ISMAN STUDIES ON EXPLOSIVE PRODUCTION OF NEW MATERIALS AND INDUSTRIAL EXPERIENCE OF BITRUB INTERNATIONAL

1
ISMAN STUDIES ON EXPLOSIVE PRODUCTIONOF NEW
MATERIALS AND INDUSTRIALEXPERIENCE OF BITRUB
INTERNATIONAL
Yu.A. Gordopolov and L.B. Pervukhin
Institute of Structural Macrokinetics and
Materials Science Russian Academy of
Sciences Bitrub International, Ltd.
EPNM-2012, ?????????
2
The analysis of defects arising in the course of
industrial production of bimetal by explosion
welding
Change of joint durability on the sample length.
250
Distribution of joint durability to tearing off
on length of sheet.
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Defects in clad sheet faulty fusion at the
initial stages, worm-holes, local tear-out of
clad material
3
The conventional theory of compound formation in
explosive welding
Scheme for explosion welding1. clad sheet2.
weld3. basic sheet 4-5. explosive charge6.
cumulative jet
The process of explosive welding is regarded as a
high-speed collision of two jets at an angle of a
liquid to form a feedback (cumulative) of the
jet. Cumulative jet takes off with a layer of
metal surfaces and welded together with the
oxides and contaminants they remove as a cloud of
dispersed particles of the welding gap. Juvenile
surface compressed under the action of detonation
products to form a metallic bond.
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4
Questions
(1) Whether or not explosive joining can be
regarded as a result of oblique collision and
interpenetration of two liquids? (2) Whether or
not a cumulative jet is formed during
welding? (3) What is the mechanism for self-
purification of clad surfaces?

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5
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????????? LS-DYNA
First choice Elastoplastic behavior of welded
elements, taking into account the adiabatic
temperature rise.
6
Results of experiments
After explosion welding
Before explosion welding
Matching clad and base plates
The top view
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Conclusion

1. Not taking into account the resistance to
   shearing sheet clad model more in line with the
   experimental data.
2. Clad sheet is not extended in the process of
   explosive welding large steel bimetal, and the
   deformation of the ?lad sheet occurs before the
   contact point .
3. In the process of explosive welding at the point
   of impact is falling at an angle of a plane
   liquid jet on a rigid wall.

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8
Method of "traps".
The surface of a trap after welding of the
TiSteel on air. The covering from a mix oxygen
the titanium is observed on a surface.
Fe, Fe3N
The surface of traps after welding of the titan
with a steel in argon is absent a covering. In
this photo machining traces are visible.
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Conclusion

• Experimentally, the method of "traps" for large
  samples and sheets of industrial size, it is
  established that the explosion welding on the
  modes used in the manufacture of bimetal
  steel-steel, titanium-steel in argon, no effect
  is cumulative
• In the absence of cumulative process how the
  self-cleaning surfaces, and their activation and
  formation of the compound?

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10
The scheme of calculation of shock-compressed
gas area ahead of a contact point
?
?
Vk

• Two problems are in common solved
• Problems about the moved piston, define of gas
  parameters for shock-wave
• Problems about flow out velocity of gas from a
  welding gap

Vk the contact point velocity ?0
atmospheric pressure ?1 pressure in the
shock-compressed gas ? - flow out velocity of
gas from a welding gap l length of
shock-compressed gas area mgr - The grasped
weight of air mex - The expiring weight of air
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Dependence is determined by the size of the
shock-compressed gas
Dependence l f(s)
?0 density of flowing gas, b length of the
contact line, P1 pressure in the
shock-compressed gas, V? contact point
velocity, ? - velocity of the gas, l - extent
of the zone of shock-compressed gas, s
distance from the contact point
The dependence of the extent of the zone of
shock-compressed gas (l) of the distance traveled
by the contact point (s) and the width of the
welded sheets (b)
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The mechanism of purification and activation of
welded surfaces
Size of sheet, mm contact point velocity DVk, ?/? Shock compressed gas ? ???, º ? ???.?, º ? Plasma ? ??????, º ?
(264)?1400?5900 2500 2784 3125 5909
(264)?1400?5900 3500 5240 6125 11365
(264)?1400?5900 4500 8515 10125 18640
The calculated temperature  inshock-compressed
gas
The supersonic flow (56 Mach numbers) of
shock-compressed gas gives rise to thermal
ionization of gas ahead of the contact point
accompanied by formation of thin layers of
low-temperature plasma at the interface.
Dissociation oxides and pollution occurs at
influence of plasma. The positive ions of the
metals which have formed as a result dissociation
come back to the cleaned surface. Atoms of
oxygen, nitrogen, carbon form the elementary
gaseous connections ??2 and ?2? which are taken
out from technological gap by the
shock-compressed gas . Dissociation oxides leads
to the sharp increase of activation of welded
surfaces before contact point.
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13
Plastic deformation in the process of joint
formation.
Activation time of shock-compressed gas area is
0.9 10-4 s ????? ????????? ??????????? ???
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plastic deformation area is 1 10-7 s ?????
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e l / l0
pgtgts?
P pressure s? the dynamic yield strength
l length of the line connection, l0 length
of the projection
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Suggested was the following scheme of explosive
welding
1- zone of contact point, 2- zone of ahead of
contact point 3- zone of join formation. D
detonation velocity, V- velocity of
shock-compressed gas

