Table 5. Continued 



Alloy 



Exposure 



(day) 



Depth 

 (ft) 



Corrosion Rate (mpy)' 



Type of 

 Corrosion 



d 



Source 



w b 



M fc 



Austenitic cast iron, D-3 



366 



5 



3.2 



- 



G 



1NCO (3) 



Austenitic cast iron, hardenable 



123 



5,640 



2.5 



2.8 



G 



INCO (3) 



Austenitic cast iron, hardenable 



403 



6,780 



1.1 



0.4 



U 



INCO(3) 



Austenitic cast iron, hardenable 



751 



5,640 



0.7 



0.7 



G 



INCO (3) 



Austenitic cast iron, hardenable 



1,064 



5,300 



0.6 



0.7 



U 



INCO (3) 



Austenitic cast iron, hardenable 



197 



2,340 



2.8 



0.1 



G 



INCO (3) 



Austenitic cast iron, hardenable 



402 



2,370 



1.8 



0.5 



U 



INCO (3) 



Austenitic cast iron, hardenable 



181 



5 



4.2 



- 



U 



INCO (3) 



Austenitic cast iron, hardenable 



366 



5 



2.6 



- 



u 



INCO (3) 



Galvanized steel, 1 oz/ft 



189 



5,900 



1.9 



1.6 



u 



CEL (4) 



Galvanized steel, 1 oz/ft 



402 



2,370 



0.9 



0.4 



G 



CEL (4) 



Aluminized steel, 1 oz/ft 



189 



5,900 



0.2 



0.2 



u 



CEL (4) 



Aluminized steel, 1 oz/ft " 



402 



2,370 



0.0 



0.0 



G 



CEL (4) 



mpy = mils penetration per year calculated from weight loss. 



W = specimens exposed on sides of structure in seawater; M = specimens exposed in the base of the 

 structure, partially embedded in the bottom sediment. 



Symbols signify the following types of corrosion: 



C = Crevice NC = No visible corrosion 



CR = Cratering P = Pitting 



E = Edge PR = Perforation 



ET = Etched S = Severe 



G = General U = Uniform 



I = Incipient WB = Weld bead 



M = Corroded at sediment line 



Numbers after symbols refer to maximum depth in mils. 



Numbers refer to references at end of report. 



Corrosion accelerated below mud line. 

 •'Single crater, 12 mils deep_ 



^Surface exposure at Francis L. LaQue Corrosion Laboratory, Wrightsville Beach, N.C. 

 fc Welded. 



Transverse butt weld, weld bead same as plate. 



•'Circular weld bead, 3-in. diameter, in center of plate. 



k ■ 

 Pitted, 154 mils maximum, 73.4 average (15 pits), water. 



Pitting rate, mpy. 



Heat treated 900 F, 3 hr, air cooled. 



Zinc coating completely gone. 



Aluminum coating 50% gone, mottled, bare steel in places. 



"\V = no rust, 78% aluminum coating remaining; M = no rust, 60% aluminum coating remaining. 



32 



