Prediction of fracture toughness of reactor pressure vessel steels on the basis of the 'Master Curve' approach and the probabilistic model

On the basis of a probabilistic model and 'Master Curve' approach we perform prediction of the brittle fracture-toughness temperature dependence of 15Kh2NMFA reactor pressure-vessel steel in the initial and high-embrittled states. The K1c(T) curves for the initial state calculated with the Master Curve approach and the probabilistic model are compared and their good agreement is shown. Experimental values of the fracture toughness have been obtained for the embrittled 15Kh2NMFA steel through testing compact-tension specimens over a wide temperature range. It is shown that the K1c(T) curve for the embrittled steel calculated in accordance with the Master curve approach does not describe the experimental data adequately. At the same time, the agreement of the experimental data on fracture toughness and the K1c(T) curves calculated by the probabilistic model is good.