Characterization of Heat Treated Ductile Iron through Fractographic Analysis

Abstract

Ductile iron specimens are subjected to different isothermal heat treatment processes and the properties obtained are studied to be used for spent nuclear fuel (SNF) cask application. Annealing treatment on the specimen yield to increase in ductility and impact strength and tempering of the specimen resulted in higher strength and hardness compromising ductility and impact resistance. Fractographic analysis confirmed the dominance of ductility over brittleness in annealed specimen and the case is reverse for normalized and tempered specimen. Both the normalized and tempered specimens are observed to have river markings whereas dimples are clearly seen in annealed specimen, which are the characteristics of brittle and ductile fracture respectively.