The Emissions
Reducer
Our specialty graphites forthe automotive industry
SIGRAFINE®
SIGRAFLEX®
SIGRATHERM®

Graphite Materials & Systems

2

30.00
30,00
SIGRAFINE® pressed-to-size
Plain bearings made out of carbon graphite
for cooling medium pumps
Boost efficiency, reduce consumption
A water pump running on bearings made of SIGRAFINE specialty graphites will run for
up to 30,000 hours — remarkable performance by itself. But our materials also offer
major secondary benefits that keep pumps running more efficiently. The benefits
are clear: graphite's self-lubricating properties let a pump run unlubricated in media
that are not conducive to lubrication. Modern smart pumps operate decentrally
and solely on demand. The low coefficiency of friction for our SIGRAFINE specialty
graphites leads to lower breakaway torques, which in turn cuts energy consumption
significantly.

000 h3

4

Our specialty
graphites for the
automotive industry
Make a contribution to higher efficiency and lower emissions:Reap the benefits of the extraordinary material properties
and quality of our products for the type of applications foundin automotive manufacturing.

Emission control

Fuel/water pumps

Typical applications• Exhaust gas recirculation valves• Exhaust gas recirculation coolers• Electric fuel pumps• Electric water pumps

Materials made of carbon and graphite• Bearings• Graphite foils• Seal rings• Bearings• Commutator discs

SGL Carbon products• SIGRAFINE® die-molded carbon
and graphite• SIGRAFLEX® flexible graphite• SIGRAFINE® die-molded carbon
and graphite

The Emissions Reducer | Overview

Notable features
Strong thermal resistance, good self-lubricating properties,
corrosion resistance and high mechanical strength.

Take advantage of our application-technical expertise.
We are glad to advise you on how to optimize your processes
and will work with you to find specific solutions to your needs.

Our graphite materials boost efficiency in your temperature
management, brake servo, exhaust gas management, fueldelivery and convenience functions.

Gaskets

Electric brake assist pumps

Thermal management• Mechanical seals for cooling water
pumps• Cylinder head gaskets		
• Turbocharger gaskets• Diesel particulate filters• Various elastomer/polymer gaskets• Electric vacuum pumps• Batteries• Pumps• Dashboard• Armrests• Vehicle interior• Engine compartment• Seal rings• Graphite foils		
• Powder• Rotors• Vanes• Graphite foil
• Lightweight boards• Powder• Graphite/PCM materials• SIGRAFINE® die-molded, isostatic
carbon and graphite• SIGRAFLEX® flexible graphite• SIGRAFINE® die-molded, isostatic
carbon and graphite• SIGRAFLEX® flexible graphite• SIGRATHERM® products made fromflexible Graphite• SIGRATHERM® ePCM

5

6Applications for the
automotive industry
They are self-lubricating, highly resistant to heat andcorrosion, and can handle heavy compressive stresses.
Our SIGRAFINE graphite products are ideal components
in vane-type pumps, fuel and water pumps, commutators,
bearings and exhaust gas recirculation.

Water pump with mechanical seal

The Emissions Reducer | Applications

7

SIGRAFINE® specialty graphites
for vacuum pumps↑ Rotor and vanes for brake assist pumps↑ Vacuum pumps comfort seat function

Smart brake boosters
Modern gasoline and diesel motors no longer provide sufficientvacuum power to maintain brake boosters and other technicalsystems. An on-demand vacuum pump instead delivers thenecessary vacuum power in an efficient manner. The same
design is found in hybrid and electric vehicles as well.

Efficient and robust
Our rotors and vanes produced from specialty graphites orsynthetic resin-bonded materials have made a name forthemselves for their exceptional strength and very goodsliding properties. This promotes greater energy efficiency
and a longer service life for the pumps.
EconomicalPressed-to-size (PTS) technology (see page 13) reduces theneed for follow-up machining of the rotors, which in turnsaves time and money.

SIGRAFINE® products for brake booster pumps and pumps
for convenience applications
Applications

RotorsVanes

SIGRAFINE products

EK2230, EK2231
V2048, EK64, V1626

8

SIGRAFINE® specialty graphites
for fuel and water pumps
Media resistance for higher safety
Safe and reliable transportation of water and fuel throughout
the vehicle are of the utmost importance. Our specialty graphites for bearings and gaskets play a big role in this, as they
are ultra media resistant and thus highly process-reliable. Thisis especially important in fuel pumps working with the newgeneration of fuel/alcohol mixes.
Benefit: Self-lubrication
There are also benefits from the self-lubricating properties ofgraphite: the significant reduction in friction correlates into
greater efficiency; noise emissions are also significantly cut,which can be a major factor when as many as five supplementary pumps are in use.
Documented quality
Our products have achieved various quality certifications,
including IATF16949, for years.
Pressed-to-size cuts costs
Pressed-to-size (PTS) technology lets us adapt parts with up
to 80 millimeters of outside diameter into an almost perfectmatch of their final form (see page 13). This minimizes – oreven completely eliminates – the need for follow-up machining
work. This procedure can pay for itself starting with unit countsof just 2,500.

