The Effect of Shot Peening on the Fatigue Strength of Carburizing Steels.

Shot peening is one of the cold working processes performed by projecting hard particles onto the surface of works.In spite of old technology, it has been reconsidered in automotive industries as the means to improve fatigue durability in terms of "Hard shot peening".Hard shot peening is a high intensity peening technology resulting in larger amount of compressive residual stress and higher fatigue resistance than conventional intensity peening.In hard shot peening process, however, the peak value of the stress is located at the depth of 0.05mm below the surface and the surface value is not so high.To compensate this stress depression at sub-surface, additional beads peening was studied.By applying the additional beads peening further improvement of fatigue resistance has been confirmed.The beads peening process is effective to give residual compressive stress at the surface without surface degradation.1.