End Grain Corrosion: Establishing Microstructural Causes And Preventive Steps

摘要

Nuclear spent fuel reprocessing and waste management plants use nitric acid as process fluid and type 304 L stainless steel as construction material. Tubular products like bars, tubes and pipes are prone to End Grain Corrosion from the exposed cross-sectional surfaces. In this study, type 304 L stainless steel is subjected to different heat treatment to induce selective segregation of phosphorus. The susceptibility to End Grain Corrosion was established in tests using boiling nitric acid containing oxidizing Cr(VI) ions. A clear effect on End Grain Corrosion was found for heat treatment reported to induce phosphorus segregation. Finally, specific annealing heat treatment is developed that erases out the segregation, without affecting the grain size or sensitization.