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利用非线性超声检测并结合电化学动电位测试技术研究了304不锈钢敏化态与腐蚀态的无损表征。结果表明:随敏化时间的延长和敏化温度的升高,归一化非线性系数呈现增大趋势;皮尔森相关系数表明非线性系数与EPR测试具有良好的相关性,因此利用非线性超声参量评价304不锈钢晶间腐蚀敏感性是可行的;值得一提的是随腐蚀时间的延长,固溶态样品的非线性系数几乎无变化;两种敏化态样品的非线性系数则呈现相似的单调递减的趋势;且敏化时间越长,其非线性系数的下降越显著,这意味着利用非线性系数β表征不锈钢的耐腐蚀性是可行的。
The non-destructive characterization of the sensitized and eroded states of 304 stainless steel was studied by non-linear ultrasonic testing combined with electrochemical kinetic potentiometry. The results showed that the normalized non-linear coefficient showed an increasing trend with the increase of sensitization temperature and sensitization temperature. The Pearson’s correlation coefficient showed that the nonlinear coefficient had a good correlation with EPR test. Therefore, It is feasible to evaluate the sensitivity of 304 stainless steel to intergranular corrosion. It is noteworthy that the non-linearity coefficient of the solid-solution sample shows almost no change with the increase of the etching time. The nonlinear coefficients of the two samples show the similarities Monotonically decreasing tendency. And the longer the sensitization time, the more significant the decrease of non-linear coefficient, which means that it is feasible to use non-linear coefficient β to characterize the corrosion resistance of stainless steel.