Experimental study of shot peening and stress peen forming

Shot peening is a cold working process widely used to improve fatigue life of aerospace and automobile components. Stress peen forming is widely used in the aeronautic industry to produce thin components with complex shapes, involving double curvatures, such as wing skins. In this paper, quantitative relationships between the saturation, surface coverage and roughness with respect to peening time have been established based on aluminum Al2024 test strips. The influences of peening velocity and peening time on the resulting residual stress profiles have been experimentally presented. The quantitative relationships between the prebending moment and the resulting arc heights of narrow strips and square strips have been experimentally investigated. Experimental results show that with the increases of the prebending moment, the resulting arc height following the prebending direction increases and the tendency is almost linear. Quantitative equations of the saturation, coverage and roughness as well as the relationship between the prebending moment and resulting arc height can be used for the optimization of shot peening and stress peen forming process.