The effect of ductile crack growth on the temperature dependence of cleavage fracture toughness for a RPV steel with various degrees of embrittlement

摘要

The basic properties of cleavage fracture after ductile crack growth are studied on the basis pf a probabilistic model for cleavage fracture and a deterministic model for ductile fracture, proposed earlier by the authors. Investigations are applied to a 2Cr-Ni-Mo-V reactor pressure vessel steel in the initial (as-received) and embrittled states. For various temperatures, the dependencies of brittle fracture probability on stress intensity factor and extent of ductile tearing are calculated. For various states of a material, the temperature dependencies of cleavage fracture toughness are predicted with and without regard for ductile crack growth. The basic factors controlling the above dependencies are analysed. The calculated results obtained are compared with test results from CT specimens.