A new local approach to cleavage fracture and its application in a reactor pressure vessel

Abstract

The paper presents and applies a local approach to correlate the fracture behavior of a notched and fracture mechanics specimen. The random nature of cleavage fracture process determines that both the microscopic fracture stress and the macroscopic properties including fracture load, fracture toughness and the ductile to brittle transition temperature are all stochastic parameters. This understanding leads to the proposal of statistical assessment of cleavage induced notch toughness of ferritic steels according to a new local approach to cleavage fracture. The temperature independence of the two Weibull parameters in the new model induces a master curve to correlate the fracture load at different temperatures. This proposed index is applied to compare the notch toughness of a ferritic steel with two different microstructures.