Corrosion Behaviors of Stainless Steel in High-Temperature Water and Superheated Steam

Abstract

The corrosion behaviors of AISI 304 and 304L stainless steels were studied to clarify the effects of temperature, surface finish and dissolved oxygen in high-temperature water and superheated steam. In deaerated water, the steels indicated a maximum corrosion rate between 250•‹ and 350•Ž, and the corrosion rate was affected largely by the surface finish. In aerated water, the corrosion rate increased slightly with increasing temperature and was not so much affected by surface finish. In superheated steam, the corrosion rate increased largely with increasing temperature and was affected markedly by the surface finish at higher temperatures. The corrosion films produced in deaerated water and superheated steam consisted of magnetite and chromite, and the chromite content increased with increasing temperature, whereas those produced in aerated water consisted of ƒÁFe2O3. The ƒ¿ phase transformed from the austenite phase by cold-working or surface abrading decreased the cormsion resistance in deaerated water, but it greatly increased the corrosion resistance in superheated steam.