Transcript A. Mori, K. Shiramoto, M. Fujita

EPNM2012
POSSIBILITY OF LINEAR WELDING
OF THIN METAL PLATE BY
UNDERWATER EXPLOSIVE WELDING
Akihisa Mori*, Kazumasa Shiramoto,
Masahiro Fujita
Faculty of Engineering, Sojo University
*E-mail: [email protected]
Introduction
Underwater explosive welding;
A welding method using underwater shock wave
generated by the detonation of explosive in the water.
（Advantage）
Flyer plate
・ Easy to control the pressurizing
conditions by only changing the
distance between the explosive
and the flyer plate.
・A flyer plate is accelerated at a
high-velocity immediately with in a
small stand-off distance.
Base plate
Schematic of the underwater
shockwave welding method when
the high-explosive is used.
Possible to weld a thin plate
which is difficult to weld by the
conventional explosive
welding method.
Motivation
The underwater explosive welding technique is
suitable to weld the whole thin plate.
The method to weld partially be developed to
make a large-size sample, when the size of thin
plate is limited.
Amorphous film ,etc.
Thin plate/foil
(size is limited, brittle materials)
Detonating code
Detonating code (fuse):
/ flexible code with an explosive
core
/ detonation velocity: 6310m/s
/ diameter: 5.4mm
/ common usage;
ignition of explosive
KAYAKU JAPAN Corp.
Core: Pentaerythritol tetranitrate
(PETN)
Covering materials:
Thread, paper, asphalt
(for waterproof)
Welding of lap joints
(Ref: B. Crossland , Explosive welding of metals and its application)
In the past report, no welding area
is generated when the line
explosive is set on the flyer plate.
Because the flyer plate is
collided to base plate without
an angle or with a small angle
in this area.
Weldability window proposed by Wittman and Deribas
Dynamic
b
angleangle,
of obliquity,
Collision
b
Ref. M.A.Meyers, Dynamic Behavior of Materials
Relation of the
collision velocity Vp,
the collision angle β
and the horizontal
collision velosity Vc
(4)
(1)
b
Vc
Vp 
sin  b 
V p  22Vc sin2 
 2
(3)
(2)
Velocity
of welding,
Vc
Horizontal
collision
point velocity,
Vc
To obtain the good welding in explosive welding, the collision angle β
and the horizontal collision velocity Vc, or the collision velocity, Vp are
in the area enclosed with four boundary lines shown the upper figure.
Setup of underwater explosive welding
technique using detonating code
The front of
underwater shock
wave
Detonating direction
（6km/s）
Detonating
code(D.C.)
Front of the underwater shock wave
Explosive holder Detonating code
Reflector
Distance from the center of
detonating code to the
sample
Thickness of spacer
= Stand off distance
Flyer plate
Anvil
Width of gap
Spacer
Base plate
Sample setup
Welding direction
x = 0 mm
Flyer:
Al (0.3mm)
304ss (0.1mm)
Base: Cu (0.3mm)
11 mm x = 0 mm
hc Stand-off
w=5 mm, 10mm
l = 0 mm, 9 mm, 14mm
hc: distance from the center of explosive to the surface of sample
l : distance from the explosive holder to the edge of gap
Experimental assembly
Water
Reinforcement
Guide
Reflector
Bottom plate
Explosive
holder
Flyer plate
Spacer
Base plate
Bottom plate
Reflector
Detonating
code
70 mm
50 mm
50 mm
Anvil
Experimental results
w =10mm
gap
Flyer : Al (0.3mm)
Base: Cu(0.3mm)
w =5mm
l = 9 mm
x10
Spacer
(304SS)
gap
Standoff : 0.1mm
(stainless steel)
hc = 6.3 mm
x5
Al
Cu
50 μm
50 μm
x10 = 0.0 mm
x10 = 5.0 mm
50 μm
x10 = 10.0 mm
Al
Trapped
metal jet
Spacer
Cu
50 μm
x5 = 0.0 mm
50 μm
x5 = 2.4 mm
50 μm
x5 = 4.8 mm
Experimental results
w =10mm
gap
Flyer : Al (0.3mm)
Base: Cu(0.3mm)
w =5mm
l = 9 mm
x10
gap
Standoff : 0.1mm
(stainless steel)
hc = 9.3 mm
x5
Al
Spacer
Cu
50 μm
50 μm
x10 = 0.0 mm
x10 = 2.3 mm
50 μm
x10 = 4.6 mm
Al
Spacer
Spacer
Cu
50 μm
x5 = 0.0 mm
50 μm
x5 = 2.7 mm
Trapped
metal jet
50 μm
x5 = 4.9 mm
Experimental results
l = 9.0 mm, w = 5 mm
Standoff : 0.038mm
(amorphos film)
hc = 6.3 mm
Flyer : Al (0.3mm)
Base: Cu(0.3mm)
200μm
200μm
200μm
200μm
Experimental results
l = 9.0 mm, w = 5 mm
200μm
100μm
Flyer : 304 stainless steel (0.1mm)
Spacer : 304 stainless steel (0.1 mm)
hc = 6.3 mm
Experimental results
l = 9.0 mm, w = 5 mm
