Intergranular Corrosion in Stabilized 310 Stainless Steel

Abstract

The intergranular corrosion in stabilized 310 stainless steel polycrystals has been investigated from a view point of crystallographic structure of the grain boundary. The relative orientation of each grain was characterized by the Coincidence Site Lattice (CLS) model, and the Plane Matching model. For the quantitative characterization of corrosion, a scanning electron microscope with two secondary electron detectors was used to provide the profile of the corrosion groove. It was found that Σ= 3 boundaries and some certain CSL boundaries have a high resistance against the intergranular corrosion. The “random” boundaries were corroded in a different extent, particularly high corrosivity. It is concluded that the grain boundaries having low Σ-values do not necessarily provide low corrosivity. It is shown that the dissolution rate depending on the surface orientation of grains also plays an important role in the morphology of intergranular corrosion, and was found to be lowest at (100) and increases as the surface normal changes towards (110), and more so towards (111).