Safety Inspection and Life Evaluation on P91 Steel High-pressure Main Steam Piping of Domestic First 9F Gas Turbine Unit

Through the field testing and sample testing, safety inspection and life evaluation were carried out on the P91 steel high-pressure main steam piping system of domestic first 9F gas turbine, which had been running for 10 years. The results show that:there were some quality defects existing in the part sections of the high-pressure main steam piping, and the pipes were replaced; the stress of the temperature difference of the high-pressure main steam piping caused by the start-stop process of 9F gas turbine was small and negligible compared with the secondary stress of the piping; the welding joint samples of qualified hardness had a higher endurance strength at 540℃, and the residual creep life was more than 10⁵ h.