↑ Bearings made of carbon graphite

Application-specific suitability of the materials
SIGRAFINE
Applications

Products

Fuel pumps

Bearings
Seal rings
Commutator discs ²⁾
Bearings
Seal rings

Water pumps

EK23 ¹⁾

EK25 ¹⁾¹⁾ Information refers to the base material only. Different impregnations are available. ²⁾ Please also see the following page.

EK33 ¹⁾

EK79

The Emissions Reducer | Applications

SIGRAFINE® specialty graphites
for commutator discs in electric motors
Higher resistance than copper
Given the increase use of fuel mixes featuring a high shareof ethanol, commutator discs made of specialty graphites
are playing an increasingly important role in electric motors
for fuel pumps. These materials are inherently much morecorrosion resistant than standard copper discs, making thembetter suited as components in fuel pumps. This is especiallytrue when striving for compliance with safety and endurance
specifications.
SGL Carbon supplies commutator discs of pure electrographite,
produced at temperatures of approx. 3,000 °C, as well as hardcarbon discs filled with graphite components and produced at
a temperature of approx. 1,000 °C. The carbon graphite familyof materials are extremely well suited for the production ofhigh-precision discs. These special graphites represent atremendous combination of carbon's outstanding material
properties and the potential for cost-efficient large-scaleserial production. These results can be achieved thanks to thepressed-to-size (PTS) manufacturing process. The discs arepressed on fully automated high-frequency presses to achieve
the desired final contour and shape. Standard fire shrinkage isthen the only significant factor in determining the geometricalignment of the press tool when working with this material.
SGL Carbon works solely with high consistency materials andprecision press feeds to ensure that we can deliver the promised tolerances. Little to no post-production machining is thenrequired.
Another benefit of the PTS process: extensive freedom ingeometric design. As with injection molding and die cutting,this process also allows for offsets, fluting and profiling on the
top surfaces of the discs without expensive and time intensive
post-production machining. A broad range of design options
are available, so long as they adhere to the basic rules ofmaterials and processing technology. Please don't hesitate tocontact us for help in developing or optimizing your concepts
and geometries.

↑ Commutator disc for fuel pump motors

910

SIGRAFINE® and SIGRAFLEX®
specialty graphites for seals↑ PTS seal rings made of die-molded carbon↑ SIGRAFLEX foil

Performance, safety, emissions reduction
Seals naturally play a central role in achieving top driving
performance without compromising on safety or emissions.
For years we've proudly served as a trusted partner to theautomotive industry, delivering materials and products ofproven quality and value.

Unparalleled oxidation resistanceOur SIGRAFLEX foils produced from expanded graphite feature
long-term stability in their sealing performance and are extremely reliable in a wide range of extreme operating conditions.
In particular, our SIGRAFLEX APX2 foil is the clear material of
choice when it comes to oxidation resistance. More on page 23.

Tried-and-tested gaskets
Our SIGRAFINE fine-grain graphite sealing rings, such as thoseused in turbocharger seals, are known for their abrasion
and temperature resistance as well as their excellent sliding
characteristics. They have become trusted components formany automotive manufacturers.

Carbon and graphite powders improve PTFE and otherplastic compounds
We also deliver high-quality carbon and graphite powders for
PTFE and other compounds. These fillers deliver significantly
better material performance, with significantly reduced
material loss in tribological systems and improved thermaland electrical conductivity.

Application-specific suitability of the materials
SIGRAFINE
Applications

Mechanical seals
Turbocharger gaskets
Cylinder head gasket
Diesel particulate filters
Plastic compounds

Products

EK23 ¹⁾

EK33 ¹⁾

EG31

Seal rings
Seal rings
Graphite foils
Graphite foils
Powder¹⁾ Information refers to the base material only. Versions with different impregnations are available.

EG32

V1032

KG19

SIGRAFLEXA

APX2The Emissions Reducer | Applications

11

SIGRAFINE® specialty graphites
for exhaust applications
Helping reduce emissions
The entire automotive industry is focusing closely on reducing
hazardous emissions. Smart exhaust gas recirculation systems,
which cut the production of nitrogen oxides and lower fuelconsumption, represent one important step in this direction.
Our high-performance bearings exhibit precisely the properties
needed for those systems' crucial components.
Resistant, low-wearing high-performance bearings
Our bearings are built from graphite, carbon graphite and expanded graphite. The extraordinary resistance to temperature
and aggressive gases makes this material a superior choiceover alternative products. The bearings also run quiet and withminimal wear thanks to the material's outstanding sliding
properties.

↑ Exhaust gas recirculation flap

Application-specific products for Exhaust Gas Recirculation systems (EGR)
SIGRAFINE
Products

Applications

EGR valves
EGR gaskets
Exhaust manifold

Bearings
Seal rings
Seal rings²⁾ See chapter “SIGRAFLEX and SIGRATHERM,” page 22

V2142

V2064

EK23

SIGRAFLEX
APX2

AP

12

SIGRAFINE
materials andtheir properties®

Outstanding mechanical, thermal and chemical properties– especially in thermal and media resistance – make our
specialty graphite the go-to choice for a multitude ofautomotive applications.

Semi-finished product die-molded carbon and graphite

The Emissions Reducer | Typical properties

13

Manufacturing process

A manufacturing process that generates quality
The outstanding properties of our SIGRAFINE graphite andcarbons – corrosion and thermal resistance, gliding ability,
electrical conductivity, among others – are benefits of our
special production process (shown right). The seven phasesfrom high quality raw material to final product ensure consistent composition of the crystalline graphite structure;targeted changes to the process steps and the formulationneeded to influence the behavior of the material according
to need. This opens the door to near-net-shape pressing,a potential cost savings driver.

