Sufficiency of the Corrosiveness of Petroleum Oils on the Decay of Metals

Petroleum oils are the limited earth resources in which the variety of their chemical compositions are mostly composed of hydrocarbons and some trace compounds. Oils also contain various corrosive compounds. In the existing research, the major objective was the investigations of the impacts of such corrosive compounds within two different types of petroleum oils on the corrosion rates of seven different types of ferrous metals. As the methodology, the major corrosive properties of two different types of crude oils and chemical compositions of seven different types of metal were measured by standard instruments and methods. The corrosion rates of prepared metal coupons from seven different types of metals were determined by the relative weight loss method after immersion time periods separately in both crude oils in order of 15, 30 and 45 days, while qualitatively analyzing the corroded metal surfaces by optical microscope. In addition, the decayed ferrous and copper concentrations from metals into crude oils after immersion were measured by atomic absorption spectroscopy, while the status of the initial hardness of metal coupons were measured by the Vicker’s hardness tester. According to the obtained results, we saw higher corrosive stability from stainless steels which have chemical compositions of at least 12% of chromium with sufficient amounts of nickel, while in other steels, we noted relatively higher progress of the corrosion process regarding salts at lower temperatures, formations of FeS, Fe2O3, corrosion cracks and pits on the corrosion metal surfaces, significant decays of ferrous and copper from some metals into crude oils and slight reductions of the initial hardness of most metal types due to the corrosion.