Failure Analysis of Automobile Welding Axle Housing

Fracture occurred to a automobile welding axle housing in the fatigue test. In order to find out the failure mode and cause, macro and micro observation, chemical composition and hardness testing, metallographic examination and finite element analysis were carried out. The results show that the fracture is fatigue fracture occurring at the weld edge of the lower shell supporter. There was higher stress at the weld edge, and the incomplete penetration aggravated the stress concentration, which was the main cause for the initiation of fatigue crack. Based on the analysis results, some measures were put forward, such as improving welding quality and optimizing the design of the axle housing.