316L不锈钢焊缝腐蚀微电池的形成机理

发布时间：2018-01-20 21:41

本文关键词： 腐蚀微电池形成机理 L不锈钢焊缝微观组织极化曲线电化学阻抗谱　出处：《材料保护》2017年04期 　论文类型：期刊论文

【摘要】：为了探究316L不锈钢焊缝腐蚀微电池的形成机理,通过微观组织观察及电化学试验进行了分析。采用扫描电镜(SEM)对焊件三区(焊缝区、热影响区、母材区)的形貌及元素组成进行了观察分析,采用金相显微镜观察微观组织,并确定晶粒度及非金属夹杂物及其分布。结果表明:316L不锈钢焊缝形成腐蚀微电池的倾向与元素组成、非金属夹杂物和晶粒度大小等因素紧密相关;焊缝三区腐蚀电位、腐蚀电流不同,耐蚀性能差异较大,因而腐蚀电位最低的热影响区与腐蚀电位最高的母材区在电解液中比较容易形成腐蚀微电池,且热影响区可视为此微电池的阳极,腐蚀进程较快。
[Abstract]:In order to investigate the formation mechanism of 316L stainless steel weld corrosion microbattery, the microstructure observation and electrochemical test were used to analyze the three zones (weld zone and heat affected zone) of welds. The morphology and element composition of the base metal region were observed and analyzed, and the microstructure was observed by metallographic microscope. The grain size, non-metallic inclusions and their distribution are determined. The results show that the tendency to form corrosion microbatteries in the weld of W316L stainless steel is closely related to the composition of elements, non-metallic inclusions and grain size. The corrosion potential and corrosion current of the three zones of the weld are different, so the heat affected zone with the lowest corrosion potential and the base metal region with the highest corrosion potential are easy to form corrosion microcells in the electrolyte. The heat affected zone can be regarded as the anode of the microcell, and the corrosion process is faster.
【作者单位】：北京石油化工学院机械工程学院;
【基金】：北京市自然科学基金资助项目(3152011) 北京石油化工学院国家级大学生创新创业训练计划项目(2015J00043)
【分类号】：TG178;TG40
【正文快照】： 0前言316L不锈钢焊接接头不同区域暴露于同一电解质,会构成一个多电极体系[1]。域内局部构成了错综复杂的电化学电池关系,由于电极电位差异会形成各种不同的腐蚀微电池[2]。在腐蚀微电池体系中,基体表面极易形成严重的局部点蚀,点蚀不断扩展[3],通常会造成严重的后果。盐化工

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