Reinhart 



The median corrosion rate curves for the 2,350 foot and 5,500 foot 

 depths are shown in Figure 8. This figure shows quite clearly that 

 after two years the water and bottom sediment environments are alike, 

 with regard to their effect on the corrosion of steels. It also 

 shows that the bottom sediment at 5,500 feet is about the same as the 

 sea water environment at a depth of 2,350 feet. After 400 days the 

 bottom sediment at a depth of 2,350 and the 2,350 foot level sea 

 water environments are of equal aggressiveness in their corrosive 

 actions. 



Variations of from 1.5 to 9 percent in the nickel content of 

 steel were ineffectual with respect to the corrosion rates as shown 

 in Figure 9. 



Stress Corrosion 



Some of the steels were exposed in the stressed condition 

 at values equivalent to 35, 50 and 75 percent of their respective 

 yield strengths. None of these steels were susceptible to stress 

 corrosion, cracking for the periods of time exposed at the various 

 depths. 



Corrosion Products 



The corrosion products from some of the steels were analyzed 

 by X-ray diffraction, spectrographic analysis, quantitative chemical 

 analysis and infra red spectrophotometry. The constituents found 

 were: 



Alpha iron oxide - Fe203 * H2O 



Iron hydroxide - Fe(0H)2 



Beta iron(III) oxide hydroxide - FeOOH 



Iron oxide hydrate - Fe203 * H2O 



Significant amounts of chloride, sulphate and phosphate 

 ions. 



Anchor Chains 



Two types of 3/4 inch anchor chain, Dilok and welded stud 

 link were exposed at depths. The chain links were covered with 

 layers of loose, flaky rust after each exposure. The layers varied 

 from thin to thick as the time of exposure increased. Destructive 

 testing of the exposed chain links showed no decrease in the breaking 

 loads of the links for periods of exposure of at least 1,064 days. 

 Hence, there was no impairment of the strength of either of the 

 chains. The Dilok links all failed at the bottoms of the sockets 

 where the cross-sectional area of the steel was the smallest. Rust 

 was present in all these broken sockets indicating that sea water 

 had penetrated the joints. Stagnant sea water in these sockets for 



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