On striations and fatigue crack growth in 1018 steel

A study of the fractographic features developed during fatigue crack growth in a 1018 steel has been carried out with emphasis on the crack growth rate regime below 10−3 mm cycle−1. This study included the use of stereographic techniques in the examination of the geometry of striations. The relation between the rate of fatigue crack growth in 1018 steel and the spacing of striations was examined. The spacings of striations at growth rates as low as growth rate of 10−5 mm cycle−1 correlated with the observed fatigue crack growth rates, an indication that fatigue crack growth occurred on a cycle-by-cycle basis. No evidence for an intermittent process of fatigue crack growth was found.