200μm
100μm
Flyer : 304 stainless steel (0.1mm)
Spacer : Aluminum foil (0.011 mm)
hc = 6.3 mm
50μm
Experimental setup
Front of the underwater shock wave
Explosive holder Detonating code
Reflector
Distance from the center of
detonating code to the
sample
Thickness of spacer
= Stand off distance
Anvil
Width of gap
Cover plate
Amorphous
Spacer
Base plate
Amorphous film/ copper combination
l = 9.0 mm, w = 5 mm, Cover: Al, standoff: 0.038mm
Amorphous (MBF20, 38μm)
Cu(0.3mm)
l = 0.0 mm, w = 10 mm, Cover: 304SS (0.1mm), standoff: 0.011mm
Amorphous (MBF20, 38μm)
Cu(0.3mm)
Welded length (without cracks ) : about 1.2 mm
Numeical model
materials
Starting point of
detonation
(2)
solver
(1)
Water
Euler
(2)
Reflector （304SS）
Euler
(3)
Detonating code
Euler
(4)
Base plate （Cu）
Lagrange
(5)
Cover plate （Al）
Lagrange
(6)
Spacer （Al 0.1mm）
Lagrange
(7)
Flyer （Amorphous film）
Shell
(3)
(5)
(1)
(6)
(4)
x = 0 mm
x = 10 mm
gap
(7)
Numerical results
Lower limit
X
*) standoff distance = 0.1mm
Numerical results
*) standoff distance = 0.1mm
Summary
In this study, experimental and numerical results of for
the underwater explosive welding method using the
detonating code are introduced.
By the observation using the optical microscope, the
good welding was achieved in case of a thin aluminum
plate and a thin copper plate combination, even if the
standoff if the standoff was extremely short.
In the materials combination of amorphous film and a
copper plate, the welding was succeeded although
cracks were generated.
Future plan
200μm
20μm
Thank you for your attention
Research center for advances in impact
engineering, SOJO University
Water tank in explosion room
TEM
Setup of underwater explosive welding technique
using detonating code
Propagating direction of underwater
shock wave (welding direction)
Detonating direction
（6km/s）
The front of
underwater
shock wave
Reflector
Explosive
holder
D.C.
Anvil
Plan view
gap
Flyer plate
Spacer
Base plate
Top view
Detonating
code(D.C.)
In this setup, an underwater shock wave acts for the flyer plate
diagonally. Then, the welding is achieved in the limited area
because the flyer plate is collided with a certain angle
Simulation model
Φ5.5mm
60mm
9mm
15mm
11mm
10mm
35mm
15mm
ゲージ設定
ゲージ間隔:0.5mm
0.5mm
x =0mm
Simulation model(Gauge)
Experimental results
w =10mm
Flyer : Al (0.3mm)
Standoff : 0.3mm
hc = 9.3 mm x
w =5mm
gap
l = 9 mm
x5
10
Al
Cu
50 μm
x10 = 0.6 mm
50 μm
50 μm
x10 = 4.1 mm
x10 = 7.7 mm
Al
Cu
50 μm
x5 = 0.5 mm
50 μm
x5 = 2.1 mm
50 μm
x5 = 4.7 mm
Amorphous film/ copper combination
l = 0.0 mm, w = 10 mm, Cover: 304SS (0.1mm), standoff: 0.011mm
Amorphous (MBF20, 38μm)
Cu(0.3mm)
Welded length (without cracks ) : about 1.2 mm
200μm
20μm
Numerical analysis(AUTODYN-2D)
Starting area of detonation
Flyer (Al1100-H12)
Spacer (PVC or S.S. 304)
Void
Water
Explosive
holder
DF
S.S. 304
Al 1100-H12
Measuring point (0.5mm-interval)
PVC
*) Excluding the base plate
Numerical analysis(AUTODYN-2D)
Parameters with horizontal
position
(A2,
A4)
unstable
area closed unstable
area
to the spacer
area
stable area
Welding direction
14
3000
2500
12
2000
10
1500
8
1000
6
Vc [#A4]
Vc [#A2]
Beta [#A4]
Beta [#A2]
500
Collision angle, b / degrees
Horizontal collision point velocity, Vc / ms-1
3500
area closed to
the spacer
16
As shown in this figure,
parameters are
changing linearly with
the horizontal position,
excluding the position
slightly far from the
spacer and around the
end side.
4
2
0
0
5
10
15
20
25
30
35
Horizontal potion, x / mm
Parameters, such as the horizontal collision point velocity, collsion angle, with
horizontal position are shown in the upper figure.
Weldablity window obtained by numerical results
#A4: SOD 0.3mm
#A2: SOD 0.1mm
Collsion angle, β/ degrees
18
16
14
12
DKE=
200 kJ/m2
180
160
140
120
100
80
60
40
Lower limit
20
10
10
8
6
4
2
0
500 1000 1500 2000 2500 3000 3500 4000
Horizontal collision point velocity, VC / ms-1
Numerical results agree well with the experimental results ( A2: welded length
= 5.7mm, welding conditions become same values, compared with the 0.3mmstandoff case.