抄録
The authors investigated their characteristics and the strength of NH materials treated by Double Shot Peening (DSP). The results obtained are summarized as follows : (1) Increased diffusion layer hardness between the surface and depth of 400μm by DSP (2) Remarkably high residual stresses of surface residual stress with -701MPa and maximum compressive residual stress with -733MPa of the NH+DSP material (3) Considerably increased fatigue limit of the NH+DSP material. 33% (stress ratio R≧0) and 28% (R=-1) higher fatigue limit than the NH materials, respectively.
