Effect Of Shot Peening On The Fatigue Strength Of Carburized Steels

Author:  Naito, Ochi, Takahashi, Suzuki
Source:  Conf Proc: ICSP-4, (p.519-526)
Doc ID:  1990028
Year of Publication:  1990
Abstract:  
To better understand the mechanism by which compressive residual stress improves the fatigue strength of carburized gears, a crack in a rotating bending fatigue test specimen was closely examined by scanning electron microscope. Low-carbon carburizing steels were used for fatigue test specimens, which were carburized and shot peened. Based on the findings, the effect of shot peening on the improvement of the fatigue strength was analyzed, and methods of increasing fatigue strength by shot peening are discussed. A fatigue crack initiates at an early stage even if the applied stress range is lower than the fatigue limit. To increase the fatigue limit, it is important to arrest the fatigue crack at the beginning of its propagation. The improvement of fatigue properties by increasing the compressive residual stress is due to decreasing the effective tensile stress at the crack tip. The compressive residual stress of gear surface is effectively increased by increasing the peening intensity. Descriptors: Shot peening; Fatigue; Fatigue strength; Gear; Residual stress; Carburizing