Corrosion of Iron and Steel in Sea Water

Abstract

THE eighteenth report of the Committee of the Institution of Civil Engineers on the Deterioration of Structures of Timber, Metal and Concrete exposed to the Action of Sea Water contains the final results of the fifteen years exposure of iron and steel specimens in the four harbours named, and also summarizes the results, previously published, of the five- and ten-year series. The observations on ferrous specimens are therefore now complete. Although the total number of bars exposed was large, only three of each material were exposed in each position, one of the three being removed at the end of each five-year period, so that there were no actual duplicates. It follows that accidental differences have a rather large effect, and it is only possible to make roughly quantitative comparisons, best expressed in graphical form. Naturally, wide differences were found between the results at different stations, partly on account of the prevailing temperature, but also owing to local circumstances. Thus, at Colombo the rise and fall of the tide is small, so that the half-tide specimens, being for most of their time in contact with water, were more nearly comparable with completely immersed specimens at other stations, and the bars exposed to the air were so often wetted by spray as to be comparable with half-tide specimens elsewhere.