High Cycle Fatigue Behavior of High Strength Steel Q960

The high cycle fatigue properties of Q960 at room temperature are tested by axial-force-controlled method. The average value of high cycle fatigue strength limit of Q960 material is 182.5MPa. The condition fatigue limit of different survival rates is obtained. The S-N curve of Q960 is in accordance with the equation logN=9.4949-0.0162S. The morphology of the fatigue fracture is observed by scanning electron microscope under180MPa. The fatigue crack originated from the machined defect on the surface of the sample. In the crack growth region, it can be seen that there are obvious fatigue striations, fatigue steps and secondary cracks. The typical dimple fracture is found in the fatigue instantaneous fracture zone.