Microstructure evolution and property change of T92 heat resistant steel pipe after long term service

doi:10.13251/j.issn.0254-6051.2021.07.006

Abstract

Abstract: Microstructure evolution and mechanical properties of the T92 heat resistant steel pipe after 80 000 h service were studied by means of scanning electron microscopy and transmission electron microscopy and compared with the same batch of standby materials. The results show that after 80 000 h service, a large amount of M₂₃C₆ phase and Laves phase are precipitated on the martensite lath of the T92 steel, and MX phase is precipitated inside the lath. The width of the martensite slats has also increased significantly after service, but the typical martensitic slats are still maintained. The tensile strength and yield strength at room temperature and high temperature (610 ℃) of the T92 steel are reduced compared to the standby steel, and the difference of which at room temperature is small, while it decrease largely at high temperature. Precipitated phase strengthening and lath strengthening are the fundamental reasons for high performance of the T92 heat resistant steel after long-term service.

Key words: T92 steel pipe service, microstructure, mechanical properties, strengthening mechanism

CLC Number:

TG142.73

He Lijun, Zhou Long, Tang Chunpo, Guo Xiaogang, Jin Xiao, Zhao Yanfen, Xue Fei, Zhang Guodong. Microstructure evolution and property change of T92 heat resistant steel pipe after long term service[J]. Heat Treatment of Metals, 2021, 46(7): 31-36.

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