Statistical Analysis of Nonmetallic Inclusions as Initiation Sites of Pitting Corrosion for Stainless Steel by All-surface Survey

Abstract

All nonmetallic inclusions on the surface of a stainless steel sample were analyzed with a scanning electron microscope with a function of automatically observing and analyzing nonmetallic inclusions. The effect of the inclusion type and size on the tendency of pit initiation was then quantitatively evaluated by observing the pits generated on the sample surface. It was found that the probability of stable pit growth increased as the major axis of the inclusions increased, but no effect of the inclusion type was observed. However, an effect of the inclusion type on the tendency of repassivation pit initiation was observed.