Failure Analysis and Microstructural Changes of IN738LC Second Stage Gas Turbine Blades
Failure mechanisms of a second stage gas turbine blade of a 159MW heavy duty gas turbine have been investigated. The blade had been made of IN738LC and damaged just after 1800 hours of operation from rejuvenation. Fractography techniques, metallography and stress-rupture experiments were used to identify failure mechanisms of the blade. Microstructural changes were evaluated by using optical and scanning electron microscopy. Because of severe operating situation of blade, involvement of creep and fatigue in damage of the blade was probable. Nevertheless, microstructural evaluation i. e. size and morphology of y precipitates and carbides proved that the blade had not been damaged thorough creep mechanism. In addition, Larson-Miller parameter of the blade showed the same result about creep mechanism. Moreover, investigation of cracks propagated under the fracture surface revealed the ineffectiveness of fatigue in the damage. Finally, failure mechanism was diagnosed foreign object damage (FOD) due to fractography results and chemical analysis of tiny debris on the blade.
IN738LCs FOD creep life assessment methods
M. Tbrfeh H. Farhangi
Gas Turbine Division, Engineering Dept. , Mapna Turbine BladeEng. and Manufacturing Co. (PARTO), Te Department of Metallurgy and Materials Science, University of Tehran , Tehran , Iran
国际会议
4th International Symposium on Jet Propulsion and Power Engineering(第四届喷气推进与动力工程国际会议 ISJPPE2012)
西安
英文
753-757
2012-09-10（万方平台首次上网日期，不代表论文的发表时间）