抄録
As for initial fatigue crack, quantitative evaluation was onsidered to e difficulty for reasons of both sides of metal-lurgical factor and mechanics factor influence behavior and crack growth mode change. In this study, paid its attention to initial fatigue crack growth to a depth direction, and examined Stage I fatigue crack behavior. To examine a mechanics condition governing stage I fatigue crack growth, fully reversed uniaxial push-pull high cycle fatigue tests were carried out on a low carbon steel. As a result behavior of Stage I fatigue crack became clear.
