High-cycle fatigue performance analysis was carried out on a cast aluminum alloy AlSi9Cu3 steering column tube.Using the group method
the high cycle fatigue performance of the material was measured and the P-SN curve of the material was plotted.It is estimated that the fatigue strength of the material at a fatigue life of 106 times at 99% reliability reaches 120.7 MPa.Scanning electron microscopy(SEM)was used to observe the fatigue fracture of the specimens.The results reveal that fatigue source is composed of mostly pores and oxide inclusions.The type and size of the original defect can decrease the service life and increase the dispersity of fatigue life.