The dependence of magnetic properties on fatigue in A533B nuclear pressure vessel steels

Cyclic loading causes cumulative microstructural changes in materials. The magnetic properties of A533B steel are determined by both initial microstructures and microstructural changes induced by fatigue damage. From the results of a series of strain-controlled fatigue tests, the magnetic properties were found to change systematically with fatigue damage throughout the fatigue life. A linear relationship between magnetic remanence and mechanical modulus was observed. The fatigue lifetimes were also dependent on the initial microstructure, and a relationship between these lifetimes and pre-fatigue magnetic properties such as coercivity was observed. Therefore this study has demonstrated that magnetic measurements can be exploited to evaluate the progress of fatigue damage in steel