Un cas concret d’analyse de défaillance rapporté par ScienceDirect.com et publié dans « Case study in Engineering Failure Analysis ».
Un dommage du revêtement anti-corrosion associé à un processus de fatigue est responsable de cette défaillance.
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«Corrosion importante», «désagrégation avancée», «défaut de matériaux», ce sont des qualificatifs, ainsi que des photos évocatrices, qui ont été accolés à de nombreux éléments de la structure du pont Mercier de Montréal dans des rapports d’inspection rendus publics par le ministère des Transports du Québec (MTQ).
Des photos obtenues par TVA Nouvelles à l’été 2010 remettent en question la sécurité même de la structure. On y voit des poutres d’acier grugées par la rouille; des armatures de béton si endommagées que les tiges métalliques assurant la solidité sont maintenant bien exposées.
A new interesting article published in « Case Studies in Engineering Failure Analysis »
In hot rolling mills, premature failure of rolls is a major concern as it adversely affects the mill operation and as well as production. Analysis of failed roll materials and actual rolling conditions in service are therefore necessary to understand the roll failure mechanism and thereby improve the wear resistance and extend the service life of rolls.
This work describes two different types of roll failure cases and their analysis which was carried out using destructive as well as non-destructive testing techniques (NDT). The cases are as follows:
Case I: Enhanced ICDP Bottom roll of fifth stand (F#5) which failed from the neck portion.
Case II: Analysis of sub-surface defect of ICDP rolls of the last stand (F#6
A case study published in « Case Studies in Engineering Failure Analysis« .
This article highlights failure investigation of the pulleys during a press-fit assembling process. Pulleys are used to transmit power between rotational mechanical elements. Failure analysis was found that cooperative influence of higher carbon content with combination of elongated sulphides is reason for pulleys cracking. Steel cleanliness and homogeneous structure is an important factor for users of steel. The success of production process is connected with the optimal quality of steel.
A new case study of failure analysis published on Sciencedirect.com
In hot rolling mills, premature failure of rolls is a major concern as it adversely affects the mill operation as well as production. Analysis of failed roll materials and actual rolling conditions in service are therefore necessary to understand the roll failure mechanism and thereby improve the wear resistance and extend the service life of rolls.
The hot strip mill referred here consists of six stands wherein high chromium (Hi-Cr) iron rolls and Indefinite Chilled Double Poured (ICDP) cast iron rolls are being used for finishing rolling of the strips in the last two stands. The thin strip mill produces strips in the thickness range of 1.0–12.7 mm. This work describes two different types of roll failure cases and their analysis which was carried out using destructive as well as non-destructive testing techniques (NDT).
A paper published on january 2013 in « Case Studies in Engineering Failure Analysis« .
In this study a failure originated during solidification process into the femoral stem component of Hip Resurfacing prosthesis was investigated. The results exhibited hot tearing, shrinkage porosity and metal oxide films due to inadequate heat dissipation during solidification process, as a consequence of poor investment casting ceramic mold configuration. Also in this paper was improved the casting design solving this kind of defects.
ScienceDirect.com publishes a new « Case Studies in Engineering Failure Analysis« .
A failure incident of heat-exchange tubes in ammonia evaporators, which suffered from unexpected wall thinning after only one-year service with respect to their original design lifetime of fifteen years, was reported and carefully analyzed. The analysis results demonstrated that the unexpected wall thinning of tubes was primarily ascribed to multiple corrosion factors including uniform corrosion, pitting and interaction behavior between them. Relative failure mechanisms were discussed in detail and prevention measures were also proposed for ammonia evaporators under similar operating condition.
A new case studie in engineering failure analysis published on SienceDirect.com. The present article highlights failure investigation of the pulleys during a press-fit assembling process. Pulleys are used to transmit power between rotational mechanical elements. It was found that cooperative influence of higher carbon content with combination of elongated sulphides is reason for pulleys cracking. Steel cleanliness and homogeneous structure is an important factor for users of steel. The success of production process is connected with the optimal quality of steel.
Un cas de rupture de fatigue d’une pièce d’accastillage de voilier de plaisance (cadènes de haubans). Il s’agit d’un article paru en 2009 sur le site d’un non spécialiste. L’auteur fait une description bien argumentée de l’analyse qu’il a faite de la rupture de cette pièce qui permet de l’ancrage des haubans sur la coque d’un voilier.
Le Cetim a réalisé par le passé et réalise encore l’analyse des défaillances qui surviennent sur les voiliers engagés dans les grandes courses : course du Rhum, Transat, etc…. Fort de près de 50 ans d’expérience dans l’analyse des défaillances, Il apporte son soutien aux bureau d’étude des chantiers navals.
A interesting paper in « Case study in Engineering Failure Analysis » published on ScienceDirect.com.
Circular penetrable cracks occurred at the converge region of upward acid media (H2S and HCOOH) in the opposite position of traverse vapor ingress pipe of the lower part of the upper sealing head of the deaerator/sourgas stripper during the operation of the deaerator/sourgas stripper of the ammonia unit in a chemical fertilizer plant.
