Compressive Residual Stress into Titanium Alloy Using Cavitation Shotless Peening Method

Cavitation shotless peening (CSP) method, where impacts are generated by a submerged cavitating jet (without shots), was used to introduce compressive residual stress in titanium alloy, Ti-6Al-4V for the purpose of enhancing the conventional fatigue and fretting fatigue life and strength. This method provided higher compressive stress at surface as well as up to a depth of 40 m from the surface than that with the shot peening method. Further, the surface treated by CSP was considerably less rough compared to that by the shot peening method, which is a highly desirable feature to improve the fretting fatigue performance.     

Fatigue strength improvement of gears using cavitation shotless peening

Peening, using cavitation impacts induced by bubble collapse, represents a novel surface enhancement technique for machine parts without involving conventional shot peening blasting. This is known as cavitation shotless peening, CSP. The improvement in the fatigue strength of a spur gear after CSP has been demonstrated. The fatigue strength of a gear treated with CSP was improved by about 60%, compared with that of a non-peened gear.