This study investigate the abrasive wear failure of tungsten carbide hardfacing on continuous digester (CD) blade (carbon steel) in an environment of sulphuric acid and ilmenite ore mixture. Comparison being made on the hardness, thickness and microstructural of the hardfacing between unworn and 3 months old worn blade on few locations around the blade. The cross sections of the blade revealed non-uniform coverage of the hardfacing on the blade for both worn and unworn blade. The edge of the blade has the least amount of hardfacing thickness which with time acts as the point of failure during the wear process. The hardness obtained from both the unworn and worn samples are around 25% lower from the hardfacing electrode manufacturer’s hardness specification. Microstructural micrograph analysis of the hardfacing reveale
An interesting paper published in » Engineering Failure Analysis » on www.sciencedirect.com, Volume 57, November 2015.
Lightning protection system elements need to be selected from materials which are resistant to corrosion and should be protected from fast degradation. However, over the time corrosion will take place in the presence of galvanically dissimilar metals in the same electrolyte (moisture)……
This paper presents the causes of corrosion and recent developments in minimising the corrosion associated with lightning protection and grounding systems.
Une « Journée Technique » du Cetim à Toulouse le 18 mai.
La corrosion reste un mal industriel majeur. Et ce, en dépit des avancées scientifiques et des progrès technologiques continus. Elle est encore aujourd’hui responsable d’un grand nombre d’avaries et touche de nombreux domaines.Elle revêt différentes formes et un cas apparemment simple peut cacher un phénomène complexe. Ses causes étant multiples, sa détection, sa mesure et sa maîtrise relèvent de compétences variées qui en font une affaire de spécialistes !
Ayez les bons réflexes et venez profitez de l’expertise du Cetim à l’occasion de cette journée, qui vous aidera à déjouer les pièges de la corrosion.
Fatigue failure of holding U-bolt of a cooling fan blade is analyzed. Fractography of the fracture surface reveals the characteristics of a fatigue fracture. Finite element modeling is used for stress analyzing. Analysis of the loading conditions indicates that the bolts are under multiaxial fatigue. ……..
This paper presents a review of mode I fracture toughness obtained by authors from micromechanical modeling and fracture toughness test……… The mode I fracture toughness was determine using three different specimens (Single Edge Notch Bending, Single Edge Crack and Asymmetric Semi Circular Bending). Different Polyurethane foam densities were investigated. Finally, a good correlation between analytical, numerical and experimental fracture toughness results was obtained.
Failure analysis of a shaft used in a bridge crane has been carried out. The shaft fractured in the keyway with evidence of fatigue. The geometry of the keyway also promoted the initiation crack because the width and height were erroneously designed. It was concluded that all these factors produced fatigue failure.
The analysis of an abnormal failure of forklift forks is presented in this work. The investigation results suggested that failure occurred due to fatigue mechanism followed by sudden overload fracture. The orientation of fatigue fracture indicates abnormal lifting operation, favouring crack initiation from outer fork area which is the compression designed zone. Moreover, various surface flaws and weakness areas (such as surface marks, decarburized microstructures and weld zones) identified on the outer fork zone, compromise fatigue strength inducing premature crack nucleation and fast growth towards final failure.
Experts d’assurance, experts judiciaires, chefs de projets industriels, ingénieurs et techniciens de bureaux d’études, production, qualité et SAV, venez vous former au Cetim auprès de formateurs experts techniques dans le domaine de l’analyse de défaillances, intervenant dans des missions de conseil et d’assistances techniques en entreprise.
Identifier les principaux modes de rupture des matériaux métalliques ;
Those study focuses on different failure modes of internal combustion engine valves, failures due to fatigue at high temperature, high temperature effects on mechanical properties of materials, like hardness and yield strength; wear failure which is due to impact loading, and wear rate that depends on load and time. For the study of fatigue life, a combined S-N (max. stress v/s number of cycles) curve is prepared. Such a curve helps in comparing the fatigue failure for different materials at different high temperatures and may also assist the researchers in developing the valve materials with a prolonged life.