Abstract
Rotational bending fatigue tests were carried out on SAE 1547 steel modified by a fine particle bombarding, with special attention focused on the effect of the processing condition on the fatigue properties. The air pressure strongly affects the stability of the compressive residual stress and the fatigue strength of the specimen treated by high air pressure is slightly higher than that of the low air pressure specimens. The specimen treated with small particles show significantly higher fatigue strength compared to those treated by large particles. This is because the compressive residual stress remained after stress cycling at the surface of the specimens treated with small particles. In addition, the surface hollows formed by impingement of the particles were smaller than those treated by large particles.
