Fatigue Fracture of a High-Resistance Structural Steel Component Destined to Sustain Severe Loads Under Service Conditions, J. Failure Analysis and Prevention, Vol. 17(1) (2017) pp. 79-85.
S. Papaefthymiou, A. Vazdirvanidis, G. Pantazopoulos, C. Goulas
AbstractÂ
A structural steel component that failed under fatigue was examined with the aim to identify
the root causes of this failure. Fractographic examination revealed the presence of multiple
beach marks; the position and arrangement of those signified the occurrence of fatigue
fracture under the presence of combined loading conditions, involving torsion and bending
stress components. Crack initiation was observed also at the corners of the steel plate where
non-metallic inclusions were located. Stereo-microscopical examination of the fracture
surface likely revealed the presence of casting inclusions, probably fluxes or slag particles,
near the surface and in the interior of the component. These inclusions could be considered
inherent—metallurgical stress raisers, behaving as locations of prominent crack nucleation
under cyclic fatigue loading, stimulating subsequent crack propagation and final ultimate
rupture.