A study on NDE method of thermal aging of cast duplex stainless steels Original Research Article

To maintain the integrity of applications of the duplex stainless steels currently in service, a study was conducted to develop a method to nondestructively estimate their Charpy-impact energy at room temperature. It was found that hardness of the ferrite phase is a reliable indicator of the process of embrittlement during long-term heating of duplex stainless steels. However, further information on the ferrite phase and the austenite phase is required for the estimation of Charpy-impact energy. An equation composed of the hardness values of ferrite and austenite phases, the ferrite content and the average spacing of ferrite phase islands was presented as a method applicable to the nondestructive estimation of Charpy-impact energy at room temperature.