<p>Front axles of commercial vehicles play a critical role in ensuring stability, load capacity and steering control, making them critical components for vehicle safety and performance. This paper presents the results of the material characterization and fractographic analysis of the stub axle of a bus, which failed during service operations. Materials characterization included determining the chemical composition of the alloy, microstructural analysis and microhardness profiles. Fractographic analysis was accomplished by visual observation, scanning electron microscopy and metallographic essays in selected zones close to the fracture surface. The results indicated a ductile failure due to torsional overstress linked to microstructural anomalies on the surface of the component.</p>