Abstract
The effect of the plastic deformation on the fatigue property was investigated with consideration of the pre-strain level, the surface roughness and the residual stress. The test materials were a mild steel sheet SPCC, that nominal thickness was 3mm. Bending fatigue test was carried out using a Schenk-type bending fatigue apparatus at room temperature, where the sine stress wave was imposed on the specimen with 30 Hz. The plastically deformed sheet with several strain levels were prepared, which underwent the simple tension. The fatigue strength elevates in accordance with the magnitude of the plastic strain, however, the effect of surface roughness was not prominent.