1

3

2

Increased cost-effectiveness: PTS technology
We can implement pressed-to-size technology (PTS) in many
areas: Near-net-shape pressings make it possible to manufacture complex component parts in large numbers at low
materials usage. Since mechanical end machining is entirely orlargely unnecessary, this process is especially cost-efficient.

45Impregnation for optimized properties
Metal, phosphate, and synthetic resin impregnations improvephysical properties, reduce wear and increase thermal resistance. We impregnate our SIGRAFINE specialty graphites withmetals and metal alloys such as antimony as well as synthetic
resins and salts.

6

8

9

All carbon – the universal alternative
Our portfolio also includes various synthetic resin-impregnatedgraphites, with the synthetic resin subjected to a subsequentcarbonization process. This offers good media resistance andcan be universal used in temperatures up to 350 C°.

7

10

+

1 Coke, graphite
2 Grinding
3 Binder pitch
4 Mixing
5 Extruding
6 Vibromolding,-2500 – 3000 °C / 4532 – 5432 °F

Die molding

7 Isostatic pressing
8 Carbonizing
9 Impregnating
10 Graphitizing
11 Machining

11

Material properties of our various SIGRAFINE® fine-grain graphites
Die-molded carbon and graphite
Typical properies

Density
Hardness
Flexural strength
Young’s modulus

Isostatic graphite

Units

EK23

EK25

EK33

EK64

V2142

V2064

V1626

g/cm³
Rockwell B
N/mm2
GPa

1.75
105
40
14

1.69
100
45
16

1.6
110
73
16

1.72
90
70
16

1.85
103
80
15

1.83
56
54
16

1.85
90
58
13

Thermal expansion(20 – 200 °C / 68 – 392 °F)

10⁻⁶K⁻¹

5.0

4.5

5.1

4.0

4.7

6.3

4.0

Thermal resistance inoxidizing atmosphere

°C
°F

350
622

350
622

350
622

220
428

550
1022

600
1112

600
1112

14

Wear Properties
Low wear and long-term stability
Our die-molded graphites and carbon graphites exhibit low
material wear, which leads to a longer service life. Our broad
portfolio and wealth of materials expertise allows us to offer
graphite types that optimally match the respective partner
material. This is particularly impactful in combination withrotors and vanes.
Application competency and materials consulting
Many factors influence wear behavior: material pairing, sliding
speed, strain, finish of bearing surfaces and operating conditions. We take a holistic view of the tribological system to findthe material solution best suited to your specific requirements.
↑ PTS flange bearings

Variety with low wear rates

Variety in friction

Wear behavior of some SIGRAFINE material types in wet running conditions

Coefficient of friction depending on temperature in SiC discs (Ra ≈ 0.2)

Wear [µm/h]

Coefficient of friction [µ]

EK20
EK24

EK2240
EK3245

EK2200
EK3205

EK3205
EK3245

EK20
EK24

0.9 —
1—

0.8 —
0.7 —
0.6 —
0.5 —

0.1 —

0.4 —
0.3 —
0.2 —
0.1 —

0.01 —

0—
0

1

2

3

4

0

5

60

80

100

120

Load [N/mm2], bearing o 30/20 x 20 mm (ø 1.18/0.79 x 0.79 in)Disc temperature [°C]

Wear behavior of some SIGRAFINE material types in dry running conditions

Coefficient of friction depending on temperature in gray cast iron 20 (Ra ≈ 0,3)

Wear [µm/h]

Coefficient of friction [µ]

EK200
EK24

EK305
EK2240

EK3245

EK3205
EK3245

EK2200EK24

EK2240
EK20

0.9 —
0.8 —

10 —

0.7 —
0.6 —
0.5 —
0.4 —

1—

0.3 —
0.2 —
0.1 —
0.1 —

0—
0

1

2

Load [N/mm2], bearing o 30/20 x 20 mm (ø 1.18/0.79 x 0.79 in)

3

0

60

80

100

120

Disc temperature [°C]
The coefficients of friction were determined in a pin-on-disc test at 11 m/s(36.1 ft/s), a relative relative air humidity between 36 % and 43 % and a heated disc.

The Emissions Reducer | Typical properties

15

Thermal Conductivity

Resistance to thermal shock

Thermal conductivity – a key property
SIGRAFINE materials convince with excellent thermal conductivity. It is usually more pronounced in graphite than in
the surrounding components, thereby preventing overheatingand excessive abrasion, and extending the service life of thesystem.

Safety from temperature and thermal shock resistance
Of all known materials, graphite has the highest temperaturechange resistance. Thanks to these properties, SIGRAFINE materials of graphite and carbon-graphite contribute significantly
to process reliability.
Control uniform expansion behavior
Good physical compatibility of the materials employed is also
relevant. To achieve this, they must display the same or similar
thermal expansion coefficients.
Our broad portfolio and deep wealth of materials expertise
allows us to offer optimal graphite types for the respective
partner material. This is particularly impactful in combination
with rotors and vanes.
We are glad to advise you. Take advantage of our in-depth
application know-how!

