Paper Info
Revista
Engineering Failure AnalysisAño de publicación
2010Tematica
Integridad estructural / análisis de fallo
Corrosión
Fatiga
Caracterización mecánica
Failure analysis of a steam generator superheater drain tube used in a dump
Cicero González, Sergio | Lacalle Calderón, Roberto | Cicero González, Román | García Cid, Javier |Abstract
This paper analyses the failure of a superheater drain tube of a steam generator used in a dump to obtain energy from the biogas produced by organic waste. Chemical and microstructure analyses, together with microhardness measurements, have been performed in order to check any possible deviation from the material specification, finding as the only deviation significant increases in hardness in the failure section, suggesting that the failure section is located in the heat affected zone of a nearby weld. Also, the failure mechanism has been analysed by both visual and SEM inspection of the fracture surface, identifying fatigue as the major cause of the final failure, assisted by corrosion processes. The different areas found on the fracture surface suggest that fatigue processes were caused by the maintenance operation consisting of hitting (hammering) the collector tube to which the drain tube is joined. No evidence has been found in relation to any other anomalous operating conditions, such as overpressure or unexpected high temperatures.