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HSLA-115 Procured for Fabrication of CVN 78: Will Reduce Top-Side Weight/Lower Center of Gravity

For Immediate Release: Apr 06, 2009

Problem / Objective

The Navy is seeking solutions to reduce weight and lower the center of gravity for surface ships to improve their performance at a reasonable cost. The goal of this Navy Metalworking Center (NMC) project is to reduce top-side weight and lower the center of gravity on the CVN 21 class of ships. An initial solution using 10Ni steel did not produce the intended results. Instead of ending the project, the Integrated Project Team (IPT) pursued an alternate path--increasing the performance and strength of HSLA-100* steel through heat treatment so that it could be used at reduced thickness, and thus, reduced weight, while meeting performance requirements.
* HSLA = High-strength, low alloy

Accomplishments / Payoff

Process Improvement:
Successful vendor qualification of first article, full-size production plates of HSLA-115(named for its increased minimum yield strength of 115 ksi), weld qualification evaluations and explosion testing and completion of Material Selection Information (MSI) certification data have been achieved. NMC and the IPT successfully submitted the MSI document ahead of schedule to support key shipyard need dates.

Implementation and Technology Transfer:
The Future Aircraft Carriers Program Office recently approved the incorporation of HSLA-115 into a CVN 78 application baseline design. HSLA-115 has been incorporated into the ship specifications and fabrication document, allowing its use. The MSI document was submitted in August 2008, and in March 2009, NGSB-NN procured the first order of HSLA-115 for CVN 78. Fabrication is expected to begin later in 2009. HSLA-115 may be considered for additional future applications to improve performance and reduce weight.

Expected Benefits:
Implementation of HSLA-115 into CVN 78 provides improved survivability, strength and weight reduction at an affordable price.

  • HSLA-115 will reduce top side weight by 100 to 200 long tons per hull and lower the center of gravity by 0.05 ft.
  • Factors of safety are improved where thickness is not reduced to improve performance for critical applications.
  • The HSLA-115 implementation is projected to have an overall neutral acquisition cost impact; $1M in cost avoidance has been achieved by qualifying existing welding processes with HSLA-115.
  • Reducing weight and maintaining survivability performance aid the warfigthter to carry out the mission.

Participants

  • PEO Aircraft Carriers
  • Naval Surface Warfare Center Carderock Division
  • Naval Sea Systems Command
  • Northrop Grumman Shipbuilding-Newport News
  • Navy Metalworking Center
  • Arcelor-Mittal Steel
  • DDL Omni Engineering
  • Puget Sound Naval Shipyard
  • Navy Joining Center

About the Office of Naval Research

This year, the Department of the Navy’s Office of Naval Research (ONR) marks its 80th anniversary. For 80 years, ONR — including headquarters, ONR Global and the Naval Research Laboratory — has been a leader in advancing American naval warfighter readiness and dominance through innovations in science and technology for the Navy and Marine Corps. Today, ONR’s continued dedication to providing the Fleet and Force with the technological edge is catalyzing the advancement and delivery of combat systems, sensors, weapons, materials, robotic and autonomous systems and numerous other state-of-the-art, naval platforms and capabilities.