Failure analysis of counter shafts of a centrifugal pump

An analysis of the premature failure of two counter shafts used in centrifu gal pumps for lifting slurry has been carried out. Chemical analysis, micro structural characterisation, fractography, hardness measurement, tensile an d Charpy impact tests were used for the analysis. The chemical compositions for the shafts were as per recommendation. The microstructure of one of th e shafts was ferritic-pearlitic and its mechanical properties were inferior to the recommended values. For the other shaft the microstructure was temp ered bainite; although the impact energy satisfied the specification, the o ther properties (hardness, UTS) were inferior. It was concluded that the im proper heat treatment was the prime cause for the premature failure of the shafts. (C). 1999 Elsevier Science Ltd. All rights reserved.