基于非线性超声无损评价304不锈钢晶间腐蚀敏感性

Nondestructive evaluating the intergranular corrosion sensitization of 304 stainless steel based on nonlinear ultrasonic

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 304 stainless steel sensitized as well as corroded state was studied using the nonlinear ultrasonic combining with electrochemical electro kinetic potential testing. The results indicate that the normalized nonlinear parameters show a monotonous growth trend with the endurance of the time as well as the elevating temperature sensitized. The Pearson correlation coefficient manifests the good correlation between nonlinear parameter and EPR results, so that it is feasible to use nonlinear parameter to evaluate the intergranular corrosion sensitization. In addition,it is worth mentio- ning that the nonlinear parameters of samples sensitized also show the decreasing trend with the extension of corrosion time compared the solid solution sample with less variation of nonlinear parameter, which im- plies It is available to characterize the corrosion resistance of stainless steel by using nonlinear coefficient.