Effect of residual stress on fatigue strength of steel modified by WPC process

Rotational bending fatigue tests were carried out on low carbon Cr-Mo steel modified by a combination of Wide Peening Cleaning (WPC) and carburizing, with special attention focused on the effect of surface residual stress on fatigue properties. By combining the carburizing and the WPC process, it is possible to generate a high compressive residual stress near the surface, maintaining a deep layer of compressive residual stress associated with the carburizing. The notched specimens modified by the combined process show significantly higher fatigue strength compared to those modified by single process of carburizing. This is because the extremely high compressive residual stress remained after stress cycling at the surface of the specimens modified by the combined process.