Prediction of fracture toughness of reactor pressure-vessel steels using the master curve concept and probabilistic model

Abstract

Using a probabilistic model and the “Master curve” approach, the temperature dependence of the brittle fracture toughness of reactor pressure-vessel steel 15Kh2NMFA in the initial state and highly embrittled state is predicted from the results of fracture toughness testing of a cracked Charpy-type specimen at a given temperature. A comparative analysis has shown that for the steel in the initial state the \(K_{{\text{I}}c} (T)\) curves calculated by the probabilistic model and by the Master-curve approach are in good agreement. By testing compact-tension specimens of embrittled 2T-CT steel in a wide temperature range the authors have obtained experimental fracture toughness values and compared them with the calculated \(K_{{\text{I}}c} (T)\) curves. It is demonstrated that, in the case of the embrittled steel, the \(K_{{\text{I}}c} (T)\) curve as calculated by the Master-curve approach fails to describe adequately the experimental results, while the \(K_{{\text{I}}c} (T)\) curves plotted by the probabilistic model agree well with the experimental fracture toughness values.