Non-destructive evaluation of thermal embrittlement in cast stainless steel using eddy current testing

Background Thermal aging of cast stainless steel in nuclear reactors calls for reliable non-destructive evaluation methods. Objective To investigate the feasibility of using eddy current testing (ECT) to evaluate thermal embrittlement in CSS. Methods Accelerated aged specimens were characterized using multi-frequency ECT and Charpy impact tests. ECT amplitude features were fused with PCA and correlated with impact energy to establish a quantitative relationship. Results A strong correlation was found between the impact energy and the first principal component (PC1) of the ECT amplitude, both of which decreased with aging. Conclusions This study demonstrates that ECT provides a feasible method for evaluating thermal embrittlement in CSS by using a PCA-fused amplitude feature to quantify toughness and the low-frequency phase CV to track material inhomogeneity.