Investigation of Probable Cause of Premature Cracking of Downcomer Nozzle of Heat Recovery Steam Generator
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The premature failure (cracked) of a downcomer nozzle attached with intermediate pressure drum of heat recovery steam generator was investigated. The conventional wet fluorescent magnetic particle and dye-penetrant testing along with macro analysis, sulfur print, and microstructural examination were used in the investigation. In addition, energy dispersive spectroscopy was also carried out to understand the reason of premature failure. Finally, it was concluded that presence of excessive multiphase inclusions containing manganese in localized areas caused formation of cracks at those locations during forging.
KeywordsDowncomer nozzle HRSG Failure EDX Inclusions
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