SHAFT FAILURE S045
Shaft failure from excessive radial loads occurs in the middle of the span in double suction or multi-stage pumps.
Shaft failure in end suction centrifugal pumps usually occurs at the shoulder of the shaft where the impeller hub positions against the impeller sleeve.
Some engineers recommend substituting chrome steel shafts for the 300 series stainless steel shafts normally found in fresh water service because the endurance limit of the 300 series stainless steels is less than that of the chrome steels in fresh water.
All of this means that the endurance limit of the shaft material is very much affected by the liquid being pumped.