1

EXPLOSIVE WELDING EXPLOSIVE WELDING USING THE EMULSION USING THE EMULSION EXPLOSIVESEXPLOSIVES

Lavrentyev Institute of HydrodynamicsSiberian Branch of Russian Academy of Sciences Novosibirsk, Russia

Victor V.Victor V. SilvestrovSilvestrovA.V. Plastinin, S.I. Rafeichik, A.V. Plastinin, S.I. Rafeichik, M.A. Gulevitch, and V.V. PaiM.A. Gulevitch, and V.V. Pai

E-mail: silver@hydro.nsc.ruE-mail: silver@hydro.nsc.ru

X International Symposium on Explosive Production of New Materials: Science, Technology, Business, and Innovations (EPNM-2010)

June 7 – 11, 2010, Bechichi, Montenegro

D = 1.9 km/sec

2

GoalsGoals

• The decrease of the velocity of detonation (VOD) to 2‒3.5 km/sec for the emulsion explosives

• The application of the compositions for explosive welding of metals

3

OutlineOutline Emulsion Explosives with detonation velocity 2-3.5

km/sec and high detonation ability VOD vs charge diameter. Detonation limits Shell-life. Effect of casing Particle velocity – time profile, detonation pressure Throwing ability of low VOD emulsion explosives

Examples of explosive welding applications Cladding of metals by foils with thickness up to 100

microns (without buffer layer) Explosive welding of small diameter tube with tubeplate

model (the thermal welding to pressurize the tube/tubeplate connection is not needed)

4

History History of low VOD emulsion of low VOD emulsion explosivesexplosives Yoshida, M., Iida, M., et al., 8th Symp. Intern. on Yoshida, M., Iida, M., et al., 8th Symp. Intern. on

Detonation, 1985: Detonation, 1985: ddcrcr < 6 mm, < 6 mm, ΔΔcrcr < 1 mm in wedge test for < 1 mm in wedge test for handmade emulsion explosiveshandmade emulsion explosives

Matsuzawa, T., Murakado, T., et al., “Method for Matsuzawa, T., Murakado, T., et al., “Method for explosive cladding” US Patent 4844321, 04.07.1989: explosive cladding” US Patent 4844321, 04.07.1989: D = 2-5 km/sec, but the details and detonation limits were not D = 2-5 km/sec, but the details and detonation limits were not discusseddiscussed

Petel, O.E., Mack, D., et al., 13th Symp. Intern. on Petel, O.E., Mack, D., et al., 13th Symp. Intern. on Detonation, 2006: Detonation, 2006: D ≥ 3 km/sec,D ≥ 3 km/sec, ddcrcr ≈ 13 mm, ≈ 13 mm, ΔΔcrcr = 3.3 mm = 3.3 mm in PMMA casing for commercial explosivesin PMMA casing for commercial explosives

There are only the There are only the scanty information scanty information forforthe low detonation velocity emulsion explosivesthe low detonation velocity emulsion explosives

5

Main IdeasMain Ideas

Use of fine emulsion matrix to increase of detonation ability of explosives

Introduction of large amount of light hollow glass microballoons (GMB) into the emulsion matrix to decrease the explosive density and the detonation velocity

6

CompositionsCompositionsComponents, wt. % EmExp–8 EmExp–50

Ammonium Nitrate 67

Sodium Nitrate 14

Water 12

Paraffin, solid 3

Industrial Oil 2

Sorbitan monooleate 2

Sensitizer (GMB), μ 8 50

Explosive Density, g/cc 1.0 0.5

Maximal VOD, km/sec 4.76 2.1

Minimal VOD, km/sec 2.67 1.8

Critical diameter / thickness, mm 4.8 / 2 13 / 12

μ = GMB weight / Emulsion matrix weight

7

Fine EmulsionFine EmulsionOptical pictureBetween marks 12 μm

The size of oxidizer droplets is lower 1-2 μm

Non-Newtonian elastoplastic fluid,Apparent viscosity 30–40 kP at 60°C

High detonation ability

8

Domestic GlassDomestic Glass MicroballoonsMicroballoons

0,0

0,1

0,2

0,3

0,4

0 50 100 150 200

2

f( )

3

1

1 – optical analysis, 3 – 3M Belgium, 2 – sieve analysis

d, μm

58 μmρ00 = 0.15 g/cc

Trade mark MS-V

9

Synchrotron RadiationSynchrotron Radiation--AAided ided TTomographyomography

According to Pruell Ed.R., Ten K.A. (2009, LIH)

1 mm

A small morsel of emulsion explosive

at μ = 8 %

Like as “Honeycombs of wild bees”

3D structure3D structure

10

Effect of GMB quantityEffect of GMB quantity

0.75 0.5 g/cc

Ø 20 mmØ 20 mmOur dataOur data

«Explosive Welding» areaμ = 20 50 wt.% GMB, D = 2 3.5 km/sec

Ø 30 mmØ 30 mmUS PatentUS Patent

11

Steady-State Steady-State DetonationDetonation

Weak dependence of detonation velocity on charge diameter at μ ≥ 20 %

GMB, wt. %: 1 – 8 2 – 203 – 254 – 35 5 – 50 6 – 50 in casing

8 %

50 %

20 %

μ is increasing

Only one explosive component is ammonium nitrate →→ high safety of blasting

12

Detonation LimitsDetonation Limits

1 – Di

2 – Dcr

3 – cr

dcr

dcr/cr

4 – dcr

13

Effect of Effect of CasingCasing

dcr. w/o case/ dcr. metal case≈ 7-8 as for individual HE’s

0

0.5

1

1.5

2

2.5

3

0 2 4 6 8 10 12d, мм

D, км/с

Thin PE case, 12.4 mm

PTFE, 6.2 mm

Duralumin, 1.7 mm

Steel, 1.5 mm

Cylindrical charge diameter, mm

D, km/sec μμ = 50 % = 50 %

Sou

nd v

elo

city

S

ound

ve

loci

ty

for

emu

lsio

n m

atrix

for

emu

lsio

n m

atrix

12.4 mm1.7 mm

L/d = 12 – 30 L/d = 12 – 30

14

Shell-LifeShell-Life of low VOD of low VOD emulsionsemulsions

industrial oil () and solid paraffin (▲)

