Study on microstructure and mechanical properties of P92 steel aged at 650°C

The evolution of microstructures and mechanical properties of P92 steel, which was aged at 650°C with different time of 500, 1000, 3000 and 10000 h was studied respectively. Microstructures and mechanical properties were compared between original sample and aged samples. The results show that the microstructural development of P92 steel during ageing is mainly precipitation of Laves phases, most Laves phases are precipitated in boundaries including the prior austenitic grain boundaries and martensitic lath boundaries. The content of Laves phase increased monotonously with ageing time, but the increasing rate is decreased monotonously. As ageing time goes by, the area fraction of Laves phase in P92 steel tends to stability. The growth rate of Laves phases particle is much higher than M23C6. As ageing time increases, the impact absorbed energy decreases monotonously and the P92 steel is embrittled. The evolution of Laves phases' content is related the impact absorbed energy. Also, the hardness reduced slightly with ageing time. © 2009 Chin. Soc. for Elec. Eng.