explosive froming

8/4/2019 Explosive Froming

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C. W entzel, Product m anager explosive

t

TNO Prins M aurits Laboratory

New concepts for cold form ing of non-ferrous materials

Explosive form ing techniques


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23 M ay 2002Explosive form ing techniques 2t

Outline

Explosive m aterialprocessing

form ing

w elding

Challengesin form ing high perform ance alloys

Basic principles

Novel concepts

Exam ples


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W hat is explosive form ing?

= High Velocity Form ing

Explosive Shockw ave inw ater Kinetic energyPlastic w ork

Advantages: potential for lower recurring cost

one-sided tooling

unlim ited power (size)

extended form ability unique form ing schem es


4/2823 M ay 2002Explosive form ing techniques 4t

Illustration of technology

Explosive:

detonating chord is the w ork

horse shape as appropriate

charge size as appropriate

Process in practice built-up w aterbassin

w ater tank



Challengesin form ing high

perform ance alloys Typical alloys

Alum inium 2xxx, 7xxx, 6xxx

Titanium pure, Ti6Al4V, specialalloys nickel based superalloys

ODSalloys(e.g. PM 1000)

Difficultiesin form ing:

Heattreatm ents required Lim itationsin pressing capacity

Hotform ing:costly tooling;thinning; alfa caserem oval(Ti)

Forgings: long lead tim es;expensive

Challenges: Cold form ing /forging beyond presentlim itations

Elim inate restrictions on size /load capacity

Develop sheetalternatives for forged com ponents



Explosive m aterialprocessing Explosive Form ing

shock wave in w ater/sand orcontact charge

free form ing ordieform ing,calibration

M echanism s

inertia-effectsin high velocity form ing

forging effectsin interaction w ith die (ironing)

Key elem entsofform ing

unlim ited size,large thickness

steer aw ay from tensiledom ain,invoke shearing deform ation

extended dynam ic form ability lim its

Explosive w elding

Explosive engraving


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Illustration of M echanism : shear

deform ation Inw ard form ing

increased deform ability due to

com bined biaxial tension and

com pression

sim ple, positive, low cost die

e1

e2

Extended

formability

Formability limit

curve


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M echanism : calibration Im pact of sheet onto die

plastic hinge

Forging process

Consolidation of shape for increased accuracy

DIE

Vim pact~ 80 m /s

sheet

Shock w ave

gap ~ 0.2m m

Plastichinge


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Sim ulation of calibrationDetonating cord

Pressure

wave Experim ents:

FM L and m onolithic sam ples

loaded by plastic w ave

Sim ulations Hydrocodes

Num erical sim ulations of

calibration process on

m icroscale dam ping and through

thickness im pact on die

Plate

Die

Cavitationzone

E+00 2.00E-01 4.00E-01 6.00E-01 8.00E-01 1.00E+00

First layer yields

Second and third layer stay below yield


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Exam ples PM1000 beaded panel

extended lim its

load capacity Ariane V ring fram e

load capacity (T3!)

inertia effects

M anifold (Exploform ) load capacity

cheap die

distributed load

M ast segm ent load capacity (size, thickness)

Titanium pressure tanks

load capacity

direction of load, inertia Beer vessel

ibid

Isogrid stiffened case

inhom ogenouspart

load capacity

Ariane v cone panels

large size,

distributed load im pact effects


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Integrally stiffened (Saturnusw affle panel)


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Isogrid product fam ily: proof of

concept Com plex ducts

Double curved products

From flat m illed sheet m etal

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 of 1.4 m segm ents

Set of four dies

Die w ear, surface contam ination

Three interm ediate heat treatm ents

Explosive form ing

Form ing of 2m m Alum inium

2024 in T3 condition

Tw o steps in single die.

Elim ination of heat treatm ent Im proved properties

Qualification ongoing

Scaled development product


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Beaded panel Aeolus(X38-rudder)

beaded panel PM 1000

Hot structure part

Im proved form ability

No pressing lim its Single tool


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Titanium 6Al4V explosive form ing

Biaxial extension at room

tem perature

rupture typical

Solution to be found in: m aterial flow ; and/or

interm ediate heat treatm ent

form ing schem e

(allow s control over deform ation

path)


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Inertia form ingRolling / Bending

Scrap rate reduction

Im proved nesting for circular

fram es Explosive pre-form ing of long

strips of m etal

Ring

Exploforming

Sections


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Explosive w elding/cladding process


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W elding interface Ta-Cu

0.3 m m


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Explosive Seam W eld fatigue

perform ance

Source: NASA

Comparative fatigue in Al 6061-T6

0

100

200

300

400

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

Max.

Tensilestr

ess[MPa]

Tensile tests Flexure tests

Explosion seam welds

GTA welds

Parent

material


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Explosive W elding exam ple

Titanium 6Al4V joint

proof of principle

Explosive Seam W eld Joint strength (notched)

prelim inary result 1200 N/m m

Potential to be explored and

developed

Process param eters

Explosive charge ( .)

Geom etry flyer end

Preset angle

Post-w elding:

m achining

heat treatm ent


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PM L Rijswijk, 24 M ayExplosive engraving 23t

Set-up of explosive engraving


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Explosive engraving of coins in Al-plate


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Details of coin engraving


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Set-up of the coinson the plate in the

bunker


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Detonography: an artistic m ethode to

duplicate natural m aterial (m etal fossil)


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explosive froming

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