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通过OM,SEM,EBSD观察和EIS谱、动电位极化曲线测试等手段分析了不同应变下冷拔珠光体钢的腐蚀形貌、组织演变及点蚀在其演变组织中的分布和铁素体取向差分布,研究了冷拔珠光体钢的横纵截面组织演变对其点蚀行为的影响.结果表明,由于横截面和纵截面组织演变规律的不同,不同应变下冷拔珠光体钢的横截面和纵截面的耐蚀性分别表现出不同的变化规律:随着应变的增加,横截面耐蚀性持续下降,而纵截面耐蚀性先降低后回升.通过表征点蚀在冷拔演变组织中的分布规律,发现珠光体组织的晶界、珠光体团界面、相界面对点蚀敏感性高,是点蚀倾向于萌生和生长的区域,冷拔变形造成界面面积增加,使横截面和处于第一阶段应变ε≤1.2的纵截面的耐蚀性显著下降.铁素体<110>织构形成导致晶体取向差分布规律的改变会使纵截面在第二阶段ε=1.6的耐蚀性改善.
The corrosion morphology, microstructure evolution and distribution of pitting corrosion in cold-drawn pearlite steel under different strain were analyzed by means of OM, SEM, EBSD observation and EIS spectroscopy, and potentiodynamic polarization curve test. The distribution of ferrite Oriented differential distribution, the influence of microstructure evolution on the pitting behavior of cold-drawn pearlite steel was investigated. The results show that due to the different microstructure evolution of the cross-section and longitudinal section, The corrosion resistance of the cross section and the longitudinal section respectively showed different variation rules: with the increase of the strain, the corrosion resistance of the cross section continued to decrease, while the corrosion resistance of the longitudinal section decreased first and then rebounded.Through the characterization of pitting corrosion, It is found that the grain boundary, pearlite interphase and phase interface of pearlite are sensitive to pitting corrosion. It is a region where pitting corrosion tends to occur and grow. Cold drawing causes the increase of interface area, The corrosion resistance of the longitudinal section at the first stage strainε≤1.2decreased significantly.The regularity of the differential distribution of the orientation of the ferrite <110> texture caused the corrosion of the longitudinal section at ε = 1.6 in the second stage improve.