Support the efforts necessary to attain the desired benefits of high strength and toughness steels and to achieve substantial weight reduction in the CVN-21 design.
Preliminary laboratory studies have shown that high strength and toughness steels have the potential to provide increased protection and/or structural strength at reduced weight. Early research has shown that these steels may also be easily weldable as a result of their low carbon content and clean melt practices. However, it is unknown if a production-sized heat will produce strength, toughness and a weldability similar to laboratory samples. Furthermore, material properties such as yield strength, ultimate strength, strain to failure, and work hardening are known to influence the survivability of ballistic steel plate during explosion events. Ongoing work by the Naval Surface Warfare Center-Carderock Division has shown that these material properties can be controlled during the manufacturing process.
The optimum combination of materials properties is unknown and requires processing refinement, specifically the evaluation of the production of high strength and toughness steels, optimization of heat treatment and analysis of material, ballistic, explosion, mechanical, structural, welding and corrosion properties.
Provided that the improved HSLA-115 material retains or exceeds material performance levels relative to the currently used HSLA-100 material, then the thickness of the steel plating can be reduced to achieve the desired weight reduction. This thickness reduction should result in a 400 long ton weight reduction and a lower center of gravity.
The technology developed under this project is expected to lead toward efforts supporting the Material Selection Information (MSI) documentation and requirements. The implementation plan is targeted to satisfy the design and construction schedule requirements for the production of CVN-78.
StakeholderLCDR Brian A. Metcalf