• Three stages form the joint by explosion welding
• Purification/activation of the welded surfaces
  are ahead of the contact point of the
  shock-compressed gas under the influence of the
  plasma flow and due to plastic deformation during
  the formation of the bump of the localized
  deformation zone
• Formation of physical contact and joint in the
  impact point
• Volume interaction with joint formation and
  plastic deformation behind a contact point

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Conclusions
The quality of explosive welding is primarily
determined by processes occurring ahead of the
contact point, ie, purification and activation of
the welded surfaces. Therefore, to ensure a
lasting connection to the beginning of the
process explosive welding, excluding the initial
fusions and areas of low strength, it is
necessary at the beginning of welding to provide
the required parameters of the shock-compressed
gas and the formation of a layer of plasma
cleaning and activation of the welded surfaces.
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Technological bases of industrial manufacture

• Choice of the scheme of welding with the account
  of properties of welded materials, features of
  narrow sides deformation and scraps of plating
  sheet
• Rational technology of surfaces preparation of
  initial materials and assemblage of packages
• Use as explosive mixtures of microporous
  ammonium-nitrate diesel oil .
• Minimising of influence of external factors for
  the account of performance of all operations on
  explosion welding preparation in shop. (On range
  the apportion of explosive is made only.)
• Quality assurance at all stages of manufacture of
  bimetal.
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CLAD METALS FOR ATOMIC POWER ENGINEERING AND
SHIPBUILDING
Clad Metal Grade, dimensions, mm Seal strength, MPa Seal strength, MPa Bending tests, angle degree Bending tests, angle degree
Clad Metal Grade, dimensions, mm Tear test Shear test Bending Lateral bending
A-516 Gr70 Ti Grade1 30(255)?3300?3800 250-350 180-230 130-135 130-135
A-240 Tp321Ti Grade1 55(505)?110?1750 305-335 280-350 130-135 130-135
A-106 GrB Ti Grade 1 38(308)?2700?2900 250-350 190-250 More than 80 More than 80
A-144 Gr E AISI 410S 104(1004)?1500?8000 370-410 250-310 180 -
4130 SA-29 Gr 4130 AISI Tp321 Forging ? 3900 420-440 270-320 180 -
Bimetallic microstructure
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Explosive used for the explosive welding

• A mixture of micro porous granular ammonium
  nitrate with diesel fuel at a ratio of 964
  provides
• The stability of the detonation of large-size
  (2x8 meters) of flat explosive charges in the
  thickness of 20-80 mm at a rate of detonation of
  1500 - 2500 m / s
• Explosive charge is not compacted layout, and
  does not cake when stored for a week, does not
  separate the components
• High quality clad metal

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  ??????? ? ????????? ???????? ? ??????????? 964
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  ????????? ????????? 1500- 2500 ?/?
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Promising new clad metals 1. Instrumental and
high-strength steel for the body armor and
armored protection2. Instrumental steel for
structural work of tillage machines3.
Three-layer steel for tanks and welded pipes4.
Seamless boiler tubes-layer5. Cylindrical
multilayer parts
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CLAD METAL FOR METALLURGICAL AND CHEMICAL
ENGINEERING
Tube-sheet blanks made of steel/brass clad metal
grade 09?2??63 Two-layer sheets of steel/copper
clad metal grade 09?2??1 Base metal thickness
30 - 200 mm Clad layer thickness 8 - 12 mm
Bimetallic current leads titanium/copper for
electrolytic tanks grade ??1-0?1, ?24?1200 ??.
High resistance to corrosion, reduction of
electricity losses
Composite plugs Electrical resistivity of ceramic
layer 15 KOhm Deviation of crimping uniformity
for the whole length /- 0,3 ??. Compression
strength of the ceramic layer 65 MPa.
Three-layer clad metal resistant to pitting
corrosion. (Corrosion resistivity is 4-30 times
higher than that of composing metals) Area of
use reactors foe chemical weapon destruction,
reservoirs for highly aggressive fluids.