Failure analysis of a cracked aluminum 7075 wing internal angle in Airbus A-300

2016-07-05_16h39_20

 

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

 

There are 16 angles in Airbus A300s wing box. On the right side, rear spur, and lower flange area of the center wing box, one of these angles had been cracked with a length of 28 mm. This crack has decreased residual strength of the part under allowed values and resulted to a rupture in the rear spur lower cap. Several reports of the same occurrences in other Airbus A300 air crafts, highlight the importance of finding the causes of this failure.  Finally, it was concluded that corrosion fatigue was the main reason which itself comes from manufacturing, maintenance, metallurgical, and geometric reasons as were discussed in this study.

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Failure analysis of low pressure steam turbine blade

This paper deals with fracture investigations of low pressure (L P) steam turbine blade of a 110 MW thermal power plant in Punjab in India. These blades were made from chrome alloy steel X20Cr13 (Tempered martensitic stainless steel). The main focus of the paper is the fracture analysis, which took place at the airfoil region at 203 mm from the root of the blade. One of the fractured blades was retrieved to identify the cause of failure. The investigations included the visual examination, SEM fractography, chemical analysis, hardness measurement, and micro-structural characterization. While preparing the test specimen, silicon rich phases were detected on the blade along with oxide scale present inside the corrosion pits and fractured region. Transgranular cleavage fractures along with beach marks are observed. The cause of failure is possibly the corrosion-fatigue. These causes of failure are also underlined in this paper.

viaScienceDirect.com – Case Studies in Engineering Failure Analysis – Fractographic investigations of the failure of L-1 low pressure steam turbine blade.

Cas de ruptures par fatigue-corrosion de pièces mécaniques en milieu industriel

Cas de ruptures par fatigue-corrosion de pièces mécaniques en milieu industriel

Titre du document / Document title

Cas de ruptures par fatigue-corrosion de pièces mécaniques en milieu industriel

Auteur(s) / Author(s)

GALTIER A. (1) ; BERTRAND J. P. (1) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Usinor R&D – IRSID, Voie Romaine, BP 30320, 57283 Maizières-lès-Metz, FRANCE

Résumé / Abstract

La rupture de pièces mécaniques en fatigue corrosion n’est pas un phénomène exeptionnel dans le milieu industriel. Au travers quatre expertises d’avaries, nous présentons les traits caractéristiques de ce phénomène.

Source / Source

Congrès
Fatigue et environnement :   ( Paris, 24-25 mai 2000 )
Société française de métallurgie et de matériaux No19, Paris , FRANCE (24/05/2000)
2000  , pp. 3.1-3.8[Note(s) : env. 180 p., ] (4 ref.) Illustration : Illustration ;

Langue / Language

Français

Editeur / Publisher

SF2M, Nanterre, FRANCE  (2000) (Monographie)