Equipment Cracking Failure Case Studies

One factor, which should always be considered when performing materials failure investigations, is the influence of human error. This section provides three examples of equipment failures due to cracking for which the root cause of failure was found to be 

The first involves the misapplication of chromium electroplating to an engine crankshaft during a rebuild procedure, which resulted in a fatigue failure shortly after the unit was put back into service. 

The second failure involves an error made during the weld repair of an electric motor drive shaft, which again resulted in a fatigue failure. 

The third example describes mistakes made during the design, procurement and construction of a high-pressure steam piping system, resulting in a catastrophic failure of a pipe connector, due to chloride stress corrosion cracking. 

Material failures can be caused by a number of factors, either individually, or in combination, including substandard materials, inappropriate materials selection, poor design, equipment abuse, unexpected stresses or environmental conditions, and poor maintenance practices and/or neglect. Many failures, in one way or another, involve human error to some extent. 

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