The very complex nature of hydrocarbon raw materials, such as crude oil, and all kinds of reactions and mutual interactions of all its components and phases with each other and with steel equipment (base metals, alloying elements and inclusions), as well as the applied temperatures and pressures in refining processes, in addition to the technical conditions of the steel equipment and storage and transportation conditions of crude oil, all this makes it almost impossible to completely dehydrate and desalinate crude oil, which is the real cause of most of the inevitable problems. Taking into account high corrosion rates, premature failures and the growing number of accidents and emergency stops, researchers face a challenging task and a great responsibility to provide a more comprehensive understanding of corrosion, and proposing deeper corrosion mechanisms that take into account the role of multiphase metal components, which are not less important than the influence of other corrosive components.