Classification and characterization of materials by means of fracture mechanics parameters

Within the scope of the “Integrity of Components” research project a large number of heats of reactor pressure vessel steels representing a broad quality spectrum have been investigated. In this paper the conventional and fracture mechanics parameters of four typical materials are presented. The difficulties in determining the reference temperature for nil ductility transition and the fracture mechanics parameters in the transition and upper shelf region of the Charpy energy are discussed. The technique developed at MPA for the evaluation of a physically meaningful crack initiation parameter based on the size of the stretched zone ahead of the crack tip is described, and values are reported.