Effect on fatigue performance of shot peened components: An analysis using DOE technique

Shot peening is widely used to improve the fatigue properties of components and structures. Residual stresses, surface roughness and work hardening are the main effects induced in the superficial layer from shot peening, which depend on the correct choice of the peening parameters. Compressive stresses are beneficial in increasing resistance to fatigue failures, corrosion fatigue, stress corrosion cracking, hydrogen assisted cracking, fretting, galling and erosion. In this paper design of experiment (DOE) technique was used in carrying out test, using an air blast type shot peening machine. This investigation examines the effect of process parameters such as pressure, shot size, nozzle distance and the exposure time on the fatigue performance of AISI 1045 and 316L material. After going through confirmation test the analysis reveals the right combination of the parameters for better process control. An ANOVA was carried out to identify significant peening parameters. Expressions correlating fatigue life and the process parameters for both materials were developed, which are useful in predicting fatigue life. This technique could prove beneficial in industries for reduction of performance variation and cost and to increase productivity.