Optimization and prediction of shot peening parameters for aluminum alloy 7075 using response surface methodology

Shot Peening (SP) is a commonly employed technique to enhance the ability of metal parts to withstand fatigue. However, achieving the ideal treatment factor optimization is a challenging task. The Response Surface Methodology (RSM) model has proven to be a reliable statistical technique for assessing the impact of multiple key treatment factors on the material's surface roughness and residual stresses. This study examines the optimization of shot peening parameters and their impact on residual stresses by applying RSM to aluminum alloy 7075. Three main parameters, such as shot medium (steel, ceramics, and glass), shot diameter (0.2, 0.4, and 0.6 mm), and shot pressure (2, 4, and 6 MPa), are optimized to achieve the optimal and best residual stress. The optimized and predicted SP parameters are obtained based on Central Composite Design (CCD) using the RSM approach. Ultimately, residual stress tests with the optimal plan showed improved fatigue lifespans for the studied specimens. The stress values before and after shot peening had adjusted R 2 values of 76.8 % and 98.8 %, respectively. The error variation between the predicted stress values and the measured values was below 5.5 %. The statistical results suggested that the RSM model had a high level of accuracy. The optimal values for SP medium, shot diameter, and pressure were observed to be ceramics, 0.2 mm, and 4.0 MPa, respectively. Furthermore, the residual stress values of the AA7075 specimens treated with optimal parameters and ceramics for shot peening showed an improvement compared to other shot mediums such as steel and glass. The suggested RSM model has shown validity in understanding and predicting the shot peening parameters for aluminum alloy 7075.