Effects of High Temperature Aging on Creep-Rupture Property of P92 Heat-Resistant Steel

P92 heat-resistant steel was aged at 650℃ for 600, 1 200 h, respectively, and then subjected to uniaxial tensile creep test at 170 MPa and 650℃. The microstructures of the tested steel after aging and creep rupture were observed and the creep-rupture property was analyzed. The results show that after aging, the lath martensite in the tested steel was coarsened, and Laves phase precipitated in the structure. The longer the aging time, the larger the number and the diameter of the Laves phase. After creep rupture, the lath martensite in the structure near fracture became equiaxed. After aging, the creep rupture life of the tested steel was shortened but the creep rupture strain increased, indicating the decrease in the creep-rupture property. The tested steel before and after aging both fractured in ductile during creep, and the dimples on the creep rupture fracture after aging were relatively small and relatively shallow.