feet. There was considerable decrease (49 percent) in the percent 

 elongation of nickel-iron-chromium alloy 902 after 402 days of 

 exposure at a depth of 2,370 feet. Since there was no visible 

 corrosion, especially pitting, on the surfaces of the specimens, 

 this decrease cannot justifiably be attributed to corrosion. No 

 reason can be given for this at this time, 



SUMMARY AND CONCLUSIONS 



The purpose of this investigation was to determine the effects 

 of deep ocean environments on the corrosion of nickel and nickel 

 alloys. To accomplish this a total of 635 specimens of 75 different 

 alloys were exposed at nominal depths of 2,350 and 5,500 feet for 

 periods of time varying from 123 to 1064 days. 



There was no significant weight loss or any visible corrosion 

 on the following alloys: nickel-chromium-iron alloy 718, nickel- 

 chromium-'molybdenum alloys 3 and 625, nickel-cobalt-chromium alloy 

 700, nickel-chromium-iron-molybdenum alloys F, G and X, nickel= 

 chromium- cobalt alloy 41 and nickel-molybdenum-chromium alloy C. 



Four alloys, cast nickel-copper alloys 410 and K-505, nickel- 

 molybdenum- iron alloy B and nickel-molybdenum alloy 2 were attacked 

 by uniform or general corrosion. Their corrosion rates were lower 

 in the bottom sediments than in sea water at both depths, 2,350 

 and 5,500 feet. The corrosion rates of cast nickel-copper alloys 

 410 and K-505 at both depths and of nickel-molybdenum- iron alloy B 

 at the 5,500 foot depth, decreased with increasing duration of 

 exposure. The corrosion rates of nickel-molybdenum alloy 2 at both 

 depths and of nickel-molybdenum- iron alloy B at the 2,370 foot 

 depth increased with increasing duration of exposure. 



Some alloys were uncorroded except for isolated instances of 

 crevice corrosion. They were nickel- iron-chromium alloys 800, 804, 

 825, sensitized 825, 825 Cb and 901. 



The remaining alloys were attacked either by crevice or pit- 

 ting corrosion or by both types of corrosion. These alloys were: 

 electrolytic nickel, nickel 200, 201, 211, 270, cast 210 and 301; 

 nickel-copper alloys 400, 402, 406, K-500 and 60; nickel-chromium- 

 iron alloys 600, cast 610, X750 and 88; nickel- iron-chromium alloy 

 902; nickel-tin-zinc alloy 23, nickel-beryllium; nickel-chromium 

 alloys 65-35, 75 and 80-20; and nickel-silicon alloy D. 



There was attack of the weld beads, at the edge of the weld 

 bead or in the heat-affected zone of the following: nickel 200 

 welded with electrodes 61 and 141; nickel-copper alloy 400 welded 

 with electrode 60; nickel-chromium-iron alloy 600 welded with 



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