Chapter 6, Problem 9P

For the interval 10³ ≤ N ≤ 10⁶ cycles, develop an expression for the axial fatigue strength ${\left(S_f^{\text{'}}\right)}_{ax}$ for the polished specimens of 4130 used to obtain Fig. 6–10. The ultimate strength is S_ut = 125 kpsi and the endurance limit is ${\left(S_e^{\text{'}}\right)}_{ax}$ = 50 kpsi.