Shot peening parameters optimization based on numerical modeling and experimental study of TC4 flange

The shot peening parameters exert a significant influence on the residual stress and warping deformation of Ti parts. To obtain a good shot peening effect, the implicit finite element modeling of shot peening is systematically investigated in this study. The results show that by considering the shape of TC4 flange and utilizing the temperature field and thermal expansion coefficient to equal the stress field, an accurate shot peening model for TC4 flange is constructed, which shows the maximum stress error of 19% compared with the experimental results. Based on the model, the effect of shot peening path, shot diameter, shot peening flow injection pressure and clamping mode on the residual stress and warping deformation of TC4 flange are revealed. The optimal shot peening parameters for the TC4 flange are simulated as follows: the diameter of 0.3 mm, shot peening flow of 3 kg/min, injection pressure of 2.5 bar, following path 1 from the small end to big end of the flange and fixed constraints at the bottom. The increase in the surface roughness of the TC4 flange with the above shot peening parameters is very small, from 0.662 μm to 0.786 μm, while the residual compressive stress increases significantly from 120 MPa to 870 MPa. Thus, the fatigue life after shot peening increases obviously, from 6 × 106 to 1.3 × 107.