Influence of sulfur dioxide content of 20% and 92% sulfuric acid on anodic behavior of stainless steels

This paper investigates steels 12Kh18N10T, 10Kh17N13M2T, 08Kh22N6T, and 08Kh21N6M2T. In corrosion of stainless steels in sulfuric acid solutions, dissolved sulfur dioxide acts as a cathodic depolarizer, capable of being reduced to elemental sulfur or forming sulfides with the metal. Depending on the conditions, this is associated with some increase in potential and greater or lesser increase in corrosion or facilitation of passivation of active steel. After passivation the influence of SO2 is negligible. The results of this investigation were used as initial data for developing systems of anodic protection for shell-and-tube heat exchangers for sulfuric acid