Aging Effect on Creep Rupture Properties of Super-clean 9% CrMoV Steel for Steam Turbine Rotors of Combined Cycle Power Plants

摘要

Focusing on heating degradation of material properties, which is one of the main factors influencing on the service lives of steam turbine rotors of power plants, aging effect on creep rupture properties of the newly developed super-clean 9%CrMoV steel is investigated in this work. For this purpose, aging treatment on the super-clean 9%CrMoV steel is performed at 630℃ for 748h. Creep rupture tests for the as-received and the aged steels are conducted at 566℃. The steel microstructures as well as the fracture surfaces and longitudinal sections of creep ruptured specimens are observed in detail with scanning and transmission electron microscopes (SEM, TEM). It is resulted that the decrease in creep strength of the super-clean 9%CrMoV steel due to the aging treatment is extremely small. It is further suggested that the super-clean 9%CrMoV steel will be a very promising rotor material corresponding to high temperature and long-term service.