作　　者：张颖 杨育智 余柳丝 王怡佳 ZHANG Ying;YANG Yuzhi;YU Liusi;WANG Yijia(School of Mechanical Engineering,Sichuan University of Science and Engineering,Zigong 643000,China;Meishan Vocational and Technical College,Meishan 620010,China;Sichuan Special Equipment Inspection Institute,Chengdu 610000,China)

机构地区：[1]四川轻化工大学机械工程学院,四川自贡643000 [2]眉山职业技术学院,四川眉山620010 [3]四川省特种设备检验研究院,四川成都610000

出　　处：《材料保护》2024年第4期106-113,共8页Materials Protection

基　　金：国家自然科学基金(51974271);四川省重点研发项目(2020YFSY0038);四川省特种设备检验研究院科研项目(SCTJ-2022-YN04)资助。

摘　　要：随着我国海洋油气资源的不断开发,管道焊接接头的腐蚀问题已成为海洋运行管线失效和安全的主要因素之一。为给海洋管道的腐蚀防护与材料选择提供更为精确的理论依据和实际指导,采用动电位极化技术和电化学阻抗谱测试方法,研究了X80管线钢焊接接头的母材区和焊缝区在不同NaCl溶液浓度(1.5%、3.5%、5.5%,质量分数)中的电化学腐蚀行为。结果表明:在不同NaCl浓度的溶液中,母材区和焊缝区的极化曲线都具有明显的阳极溶解特征,没有钝化现象;随着NaCl浓度的增加,2个区域的开路电位和自腐蚀电位负移,极化电阻先减小后增大,自腐蚀电流密度先增大后减小;母材区的热力学稳定性和耐腐蚀性始终优于焊缝区的。With the continuous development of China’s offshore oil and gas resources,the corrosion of pipeline welded joints has become one of the main factors leading to the failure and safety of marine operating pipelines.In order to provide more accurate theoretical basis and practi-cal guidance for corrosion protection and material selection of marine pipelines,the electrochemical corrosion behaviors of the base material and weld zone of X80 pipeline steel welded joints were studied in different NaCl solution concentrations(1.5%,3.5%,5.5%,mass fraction)via dynamic potential polarization technology and electrochemical impedance spectroscopy testing method.Results showed that in the solutions with different NaCl concentrations,the polarization curves of the base material and weld zone exhibited obvious anodic dissolution characteristics without passivation phenomenon.With the increase of NaCl concentration,the open circuit potential and self-corrosion potential of the two re-gions shifted negatively,the polarization resistance first decreased and then increased,and the self-corrosion current density first increased and then decreased.Furthermore,the thermodynamic stability and corrosion resistance of the base material zone were always superior to those of the weld zone.

关 键 词：焊缝区 X80管线钢 电化学腐蚀 NaCl浓度 

分 类 号：TG172[金属学及工艺—金属表面处理]