在LZ50钢车轴上制取了光滑试样和环形缺口试样, 按照AAR M-101-2009新标准测试了其旋转弯曲疲劳性能, 并观察了断口形貌。结果表明: 光滑试样的旋转弯曲疲劳裂纹萌生于试样表面, 而环形缺口试样的裂纹萌生于缺口前缘, 并呈多源开裂形式, 两种试样均形成与轴向垂直的平断口; 当车轴的拉伸强度提高5%后, 其光滑试样旋转弯曲疲劳性能也得到明显提高, 环形缺口试样虽中值疲劳强度比光滑试样的降低18%, 但其旋转弯曲疲劳极限缺口敏感系数仍与国外碳素钢车轴保持在同一水平上。

Smooth and notched specimens were prepared from LZ50 steel axle to test the rotating bending fatigue property according to the new standard of AAR M-101-2009 and observe the fracture morphology. The results show that rotating bending fatigue cracks initiated from the smooth sample surface, while the cracks in notched specimen initiated from the notch edge, and the cracking shape was multi-source. The fracture surfaces of the two kinds of samples were perpendicular to axial direction. After the tensile strength of the axle increased by 5%, the rotating bending fatigue property of smooth sample increased significantly; the medium fatigue strength of notched sample was 18% less than that of smooth sample, but the notch sensitivity coefficient of rotating bending fatigue limit remained at the same level with the overseas carbon steel axle.