Modeling and simulation of pit chemistry of 304 austenitic stainless steel under applied stress in sodium chloride solution

A mathematical model for simulating the active dissolution of a pit on stressed metal surface had been developed. Based on active dissolution mechanism, dissolution current density on the pit surface was assumed and extended through accounting for the thermal activation energy and the multiaxial stress state in pit bottom. The influence of applied tensile stress, pit radius and temperature was addressed. The distribution of solution potential and species concentration was predicted for different applied tensile stresses based on finite element calculations.

► A corrosion model was developed to simulate a stressed metal surface with a pit.
► The stress state in the pit bottom was coupled with the local corrosion environment.
► An analytical expression was established for current density of deformed pit surface.
► Local deformation had a strong effect on potential and species concentration in pits.