Abstract
Hot gas path components in gas turbines are damaged by several mechanisms due to aggressive environments. In this research, the cracking of an insert ring, which is composed of Nb-stabilized heat-resistant stainless steel, after 8000 operation hours, is investigated. The microstructure of the ring is examined by optical and scanning electron microscopes equipped with energy-dispersive X-ray spectroscopy. The generated stress and strain within the ring during a complete operation cycle (startup to shutdown) of gas turbine are simulated by finite element simulation software. The microstructural investigations indicate the formation of some precipitates that mainly contain nitrogen atoms. The development of tensile loads within the ring during shutdown and brittle N-contained precipitates leads to cracking. The indicators of both types of hot corrosion are also observed.
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Acknowledgments
This research was supported by the MAPNA Turbine Engineering & Manufacturing Co. (TUGA). The author would like to extend his gratitude to TUGA for their support and stimulating discussions.
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Saeed Khani Moghanaki is a researcher of the Metallurgy Department of Niroo Research Institute (NRI), Tehran, Iran. He received his Ph.D. in Materials Science and Engineering from Sharif University of Technology. His research interests include metal forming, failure analysis of power plant gas turbines, and physical and mechanical metallurgy.
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Sheykhlari, A.F., Moghanaki, S.K. & Khodabakhshi, M. Failure analysis of a heat-resistant stainless steel ring in a gas turbine burner. J Mech Sci Technol 34, 1539–1544 (2020). https://doi.org/10.1007/s12206-020-0316-z
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DOI: https://doi.org/10.1007/s12206-020-0316-z