Prediction of fracture toughness for a pressure vessel steel with mixed bainite-ferritic microstructure

This paper presents a model for fracture toughness prediction of a 10MnNi2Mo steel having mixed bainite-ferritic microstructure as used for the pressure components of a nuclear reactor primary circuit. In addition to cleavage microcrack nucleation in carbide particles, consideration is given to a dislocation mechanism for nucleation of microcracks in ferrite as proposed by Cottrell. The presented model showed good agreement between the predicted and experimentally determined values of stress intensity factor.