EFFECTS OF ALLOY COMPOSITION OF CARBON STEEL ON THE FLOW ACCELERATED CORROSION AND OXIDE FILM PROPERTIES IN NEUTRAL WATER CONDITION

摘要

In order to improve the theoretical prediction of flow accelerated corrosion (FAC), the individual effects of water chemistry, material composition and flow dynamics parameters should be understood. In this study, to determine the effects of minor alloying elements of carbon steel on FAC the corrosion rate of specimens of carbon steel with various concentrations of minor alloying elements was measured. Also, the oxide films on the steel were examined by surface analysis techniques, e.g. Raman spectroscopy. The effects of Cr, Ni and Cu in carbon steel on FAC behavior were as follows; 1) FAC was suppressed in the carbon steel with more than 0.03 % Cr. 2) The FAC rate decreased as Ni content increased. 3) A hematite rich oxide was observed in Ni added carbon steel, while only magnetite was observed in Cr added carbon steel. 4) No clear effect of Cu on FAC rate was observed.