c. Flash welded tube. 



d. Flash welded sphere. 



e. Piece from a broken sphere. 



There was no visible corrosion on any of the above specimens except 

 for the Type 304 swaged fittings and the mild steel wire. The faying 

 surfaces of the Type 304 swaged fittings were severely attacked by 

 crevice corrosion. The mild steel wire used to tie the end of one 

 titanium cable was corroded almost through by galvanic corrosion; 

 the mild steel wire being anodic to the titanium cable. 



The Naval Research Laboratory, Reference 12, and the Naval 

 Applied Science Laboratory, Reference 13, reported no corrosion of 

 titanium alloys, both unwelded and welded, at depths of 4,250 and 

 5,600 feet in the Tongue-of-the-Ocean, Atlantic Ocean after exposures 

 varying from 102 to 1050 days. 



Stress Corrosion 



Specimens of the alloys stressed in various ways and to values 

 equivalent to 35, 50 and 75 percent of their respective yield strengths 

 were exposed at the surface for 180 days and at nominal depths of 

 2,500 and 6,000 feet for different periods of time. 



The majority of the specimens were deformed by bowing to obtain 

 the desired tensile stress in the central 2 inch length of the outer 

 surface of the specimen as described in Reference 2. Many of these 

 specimens, butt welded by the TIG process, were positioned such that 

 the transverse weld bead was at the apex of the bow in the 2- inch 

 length. Other specimens, 6" x 12", had a 3" diameter circular weld 

 bead placed in the center as shown in Figure 3. The stresses induced 

 by the welding operation were not relieved in order to retain the 

 maximum residual stresses in the specimens. Still other specimens 

 were in the shape of welded rings 9-5/8 inches outside diameter which 

 were deformed different amounts in order to induce tensile stresses 

 in the periphery at the ends of the restraining rods as shown in 

 Figure 4. 



The results of the stress corrosion tests are given in Table 4. 

 There were no stress corrosion cracking failures of any of the 

 alloys, both unwelded and butt welded, stressed at values equivalent 

 to as high as 75 percent of their respective yield strengths for 180 

 days of exposure at the surface, 402 days at the 2,370 foot depth 

 and 751 days at the 5,640 foot depth, except for the butt welded 

 13V-llCr-3Al alloy. The unrelieved butt welded 13V-llCr-3Al alloy 



