Abstract
The experiments are made for a soft mild steel rod (S 25C) and a steel plate (SPC-1) under the constant blasting condition, viz. blasting pressure, 3 kg/cm2 (the bead speed measured at the middle point on the nozzle centerline about 100 m/s) : blasting distance, 100 mm : weightmixing ratio of water with glass beads, 1/1.8 (glass beads of 158 μ in mean shot diameter). The fatigue strength under the rotatory bending and the residual stress calculated from the variation of camber on the etching are inspected.
Comparing the experimental data with those of the usual shot peening, main results obtained are as follows :
1) The endurance limit ratio is greater than or equal to that in shot peening, and the influence of “over peening” is very little.
2) The residual stress zone is decreased by about one-fifth, and the maximum value of residual stress exists in a nearer part to the blasted surface. These results mean that the fatigue strength becomes to be high.
3) The obtained surface is smooth and grossy satin or matte.
