Fatigue Characteristics of High‐Speed Train Axles with Different Prefabricated Surface Notches

High-speed train axles with prefabricated surface notches are critical for evaluating fatigue resistance under cyclic loading. This study investigates the fatigue characteristics of axles with circumferential V-shaped notches of varying depths (0.538–1.760 mm) and stress concentration factors (2.48–5.49). Fatigue tests were conducted at 19.8 Hz with a stress ratio of −1, up to 2 × 107 cycles, following EN 13261 standards. Magnetic particle inspection revealed no crack initiation in notched segments, even at maximum local stresses reaching 1082.8 MPa. Results demonstrate excellent fatigue resistance of axle materials, with deeper notches (up to 1.760 mm) still maintaining integrity. The findings challenge conservative overhaul specifications (allowing impact depth less than 0.3 mm), suggesting potential relaxation based on experimental evidence. This work highlights the need for comprehensive fatigue assessment beyond local stress concentration alone.