Commander Fred Latrash,
U.S. Navy (retired)
VP, Business Development, Navy and Air
Force Programs, Alcoa Defense
1
Introduction
• Aluminum has proven itself as a
lightweight, durable and affordable
material that allows naval ships to go
faster speeds, carry bigger payloads and
travel longer ranges.
• New technologies and advancements
are making aluminum an increasingly
popular choice for military ships of all
sizes.
• Historical concerns about aluminum
ships have been resolved.
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Agenda
• 5 minutes
Intro (Latrash)
• 15 minutes
Advantages of
Aluminum (Conner)
• 15 minutes
ABS Rules for
Aluminum (Novak)
• 25 minutes
Q&A (w/Audience)
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Speakers
Brett Conner, Ph.D
Derek Novak
Segment Leader, Sea Systems,
Alcoa Defense
Vice-President,
Engineering, ABS Americas
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BRETT CONNER, PH.D
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Why Marine Aluminum?
Properties and Attributes
of Aluminum
Capabilities
High strength-weight-ratio
Fuel Savings
Density one-third that of steel
Excellent corrosion resistance
Weldable
Ease of forming, bending and
machining
Availability and diversity of
functional semi-finished products
High thermal and electrical
conductivity
Recyclable
Increased Range
Increased Payload
Higher Speeds
Maneuverability
Stability
Less maintenance
Lower total ownership cost
Non-magnetic
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Marine Alloys
• 5XXX Alloys
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Strain hardening alloys
Primary alloying element is Mg
Commonly used marine alloys: 5086,
5083, 5456 and 5454
Excellent corrosion resistance
Weldable with good as-welded strength
• 6XXX Alloys
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Heat treatable alloys
Primary alloy elements are Mg and Si
Commonly used marine alloys: 6005, 6061 and 6082
Able to extrude in multi hollow shapes
Takes a knock down in as-welded strength
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Alloys and Tempers
Alloy
Temper
5083-H116
• H Strain hardened (cold
worked) with or without
thermal treatment
• H1 Strain hardened
without thermal
treatment
• O Full soft (annealed)
6061-T6
• T Heat treated to produce
stable tempers
• T4 Solution heat treated
and naturally aged
• T6 Solution heat treated
and artificially aged
Properties:
• Yield strength
• As-welded strength
• Corrosion performance
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Material Properties
Comparing 5XXX Alloys
% Mg
5456-H116
5083-H116
Yield
Strength
N/mm2
(ksi)
4.7-5.5
228 (33.0)
179 (26)
4.0-4.9
214 (31.0)
165 (24)
Comparing 5XXX and 6XXX
6061-T6
5456-H116
As welded
Yield Strength
(butt weld),
N/mm2 (ksi)
Comparing H Tempers
Yield
Strength
N/mm2
(ksi)
As welded
Yield Strength
(butt weld),
N/mm2 (ksi)
241 (35.0)
138 (20)
228 (33.0)
179 (26)
5456-H116
5456-H111
Yield
Strength
N/mm2
(ksi)
228 (33.0)
179 (26.0)
Data from ABS Rules for Materials and Welding 2006 Part
2 ALUMINUM and FIBER REINFORCED PLASTICS (FRP)
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Wait a minute…hasn’t U.S. Navy
used aluminum before? What’s
different?
• Yes! U.S. Navy has extensive experience
with aluminum dating back to 1890s
• All U.S. surface combatants from 1947 until
DDG-51 had aluminum in their deckhouses
– Radars, sensors, weapons, helos
– Typhoon Cobra
•
What’s new?
– Aluminum revival for Navy vessels: Littoral Combat
Ship (LCS), Joint High Speed Vessel (JHSV), Shipto-Shore Connector (SSC)
– Manufacturing technology
– Design rules and tools
– New material specifications for marine plate: ASTM
B928 for 5XXX plate with greater than 3% Mg
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Reducing Acquisition Cost
• Consider an all-aluminum frigate with maximum
speed of 30 kts, endurance of 2000 nautical miles,
payload excluding fuel of 150 tons:
• Nearly 90% of cost to fabricate structure is labor but
only 1% of total ship cost is materials
• Therefore, reducing labor cost has greatest impact on
acquisition cost. How can aluminum help?
