Fracture toughness prediction of steel type 10MnNi2Mo

A model is presented of the prediction of fracture toughness of the 10MnNi2Mo steel used for pressure components of the primary circuit of nuclear power plants with a mixed bainitic-ferritic structure. Next to the initiation of fission microcracks in carbides the initiation was also considered of microcracks in the ferrite using the Cottrel model of dislocation coalescence. The model led to very good agreement between predicted and experimental values of the stress intensity factor for the values of the parameter of shape of the plastic zone near the face of the crack and the parameter of the participation of carbide particles excluded in the bainite, and the participation of ferrite grains. (author)