Abstract
In order to clarify the effect of FSP treatment on fatigue properties of SCM435H steel with two levels of hardness, high cycle fatigue tests were carried out with a rotational bending machine at room temperature. The effect of substrate hardness on efficiency of FSP treatment was discussed. In the case of higher hardness substrate, the fatigue strength was dominantly increased by FSP treatment. However, in the case of lower hardness substrate, the increasing level was very small. This was because compressive residual stress generated on the surface of the higher hardness specimen was much larger than that generated on the lower hardness specimen. Furthermore, the higher compressive residual stress was very stable under the application of cyclic loading. These results imply that the FSP treatment is very effective for higher hardness substrate.
