Second Stage Gas Turbine Blade Premature Replacement Investigation

• Published in: Journal of failure analysis and prevention 2010-08, Vol.10 (4), p.334-340
• Main Authors: Mustafa, A. H., Badairy, Hameed H., Al-Taie, Ihsan M.
• Format: Article
• Language: English
• Subjects: Applied sciences; Blades; Characterization and Evaluation of Materials; Chemistry and Materials Science; Classical Mechanics; Continuous cycle engines: steam and gas turbines, jet engines; Corrosion and Coatings; Engines and turbines; Exact sciences and technology; Failure; Gas turbine engines; Grain boundaries; Materials Science; Mechanical engineering. Machine design; Optical microscopy; Precipitates; Precipitation; Quality Control; Reliability; Safety and Risk; Solid Mechanics; Technical Article > -Peer-Reviewed; Tribology; Turbine blades
• ISSN: 1547-7029; 1728-5674; 1864-1245
• DOI: 10.1007/s11668-010-9363-6

This article investigates the root causes of the premature failure and replacement of a set of second-stage turbine blades from a heavy industrial gas turbine engine. The investigations included dye-penetrant testing, optical microscopy, X-ray diffractometry (XRD), Environmental Scanning Electron Microscopy (ESEM), and energy dispersive X-ray spectroscopy (EDS) techniques. Moreover, the effect of heat treatment process on restoring the blade microstructure so that the properties were suitable for service was also explored. As a result of the investigation, the second-stage turbine blades premature failure was attributed to the grain boundary secondary phase precipitates. These precipitates were present in the “as-found” condition of the investigated blades.