Cleavage fracture path prediction for a pressure vessel steel

This contribution presents a model for fracture path prediction applied for pressure vessel 10MnNi2Mo steel with mixed bainite-ferritic microstructure. Microcrack initiation is considered both in precipitated carbide particles and in ferrite grains. A major crack is formed by microcrack linking leading to the final fracture instability. Using crack transition probabilities the probability of crack stability in the active volume was calculated. Considering the fracture toughness as a controlling parameter of crack stability the temperature dependence of predicted fracture toughness has been set. A very good agreement with experimentally obtained temperature dependence of K IC values has been found.