304 composition did not improve its corrosion resistance. However, 
the addition of silicon resulted in some increase in corrosion resis-— 
tance; the addition of copper and molybdenum resulted in considerable 
increase in corrosion resistance; and the addition of nitrogen, silicon 
and molybdenum resulted in a wire rope which was uncorroded. 
Wire ropes fabricated from Ni-Cr-Mo 103, Ni-Cr-Mo 625, Ni-Mo-Cr 
"Cc" Ni-Co-Cr-Mo and Co-Cr-Ni-Fe-Mo were completely immune to corrosion. 
The Co-Cr-Ni-Fe-Mo rope was also immune from corrosion when stressed at 
1,600 pounds (40 percent of its breaking load). 
The fiberglass, monofilament wires, varying in diameter from 0.031- 
to 0.123-inch, became dull and brittle during exposure in the seawater. 
SUMMARY 
The purpose of this investigation was to determine the corrosion 
behavior of some alloys and the effects of welding on the corrosion of 
some alloys which had not been included in the earlier deep sea expo- 
sures. To accomplish this, 525 specimens of 60 different alloys were 
exposed at a depth of 5,900 feet in the Pacific Ocean for 189 days. 
Aluminum Alloys 
As with previous exposures of other aluminum alloys, pitting and 
crevice corrosion were more severe in the bottom sediments than in the 
seawater and were more severe at depth than at the surface for the same 
period of exposure. Welding of 5083-H113 and 7039-T64 caused some 
localized pitting in the heat affected zones adjacent to the weld beads. 
Nickel Alloys 
There was no corrosion of Ni-Cr-Mo 625 alloy in either seawater 
or in the bottom sediments, both unwelded and welded. There was no 
significant corrosion of alloys Ni-Cr-Fe 718 and Ni-Fe-Cr 825 except 
for incipient pitting or etching of the weld beads. Ni-Cr-Fe 600 
alloy was attacked by crevice corrosion while alloys Ni-Cu 400 and Ni- 
Cu K-500 were attacked by both pitting and crevice corrosion, they 
being more severe on the Ni-Cu K-500 alloy. 
The corrosion behavior of alloys Ni-Cr-—Fe 718 and Ni-Cr-—Mo 625 
was the same at depth as at the surface. Corrosion of alloys Ni-Cu 
400, Ni-Cu K-500, Ni-Cr-Fe 600 was greater at the surface than at depth. 
Alloy Ni-Fe-Cr 825 was attacked by crevice corrosion at the surface 
but was immune at depth. 
Steels, Cast Irons and Stainless Steels 
The steels, in general, corroded uniformly at depth as did the 
steels in previous exposures. However, there was some pitting in the 
weld beads of HS numbers 1 and 4 steels. 
