Effect of small scale notches on the very high cycle fatigue of AISI 310 stainless steel

ABSTRACT Fatigue behaviour of AISI 310 stainless steel has been investigated up to very high cycles. The fatigue crack initiation sites were found at the surface of the material. Persistent slip bands developed at the surface of the specimens led to the crack initiation. At lower stress levels, shallow persistent slip bands were found at the surface of the specimens, and the fatigue limit was obtained. Notched specimens showed lower fatigue lives. Notched specimens with higher stress concentration factor (Kt) showed higher fatigue strength reduction factor (Kf). It was found that shallow notches of depth ~100 µm may reduce the fatigue life substantially.