Clearly defined thermal-conductivity behavior
Thermal conductivity of different materials
Thermal conductivity [Wm−¹K−¹]
400 —

300 —

200 —

100 —

Copper Graphite SiliconcarbidePlatinumAlu- Carbon Durominum graphite plast
oxide

Thermoplast

Low expansion in heat

The clear leaders in temperature-change resistance

Coefficient of thermal expansion of various materials

Thermal shock resistance of various materials

Coefficient of thermal expansion [10-6 K-¹]

Thermal shock resistance [%]

50 —

100 —

40 —

80 —

30 —

60 —

20 —

40 —

10 —

20 —

0—

0—
TherAlu- Stainmo- minum lessplast alloys steel

Ther- Chrom- Alu- Tung- Silicon Gramoium minum sten carbide phite
set
cast oxide carbide

Gra- Carbon Boron Alu- Steel Silicon Alu- Therphite graphite carbide minum
carbide minum mooxide
set

Thermoplast

16

Information onparallel partners
and construction
Optimum system performance is achieved by selecting
the suited SIGRAFINE type and impregnation as well as by
the appropriate construction based on the recommendations
shown here.

SIGRAFINE counterface partner with plain bearings

The Emissions Reducer | Design recommendations

Counterface materials

17

Recommended counterface

SIGRAFINE is especially suitable as a counterface forhard materials such as:

For wet and dry running conditions
Our SIGRAFINE materials are suited to both conditions wet
and dry running, as well as to mixed friction. In dry-running
conditions, surface finish should be of a higher standard as inwet running conditions because the liquid film has a compensatory and friction-reducing effect, even in hydrodynamicallypoor media such as water or gasoline.

• Gray cast-iron• Steel (hard), alloyed andunalloyed, as well as nitrided• Hard metal• Aluminum oxide

Individually adjustable for maximum performance
The selection of material type and impregnation depends
on the material of the counterface. This minimizes wear andboosts cost-efficiency. The thermal expansion coefficient,
for instance, can be precisely engineered to optimally alignSIGRAFINE to the counterface.

• Silicone carbide• Glass• DLC¹⁾-coated materials

We advise you
You can rely on our comprehensive know-how. By providing application-specific materials consulting in advance, we help you
achieve a perfect counterface fit, which significantly enhances
system performance.

SIGRAFINE can also be used in some cases with soft
steel (alloyed and unalloyed), light-metal alloys, chromedmaterials, non-ferrous metal and carbon materials.
¹⁾ DLC = Diamond-Like-Carbon

Wear behavior depending on counterfaces
Wear behavior with tungsten carbide
Wear [µm/h]

EK2200
EK3205

10 —
1—
0.1 —
0.01 —
Wear behavior with silicon carbide

EK3205
EK2200

10 —1—↑ PTS sealing rings and mounted mechanical sealing

0.1 —Recommended surface finish of metallic counterface
Load
Rz μm

v < 0.5 m/s
p < 0.1 N/mm2≈1v < 1 m/s
p < 0.2 N/mm2
0.5 … 0.8v < 3 m/s
p < 0.3 N/mm2< 0.50.01 —
0

2

4

6

8

10

12

Specific load [N/mm2]
Wear behavior for counterfaces made of materials, a constant sliding speedof 9 m/s (29.5 ft/s) and increasing load. Medium: demineralized water.

Höhe / Axiallager
Höhe / Axiallager
Scharfe Querschnittübergänge
18

Scharfe QuerschnittübergängesbDesignrecommendations

ger nicht freitragend
einbauen
Flanschstärke
Scharfe
Querschnittübergänge

Scharfe Querschnittübergänge

Proven construction designs for greater safety
The following recommendations for construction
and calculation draw on our years of practicalexperience in projects and applications. Our design
recommendations are proven performers withs
many years of service and help achieve maximum
process reliability by minimizing such risks as
d1
broken bearings.

s

d1

l

l

herung Verdrehsicherung

Verdrehsicherung

Verdrehsicherung↑ Axial bearing of carbon-graphite for submersible motor pumps

15°

15°

15°

f x 45°f x 45°f x 45°d1 = bearing bore (mm)d2 = bearing outside diameter (mm)d3 = flange diameter (mm)d1

d1 d2 d3

d2 d2

d1 d2

p = spec. radial or axial load (N/mm²)ffll = bearing length, respectively height (mm)F = radial or axial load (N)rfls = bearing
d1 walld2 thickness (mm)lbb = flange thickness (mm)llv = sliding speed (m/s)
f = chamfer (mm)Zylinderlager, Bundlager

nderlager, Bundlager
Höhe / Axiallager

Höhe / Axiallager

Scharfe Querschnitt

Fitting
Recommended ISO tolerances

Max. Operating Temperature °C

d1

d2

Housing diameter

Cold press fitting

before F7
after H7 ... H8s6

H7

about 150 1

Shrink fitting

before D8
after E8 ... E9 2

s … z8x8

H7about 300 3

Method of fitting1

 or housing materials having a thermal expansion of   > 12 x 10−6/K the maximum operating temperature is correspondingly reduced.
F
Press fitting is conducted with a stepped fitting pin with a tolerance of h5.

