Corrosion Characteristics 



Corrosion of steel as a function of marine environmental conditions is 



19 

 illustrated in Figure 2. 



MARINE 

 ATMOSPHERE 



SPLASH ZONE 

 HIGH TIDE 



LOW TIDE 



QUIET 

 SEAWATER 



MUD LINE 



5 10 15 20 



TYPICAL CORROSION RATE OF STEEL (mpy) 



Figure 2 - Corrosion of Steel in the Marine Environment 



The splash zone is most aggressive since materials are generally in con- 

 tact with aerated seawater resulting from wave action. Air bubbles tend 

 to make the environment more aggressive by removing protective films or 

 dislodging coatings. 



Steels continuously immersed in seawater corrode at a uniform rate, 

 averaging 5 mpy. Long-term data show that the corrosion rate actually 

 decreases to values below 5 mpy.-*-" 



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