Cause of drive axle fracture

The drive axle of a certain type of tractor fractured in the straightening process after induction quenching. The fracture cause was analyzed by means of macroscopic observation, metallographic examination and hot acid etching test. The results show that the local overburning of the drive axle during the forging process led to a significant reduction in the strength and plasticity of the material. When the external force was too large, the part broke.