² We recommend that the bearing bore be finished to size after shrink fitting.
3For higher temperatures and for housing materials having a thermal expansion of   > 12 x 10−6/K
the special tolerances and/or a locking arrangement may be employed – please inquire about this.

bThe Emissions Reducer | Design recommendations

19

Calculation guidelines
and supplementary information
Cylindrical and flanged bearings – design guidelines and calculation
Dry running and mixed runningv (m/s) ≤ 1

projected bearing area

I x d1 ≥F
0.3 (N/mm2)l ≤ 2 d1

v (m/s) ≤ 0.1

projected bearing area

I x d1 ≥F
1.5 (N/mm2)l ≤ 2 d1

Bearing clearance

0.3 ... 0.5 %0.3 ... 0.5 %of shaft diameter at operating temperature (warm clearance)of shaft diameter at operating temperature (cold clearance)
if shrunk into a metal housing

Coefficient of friction

0.10 … 0.15
0.15 … 0.25

for mixed runningfor dry runningv (m/s) ≤ 20

projected bearing area

I x d1 ≥F
0.3 (N/mm2)l ≤ 2 d1

v (m/s) ≤ 15

projected bearing area

I x d1 ≥F
0.5 (N/mm2)l ≤ 2 d1

Bearing clearance 1

0.1 ... 0.3 %0.1 ... 0.3 %of shaft diameter at operating temperature (warm clearance)
vof shaft diameter at operating temperature (cold clearance)
if shrunk into a metal housing

Coefficient of friction

0.01 … 0.05

Bearing dimensions

Wet running

Bearing dimensions 1

1 Observe the laws of hydrodynamics.
Information for wet and dry running

Tolerances

Outside diameter
Bore

Surface finish

Outside diameter
Ra = 6.3 μm … 3.2 μm
Bore
Ra = 3.2 μm … 0.8 μm
Do not subject bearing to tension, shear or bending stress
Cold fitting, shrink fitting, bonding
IGenerally hard materials, e. g. HRC > 50, Rz = 0.5 … 0.8 μm

Bearing design
Fitting
Counterface materials (surface finish)

IT 6/IT 7
IT 7/IT 8

Axial bearings – calculation guidelines and supplementary information
Dry running and mixed runningA≥F
0.3 (N/mm2)

Wet runningv (m/s) ≤ 20

A≥F
1.0 (N/mm2)

Bearing area A (mm²)

v (m/s) ≤ 1

Coefficient of friction
Surface finish
Bearing design
Fitting
Counterface materials (surface finish)

0.1 … 0.25
0.01 … 0.05
Bearing surfaces fine-ground to lapped
Bearing surface lapped
Solid or split
Solid or split, lubricating grooves
Cold press fitting, shrink fitting, screws, nuts and form closure
Generally hard materials, e. g. HRC > 50; Rz = 0.5 ... 0.8 μm

20Implementation examples
Example: Axial bearing calculation

Example: Cylindrical bearing calculation

Wet running

Dry running

Bearing dimensions

Bearing dimensions

Bearing bore

d1 = 20 mm (given)

By going back and calculating
Bearing outside ø d2 from the required area
500
F
A =  
= 500 mm2
=  
1.0
1.0
A=

d2 =

(d₂2 – d₁2)
4
Ax4

+ d12

this results ind2 =500 x 4 + 202

F150== 500 mm2
0.3
0.3

Projected
bearing areal x d1 >Bearing bore

d1 >chosen as
rounded up

d1 = ld1 = 500 = 22.36 mm
d1 = 23 mm

Bearing lengthl=rounded up

l = 22 mm

I
2500= 21.7 mm
23

d2 = d1 + 2s
smin = 0.15 x d1 = 3.45 mm
23 + 2 x 3.45 = 29.9 mm
rounded up
d2 = 30 mm
Bearing dimensions ø 30/23 x 22 mm
Bearing outside ø

d2 = 32 mm
Bearing outside øchosen as
Bearing heightchosen as

d2 = 35 mm
l > 0.1 d2
l = 5 mm

Given values: Shaft ø 20 mm; Sliding speed v = 3 m/s; Load F = 500 N; Medium
Water; Temperature 30 °C

Bearing play
Dry running
Shaft ø 20 mm

0.3 ... 0.5 % of shaft ø d
d = 23 h6

Bearing clearance(min.)

0.3 % x 23 = 0.069 mm(added to nominal bore)

Bearing tolerances
Bearing outside ø
Bearing bore
This results in:chosen s6 (cold press fitting)chosen F7
Ø 30 s6 / 23.069 F7 x 22 mm

Given values: Sliding speed v = 0.5 m/s; Load F = 150 N; Temperature 60 °C↑ Cylindrical bearing made of die-molded carbon

1

2

The Emissions Reducer | Construction recommendations

21l

Axiallager

Höhe / Axiallager

Scharfe Querschnittübergänge

d2

s

d1 d2

l

l

b

Höhe / Axiallager

Höhe / Axiallager

Scharfe Querschnittübergänge

Design recommendations

itragend einbauen

Flanschstärke

Scharfe Querschnittübergänge

Scharfe Querschnittübergänges

Avoid sharp steps
in the bore and on theoutside. Break sharpedges!
b
Zylinderlager nicht freitragend einbauen

rdrehsicherung

Verdrehsicherung
Scharfe Querschnittübergänge

Cylinder thickness
I ≤ 2d1
s = 0,15 ... 0,2 x d1;
smin = 3 mmsd1

Flanschstärke

Höhe / Axiallager

d1 d2
15°

f x 45°f x 45°d1 d2 d3

r

d1

l

d1

f

d2

f

l
Höhe / Axiallager

b

1

l

Höhe / Axiallager

Scharfe Querschnittübergänge

l

l

l

Verdrehsicherung

Zylinderlager, Bundlager
VerdrehsicherungbVerdrehsicherunglZylinderlager nicht freitragend einbauen

