Archives du mot-clef Heat Exchangers

Failure analysis of tube-to-tubesheet welded joints in a shell-tube heat exchanger

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An article in progress in « Case Studies in Engineering Failure Analysis », Volume 7 (october 2016).

In this work, fracture failure of a shell-tube heat exchanger at the tube-to-tubesheet welded joints was investigated. Fatigue started at initial defects of the welded joint was confirmed as the failure mechanism of the heat exchanger. Bad welding and unsuitable expansion gave rise to the formation of initial cracks. The alternating stress comes from various reasons such as the resonant vibration.

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Analyse de défaillance de tubes en acier inoxydable (304) dans un échangeur d’unité de production de chaleur

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un cas intéressant de fatigue corrosion

Auteur (s): MR Jahangiri 

Métallurgie Département, Niroo Research Institute, Téhéran 14686, Iran

This work includes results of studies and experiments conducted on heatexchanger (heater) tubes of an energy production unit to determine the causes of their fractures. Experiments indicated that the main mechanism of such tube fractures is the simultaneous presence of relatively high vibrational bending stresses and corrosive agents. It was shown that the role of a vibrational bending stress due to high velocity of input steam is very impressive. The important point in this study was the branching of corrosionfatigue cracks during their growth in presence of NaOH and chloride ions. The use of impingement plates and water chemistry control were the most appropriate methods to prevent such failures.

©2011 American Society of Mechanical Engineers

Pour en savoir plus : Analyse de défaillance de type 304 Tubes en acier inoxydable dans une production de chaleur Echangeurs énergie des usines.