Shell-life is larger than one month

16 mm

15

Particle velocity - time Particle velocity - time profilesprofiles

GMB, wt. %: 1 – 8 2 – 203 – 354 – 50

Original free-contact electromagnetic method(Pai V.V. et al, 1998) was used

Chemical spike predicted by ZND theory = YES except for curve (4)

80 mm, 230 mm (L)

16

Estimations of Detonation Estimations of Detonation ParametersParameters

ρ0,

g/cc

UD, km/sec

PD,

GPa

tR,

μs

aR,

mm

n

1.04 1.08 5.1 0.4 1.3 3.2

0.75 0.86 2.0 0.4 0.9 2.6

0.63 0.6 0.9 0.8 1.3 2.9

0.5 0.77 0.75 ‒ ‒ 1.5

Detonation pressure, PD 0.7 ~ 5.1 GPaParticle velocity, UD 0.6 ~ 1.1 km/sec Reaction zone width, aR ~ 1 mm

Detonation product’s index, n 1.5 ~ 3.2

Reaction time, tR 0.4 ~ 0.8 μsec Detonation energy, Q 0.6 ~ 1.4 kJ/gQ = D2/(2(n2-1))

17

Acceleration of Plate by

Sliding Detonation To study the throwing ability of emulsion explosives it was determinate the 2D X-Y profile of test copper plate (inclined resistive wire method)

1 – Nichrome wire 40 μm 2 – copper plate 1 mm 3 – plane layer of explosive 4 – pins 5 – detonation front

18

Comparisons Comparisons of 2D Experimental and Computed Plate of 2D Experimental and Computed Plate ProfilesProfiles

Experimental profiles

P ~ ρn

Hydrodynamic approximation2D numerical calculations

with n - target values

n valueBend angle

Plate velocity

Solid curves – experiments, markers – 2D calculations

19

nn - index of Detonation - index of Detonation ProductsProducts

For developed emulsion explosives n – index depends on the initial density and on the thickness of flat layer of explosives

(a) 1 – cylindrical and 2 – flat charges(b) μ = 8 (3), 20 (4), 50 (5) wt. %

20

Results of lateral Results of lateral accelerationacceleration The plate velocities are ranged from 0.5 up to

1.3 km/sec, and the bend angles from 10 to 27 degrees.

These collision values are close to the necessary ones to explosive welding of metals.

21

Explosives Cladding by foilsExplosives Cladding by foilsClad layers: foils 100-300 μm – aluminum, titanium, stainless steel, bronze,

nickel, copper, molybdenum

Emulsion explosives: 2-3 or 6-12 mm (T), 50 mm (W), up to 300 mm (L)

Base plate: copper, mild steel

Bronze 0.29 mm/steel 10 mm, Expl = 3.4 mm

After shot

Without shock buffer layer between explosives and foil

22

Emulsion Explosives Cladding Emulsion Explosives Cladding by Foilsby Foils

≈ 150-200 m, a/ ≈ 0.1-0.2 VC = 2.0 – 3 km/sec, Δexp = 2 – 12 mm

Cu 0.2 mm / Steel

100

Ti 100 μm / stainless steel Mo 200 μm / steel

Cu 1 mm / steel

0.1 mm

0.2 mm

1 mm

exp = 3 mm

exp = 2.7 mm

Al 0.2 mm / Copperexp = 2 mm

exp = 12 mm

Ni 0.3 mm / Steelexp = 3 mm

23

Explosive Welding Tube to Explosive Welding Tube to CollarCollar pressing-out, r = 0.27pressing-out, r = 0.27

Ø11 мм

explosive cartridge: < 11 mm in diameter, D ≈ 3 km/s, 0.75 g/cc

air gap

welding, welding, r = 0.32r = 0.32

section of the connection zone

model of tubeplate is the mild steel sleevestainless steel tube, Ø12.5/11 mm

wavy seamwavy seam

The thermal welding to pressurize the tube/sleeve connection is not needed

24

ResultsResults

Emulsion explosives with a detonation velocity of 2–3.5 km/sec, detonation pressure of 0.7-2.0 GPa and high detonation ability are developed

Emulsion explosive based on fine emulsion has a very small critical diameter if the charge is enclosed to strong casing

Two applications of the low velocity detonation emulsion explosives for explosive welding are tested:

• cladding of metals by foils up to 0.1 mm in thick

• welding of small diameter tubes to a tube collar

25

AcknowledgmentsAcknowledgments

The work was supported by the RFBR (grant # 09-08-00164-a), by the Siberian Branch of RAS (project 2.10), and partially by the Grant of President of the Russian Federation (project NSh-5770.2010.1)

Thank YouThank You forfor AttentionAttention

26

X-ray pictureX-ray picture of detonatingof detonating chargecharge

Cylindrical charge 20 mm in diameter, 0.5 g/cc, Detonation pressure 0.7-0.8 GPa

Bend angle of casing (PE 0.7 mm + 30 μm Lead) 35 º

D = 1.9 km/sec Detonation fronttR < 0.5 μsec, aR < 1 mm

27

Optical Fiber TechniqueOptical Fiber Technique for VOD measuring at

d<4 mm

Optical fibers

Contact / ion pins

Pins

Detonation cord

L/d = 20 – 35

3 fibers