Reasons Analysis on Fracture of Drill Pipe Elevator Axis Pin

The fracture reasons of a drill pipe elevator axis pin were analyzed by means of chemical compositions analysis, fracture analysis, metallographic examination and mechanical properties test. The results show that there were original quenching cracks in outer surface of the axis pin, coupled with its poor impact toughness and ductility. So unstable propagation of the cracks and brittle fracture of the axis pin happened under the action of larger impact loads.