Model to Study the Effect of Composition of Seawater on the Corrosion Rate of Mild Steel and Stainless Steel

Mild steel and 304 stainless steel are the versatile materials of construction for various structures in ocean water, whose composition varies widely in the vast global marine environment. The major parameters influencing the rate are salinity, sulfate, bicarbonates, pH, and temperature and dissolved oxygen. Prediction of the rate of degradation is a challenging task for design and corrosion engineers for existing as well as new structures to be constructed. Endeavors have been made to model the corrosion rate of mild steel and 304 stainless steel as function of five parameters, namely chloride, sulfate, dissolved oxygen, pH, and temperature, based on laboratory experimental data. The number of experimentations and compositions of experimental artificial seawater were based on 2 (k) factorial design of experiment. The model was validated with additional generated experimental data as well as real field study from the literature. Three-dimensional mappings of corrosion behavior of mild steel and stainless steel reveal that the effects of these parameters are interrelated and influenced by one another.