Abstract
The effect of shot peening on the fatigue strength in the long life range of (10)^7 to (10)^8 cycles were investigated in a β-titanium alloy (Ti-4Al-22V alloy). The specimens were solution treated at 750℃ and then aged at 500℃ (material STA). The fatigue strength for (10)^8 cycles of material STA was 580 MPa. The fatigue strength of the shot peened specimens was 680 MPa. The increment of the fatigue strength was 100 MPa (17%) by shot peening. The strengthening effect originated by cold working prior to the aging was not identified.
