Fracture causes of electric rear axle housing

The electric rear axle housings proucluced by a company fractured many times during bench test and road test, and the fracture occurred at the circumferential weld between the cladding and the casing. The causes of the electric rear axle housing fracture were analyzed by macroscopic observation, scanning electron microscopy analysis, chemical composition analysis, metallographic examination, weld penetration inspection, finite element simulation analysis and other methods. The results show that the inner diameter of the cladding and casing of the rear axle housing was inconsistent. After assembly, there was a gap between the bushing step and the cladding, which caused the cladding to be unable to be fully welded, and sharp corners were formed on the end face. The stress concentration at the sharp corners was the main reason for the fracture of the rear axle housing. It was suggested to optimize the design scheme, changed the design of internal misalignment between the cladding and the casing to external misalignment, cancelled the bushing steps and reduced the bushing opening, eliminated the sharp corner of the section, and prevented stress concentration.