Studying the Effect of Wind Direction and Specimen Orientation on the Corrosion of 1018 Steel using a Compact Octagonal Prism Portable Exposure Rack

摘要

A compact,octagonal-prism portable exposure rack(COP-PER)was devised to assess atmospheric corrosion in a marine environment as a function of wind direction and specimen orientation.Specimens in quadruplet were oriented facing north,northeast,east,southeast,south,southwest,west,northwest,up,and down.Chloride deposition rates and corrosivity index values were also monitored in all of the directions and orientations.Statistical analyses confirmed that the average corrosion rates measured on the 10 faces(i.e.,north,northeast,east,southeast,south,southwest,west,northwest,up and down)of the COP-PER were statistically different.The average corrosion rates generally increased with chloride deposition rates and corrosivity indices with R2 values of 0.62.and 0.89,respectively.The highest average corrosion rates for the vertically oriented samples were facing the onshore trade winds from the northeast,which deposited the highest amount of chlorides.The highest average corrosion rates for all directions/orientations was the horizontally-mounted upward facing samples.Analyses of the corrosion products by XRD indicated the presence of the rust phase lepidocrocite.