SURFACE 



^ 2 



n 



O 



^3 



Q. 4 

 ill 



OXYGEN 

 CONTENT 



CARBON AND LOW 

 ALLOY STEELS 



12 3 4 5 6 7 8 



OXYGEN (mm) OR CORROSION RATE (mpy) 



Figure 4 - Corrosion of Steels Versus Depth 

 After 1 Year of Exposure 



Fouling and Its Effect on Corrosion 



Steel structures foul in seawater. The rate of fouling is a function 



of depth; less fouling occurs in deep waters. Attachment and growth of 



25 

 marine organisms influence the tate of steel corrosion in seawater, as 



indicated by the results obtained in a 16-yr investigation in Panama.^" 



The long-term data reveal the protective effect of microfouling against 



normal corrosion and the development of constant-rate bacterial corrosion. 



The study suggests that selective control of marine bacteria could be a 



key factor in achieving very low corrosion rates of structural steel in 



seawater .25 



13 



