Failure analysis on unexpected wall thinning of heat-exchange tubes in ammonia evaporators

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.

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Influence of Weld Defects on the Fatigue Resistance of Thick Steel Plates

Conférence présentée par P. Schaumann et M. Collmann du ForWind-Center for Wind Energy Research, Institute for Steel Construction, 30167 Hannover, lors de la 5th Fatigue Design Conference, Fatigue Design 2013 qui s’est tenue en novembre 2013 au Cetim à Senlis.

Abstract : Multi-wire submerged arc welding (SAW) process is conventionally used for long welds with large cross sections in tubular steel tower manufacturing. By applying non-vacuum electron beam welding (NVEBW), the number of passes and the heat input can be notably reduced. For plate thicknesses of 20 mm or more the continuous appearance of solidification cracks inside the weld cross section rouse a great challenge. The fatigue resistance is reduced significantly and the safety of the component cannot be ensured. In this paper analytical and experimental investigations are discussed for predicting fatigue life of defective welds.

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Aeroform – Cetim – Centre technique des industries mécaniques

L’Expertise CND en émission acoustique du Cetim, permet de  minimiser fortement les temps d’intervention et les arrêts coûteux et permet un diagnostic global.

Spécialisée dans la fabrication de moyens chauds pour la cuisson des composites, Aeroform sous-traite au Cetim les opérations de requalification des autoclaves industriels afin de mieux équilibrer la charge de ses équipes.

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Failure analysis of the pulleys during the press-fit assembling process

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.

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