Evaluation of fracture appearance transition temperature to forged 3Cr–1Mo–0.25V steel using ultrasonic characteristics

This paper reports that the ultrasonic methods can be used to accurately characterize forged reactor vessels. The Charpy V-notch impact tests were conducted on the respective specimens with three different types of heat history. Various test results including fracture appearance transition temperature (FATT) were obtained. A pulse-echo method with longitudinal waves was used to measure attenuation and velocity of ultrasonic wave. The velocity was measured repeatedly nine times on each specimen. The attenuation coefficient of the ultrasonic wave changed with heat treatment temperature and conditions (as-quenched, tempered, PWHT). The fracture appearance transition temperature can be predicted using the ultrasonic characteristics.