The mechanical properties of Type D-2C austenitic cast iron were 

 adversely affected by exposure for six months immersion in surface sea 

 water . 



Stainless Steels 



All the stainless steels were attacked by crevice corrosion. Those 

 with only incipient crevice corrosion were AISI Types 310, 317 and 329; 

 20Cb, 20Cb-3 and AM350. 



Other types of corrosion on the alloys were pitting, edge or 

 tunnel or combinations of these types. 



The Type 300 stainless steels were less corroded than Type 200, 

 Type 400 and the precipitation hardening stainless steels. 



Crevice corrosion was more severe at the surface than at depths 

 of 2,500 and 6,000 feet in the Pacific Ocean. 



The mechanical properties of the alloys were not adversely affect- 

 ed. 



Titanium Alloys 



Titanium alloys unwelded, butt and circular welded titanium alloy 

 75A; unwelded, butt and circular welded titanium alloy 6A1-4V; butt and 

 circular welded titanium alloy 0.15 Pd ; butt and circular welded titan- 

 ium alloy 5A1-2.5 Sn; butt and circular welded titanium alloy 7Al-2Cb- 

 lTa; and butt welded titanium alloy 13V-llCr-3Al were uncorroded after 

 six months of exposure at the surface and at depths of 2,500 and 6,000 

 feet. 



Titanium alloy 13V-llCr-3Al with an unrelieved circular weld 

 failed by stress corrosion cracking after six months of exposure at the 

 surface. There were no failures of companion specimens after comparable 

 periods of exposure at depths of 2,500 and 6,000 feet. 



The mechanical properties were unimpaired by six months of expos- 

 ure either at the surface or at depth. 



Miscellaneous Alloys 



The iron-nickel-chromium-molybdenum alloys, columbium, tantalum and 

 tantalum- tungsten alloy Ta-60 were uncorroded. 



Molybdenum and tungsten corroded uniformly at low rates. Chemical 

 lead, antimonial lead and tellurium lead also corroded uniformly but at 

 higher rates than molybdenum and tungsten with chemical lead being the 

 most resistant to sea water. 



Tin, zinc and lead-tin solder corroded at appreciable rates in 

 sea water with tin and zinc being pitted. 



Magnesium alloy AZ31B was disintegrated by corrosion. 



Iron-nickel- chromium alloys were attacked by crevice corrosion in 

 surface sea water exposure but were uncorroded at depth in sea water. 



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