Environmentally-assisted cracking (EAC) of low-alloy steels in elevated temperature aqueous enivornments is readily observed in many laboratory experiments conducted in autoclaves, yet the observation fo EAC in actural components operating in the same environments is quite rare. Mass transport of sulfides fromt he crack enclave by diffusion and convection occurring in operating components provides one plausible explanation to this apparent paradox. Another contribution to EAC mitigation may also arise from the non-constant stress amplitudes typcial for amny operating components. This paper provides d demonstration of how a single tensile overload to 40-percent above a steady-state maximum fatigue stress can ratard subsequent crack growth at the steady-state level for a sufficient period of time that diffusional mass transport can reduce the crack-tip suifide concentration to a level below that necessary to sustain EAC.
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