Drastic corrosive coliation of petroleum oils and the decay of metals

In the industry of petroleum oil refining industry the term of corrosion is frequently applicable regarding the several incidents because of the corrosiveness of petroleum oils due to the presence of trace corrosive compounds in such petroleum oils since the occurrences. Usually the corrosion is the results of chemical or electrochemical process of metals when it is exposing to the corrosive environment. The investigations of the impact of the organic acids, salts, elemental sulfur and the Mercaptans on the corrosion rates of seven different types of ferrous metals and the analysis of the nature of the corrosion between these materials were the objectives of the existing research. The relevant corrosive properties of two different types of selected crude oils and the chemical compositions of selected seven different types of ferrous metals were tested by the standard methods and instruments. A batch of similar sized metal coupons was immersed in both crude oil samples separately as three homogeneous metal coupons per each crude oil container. In order of after 15, 30 and 45 days from the immersion the corrosion rates of such metal coupons were determined by the weight loss method as three sets of samples while observing the corroded metal surfaces through an optical microscope. In addition, the decay of ferrous and copper from metals into crude oils while the interaction and the deductions of the initial hardness of metals were tested. As the basic investigations there were observed the relatively lower corrosion rates from stainless steels, relatively higher impact from salts on the metallic corrosion at lower temperatures, formations of FeS, Fe2O3, corrosion cracks and pitting, significant decays of ferrous and copper from some metals and the slight reductions of the initial hardness of metals after the interaction with the petroleum oils