Microstructure-Based Numerical Modeling of Pitting Corrosion in 316 Stainless Steel

Abstract

Pitting involves localized corrosion of metals that can result in catastrophic events through crack initiation and failure. Beside the magnitude and mode of loading, the transition from pit to crack is also influenced by the pit shape, which in turn is affected by the microstructure of the corroding material. Thus, predicting the influence of microstructure on pit shape can assist in developing microstructures more resistant to stress corrosion cracking. This work presents numerical modeling of the stable pit growth based on direct incorporation of the actual microstructure in simulations. While many microstructural attributes can contribute towards corrosion, the current work focuses on the effects of the crystallographic orientation of the grains on pit growth through variation in corrosion potential with orientation. Two-dimensional simulation results show the strong influence of the crystallographic orientation on pit shapes and growth under the assumed 5% and 10% variation in corrosion potential, delineating the critical place of crystallographic orientation in pit growth to failure.