Deformation field in 316L stainless steel by single shot peening

The experiment of the single shot impacting the 316L stainless steel surface was carried out using a surface nano-crystallization testing machine. Three-dimensional morphology of the dimple was observed with a laser scanning confocal microscope, and the dimple's diameter and off-plane displacement in different vibration frequencies were also measured. The in-plane strain around the dimple was measured by moiré interferometry. The effect of the vibration frequency and the way of impacting on the dimple size, the plastic strain size and the plastic strain zone were also analyzed. In comparison with the experimental result, the strain field was simulated using the finite element method, and the distribution of the residual stress around the dimple was also analyzed. The result showed that the crater diameter and the off-plane displacement increases with the increase of the vibration frequency. When the frequency is from 50 to 55 Hz, the crater diameter experiences mutations. When the shot impacts the surface vertically, the greater the vibration frequency, the greater the plastic strain and plastic strain zone, and the plastic strain zone are two times larger than the crater diameter. The plastic strain by the vertical impact is slightly greater than the plastic strain by the oblique impact, but it has little effect on the plastic strain zone. The experimental U field strain is in fairly good agreement with the numerical simulation result, and the maximum error is less than 10%.