Technology has been proven to work in its final form and under
In 1989, NAVSEA certified HSLA-100 steel for surface ship
construction in thicknesses up to 4 inches. At that time, the USS JOHN C.
STENNIS (CVN 74) was approved, indicating that HSLA-100 steel was a
qualified substitute for HY-80/100 steel in CVN construction. Fabrication was
to be conducted in accordance with MIL-STD-1689A(SH), Fabrication, Welding,
and Inspection of Ships Structure. The experience base for welding
HSLA-100 steel was too limited to allow the wholesale substitution for all
HY-80/100 steel in the unrestricted areas of the carrier. Therefore, an
implementation plan for incorporation was submitted, and NAVSEA approved this
The CVN 74 main deck was the chosen area for HSLA-100, and
approximately 770 LT were earmarked. The thicknesses in this area were
7/8-inch and 1-inch thick HSLA-100. The fabrication results were excellent. A
total of 16,656 inches of butt joints in the 7/8-inch plate were welded, with
only 8 inches requiring repair. In the 1-inch plate, 16,524 inches of butt
joints were welded, and no defects were found. Since the ship was under
construction at the time of the implementation plan, the total tonnage
inserted into CVN 74 was limited to 1,250 LT, mostly above main deck.
NNS used HSLA-100 steel during CVN 74 construction.
Approximately 700 tons of HSLA-100 steel plate in 7/8- and 1-inch thicknesses
were used for main deck panel assemblies with longitudinal and transverse
stiffeners without preheat (65 to 80°F shop temperature). One hundred percent
magnetic particle inspection was performed on all HSLA-100 butt welds. In
1,400 feet of 7/8-inch thick HSLA-100 butt weld inspected by MT, only 2
repairs (8 inches total) were required, not related to hydrogen-type defects.
The same length of 1-inch thick HSLA-100 butt weld inspected by magnetic
particle inspection showed no defects. A total of 1,250 tons of HSLA-100 were
used in CVN 74, with over 4,000 feet of weldment inspection requiring 32
inches total repair (less than 0.01 percent).
NNS completed weld qualification and weldability testing to
conduct pulsed-arc GMAW and SAW of HSLA-100 in thicknesses greater than 1 inch
through 1-5/8 inch at 60°F preheat using MIL-100S-2 electrode. NAVSEA approved
the procedures. It should also be noted that ISD conducted weld qualification
and weldability tests of HSLA-100 up to 1-inch gage using both HY-100- and
HY-80-type welding consumables and processes. The flight deck of the USS
BATAAN (LHD 5) was successfully fabricated with HSLA-100 plate (in place
of HY-100 steel) for cost savings, as were subsequent vessels of the same
Christein, J.P. and J.L. Warren, “Implementation of HSLA-100
Steel in Aircraft Carrier Construction - CVN 74,” Journal of Ship
Production, Society of Naval Architects and Marine Engineers,