The data in the column labeled "Crevice" in Table 4 show that 

 there were no significant changes in the corrosion rates of these 

 alloys due to crevice corrosion. Although crevice corrosion is 

 reported in some cases, the intensity and amount was not great 

 enough to significantly change the corrosion rate of that particular 

 alloy. 



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. The steels, stresses, depths, days of exposure and the 

 susceptibility to stress corrosion cracking are given in Table 6. 

 None of these steels were susceptible to stress corrosion cracking 

 for the periods of time exposed at the various depths o 



Mechanical Properties 



The percent changes in the mechanical properties of the exposed 

 steels are given in Table 7. There were no significant changes in 

 the mechanical properties due to corrosion except for the AISI Type 

 502 steel,, The decreases in elongation, 34-38 percent, of the AISI 

 Type 502 steel were considered significant and were attributed to 

 the pitting corrosion. 



Corrosion Products 



The corrosion products from some of the steels were analyzed by 

 X-ray diffraction, spectrographic analysis, quantitative chemical 

 analysis and infrared spectrophotometry „ The constituents found were; 



Alpha iron oxide - Fe203 " H2O 



Iron hydroxide = Fe(0H)2 



Beta iron (III) oxide hydroxide - FeOOH 



Iron oxide hydrate - Fe2^3 " ^^?^ 



Significant amounts of chloride, sulphate and phosphate ions. 