Scharfe
Querschnittübergänge
Cylindricalbearings should

Höhe / Axiallager
ehsicherung

not be fitted to be self-15°
f x 45° should be
supporting. They
fully supported by the housing
d d dor by a special metal bushing.

15°

1

f x 45°2

d1

d2

f x 45°

3

1

b

f

Flange thickness
should be at least equal to wall thickness.
15°
A transitional angle should be radiused;machine the housing thrust face for theddflange. b ≥ s

s

r
d3

Höhe / Axiallager

Any arrangement such as a check plate orplain pin to prevent rotation should be providedsin an unloaded area, not in the bore. Any keywaysd should be axial and milled out carefully to avoid
breakage.

d2

s

d1 d2

l

l

Verdrehsicherung

15°

d1 d2

d2

Scharfe QuerschnittübergängelHeightI ≥ 0.1 d2; notunder 3 mm,
if possible

l

f

2

f
l

b

Zylinderlager nicht freitragend einbauen

Flanschstärke

Flanschstärke
Zylinderlager, Bundlager

Scharfe Querschnittübergängelb

Zylinderlager, Bundlager
Flanschstärke

Scharfe Querschnittübergänge

Verdrehsicherung

Verdrehsicherung

s

d1
15°
f x 45°sld1rVerdrehsicherung

Verdrehsicherung

Verdrehsicherung

f

b
l

l
15°

15°

erdrehsicherungf x 45°f x 45°

Verdrehsicherungd1 d2 d315°15°

f x 45°r↑ Various bearings made of die-molded carbonff x 45°

d1

f
l

b
l

d1 d2 d3d1d2Zylinderlager, Bundlager

d2

22

SIGRAFLEX and®
SIGRATHERM®

Our SIGRAFLEX and SIGRATHERM products
made from flexible expanded natural graphite
are specifically designed for different areasof automotive manufacturing and have beenused in the most demanding applications for
decades.

SIGRAFLEX foil

The Emissions Reducer | Typical properties

Highest quality standards
For manufacturing SIGRAFLEX materials, we use only highquality natural graphite, which is expanded in a thermal process
and compressed without binders, adhesives or fillers. This
leads to products meeting the highest quality requirements.

23

Quality features
Excellent sealing properties• Low permeability to gases and liquids

Performance and safety provided by quality
SIGRAFLEX is the first choice of sealing material to meet low
emission standards. The proven reliability of our materials
leads to increased safety in applications.

• Smooth temperature change behavior• No cold or warm flow up to the maximum permissible
gasket stress

Stability

Resistance and long term stability
Products made from SIGRAFLEX are chemically resistant tothe vast majority of media e.g. oils, lubricants and coolants.
Oxidation inhibitors are added in some grades to additionallyenhance reliability and long term stability.

• Excellent resistance to chemical media andtemperature• Absence of binders means no ageing, fatigue or
embrittlement

Large dimensions
Our SIGRAFLEX foils are also available in large dimensions up toa width of 1.5 m (60”) in sheet or roll format allowing engineers
to choose the best product for their application design needs.

Anisotropic properties• High in plane electrical and thermal conductivity

User benefits

Material combinations with improved properties
Graphite can easily be combined with other materials. For
example, as composite material with phase change materials(PCM) products for latent heat and cold storage can be offered.

• Low density• Soft and flexible, easy to process and to adapt tosurfaces• Non-flammable• No health risks and environmentally friendly

Custom-designed features of our SIGRAFLEX® and SIGRATHERM® products
SIGRAFLEX
Foil

Gaskets
Bearings for EGR valves
Conductivity additives
Heat/cold storage
Heat/cold transfer

SIGRATHERM
synthetic
HD foil graphite foil

GFG

L

ePCM

L/PCM

GFG/PCM

PTS
PCM

24

SIGRAFLEX® flexible graphite
for sealing applications
Government regulations are continuously requiring automotive
and large diesel engine manufacturers to reduce CO₂, NOx
and diesel particulate emissions at even higher combustion
temperatures.
For high demands
SIGRAFLEX flexible graphite grades are used in sealing applications which demand great durability, reliability, safety andimpermeability and call for resistance to extreme temperatures and enhanced sealing characteristics.
Extremely versatile
Our flexible graphite foil is available in various densities andcan be adapted to a wide variety of sealing applications
with great versatility like cylinder head and exhaust system
gaskets. SIGRAFLEX is suitable for highly automated manufacturing of engine technology gaskets and seals and mass
production.
↑ SIGRAFLEX APX2 products for a wide range of automotive applications

