Vallourec mêle performance en étanchéité et conditions extrêmes.

2016-11-17_11h50_21Est-il possible d’effectuer des essais d’étanchéité en mettant en œuvre des ressources moins importantes, tout en conservant la représentativité du fonctionnement des produits ? C’est la question posée par Vallourec, spécialiste des tubes sans soudure pour l’industrie du pétrole et du gaz,  aux experts du Cetim, en les chargeant de démontrer la faisabilité d’essais d’étanchéité sur une portion réduite (la zone de connexion) de ses tubes Oil country tubular goods (OCTG).

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An investigation of cracking causes in an outlet RTJ flange in ISOMAX unit

2016-11-16_18h55_18A paper published in « Case Studies in Engineering Failure Analysis« , available on

Corrosion has always been a problem in the petroleum refining and the petrochemical operations. The equipment of ISOMAX unit, such as reactors, furnace tubes, valves, and pipelines are frequently performed at high temperatures and high pressure condition. This working conditions, accelerates the failures due to corrosion. Therefore, heat- and corrosion-resistant alloys, e.g., austenitic stainless steels, have been widely used in this unit because of their excellent corrosion resistance, mechanical strength and toughness.

This paper describes failure analysis procedure of a cracked high pressure 321 SS RTJ flange in ISOMAX unit. In order to get conclusions related to crack propagation mechanisms of the flange, some investigations were done on the cracked flange that is mentioned in the body of the paper.

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Failure analysis of titanium alloy fasteners for aerospace applications

2016-11-16_18h46_14A paper published in « Case Studies in Engineering Failure Analysis« , available on

As a qualification of bolt for flight assembly, the bolt assembly has undergone proof pressure test at 2.4 MPa, Vibration test at frequency range of 20–100 Hz, ±3 db/oct for 120 s in both lateral and longitudinal directions and flight acceptance test. During routine visual inspection before electrical check, it was observed in one of the three fasteners that the head of the bolt had got sheared off from the shank portion of bolt. Further, a failure analysis was carried out on the failed bolt.

The objective of the study is metallurgical analysis of the failed bolt, fractography study to find out the root cause of the failure, and optimization of processing parameters for fastener manufacturing.


Catastrophic failure of a carbon steel storage tank due to internal corrosion

A paper published in « Case Studies in Engineering Failure Analysis« , available on

Catastrophic failure of a 10 m high, 8 m diameter steel storage tank containing approximately 350 m3 of waste solvent led to a significant environmental incident in 2009. An investigation was carried out to establish the root cause and to learn lessons that might prevent a reoccurrence.

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Failure analysis of a high strength low alloy  steel pressure vessel

2016-11-16_18h21_36A paper published in « Case Studies in Engineering Failure Analysis« , available on

High strength low alloy (HSLA) steel with a nominal composition of 0.15C–1.25Cr–1Mo–0.25V is being extensively used in space programme. Owing to its ease of fabrication and welding, a tank was fabricated out of this alloy. The tank is used to contain strontium per chlorate which on combustion develop secondary thrust, effectively used during attitude control of satellite launch vehicle. During one of the routine qualification tests, a tank had failed at an internal pressure of 109 bar, against a designed proof pressure of 120 bar.

Failure was initiated from long seam weld of a cylindrical shell and propagated into the parent material thereafter. Detailed metallurgical investigation has been carried out to understand the cause of failure. This paper brings out the detail of investigation carried out.


Non-Destructive Investigation of Bulk Residual Stress in Automobile Brake Pads with its Service Life

2016-11-16_18h02_45A paper published in « Journal for Foundations and Applications of Physics »,  available online at

Automobile brake systems transform kinetic energy into heat for the purpose of speed control. During this operation, rapid heating and cooling cycles cause the formation of residual stress in the brake pad backing plate. In this study, the relation between residual stress magnitude and the operation period is investigated to predict the service life of brake pads. ….

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Design and fabrication of Impact Die for Powder Metallurgy

2016-11-16_17h43_25A paper publihed in « Materials Today: Proceedings », available online at

Die design is one of the most important steps in Powder Metallurgy process because the shape and attributes of the die will directly affect the final component. Die design has a number of steps and considerations to be made before fabrication. This project is an attempt to design and fabricate a die for cold compaction process used in the powder metallurgy process.

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Tesseract inaugure les essais sismiques

Avec la plateforme d’essais sismiques « Tesseract » inaugurée le 8 novembre 2016 à Bordeaux, le FCBA et le Cetim proposent aux fabricants d’équipements, notamment nucléaires, des moyens inédits alliant simulation et essais sismiques.   Pour répondre aux exigences accrues de stabilité des équipements des centrales nucléaires en conditions sismiques suite à la catastrophe de Fukushima, le FCBA (Forêt Cellulose, Bois-construction Ameublement) et le Cetim allient à nouveau leurs expertises

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Rolling element bearing failure analysis: A case study

A paper published in « Case Studies in Engineering Failure Analysis« , january 2013

This paper addresses Rolling Contact Fatigue (RCF) occurs due to the result of cyclic stress developed during operation and mechanism that involve in fretting failure of rolling element bearing. As bearing raceways of non-rotating rolling element bearings exposed to vibration or sliding oscillation false Brinelling occurs. Bearing surface due to false Brinelling tends to damage within a short period, due to cavities created on the bearing raceway. Recommendation towards enhancement of bearing life is also suggested.

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Cracking of underground welded steel pipes caused by HAZ sensitization

An article on case study, published in « Case Studies in Engineering Failure Analysis« , on january 2013.

Low alloy steel welded pipes buried in the ground were sent for failure analysis investigation. Failure of steel pipes was not caused by tensile ductile overload but resulted from low ductility fracture in the area of the weld, which also contains multiple intergranular secondary cracks. The failure is most probably attributed to intergranular cracking initiating from the outer surface in the weld heat affected zone and propagated through the wall thickness.