Influence of Marine Organisms on the Life of Structural Steels in Seawater
NAVAL RESEARCH LAB WASHINGTON DC
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Data presented in this report reveal the dominant influence of marine organisms in regulating the corrosion rate of steels in seawater. Both fouling organisms and marine sulfate-reducing bacteria become established during the first year of exposure. Once established, the synergistic activity of these macro- and micro-organisms resulted in a steady-state corrosion rate for both general corrosion and pitting. To investigate these effects in different climates and with different organisms present, racks of carbon steel specimens were immersed at five ocean locations. At all sites, after sufficient fouling collected, bacterial corrosion became the dominant type over most of the specimens. At that point corrosion rates stabilized to a constant value. These steady-state rates were found to be lower than expected and surprisingly uniform for the different marine environments, ranging from two to three mils per year.
- Properties of Metals and Alloys