(in lingua inglese)
This study analyzed the failure of a bridge crane shaft, the analysis allowed concluding as follows. Stereography examination revealed the presence of beach and ratchet marks on the fracture surface and the fractography examination shows striations; all of this evidence indicates the shaft was fractured by fatigue. The shaft material did not satisfy the chemical composition standard; on the other hand, the microstructure was not adequate for this application because it has low mechanical properties and large amount of defects near to the fracture zone. Specifically, the study found the length of MnS inclusions above the value of critical inclusion size parameter, which produced a drastic decrease in fatigue life.