Pit to crack transition and corrosion fatigue lifetime reduction estimations by means of a short crack microstructural model

A microstructural model is presented to assess pit-to-crack transition and corrosion fatigue strength in pitted components in different environments. The model is first validated using available experimental data in the literature for pitting corrosion fatigue strength and S-N curves for both carbon and stainless steels. The value of the method proposed and its applicability is then shown by the development of fatigue knock down factor maps to the in-air S-N curve. Finally, the influence of pit local topology on pit-to-crack transition damage tolerance and the links to the NDE methods quantitative resolution necessary to account for defect shape or acuity in structural integrity assessments are discussed.