침탄질화 처리된 SCM415재의 피로거동에 대한 통계적 연구

In this research, the statistical characteristics of non-heated and nitro-carburized specimens are investigated under two stress levels (1.15α_w ≤α_α≤1.25≤α_w). Seven specimens of each stress level are tested by rotary bending fatigue tester. The cycles about each crack length and crack propagation rate are used as statistical variable of weibull distribution. The crack propagation rate is verified by small-crack growth law( d2_a/dN ?? αⁿ_α(2_a)).