• Diverse product forms such as sheet/plate,
extrusions, castings and forgings enable parts
consolidation & design simplification
• Joining technologies: automation and
mechanization
• Alcoa is your partner for reducing cost in shipbuilding
LBP
Beam at DWL
Depth
Draft
Propulsion Power
Light Ship Weight
Displacement
Aluminum Reduced
Draft
91 m
12 m
8.5 m
3.66 m
28,800 kW
1630 t
2122 t
Sources: Lamb, Beavers, Ingram and
11 Lamb and Beavers (2010)
Schmieman (2009),
Building Ships with Aluminum
• Materials
– Bending and forming
– Extrusions
• Specialty extrusions
• Integrally stiffened panels made from
joined extrusions
• Joining
– Automated and mechanized linear
welding
• Friction Stir Welding
• GMAW and HDGMAW
• Laser and Laser-Stir Welding
– Manual welding: Pulse MIG welding
Did you know?
– Mechanical fastening
 In U.S., 44 shipyards and ship repair
– Adhesive bonding
• Cutting and handling
– CNC cutting and routing
– Handling at the shipyard
facilities in 15 states build and repair
with aluminum.
 Around the world, there are more
than 430 ship builders in more than 60
countries with the capability to build and
repair aluminum ships.
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Reducing Total Life Cycle Cost
• Most of the total ownership costs
reside in operations and sustainment
• Lighter structure results in fuel savings.
For this frigate, the fuel savings will be 71
tons per voyage with an annual cost
saving of $1,278,000 over an all-steel
design.
• For a 25 year life-cycle, fuel cost savings
would be $32 million.
• Painting: No need to paint 5XXX
aluminum.
• Recycling: higher residual value at end of
life scrapping.
• Nearly 75% of the aluminum ever
made is still in use today
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Keeping Total Ownership Costs
Down: Avoid past pitfalls!
• Prevent fatigue cracking: analyze
stresses especially at details and
perform a spectral fatigue analysis
• Material selection to prevent stress
corrosion cracking
– Marine plate with greater than 3% Mg must
be certified to ASTM B928
– If service temperatures exceed 65C or 150F,
choose an alloy with less than 3% Mg such
as 5454
• Galvanic corrosion
– Isolate from steel
– Store and handle appropriately
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Alcoa Advantage
• Largest vertically integrated aluminum
company in world: Know aluminum from
production to application to recycling
• Multiple product forms for optimized
marine solutions: Rolled products
(sheet/plate), extrusions, castings and
forgings
• Alcoa Collaborative Development
Approach to work with customers to
develop product solutions
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DEREK NOVAK
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Overview
• ABS Experience
• ABS Requirements for Aluminum
Construction
• Approved Alloys
• Welding Solutions
• Design Solutions
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ABS Aluminum Projects
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HSNC Projects
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Joint High Speed Vessel (All Aluminum)
LCS Freedom Class (Aluminum Deckhouse)
LCS Independence Class (All Aluminum)
SEA FIGHTER
ONR E-Craft (Aluminum “Barge” Hull)
HSV-2
USCG Fast Response Cutter, Sentinel Class (Aluminum
Deckhouse)
USN Torpedo Weapons Retriever (All Aluminum)
USNA YP’s (Aluminum Deckhouse)
Egyptian Navy Fast Missile Craft (Aluminum Deckhouse)
Egyptian Navy Patrol Craft (All Aluminum)
Oman Patrol Craft (All Aluminum)
Canadian Navy YAP (All Aluminum)
Commercial Vessels
– Gulf of Mexico Crewboats
– Passenger Ferries
•
Motor Pleasure and Charter Yachts
– Trinity Yachts
– Burger Boats
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ABS Rules for Aluminum
Construction
• Aluminum Vessel Rules
• Rules for Steel Vessels Under 90m
– Allows for aluminum superstructures
– Uses Q-factor approach
• Guides for:
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Motor Pleasure Yachts
Offshore Racing Yachts
High Speed Craft
High Speed Ferries, Crewboats
High Speed Naval Craft
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Typical Aluminum Alloys:
5000 Series
•
5000 Series Aluminum Alloys
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•
•
•
•
Corrosion resistant in marine environments
Readily weldable
Non heat treatable aluminum magnesium alloys
Good as-welded strength
The most popular base metal for shipbuilding in the
United States is 5083
The 5083 base alloy was registered with the Aluminum
Association in 1954. Advantages for shipbuilding are
its availability, excellent strength, corrosion resistance,
formability and weldability.
