Failure analysis of a first stage IN738 gas turbine blade tip cracking in a thermal power plant
| Autor: | Sushila Rani, Vikas Rastogi, Atul Kumar Agrawal |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
0209 industrial biotechnology
Leading edge animal structures Materials science IN738LC nickel alloy Turbine blade 02 engineering and technology engineering.material Corrosion law.invention First stage gas turbine blade 020901 industrial engineering & automation stomatognathic system 0203 mechanical engineering Coating law Corrosion pits Safety Risk Reliability and Quality Overheating (electricity) Stress concentration Metallurgy food and beverages Superalloy Coating degradation 020303 mechanical engineering & transports lcsh:TA1-2040 SEM engineering TCP lcsh:Engineering (General). Civil engineering (General) Aluminide |
| Zdroj: | Case Studies in Engineering Failure Analysis, Vol 8, Iss C, Pp 1-10 (2017) |
| ISSN: | 2213-2902 |
| DOI: | 10.1016/j.csefa.2016.11.002 |
| Popis: | This research paper deals with the investigation of causes of failure of the first stage gas turbine blade of 30 MW gas turbine having tip cracks at the trailing as well as leading edge. This blade is made of nickel based super alloy IN738LC, having directional solidified grain structure and contains aluminide coating (Pt–Al 2 ) by diffusion process. The main focus of the paper is evaluation of tip crack at the trailing edge and further degradation of blade coating. The investigations included the visual observations, material composition analysis, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). During examination of the failed blade, it is found that the blade surface is completely degraded due to overheating. Corrosion pits are formed on the blade surface, these pits act as a notch to produce stress concentrations and cracks is initiated due to fatigue which further propagate due to hot corrosion. It is also reported that the Al-Pt coating is completely degraded, heavily oxidized. From these investigations, it is concluded that the failure of gas turbine blade takes place due to the combined effect of surface degradation caused by overheating, oxidation, hot corrosion and degradation of coating heavily oxidized. |
| Databáze: | OpenAIRE |
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