FABRICATION ANALYSIS 



No unusual problems were encountered in welding the assembly. 

 Nondestructive tests on the as-welded assembly showed no indications 

 of surface or internal discontinuities. Visual and dye penetrant 

 inspection of the machined disc, prior to forming, showed no evi- 

 dence of surface discontinuities. Radiographic examination of the 

 disc, however, revealed evidence of widely scattered porosity and a 

 small lack of fusion defect in the weld, the latter approximately 

 10 inches from the edge of the disc. Ultrasonic examination of the 

 disc confirmed the lack of fusion defect observed by radiography 

 and also disclosed three additional small discontinuities along the 

 weld/base metal fusion line. All of the discontinuities appeared 

 to be located on one side of the weld, and this side was selected 

 to be the inside of the formed head. 



Although the hot pressing operation was the first of its kind 

 to be performed on welded titanium plate, careful attention to de- 

 tail resulted in successfully forming the head without unusual 

 difficulties. It was noted, however, that localized bulging had 

 occurred at the weld joint on the inner surface of the formed head 

 for a distance of about 10 inches from the open end, as may be 

 seen by close examination of Figure 9 in the bracketed area. After 

 the steel jacket was removed, several minor fissures were found on 

 the outer surface in the weld area near the apex of the head. There 

 were no indications, however, that these fissures were associated 

 with the internal discontinuities that had been detected in the weld 

 during examination of the disc prior to forming. It was noted that 

 the thickness of the weld, in the region where fissuring was ob- 

 served, was less than that of the surrounding base plate, indicat- 

 ing that this region of the weld had undergone a reduction in area 

 as a result of the forming operation. 



Dye penetrant examination of the head after machining revealed 

 three small fissures in the weld, on the outer surface of the head, 

 in a region extending from about 6 to 9 inches from the apex. X-ray 

 radiography and ultrasonic examination indicated that there were 

 numerous internal fissures in the weld, extending from 3/4 to 12 

 inches from the apex, on both sides. Radiographic prints of a 5 

 inch long section of the weld in this region, before and after 

 forming, are shown in Figure 12. The extensive fissuring in the 

 weld area, after forming, may be noted in these prints. There 

 were no indications of similar defects in the area of the weld that 

 had bulged during forming nor in any areas of the formed base metal. 



The wall thickness of the head after machining was not uniform 

 and varied from 1.85 inches at the apex to 2.45 inches at the edge. 



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