Effects of short cracks on fatigue life calculations

In this study, the potential impact of the short crack problem in En7A steel with a high content of elongated MnS inclusions has been observed. Experimental short crack data were compared first with the predicted S-N curves determined using long crack growth parameters and second with the calculated lives using only long crack data and using both short crack and long crack data. All these life predictions revealed that long crack data alone cannot be used in fatigue lifetime analyses that treat short crack growth, because they can all lead to dangerous over-predicted lives