CORROSION OF MATERIALS IN HYDROSPACE 



PART III - TITANIUM AND TITANIUM ALLOYS 



Technical Note N- 921 



Y-F015-01-05-002a 



by 



Fred M. Reinhart 



ABSTRACT 



A total of 475 specimens of 10 titanium alloys were exposed at two 

 different depths in the Pacific Ocean for six different periods of time 

 varying from 123 to 1064 days to determine the effects of deep ocean 

 environments on their corrosion resistance. Specimens of the alloys 

 were also exposed in surface seawater for 181 days for comparison purposes, 



Corrosion rates, types of corrosion, pit depths, effects of welding, 

 stress corrosion cracking resistance and changes in mechanical properties 

 are presented. 



The alloys were immune to corrosion and stress corrosion cracking 

 except alloy 13V-llCr-3Al with unrelieved circular welds. This alloy 

 with unrelieved circular welds failed by stress corrosion cracking 

 after 181 days of exposure at the surface, 403 days at 6,780 feet and 

 402 days at 2,370 feet. The 13V-llCr-3Al alloy with unrelieved butt welds 

 failed by stress corrosion cracking when stressed at 75 percent of its 

 yield strength after 35, 77 and 105 days of exposure at the surface. 



The mechanical properties of the alloys were not affected. 



Some information from TOTO in the Atlantic Ocean is included for 

 comparative purposes. 



Each transmittal of this document outside the agencies of the 

 U. S. Government must have prior approval of the Naval Civil 

 Engineering Laboratory. 



