Failure Analysis of a Hydraulic Fracturing Pump Fluid End

Hydraulic fracturing for oil and natural gas recovery is typically performed with specialized “frac pump”, which injects a mixture of largely sand and water underground at high pressure to break up rock and allow the oil and gas to easily flow into the well. These pumps operate on positive displacement, consisting of a fluid end and a power end, and must withstand high cyclic pressures (in excess of 15 ksi) and the abrasive injection fluid. In this investigation, an analysis was performed on a fluid end pump composed of 15-5 PH stainless steel which had failed due to high cycle fatigue (HCF) cracking initiating from within the threaded connection between the pump block and adjoining cover nut component. The talk will present findings from the metallurgical analysis, fracture mechanics analysis and process evaluation that was performed as part of this investigation.