Lower strength alloys (5052 and 5086) have been
used for lower stress locations and smaller vessels
5456 is a higher strength alloy typically used in military
applications
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Typical Aluminum Alloys:
6000 Series
• 6000 Series Aluminum Alloys
– Heat treatable aluminum magnesium silicon
– Used frequently as extruded shapes and
sections
– 6000 alloys need to be protected from sea
water
– Poor as-welded strength
• The most popular extruded alloy for
shipbuilding in the United States is 6061
• Lower strength alloys (6005A and 6063)
have been used for lower-stressed
locations
• 6082 is the most common extrusion in
Europe and Australia
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Aluminum Welding Issues
• Problems:
– High distortion
– Burn through
– Weld quality
• Solutions:
– Friction Stir Welding
– Specialty Extrusions
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Friction Stir Welding (FSW)
ABS has issued series of five documents identifying requirements for FSW:
•
FSW I: Essential Elements of a Friction Stir Weld Procedures, Re-welds
and Repairs
– Includes essential elements, limits on those elements, and changes to the
procedure that would require requalification
•
•
FSW II: Friction Stir Weld Procedure Qualification Test Requirements
FSW III: Friction Stir Weld Operator Qualification Test Requirements
– FSW II and III list the destructive and nondestructive evaluations
to be used in qualifying a procedure and operator
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•
•
FSW IV: Friction Stir Welding Fabrication Requirements
FSW V: Friction Stir Welding Procedure, Operator Qualification,
and Production Non-Destructive Testing Requirements
FSW I-FSW V have been provided to the Navy technical
authorities for comment
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Specialty Excursions
• Extrusions are designed for weld joint
• Plank-to-plank connections need to be
designed
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Design Issues
• Problems
– Reduced mechanical properties when
welded
– Lower fatigue life
• Solutions
– Extrusions
– Good structural details
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Use of Specialty Extrusions
• High Strength to Weight Ratios
• Optimized Scantlings
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Use of Specialty Extrusions
• ABS recognized that aluminum extruded
planking could safely allow for structure
that is thinner than conventional
plate/stiffener combinations
• ABS developed scantling criteria for
these extrusions in the High Speed
Naval Craft Guide (Section 3-2-3/2)
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Design Details
• Soft toe brackets
• Specialty extrusion used to connect extrusions
together
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Summary
• Advancements in ship design,
analysis and manufacturing
methods have overcome past
concerns with aluminum regarding
corrosion, sensitization and repair
• Acquisition costs of aluminum
ships are competitive with steel
ships, but aluminum ships have a
clear advantage in total ownership
costs
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How to Contact Speakers
• Derek Novak - ABS
– dnovak@eagle.org
• Brett Conner, PhD – Alcoa Defense
– brett.conner@alcoa.com
• Fred Latrash – Alcoa Defense
– frederick.latrash@alcoa.com
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Additional Resources
• Download Today’s Slides
– alcoadefense.com
• Replay of Today’s Webinar (audio & video)
– E-mailed to you early next week
• ABS
– www.eagle.org
• Alcoa Defense
– www.alcoadefense.com
– Download White Paper
“Aluminum & Shipbuilding”
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Question & Answer
• To ask question over telephone…
– dial *1 to ask a question
• To ask question over via chat…
– use “Q&A” box on screen, type
question, click “submit question”
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Thank You
• Webinar Replay
– Download slides today
– Replay (audio/video) emailed next week
• Feel free to contact:
– Derek Novak
• dnovak@eagle.org
– Brett Conner, PhD
• brett.conner@alcoa.com
– Fred Latrash
• frederick.latrash@alcoa.com
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