Optimization of the Shot Peening Parameters

The shot peening process is a complicated mechanism in materials science, which is still not fully understood. Despite a long history and a large number of investigations into the process it is still characterized by many areas of uncertainty. Notwithstanding this situation the aerospace and automotive industries have for years consi-dered shot peening as a state-of-the-art process for the surface improvement, forming and life improvement of many parts. The work described in this papcr is a study of the effect of a range of process parameters on the residual stress profiles produced by shot peening coupons of case carburized 17CrNiMo6 steel. The peening process utilized for the research was undertaken using a commercial shot-pee-ning unit supplied by USF Vacu-Blast Limited using 0.6mm diameter shot. The process para-meters investigated included air pressure, the mass flow, the impact angle, the distance between the nozzle and the specimen, the exposure time and the nozzle size. Using Minitab v12 software regression analyses were performed on the results obtained from the statistically designed expe-riments. It was found that the most significant parameters were air pressure, the mass flow, the impact angle and the exposure time. Further important and significant interactions were also de-tected between exposure time and air pressure; nozzle size and mass flow; air pressure and im-pact angle; nozzle size and air pressure