Modelling SCC crack tip electrochemistry of austenitic stainless steel in high temperature water

Abstract

The Stress Corrosion Cracking (SCC) behavior of the austenite stainless steel in high temperature water was studied by a multi-physics coupling Finite Element (FE) model. The calculation of the bare metal corrosion current density at the crack tip was achieved to quantify the contribution of the loading in SCC crack growth rate (CGR) prediction model by a combination of the electrochemistry experiments and a mechanochemistry model. The plastic strain and the corrosion current both increased with the increase in loading, which further resulted in the metal cations and the aggressive ions concentrating more severely near the crack tip. This would induce a higher SCCGR based on the slip-oxidation model, which was verified by the previous works. The time-dependent response of the electrochemistry behavior indicated that the re-passivation occurred consequently after metal dissolution and reduced the corrosion rate during a film rupture period.