Long-term immersion corrosion of steel subject to large annual variations in seawater temperature and nutrient concentration

The corrosion of steel in open seawater is influenced mainly by water temperature. If nutrients critical for bacterial activity are available, it also may be influenced by microbiological activity. The combined effect is investigated here for the case of large variations both in the seawater temperature and in concentration of dissolved nutrients. A theoretical analysis is given for these effects acting in conjunction, with or without time-dependent differences. Field observations of corrosion losses for steel sheet piling exposed at three different locations at sea sites near Vladivostok, Russia, are used in conjunction with local temperature and nutrient concentration data to obtain trends for longer term corrosion. The main objective of the paper is to build a new long-term predictive model of corrosion which may be effectively used in conditions with large variable seasonal in water temperature and in nutrient availability.