Effect of Aging on the Creep Properties and Microstructural Evolution of P92 Steel

Abstract

The P92 steels were aged at 632°C for 500hrs and 1,000hrs, and creep ruptured at 650°C~625°C with stress of 120~110 MPa. The creep rupture life (CRL) of the aged samples was decreased with the aged time. The microstructure of the P92 steel was observed as fine tempered lath with dispersion of Cr-rich M23C6 along various grain boundaries. Upon aging and creep, recovery of lath and precipitation of coarse W-rich Laves phase were characterized as the main microstructural change. The M23C6 is relatively stable upon the short-term aging and creep. Decrease of the CRL of the aged specimens is considered as the degradations of microstructure such as the recovery of lath due to the dislocation annihilation and precipitation of coarse Laves phase.