WELDING 



The plate was saw cut into two pieces, each 24" wide by 48" long, 

 and one long^ edge of each plate was machine beveled in preparation 

 for welding, as shown in Figure 1. The bevels were machined to pro- 

 vide a 60" included angle, sharp nosed, double "V" weld joint. The 

 two plates were then joined by welding to form an assembly 48" square. 

 Weld run-on and run-off tabs were attached to the plates prior to 

 joining in order to avoid the effects of arc starting and stopping 

 in the main weld and also to provide sample weld material for test 

 and evaluation. 



Welding was performed in three separate stages, as depicted in 

 Figures 2, 3 and 4. A balanced welding sequence was used in each 

 stage with weld metal deposited first on one side of the joint and 

 then on the other, to avoid excessive distortion and weld cracking. 

 The first stage, welding the root passes, was performed by gas metal 

 arc (GMA) short-circuit welding in the vertical welding position as 

 shown in Figure 2. The second stage, during which the large bulk 

 of the weld was deposited, was performed by the gas metal arc (GMA) 

 spray welding process, in the flat welding position. Figure 3. The 

 final stage was performed by gas tungsten arc (GTA) welding in the 

 flat position to provide the capping passes as shown in Figure 4. 

 A total of fifty-seven weld passes were required to complete the 

 joint. 



Welding conditions for each of the three stages are listed in 

 Table 3. 



The completed, four foot square weld assembly, weighing approx- 

 imately 1300 pounds, is shown in Figure 5. 



FORMING 



In order to provide the appropriate shape for the forming opera- 

 tion, the weldment was machined to a 42" diameter disc, 2-11/16" 

 thick, with both surfaces flat and parallel, as shown in Figure 6. 



The disc was then shipped to a contractor, the Lukens Steel 

 Company, for the press forming operation. In view of the experi- 

 mental nature of the work and because of the high cost of special 

 dies, available dies were used to press-form the disc. Since the 

 dies had been designed for use with 4" thick plate, it was necessary 

 to use a 1-1/4" thick, carbon-steel liner plate as a spacer, in 

 combination with the 2-11/16" thick titanium disc, to fill the die. 



105 



