Use of corrosion-resistant steels and alloys in sulfuric acid media

Within the chemical industry, and also in some other branches, there is extensive use of sulfuric acid solutions of different concentration and corrosiveness, containing metal ions of varied valency (Cu²⁺, Fe³⁺, Ni²⁺, Cr³⁺, etc.), which appear in a medium, for example, as a result of equipment corrosion, etc. In sulfuric acid media, corrosion can be uniform or local, i.e., pitting, spot corrosion, intercrystalline corrosion (ICC). Whereas uniform corrosion develops as a gradual reduction in the thickness of an original vessel, equipment, and machine component elements, whose corrosion rate may be calculated previously from existing data for the corrosion resistance of structural materials in specific production media, it is almost impossible to predict ICC development, and therefore in many cases it leads to sudden structural breakdown. In order to predict corrosion, it is recommended to use for article manufacture corrosion-resistant steels and alloys with alloying providing in sulfuric acid solutions resistance to uniform and local corrosion with the required heat treatment and monitoring for ICC resistance.