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

Thermal aging of cast stainless steel in nuclear reactors calls for reliable non-destructive evaluation methods. To investigate the feasibility of using eddy current testing (ECT) to evaluate thermal embrittlement in CSS. 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. 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. 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.