Some Effects of Strain Rate on the Transgranular Stress Corrosion Cracking of Ferritic Steels in Dilute Near-Neutral-pH Solutions

While evidence is presented of the ingress of hydrogen to steels from near-neutral-pH solutions at potentials in the vicinity of open-circuit values, there is also evidence of dissolution occurring simultaneously. Such synergism presents problems in formulating a mechanism-based quantitative expression for crack growth rates, implying that there is a need for experimental data in modeling cracking for life prediction purposes. It is shown that crack tip strain rates calculated for slow strain rate tests provides an empirical relation to crack growth rates and gives approximate agreement with a similar expression for cyclic loading tests reported in the literature, suggesting that the incorporation of crack tip strain rates in modeling should be considered.