Improved probabilistic model for fracture toughness prediction for nuclear pressure vessel steels

Abstract

An improved probabilistic model for fracture toughness prediction is represented which is based on the local criteria for cleavage and ductile fracture proposed by the authors and an improved approximate solution for the problem of the stress–strain state near the crack tip. The main considerations of the previous probabilistic model are also used and some inexact considerations of the previous model are eliminated. The probabilistic model allows prediction of the dependence of K IC on temperature for any given probability of brittle fracture, gives a description of the effect of specimen thickness on K IC, and allows determination of the scatter band for the brittle-to-ductile transition temperature. Comparison of experimental and calculated results as applied to 2.5Cr–Mo–V nuclear pressure vessel steel has been performed.