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FLEXIBLE GRAPHITE
Flexible
graphite sheets are manufactured from high quality natural
graphite flakes. Flexible graphite sheet is a binderless material.
It can be used in high temperature environments and is resistant
to most chemicals. It is very anisotropic with respect to
characteristics such as gas permeability, electrical resistivity,
and coefficient of thermal expansion and thermal conductivity.
Unlike
conventional artificial graphite, flexible graphite sheet is flexible,
compressible and has a high degree of resilience.
GENERAL PROPERTIES:
Flexible graphite sheet can be used from cryogenic
temperatures to very high temperature: up to 450°C in
oxidising atmosphere and up to 2500°C in an inert atmosphere.
Some
of the properties are
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» |
Flexibility. |
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Elastic in
nature. |
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Self
lubricating. |
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Thermal conductivity is
good. |
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Compacting
ability. |
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Resistant to thermal shock.
|
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Resistant to most
chemical. |
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Does not detoriate over long period of
time. |
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Impervious to gasses and liquids. |
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May be used at high pressure
- temperatures. |
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Does not age, shrink; harden or flow on
heating. |
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Does not stick. |
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Not effected by
electrocorrosion. |
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Compensates for
surface irregularities in metal surfaces, pits, scratches, and
grooves. |
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Reflective
power |
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Ability to withstand vacuum and pressure in all
conditions |
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Unlike asbestos this material is non-polluting. |
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Easy to cut into different sizes and
shapes |
CHARACTERISTICS :
| Sl.
No |
Properties |
Units |
Value |
|
|
1 |
Apparent
Density* |
g/cc |
1.1(±0.05) |
|
|
2 |
Tensile Strength
(for 1.1 g/cc density) |
kg/cm² |
|
45
min |
|
3 |
Compressibility
( _|_ to the surface)
ASTM
method (F 36-95) (for 1.1 g/cc density) |
% |
45
max |
40
min |
|
4 |
Recovery
( _|_ to the surface)
ASTM
method ( F 36 - 95) |
% |
18
max |
15
min |
|
5 |
Specific
Electrical resistively |
micro
ohm-m |
7.3 |
|
|
6 |
Leachable
chloride |
ppm |
20
max |
|
|
7 |
Ash
content
at
850°C for 14hours in air. |
% |
0.6max |
|
|
8 |
Sulphur |
ppm |
450max |
|
|
9 |
Fixed Carbon |
% |
99 |
|
|
10 |
Residual
Stress |
|
30
N/mm² |
|
|
11 |
Analysis
of ash
Silicon
Iron
Aluminium
Manganese
Phosporus
Chromium
Copper
Zinc
Magnesium
Lead |
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm
ppm |
240
max
48
max
300
max
200
max
100
max
8
max
<0.5max
<0.5max
<0.5max
<0.5max |
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*Flexible Graphite is availabie in 0.7 glcc to 1.2
g/cc Apparent Density. The values of S1. No. 2, 3, 4, 5 & 6 will change with density of the material. |
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OXIDATION
PROPENSITY OF FLEXIBLE GRAPHITE IN AIR
| Temperature |
Wt.
Loss, % |
|
450°C
1
2
3
Avg. |
One
Hour
0.05
0.05
0.07
0.057 |
Four
Hours
0.16
0.22
0.26
0.21 |
|
650°C
1.
2.
3.
Avg. |
One
Hour
1.45
2.20
2.63
2.09 |
Four
Hours
9.73
15.80
19.03
14.85 |
|
850°C
1.
2.
3.
Avg. |
One
Hour
27.27
23.22
24.78
25.09 |
Four
Hours
98.56
94.09
95.14
95.93 |
APPLICATIONS:
Flexible graphite is used to make
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Sealing rings for
pumps. |
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Sealing rings
for valves. |
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Sealing rings for
chemical equipment. |
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Rotating
rings. |
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Valve seats. |
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Flange seals. |
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Joints for exhaust gas
collectors. |
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Cylinder head
gasket. |
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Pump casing
seals. |
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To improve the
electric contacts at high temperatures. |
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To protect
equipment against hot gasses or corrosive liquids. |
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To protect
ingot moulds, crucibles, casting moulds for molten metals. |
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As thermal
screens in furnaces. |
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As heating
elements. |
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As thermal
insulation in furnaces. |
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As sealing
material in high temperature furnaces. |
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Because
of its chemical, physical and mechanical properties, flexible
graphite based seals, gaskets are being used in
1.
Chemical industries.
2.
Petrochemical Industries.
3.
Refineries.
4.
Energy.
5. Automobiles.
6. Mechanical
Industries.
7.
Submersible Equipment's and Machinery.
STANDARD
SIZE :
| Sl.
No. |
Standard
Dimensions (A.D. from 0.7 to 1.2 g/cc) |
|
1. |
0.38
x 500 x 1400 mm |
|
2. |
0.40
x 500 x 1400 mm |
|
3. |
0.50
x 500 x 1400 mm |
|
4. |
0.70
x 500 x 1000 mm |
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5. |
0.75
x 500 x 1000 mm |
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6. |
1.00
x 500 x 1000 mm |
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7. |
1.20
x 500 x 1000 mm |
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8. |
1.50
x 500 x 1000 mm |
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9. |
2.00
x 500 x 1000 mm |
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10. |
2.50
x 500 x 500 mm |
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11. |
3.00
x 500 x 500 mm |
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12. |
3.50
x 500 x 500 mm |
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Note :
1.5mm thick to 3.5mm thick sheets made without using
adhesive. |
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