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GRAPHITE FOR FRICTION. INTELLIGENCE IN GRAPHITE www.gk-graphite.com
www.gk-graphite.com
GRAPHITE FOR FRICTION.
INTELLIGENCE
IN GRAPHITE
www.gk-graphite.com
www.gk-graphite.comwww.gk-graphite.com
GRAPHITE IN FRICTION LININGS. Graphite is a critical material in the friction industry, especially in the production of brake and clutch linings. Numerous components are combined with graphite for the production of brake linings, including metals, mine-ral fibres, sulphides and resins. With its lubricating properties, graphite modulates the braking effect of friction linings and essentially contributes to braking comfort and noise reduction.
OUTSTANDING GRAPHITE PROPERTIES. The outstanding thermal conductivity properties of graphite also play an important role in friction linings. The main fields of application are the automotive sector and rail range (e.g. brake and clutch linings) as well as mul-tilayered applications in the industry (e.g. sinter surfaces).
FRICTION
Reduction of braking
noise and wear
Parting agent
in welding process
Encouragement
of braking comfort
Impr
ovem
ent
of
fric
tion
coe
ffici
ent
Res
ista
nce
to
oxid
atio
n an
d cy
clic
te
mpe
ratu
re s
tres
s
Excellent
plastic formability
ADVANTAGES OF GRAPHITE IN FRICTION.
SPECIFICATIONS.
Friction coefficient: Increasing graphite content minimizes the friction coefficient Thermal conductivity: Reduction of „hot spots“ Lubricating properties: Filling and smoothing of unevenness
Plastic formability: Balancing of unevenness on coat and disc
The main objective of using graphite is to sustain the heat dissipation after kinetic energy is transformed into thermal energy. The different compositions in the respective brake lining must be mixed homogeneously. The graphite film, applied by the friction, will be removed by the rough petroleum coke. This interaction then leads to the appropriate braking effect.
COEFFICIENT OF FRICTION.
GRAPHITE TYPE
FR
ICT
ION
CO
EF
FIC
IEN
T [µ
]
Amorphous Graphite
(Fine Grade)
Macrocrystalline, Natural Graphite
(Corser Grade)
Synthetic Graphite
(Fine Grade)
Steel on Steel Macrocrystalline, Natural Graphite
(Fine Grade)
Synthetic Graphite
(Corser Grade)
0
0,02
0,04
0,06
0,08
0,10
0,12
0,14
0,16
0,18
0,20
0,22
0,24
0,26
0,28
0,268
0,171
0,1180,129
0,158 0,155
PARAMETERS FOR GOOD LUBRICATING EFFECTIVENESS.
PURITY CRYSTALLINITY PARTICLE SIZE ORIGIN
Note: Results are based on own investigations.
Ref
eren
ce v
alu
e; w
ith
ou
t g
rap
hit
e
Graphit Kropfmühl GmbH Langheinrichstr. 1 94051 Hauzenberg GERMANY T: +49(0)8586 609-0 | F: -112 [email protected] www.gk-graphite.com
FRICTION
OUR PRODUCT PORTFOLIO.
BRAKE / CLUTCH SYSTEM GK GRAPHITE GRADE PARTICLE SIZE
Organic or resin bonded brake and clutch linings (automotive, rail range)
NATURAL GRAPHITE
GP 90/92 Shiny powder max. 5% > 100 μm
KP 90/92 Crystal powder max. 10% > 160 μm
NFL 90/92 Normal flake min. 70% > 160 μm
MFL 87/90 Medium flake min. 70% > 160 μm min. 20% > 315 μm
SYNTHETIC GRAPHITE
Q809 Artificialmin. 4% > 75 μm min. 16% > 45 μm max. 80% < 45 μm
Q813 Artificial
min. 5% > 840 μm min. 25 - 45% > 400 μm min. 35 - 55% > 150 μm max. 5 - 20% < 150 μm
Sintered metal brake linings
NATURAL GRAPHITE
UF 4 99,5 Ultra fine grinding d90 ≤ 15 μmd50 5,5 - 7 μm
FP 96/97 Fine powder max. 10% > 71 μm
Based on carbon
NATURAL GRAPHITE
UF 2 99,9 Ultra fine grinding d90 ≤ 12 μmd50 4 - 5,5 μm
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