Structural Effects of Tempering on Cr Steels for Reactors

Abstract

Structural evolution during tempering at various temperatures of martensitic steels has been followed by means of X-ray diffraction analysis metallography in SEM and hardness measurements.

Effects of Cr content and of quenching rate have been considered. Persistence of large internal strains has been found even after full recovery of hardness. These strains are related with the large densities of bubble and void nucleation centres, which seem responsible for the swelling resistance of these alloys.