It was determined by visual inspection that the anticorrosive coating was delaminated from the metal surface and that
the zone of the shaft-flange transition radius was directly exposed to the effects of river water due to inadequate sealing of
the shaft seal box.
In the same time when this failure analysis was conducted, the non-destructive testing of other turbine shafts of the same
type revealed numerous cracks, Fig. 18. The cracks were found in zone of the same width as obtained by Finite element calculation,
Fig. 16, for the load case 2. The pattern of the cracks at the metal surface and the presence of the one major crack
accounting for failure indicate corrosion fatigue as the cause of the failure [12–14]