Effect of Inclusions on High Cycle Fatigue Characteristics of Spring Steel

In this paper the size and quantity of inclusions in different parts of spring steel slab and steel was determined by using Aspex inclusion automatic scanning electron microscope,and the fatigue properties of the materials were tested using a rotating bending fatigue tester.The rules of the distribution of inclusions in steel was revealed,and the influence mechanism of different defect forms and distributions of steel on the failure of materials was analyzed.The results show that when the rotation bending fatigue limit is σ_-1= 764 MPa,the ratio of fatigue limit to tensile strength is 0.45.Fatigue failure occurs at a lower cycle（＜10⁶）,when the average size of inclusions is greater than 24.9 μm and is distributed near the surface of the steel.