Low alloyed steels behaviour in organic media in the presence of water andadipic acid

The paper studies the behavoiur of 3 steel types, i.e. OL 37, OL 50 and OL 60, with the carbon concentration at the limit between cementite and Fe-C s olid solution, in a system made up of ethylenglycol and adipic acid 5% wher e the water concentration varied between 1 and 5%. After 60 days of exposur e the weight loss was determined and the P and K indices were calculated. T he metallic surface was studied by electron microscopy, the polarization cu rves corresponding to 5% water concentration were drawn and the corrosion k inetic parameters were established. The corrosion products were analysed by X-ray and IR spectroscopy as well as by elementary analysis, the corrosion mechanism being established. An important conclusion of this study is the fact that the corrosion rate does not depend on the concentration in water and therefore water cannot participate in the passive oxihydroxyllic layer. formation.