Abstract
This paper presents a procedure for numerical quantifying the probability of brittle failures in steels controlled by size distribution of initiated microcracks. It shows how the fracture probability varies with the stress intensity factor, the temperature, and with the deformation characteristics of steel. The application of the proposed method on Ni-Cr steel demonstrated very good agreement of predicted temperature dependence of scatter in fracture toughness with experimental results. Controlling micromechanism of initiation and propagation of brittle fracture and its stages were identified from results of fractography analysis. Newly, using two ways the characteristic distance as the radial distance from the crack tip where the microcrack initiation is most probable has been calculated in dependence on temperature.
