Degassed processing (DG) is very excellent method for improvement of fatigue property on casting alluminum alloy. In this study, with the aim of more fatigue property improvement of the casting alumium alloy AC4CH, the short peening treatment was applied, and rotating bending fatigue tests with the shot peened DG AC4CH, were carried out. As the results of fatigue tests, fatigue life property of shot peened DG AC4CH is more improved. To investigate the cause of the fatigue life improvement, hardness distributions of near the surface layer was measured and fracture surface of all specimens were observed with SEM.
