Investigating plastic deformation around a reheat-crack in a 316H austenitic stainless steel weldment by misorientation mapping

Abstract

Creep degradation in austenitic stainless steels is associated with nucleation and growth of cavities that can link up to form micro- and macro- cracks, usually along grain boundaries. A reheat crack found near a header nozzle weld removed from a nuclear power station has been examined using both electron backscatter diffraction (EBSD) and hardness mapping. The EBSD studies revealed higher levels of lattice misorientation towards the weld region where the crack initiated with strain particularly concentrated at grain boundaries. The pattern of deformation shown by the EBSD measurements was confirmed by the hardness survey.