Failure Analysis of a Centrifugal Compressor Impeller Made of 17-4PH Steel in the Moist Hydrogen Sulfide Environment

The impeller under consideration is a rotor wheel of centrifugal compressor, made 17-4PH martensitic precipitated hardening stainless steel. Its total operating lifetime was estimated to 80,000 h, but it fractured beforehand, 4 days after the scheduled overhaul without any observed pre-symptoms. important causes failure were its working conditions: moist H2S environment, applied shaft fitting stress, and structure material. In article post-failure analysis an described, explaining root cause by means both experimental Finite Element Methods (FEM). Sulfide Stress Cracking (SSC) found be primary mechanism for investigation. Details investigations possible corrective measures improve performance impellers used harsh environment conditions are discussed.