Explosive forming techniques - FSB

New concepts for cold form ing ofnon-ferrous materials
Explosive form ing techniques
TNO Prins Maurits Laboratory
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C.W entzel,Product manager explosive

Outline
• Explosive materialprocessing
• form ing
• welding
• Challenges informing high perform ance alloys
• Basic principles
• Novelconcepts
• Exam ples
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What is explosive form ing
• = High Velocity Form ing
• Explosive Shockw ave in
water Kinetic energy
Plastic work
• Advantages:
• potentialfor low er recurring cost
• one-sided tooling
• unlimited pow er (size)
• extended form ability
• unique form ing schem es
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Illustration of technology
• Explosive:
• detonating chord is the work
horse
• shape as appropriate
• charge size as appropriate
• Process in practice
• built-up w ater bassin
• water tank
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Challenges informing high
perform ance alloys
• Typicalalloys
• Alum inium 2xxx,7xxx,6xxx
• Titanium pure,Ti6Al4V,specialalloys
• nickelbased superalloys
• ODSalloys (e.g.PM 1000)
• Difficulties informing:
• H eat treatm ents required
• Limitations inpressing capacity
• Hotform ing:costly tooling;thinning;alfa case rem oval(Ti)
• Forgings:long lead times;expensive
• Challenges:
• Cold form ing /forging beyond presentlimitations
• Eliminate restrictions on size /load capacity
• Develop sheetalternatives for forged com ponents
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Explosive materialprocessing
• Explosive Form ing
• shock wave in water/sand or contact charge
• free form ing or dieform ing,calibration
• Mechanism s
• inertia-effects in high velocity form ing
• forging effects ininteraction with die (ironing)
• Key elem ents ofform ing
• unlimited size,large thickness
• steer aw ay from tensile dom ain,invoke shearing deform ation
• extended dynam ic form ability limits
• Explosive w elding
• Explosive engraving
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Illustration of Mechanism :shear
deform ation
• Inw ard form ing
• increased deform ability due to
com bined biaxialtension and
com pression
• simple,positive,low cost die
Formability limit
curve
Extended
formability
1
2
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Mechanism :“calibration”
• Impact of sheet onto die
• “plastic hinge”
• Forging process
• Consolidation of shape for increased accuracy
Plastic
hinge
Shock wave
sheet
gap ~ 0.2m m
DIE
V impact ~80 m/s
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Simulation of calibration
Detonating cord
• Experiments:
• FM L and monolithic sam ples
loaded by plastic wave
• Simulations
• “H ydrocodes”
• Num ericalsimulations of
calibration process on
microscale
• dam ping and through
thickness impact on die
Plate
Die
Pressure
wave
First layer yields
Second and third layer stay below yield
Cavitationzone
0E+00 2.00E-01 4.00E-01 6.00E-01 8.00E-01 1.00E+00
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Exam ples
• PM 1000 beaded panel
• extended limits
• load capacity
• Ariane V ring fram e
• load capacity (T3!)
• inertia effects
• Manifold (Exploform )
• load capacity
• cheap die
• distributed load
• Mast segm ent
• load capacity (size,thickness)
• Titanium pressure tanks
• load capacity
• direction ofload,inertia
• Beer vessel
• ibid
• Isogridstiffened case
• inhom ogenous part
• load capacity
• Ariane v cone panels
• large size,
• distributed load
• impact effects
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Integrally stiffened (Saturnus ‘w afflepanel’)
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Isogridproduct fam ily:proof of
concept
• Com plex ducts
• Double curved products
• From flat milled sheet metal
• Proof of principle:
• grid on inside & on outside
• Alum inium 5000-series
• Applied process:
• ad-hoc solution
• Result:
• Good,
considering
first trials
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Ariane V Rocket Fram e
• Current process:
• Drop ham m er form ing of1.4 m segm ents
• Set offour dies
• Die wear,surface contam ination
• Three interm ediate heat treatm ents
• Explosive form ing
• Form ing of2m m Alum inium
2024 in T3 condition
• Tw o steps in single die.
• Elimination ofheat treatm ent
• Improved properties
• Qualification ongoing
Scaled development product
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Ariane V cone panels:“impact curving”
V ~ 50 -100 m/s
++++++++++++
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Beaded panel
• Aeolus (X38-rudder)
beaded panelPM 1000
• Hot structure part
• Improved form ability
• No pressing limits
• Single tool
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Titanium 6Al4V explosive form ing
• Biaxialextension at room
tem perature
• rupture typical
• Solution to be found in:
• materialflow ; and/or
• interm ediate heat treatm ent
• form ing schem e
(allow s controlover deform ation
path)
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Inertia form ing
• Scrap rate reduction
• Improved nesting for circular
fram es
• Explosive pre-form ing oflong
strips ofmetal
Rolling / Bending
Exploforming
Ring
Sections
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Explosive welding/cladding process
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Explosive welding/cladding
• Room tem perature process
• dissimilar and similar metalwelding
• e.g.Ti-Steel,SS-Cu,Al-Steel,Ni-steel,also Ti-Ti
• welding ofsurfaces (planar/curved,sheet/foil)
• localwelding (“seam weld”)
• Metalbonding without melting/re-solidification
• Strong bonds
• High deform ability for further processing
• High heat conductivity
• High electricalconductivity
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Welding interface Ta-Cu
0.3 mm
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Explosive Seam Weld fatigue
perform ance
Comparative fatigue in Al 6061-T6
400
Explosion seam welds
Max. Tensile stress [MPa]
300
200
100
GTA welds
Parent
material
t
0
Tensile tests
1.E+00 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 1.E+06
Number of cycles to failure
Flexure tests
Source: NASA
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Explosive Welding exam ple
• Titanium 6Al4V joint
• proofofprinciple
• “Explosive Seam Weld”
• Joint strength (notched)
• preliminary result 1200 N/mm
• Potentialto be explored and
developed
• Process param eters
• Explosive charge (… .)
• Geom etry flyer end
• Preset angle
• Post-welding:
• machining
• heat treatm ent
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Set-up of explosive engraving
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Explosive engraving PM L Rijsw ijk,24 M ay 23

Explosive engraving of coins in Al-plate
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Explosive engraving PM L Rijsw ijk,24 M ay 24

Details of coin engraving
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Set-up of the coins on the plate in the
bunker
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Explosive engraving PM L Rijsw ijk,24 M ay 26

Detonography:an artistic methode to
duplicate naturalmaterial(metalfossil)
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Explosive engraving PM L Rijsw ijk,24 M ay 27

Concepts to be explored
• Bulkhead /hem isphere
• pure hem isphere
• elliptical
• gas explosive form ing alternative
• Hybrid assem bly
• explosive weldofsolid parts onto sheet
• alternative to integralmachining from plate (e.g.alum inium ribs)
• alternative to forging (com pressorblade)
• alternative to casting
• Stiffened sheetform ing
• singlecurvature
• double curvature
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