Prediction of fracture toughness for turbin rotor steels from their mechanical test results

Mechanical properties tests and fracture toughness tests of turbine rotors were performed in the wide range of temperatures, -150 deg C ∼ + 150 deg C, and fracture toughness values from above tests were compared with the estimated values from mechanical properties at lower and upper shelf temperatures and FATT. The relations between mechanical properties and KIC properties proposed by Rolfe and Begley were reviewed and confirmed through these experimental results. On the fracture surfaces of some specimens which were satisfied with the Ikeda's KIC criterion, micro dimple zone was detected at the rear of fatigue crack zone and it was confirmed that these specimens were not satisfied with the thickness requirement of ASTM E 399. (Author)