Analysis of catastrophically failed industrial bolt

This article provides a summary of the findings from examining a failed industrial bolt used in a vulcaniser for splicing conveyor belt. In summary, the fracture plane is nearly completely catastrophic. There is a small area which does appear to be fatigue failure. The surface is perpendicular to the thread edge and located at the stress concentration at the thread which is typical of fatigue crack initiation. The fatigue failure area is quite small compared to the rest of the failure surface which indicates that the part is susceptible to catastrophic failure after relatively little fatigue which therefore suggests that the inspection for fatigue must be done quite often and in quite a detailed fashion to detect the crack.