Material data of our SIGRAFLEX® graphite foils ¹⁾
SIGRAFLEX
Typical properties

Test method

Unit

APX2

APX

AP

A

Thickness
PurityAsh content

ASTM F104
ASTM D5373
ASTM C562

mm
in
%
%

0.25 – 1.52
0.01 – 0.06
≥ 98
≤20.35 – 1.00
0.014 – 0.04
≥ 98
≤20.25 – 2.00
0.01 – 0.08
≥ 98
≤20.25 – 2.00
0.01 – 0.08
≥ 95
≤5ASTM C599
ASTM D42398
ASTM D4327/D5542

g/m³
lb/ft³ppm
ppm

1.0 – 1.12
62.4 – 70.0
< 300
≤ 25
yes

0.7 – 1.00
43.7 – 62.4
< 300
≤ 25
yes

1.0 – 1.12
62.4 – 70.0
< 300
≤ 50
yes

1.0 – 1.12
62.4 – 70.0

%/h

≤1

≤3

≤2

DensitySulfur content
Leachable chloride content
Oxidation inhibitor

Weight loss in air
ASTM D7582
at 670°C (1238°F) (TGA) ¹⁾
LECO TGA¹ ⁾ Values for material thickness ≥ 0.5 mm and density ≥ 1.0 g/cm³

≤ 50
no

The Emissions Reducer | Typical properties of SIGRAFLEXSIGRAFLEX® APX2 –absolute top numbers
SIGRAFLEX APX2 foil was developed to meet rigorous
demands and is currently being used in a wide range ofsealing applications including:• Exhaust gasket rings• Exhaust gas recirculation (EGR) bearings• Gaskets for diesel particulate traps

Unmatched performance on the market
SIGRAFLEX APX2 flexible graphite foil meets the increasing
temperature requirements in modern exhaust systems. It
has extremely little weight loss due to oxidation even at hightemperatures (typical only 0.6 % per hour at 670 °C). Our proprietary oxidation inhibitors and production process allow theinhibitors to be incorporated into the structure of the graphite
foil, fully optimizing the oxidation resistance behavior. This isunmatched performance in the industry.
↑ SIGRAFLEX flexible graphite foil for automotive applications

APX2 1800 times tighter than mica
after 5 h at 500°C (932°F)
Loss of leak-tightness of nitrogen [ml/min]

Relative weight loss of SIGRAFLEX foils:
APX2 is “Best in Class”
1 h at 100 °C/212 °F
5 h at 500 °C/932 °F

Typical relative weight loss of SIGRAFLEX foils in air at 670 °C/1238 °F

100 —Weight loss [% / h]

10 —

2.0 —
1800 x

1—

1.5 —

0.1 —

1.0 —

0.01 —

0.5 —
0.0 —

0.001 —SIGRAFLEX APX2

Mica

APX

AP

APX2

25

26

SIGRATHERM® flexible graphite products
for automotive thermal management
SIGRATHERM products made of flexible graphite are designed
to meet the old and new challenges of mobility. Especiallynew powertrain systems require new concepts for thermal
management.
We use our experience we have made in the sealing businessto develop products suited to the demands of tomorrow – inparticular in the field of intelligent thermal management inorder to support CO₂ reduction, longer lifetime of components,
reduction in energy consumption, increased safety, andenhanced customer satisfaction.

↑ SIGRATHERM ePTS sheet manufactured from flexible graphite andencapsulated PCM, also available as pressed-to-size component

Thermal conductivity of SIGRATHERM HD foil
exceeds the performance of copper
Thermal conductivity [W/mK]

Density [g/cm³]500 —Intelligent thermal management
Wherever heat or cold has to be managed or stored under
extreme conditions within the vehicle, SIGRATHERM products
made of flexible graphite can provide solutions – due to theirhigh thermal conductivity and their fast response characteristiccompared to standard heat management systems. Graphite issuitable for heat and cold transport and dissipation as well as
for heat and cold storage.

—9

375 —

—6

250 —
—3

125 —
0—

—0
Aluminum

CopperSIGRAFLEX
foil

SIGRATHERM
HD foil

The thermal conductivity of SIGRAFLEX foils is strongly direction dependent (anisotropy) and can thus be regulated
Thermal conductivity of SIGRAFLEX foils as a function of density (at room temperature),
left: parallel to surface, right: perpendicular to surface
Thermal conductivity [W/mK]

Thermal conductivity [W/mK]

500 —

7—
6—

400 —

5—
300 —

4—

200 —

3—
2—

100 —

0.0

1—

0.2

Density [g/cm 3 ]

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

0.0

0.2

Density [g/cm 3 ]

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

The Emissions Reducer | Typical properties of SIGRATHERM

27↑ SIGRATHERM L sheet filled with PCM and powder GFG 5↑ SIGRATHERM graphite/copper composite and HD sheet

Graphite/PCM combinations for storage
When excessive heat or cold needs to be buffered and reused afterwards, very often Phase Change Materials (PCM)
come into play, despite their very low thermal conductivity.
A combination of graphite and PCM is here the best choice:
Graphite/PCM composite materials allow for production of highperformance heat and cold storage systems since graphite
increases the thermal conductivity of the PCM and leads tofaster reaction times. Another customer benefit is the temperature stabilization leading to increased passive security.

Customer specific material combinations
Due to our long-standing experience in the field of flexible
graphite, we are able to customize material characteristics
and combine different materials in order to provide the solution
for our customers’ needs. Just ask us!

