Table 40. Corrosion rate of some common metals, 





Consumption Rate 



Metal 



(newtons per ampere-year) 



Lead 



333.6 



Copper 



204.6 



Tin 



191.3 



Zinc 1 



102.3 



Iron 



89.0 



Magnesium 1 



75.6 



Aluminum - 1 



26.7 (seawater) 



Carbon 1 



8.9 



High Silicon Iron 2 



less than 0.44 



Magnetite Fe^O^ 2 



less than 0.044 5 



Lead-Silver 2 



less than 0.044 5 (seawater) 



Platinized Titanium 2 



less than 0.000 044 (seawater) 



Galvanic anode material 

 2 Impressed current anode material 



PIPELINE 



a. Single cell 



PIPELINE 



CATHODE CATHODE CATHODE 

 I JkNODE ANODE ^. -^ ANOOE 



b. Multiple cells 



Figure 91. Corrosion process in pipelines. 



320 



