冷弯加工对国产301L不锈钢耐点蚀性能的影响

采用化学浸泡法、电化学测试研究了冷弯加工前后轨道交通装备用国产301L高强不锈钢腐蚀行为,并对化学腐蚀和电化学腐蚀后样品的表面进行扫描电镜和能谱分析。化学浸泡法结果表明,冷弯后的国产301L高强不锈钢在50℃的6%(质量分数)FeCl_3溶液中浸泡72h后发生了明显的点蚀,腐蚀速率随时间的延长而迅速增大,72h后腐蚀速率达到128.5g/(m~2·h)。电化学测试结果表明,国产301L高强不锈钢经过冷弯加工后,在3.5%(质量分数)NaCl溶液中的点蚀电位下降365mV,钝化区宽度减小150mV,增加了点蚀敏感性。

Influence of cold bending process on pitting corrosion resistance of domestic 301L stainless steel

Corrosion behaviors of domestic 301L high- strength stainless steel for railway transportation equipment before and after cold bending processing were studied by chemical immersion method and electrochemical test. Meanwhile，surfaces of the samples after chemical corrosion and electrochemical corrosion were analyzed by SEM and EDS. The results of chemical immersion method show that pitting corrosion occured evidently on cold bended domestic- made 301L high- strength stainless steel after immersing in 50℃ 6% (mass fraction) FeCl3 solution for 72h，and the corrosion rate in FeCl3 solution increased with prolonging of time，and reached to 128.5g/（m2·h） after 72h. The results of electrochemical test show that after cold bending processing，the pitting potential of domestic 301L high- strength stainless steel in NaCl solution decreased by 365mV，and the width of passivation region was reduced by 150mV，and the pitting sensitivity was enhanced.