AN INVESTIGATION OF THE FEASIBILITY OF HOT PRESSING 



A HEAVY WALLED HEMISPHERIC HEAD 



FROM WELDED TITANIUM ALLOY PLATE 



H. Nagler, Welding Engineer 

 F.J. Lengenfelder, Physical Metallurgist 

 R . J. Wolfe, Head, Titanium Program 



Naval Applied Science Laboratory 

 Brooklyn, New York 112 51 



ABSTRACT 



Thick plate alloy titanium is being considered by the Navy as a 

 potential material for deep diving submersible pressure hulls. The 

 production of very large titanium plates (160" or more in diameter 

 and 4" or greater in thickness) that may be required for such appli- 

 cations approaches the limit of mill capacity in this country. 



To provide an alternative method for the production of very large 

 plates, a feasibility study was undertaken to determine if small 

 plates, joined by welding to produce a large plate, could be hot 

 formed into a hemispheric head of the type that might be used for 

 the construction of a pressure hull. 



Out" of- chamber welding techniques developed at NASL were used to 

 join two 3" thick by 24" wide by 48" long Ti-721 alloy titanium plates 

 to produce a 4' square weldment. A 2-11/16" thick by 42" diameter 

 disc was machined from the weldment and then hot press formed to 

 make a 24" diameter head. Non-destructive tests and niechanical prop- 

 erty evaluations were conducted on the formed head to determine the 

 effects of forming on the quality and properties of the finished 

 head. 



The results of this investigation indicate that it is feasible 

 to hot press form a heavy walled hemispheric head from welded alloy 

 titanium plate. However, the head produced during the course of 

 this investigation was not of acceptable quality because of fissur- 

 ing in certain areas of the weld deposit during the forming operation. 



Successful hot forming of welded alloy titanium plate would 

 appear to require that weld properties at least match those of the 

 base plate at the forming temperature, either by appropriate selec- 

 tion of weld filler wire or by design of the weld joint. In addi- 

 tion, the welding process used to join the plates should be one that 

 is not prone to lack-of-fusion type defects. 



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