Polythionic acid Stress Corrosion Cracking (SCC) of refinery equipment, particularly desulfurizers, hydrocrackers, and amine scrubbers, is a very serious problem in the petroleum industry. The investigations in polythionic acids carried out by Dravnieks and Samans,1 Samans,2 Piehl,3 Brophy,4 and Lendvai-Lintner5 were mostly concerned with evaluation of material performance from a phenomenological point of view. Little attention was paid to the understanding of the chemistry of polythionic acids and the electrochemical characteristics of stainless steel. An attempt, therefore, has been made in the present investigation to establish anodic polarization characteristics of sensitized 304 stainless steel in Samans solution, which represents the polythionic acid environment formed in equipment during shutdown in the petroleum industry, and the various constituents of Samans solution.
The polythionic acid was prepared by following the standard method proposed by Samans,2 thus the solution is known as Samans solution” or “Wackenroder’s liquid.” Sulfur...
