Failure mechanism tracing of the crankshaft for reciprocating High-Pressure plunger pump

Abstract

Crankshaft fracture is a typical failure form of reciprocating high-pressure plunger pump. Different from traditional power machinery, the number of plungers in plunger pumps is usually odd, which leads to unbalanced radial force of the crankshaft and greatly increases the risk of failure. The crankshaft of a 250 kW high-pressure plunger pump was fractured, and the fracture morphology was river-shaped, which was a typical fatigue failure. To trace the failure of the crankshaft, a Constructure-Kinematics-Materials-Craftsmanship (CKMC) method was brought out. The microstructure of the damage zone was observed, and a three-dimensional transient finite element model was established to find the most dangerous zone and damage mechanism. The results show that high-cycle fatigue of fillet zone is the main reason for crankshaft fatigue failure. Material defects and lack of nitrided layer at fillet are the key factors to accelerate crankshaft failure. Finally, recommendations for preventing future failures were presented.