locations (5,73 vs 1,4 ml /I) with the possibility that some of the 

 corrosion mighc be due to the difference in the currents (unknown 

 in the Atlantic but practically stagnant in the Pacific). The 

 difference between the corrosion rates on the surface at Harbor Island, 

 N- C, and at a depth of 5,600 feet in TOTO is attributed to dif- 

 ferences in depth (pressure, vs 2520 psi) and temperature (19'-'C vs 

 4.20c). 



Corrosion rates for steel at a depth of about 4,500 feef^-^' ^ in 

 TOIO were practically the same as those at the surface at Harbor 

 Island for comparable periods of time. 



The corrosion rates of wrought iron and A.rmco iron at depths 

 were, comparable with those of Al'rl 1010 steel as shown in Figure 4, 

 The corrosion rate of wrought iron at the surface at Fort Amador in 

 the Pacific Ocean Panama Canal Zone"^^ after about 3 years of exposure 

 was approximately 7 times greater than 3.t a depth of 5,500 feet in 

 the Pacific Ocean, 



The corrosion rates of all the alloy steels at depths of 5,500 

 and 2,350 feet in sea water are shown in Figure 5. These values are 

 shown as shaded areas encompassing m.ost of the values. The corrosion 

 rates for these steels decreased similarly to those for carbon steel 

 with time of exposure at both depths. Although the corrosion rates 

 at a depth of 5,500 feet varied between 1.9 and 6.0 MPY after 123 

 days of exposure they were all essentially the sa,me .^.fter 1,064 days 

 of exposure (0,5 to 0.9 'iPY). .The performance of these same steels 

 when partially embedded in cne bottom sediments is shown in Figure 6o 

 After 1,064 days of exposure at a depth of 5,500 feet, the corrosion 

 rates were the same as those in the sea water above the bottom sedi- 

 ments. However, the corrosion rates for many of the steels after 

 403 days of exposure in the bottom sediment at a depth of 6,780 feet 

 were less than 0.5 MPY; this is attributed to the greater proportion 

 of each specimen that was embedded in the bottom sediment. The 

 specimens of these particular steels were about 2 inch dii.m.eter discs 

 and in all probability were nearly completely embedded in the bottom 

 sediment . 



The data for all the steels was analyzed statistica ily c The mean 

 curve of the corrosion rates and 95 percent confidence limits are 

 shown in Figure 7 for the specimens exposed in the sea water and in 

 Figure 8 for the specimens partially embedded in the bottom, sediments „ 

 The corrosion rate carves for AIST 1010 steel and high-strength-low 

 alloy steel #2 exposed at a depth rf 5,600 feet in TOTO are also 

 included to reveal that they are outside the 95 percent confidence 

 limits. The fact that they are outside the 95 percent confidence limits 



