UNDERSEA TECHNOLOGY 



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HY 130/150 steel cylinder model. This model was used to study fabrica- 

 tion and the structural performance of welded HY-130/150 steel, the huU 

 material to be used in the Navy's Deep Submergence Rescue Vehicle (DSRV). 



at least 3500 ft. The DSRV pressure hull is made up of three small spheres 

 (less than eight feet in diameter), which are joined together. High precision 

 procedures are being used to fabricate the DSRV, and will be required on 

 all deep submergence pressure hulls, regardless of size. The fabrication of 

 deep submergence pressure hulls in shipyards will require extensive de- 

 velopmental work, including fabrication trials to familiarize and train ship- 

 yard personnel in large scale prototype construction for fatigue models and 

 explosion-implosion and impact tests. 



HY 180/210 Steel 



Higher strength steels for the hulls of deep-submergence vehicles are 

 being developed and evaluated. These steels are in the yield strength range 

 of 180,000 to 210,000 psi (50 ft-lb Charpy-V-notch impact value). The 

 steel plates should be weldable in sections up to four inches thick. 



Also being evaluated is HP-9Ni-4Co-XC steel, which is a quenched and 

 tempered steel in which the cobalt is added to low carbon steel containing 



