Failure Analysis on Fracture of 35CrMo Steel Driven Shaft of a Mud Pump

Fracture failure of 35CrMo steel driven shaft at the power end of a mud pump occurred during operation. The failure causes of driven shaft were analyzed by means of macroscopic observation, chemical composition analysis, mechanical property test, scanning electron microscope analysis, metallographic examination, inclusion and loose defect analysis. The results show that there were a lot of defects and inhomogeneous structures in the center of the driven shaft of the power end of the mud pump, such as dendrite structure, inclusions and porosity, which significantly reduced the mechanical properties of the driven shaft, which was the main reason for the overload brittle fracture failure of the driven shaft.