No leakage, easy processing
Our proprietary material combination and process set-up
ensures that PCM material cannot leak out of the product –a well-known problem for a long time – and our products canbe easily cut-to-size or even pressed-to-size. Fusion enthalpy
and melting point can be adjusted by selecting the right phasechange material for the application.

Low density – reduced consumption
Reduction in energy consumption goes in line with weight
reduction of the entire vehicle: due to the low density offlexible graphite, solutions show a great potential to reduce
total weight. Flexible graphite demonstrates by far lower
densities than standard materials like aluminum or copper.

Properties of expanded graphite/PCM compound materials
Expanded graphite/PCM compound materials
Typical properties

Max. dimensions
DensityFlexural bending strength
E-modulus
Thermalconductivity
Heat storage capacity
Melting point*

Unit

ePCM28mm
ing/cm³
MPa/Psi
MPa/Psi
W/mK ||
W/mK _I
J/g

15 x 300 x 300
0.6 x 11.8 x 11.8
0.85
2.0 / 290
105 / 15,200
5.0
2.5140 (28 °C/82 °F)°C°F

28 – 65
82 – 149* Depending on the phase change material used

Slurry, GFG1200

L/PCM5PCM10

0.8

140 x 170 x 170
5.5 x 6.7 x 6.7
0.5

140 x 170 x 170
5.5 x 6.7 x 6.7
1.0

3.5
3.0
120 – 150 (adjustable)

100
7.0
80 – 100*220
5.0
60 – 80*

5 – 10241 – 216

5 – 10241 – 216

5 – 10241 – 216

28

Successful
together
We do more than just manufacture products. We pride ourselves on offering
intelligent and enduring solutions forour customers.
Our comprehensive know-how in different
areas of application make it possible.
By working in close conjunction withour customers and understanding their
specific requirements, we develop new,forward-looking solutions, as well as
responses to specific needs.
This has given rise to most of
our innovations, such as our
SIGRAFINE V2064 and V2142
material.

The Emissions Reducer | Successful together

29(Less e)mission possible
The recirculation of partially combusted exhaustgases reduces fuel consumption and emissions.
This makes an important contribution to moreenvironmentally friendly mobility. At the same time,
the higher temperatures needed in this functionpose significant challenges for the used parts.
With this in mind, we developed a material for use invalves for exhaust gas recirculation systems that isprecisely tailored to these ambient conditions: ourspecialty graphite SIGRAFINE V2064. It is extremely
oxidation resistant and stable over long periods evenat temperatures up to 600 °C.
This product is our reaction to a stated need on thepart of our automotive customers. Beyond this, ouruse of pressed-to-size (PTS) technology allows us todeliver parts that are almost perfectly matched with
their final form, reducing the need for post-production machining. This saves time and money – and is agood example of our intelligent, application-focused
solutions.

30

Smart
Solutions
Be it materials, components or production
processes, we focus our thinking and actions on
the customer and keep an eye on the big picture.
Our solutions already anticipate the future today.
The following examples show a selection of ourunique product range.

Mobility• Lightweight components and structural parts
based on fiber-reinforced composites for automotive and aerospace manufacture• Graphite anode material for lithium-ion batteries
in electric vehicles• Carbon-ceramic brake disks for sports cars andluxury sedans

Energy• High-temperature solutions based on specialty
graphites and fiber materials for the photovoltaic
industry• Carbon fiber materials for rotor blades• Gas diffusion layers for fuel cells• Systems for more efficient heat exchange andheat recovery• Carbon fibers for pressurized gas containers

Digitization• Carbon, graphite, and CFC components forpolysilicon and monocrystal pulling in thesemiconductor industry• High precision, coated graphite carriers for the
production of LEDs

→ State-of-the-art green production withthe world’s largest isostatic press

SGL Carbon

31

SGL Carbon
We are leaders in the development and manufacture of products based on carbon, graphite,
carbon fibers, and fiber-reinforced composites.
In partnership with our customers, we develop
intelligent, trendsetting, and sustainable
solutions that deliver a clear benefit.
With our in-depth material, engineering, andapplication know-how, we make a substantial
contribution to the major future topics mobility,
energy, and digitization.

Contact
Europe / Middle East / Africa
SGL CARBON GmbH
Drachenburgstrasse 1
53170 Bonn/Germany
mechanical-europe@sglcarbon.com
Americas
SGL CARBON LLC
900 Theresia Street
PE 15857 St. Marys / USA
mechanical-americas@sglcarbon.com
Asia / Pacific
SGL CARBON Far East Ltd.
151 Huan Chen Dong Lu
Shanghai Fengpu Industrial Development Zone
201 401 Fengxian/China
mechanical-asia@sglcarbon.com®

registered trademarks of SGL Carbon SE

This information is based on our present stateof knowledge and is intended to provide generalnotes on our products and their uses. It should
therefore not be construed as guaranteeing
specific properties of the products describedor their suitability for a particular application.
Any existing industrial property rights must be
observed. The quality of our products is guaranteed under our «General Conditions of Sale».

10 2018 / 1 E Printed in Germany

Graphite Materials & Systems
SGL CARBON GmbH
Soehnleinstrasse 865201 Wiesbaden / Germany
www.sglcarbon.com/gms