A Charpy impact test and magnetic hysteresis measurement were performed on Fe-0.15wt%C steels with different cold-rolling ratios. As the cold-rolling ratio was increased, the ductile-brittle transition temperature (DBTT) and coercive field increased simultaneously. This correlation originated from an increase in the dislocation density induced by plastic deformation. This study shows the possibility of applying magnetic methods to pressure vessel surveillance at nuclear power plants.
