Efficiency Analysis of Shot Peening Parameters on Variations of Hardness, Grain Size and Residual Stress via Taguchi Approach

In the present study, the main purpose is to detect the most key factors of shot peening (SP) process on the microhardness, grain size, and residual stress of AISI 1060 high carbon steel. The specimens were treated using various types of SP process namely conventional shot peening and severe shot peening. Several experiments were performed to study metallurgical and mechanical properties of AISI 1060 steel. Almen intensity and surface coverage from one side and microhardness, grain size, and residual stress from the other side were considered as input and output parameters for the design of experiment methodology, respectively. The $L_{18}\left(2^{1}and{3}^1\right)$ mixed level of Taguchi orthogonal array design was used to study all cases. The test results were investigated by signal-to-noise ratio formula. It was identified that the surface coverage is the most key factors for shot peening process considering the affected depth. Also, the effect of this parameter on the microhardness, grain size and residual stress was obtained approximately 68, 89 and 57%, respectively. Eventually, the results obtained from all Taguchi sensitivity analysis indicated that it would be better to adjust the surface coverage factor in comparison with Almen intensity factor in order to create the surface compressive residual stress on the material and consequently to increase the fatigue lifetime of component using shot peening treatment.