The titanium disc was centered on the liner plate and charged, as 

 a pack, into a gas-fired oxidizing atmosphere furnace at ISSO^F. The 

 furnace and charge were stabilized at 1750° F and held at this temper- 

 ature, until the pack reached a uniform temperature throughout. Furnace 

 temperature was then raised to 1960°F and the pack heated until the 

 outer edges had reached 1950°F and the center was at 1925°F. This 

 differential was considered desirable to allow for the more rapid cool- 

 ing at the edges during transfer to the press. The pack was removed 

 from the furnace, transferred to the 2000 ton capacity forming press, 

 and centered on the lower platen as shown in Figure 7. The pack was 

 then pressed through the bottom ring die with one steady stroke of the 

 upper ram and male die. The estimated pressure required to form the 

 pack was less than 1000 tons. Temperature of the pack at the time of 

 contact with the male die was 1750°F, uniform witliin 10°F from edge 

 to center; the finishing temperature, measured on the steel liner was 

 1710°F. Quenching effects were reduced by preheating male and female 

 dies to approximately SOO^F. The formed titanium head, encased in 

 the steel spacer plate, was allowed to cool in still air. A view of 

 the head within the spacer plate is shown in Figure 8. After return 

 of the jacketed head to the Laboratory, the steel jacket was removed 

 by oxy-acetylene flame cutting. Figure 9 shows the head after removal 

 of the spacer plate and Figure 10 shows the head after machining. 



QUALITY ASSURANCE 



At every stage in the fabrication of the head, nondestructive 

 inspection techniques were used to monitor the quality of the pro- 

 duct. The original plate was dye penetrant and ultrasonically in- 

 spected. During the welding operation every weld pass was monitored 

 by visual examination and ultrasonic hardness-inspection tests. 

 Dye penetrant. X-ray radiography and ultrasonic inspection tech- 

 niques were used to assess the quality of the as-welded assembly, 

 the machined disc, the as-formed head and the head after machining. 



In addition to the nondestructive tests, specimens were machined 

 from the original plate, from run-off tabs on tlie welded assembly 

 and from the formed head in both the weld and base plate areas of 

 the straight flange section to provide mechanical property data for 

 assessment of the effects of forming on properties. A section, oxy- 

 acetylene cut from the machined head to provide test material from 

 the curved portion of the head, is shown in Figure 11, Specimens 

 prepared for test included: tensile, side bend, Charpy V-notch, 

 and sections for macro and microexamination. 



106 



