products manufactured from flexible graphite...

Products Manufactured from Flexible Graphite Foil

Expanded Graphite

SIGRAFLEX®

Broad Base. Best Solutions.

S I G R A F L E X ®


SGL Group – The Carbon CompanyOne of the word�s leading manufacturers of carbon-based products Page 4

Sealing Products Made fromExpanded Natural Graphite Page 5

Production and CharacteristicProperties Page 6

Product Designations Page 7

Product Overview Page 8

Mechanical and PhysicalProperties of

� SIGRAFLEX Foils Page 9

� SIGRAFLEX Sheets, Unreinforced Page 11

� SIGRAFLEX Sheets, Reinforced Page 14

Approvals and Certificates Page 17

Chemical Resistance of SIGRAFLEX Page 18

Market Approach and Customer Service Page 20

Our Expertise is Your Advantage Page 21

Processing of

� SIGRAFLEX Foils Page 22

� SIGRAFLEX Sheets Page 23

Advice on Application for Stuffing Box Packings Page 24

Advice on Application for Gaskets Page 25

High-Quality SIGRAFLEX Gasket Systemsand Fields of Application Page 26

Recommended SIGRAFLEX Products forVarious Applications Page 27

Commonly UsedConversion Factors Page 28

Definitions of Gasket Factors 1

Contents

3

S G L G r o u p – T h e C a r b o n C o m p a n y

4

SGL Group – The CarbonCompany – is one of theworld's leading manu-facturers of carbon-based products. Ourcomprehensive portfolioranges from carbon and graphite products to carbon fibers andcomposites.

Due to their unique properties,carbon and graphite areindispensable materials for manyindustries, such as the steel,aluminum, semiconductor,energy, automotive, aerospace,sporting goods, chemical andenvironmental protectionindustries.

We constantly aim to improveour products and services to meet our customers’ specificrequirements. Our company-wide SGL Excellence Initiativeand Six Sigma, which we apply as core methods, are state-of-the-art tools for bringingcontinuous improvement to allareas, including our processes,engineering know-how, productdevelopment and innovation, as well as the expertise of ourworkforce. We keep in closecontact with our customers,suppliers and logistic partners to help achieve this.

Many decades of experience in handling carbon materials of all kinds and also intensivedevelopment work haveenabled us to optimize ourmanufacturing processes at ourglobal production sites inEurope, North America andAsia.

E x p a n d e d G r a p h i t e

5

SIGRAFLEX®

Sealing Products for aClean Environment

Our Business Line ExpandedGraphite manufactures flexiblegraphite foils and graphitesealing sheets from expandedgraphite. They are marketedunder the SIGRAFLEX®

trademark to the automotiveand industrial sealing industryworldwide. SIGRAFLEX isavailable in all majorindustrialized countries. All standard SIGRAFLEX prod -ucts are available from stock.

We carry out constant productmonitoring using non-destructivemethods during manufacturingoperations and also conductrandom checks involving speci -fied analytical processes.Needless to say that our qualitymanagement system is certifiedunder the relevant standards.

Thanks to their high quality, our products can be used even in the most demandingapplications. By offeringproducts of guaranteed quality,we can enter into long-termcooperation agreements in a spirit of mutual trust.

Our technical and marketingstaff maintain close contactswith the company’s customers,such as plant constructors and operators of complexplants in the chemical andpetrochemi cal industries,power stations and foundries.Besides choosing the rightproducts for particularapplications, they are alsoavailable to carry out the design calculations for seals.

SEALING PRODUCTS MADE FROM EXPANDED NATURAL GRAPHITE

SIGRAFLEX® sealing sheets and gaskets

Sabic Polyolefine GmbH productionplant at the Gelsenkirchen site


6

PRODUCTION ANDCHARACTERISTICPROPERTIES

The raw material used in theproduction of SIGRAFLEX isnatural graphite flake with well-ordered crystalline struc -tures. We select the highest-quality raw materials from the various grades availablearound the world. Graphiteintercalation compounds areproduced from the naturalgraphite flakes. The thermaldecomposition (expansion) of these compounds leads to the formation of loose “worms“ of pure graphite, which arecompressed into foils withoutbinder or filler. The resultingalignment of the graphiteparticles and their planarstructures produces a highdegree of directional depen -dence (anisotropy) in theproperties. The high purity ofSIGRAFLEX derives from theraw materials used, as well as from the quality of themechanical, chemical andthermal purification processes.

Graphite sheets are manu fac -tured in various forms, namelyunreinforced, impregnated orreinforced. A distinction ismade between sheets rein -forced with perforated sheetsteel and those using smoothstainless steel foil reinforcement.The special impregnation ofour sheets ensures scratchresistance, antistick behavior,greater strength and lower gas permeability.

Characteristic Properties

� Low permeability to gases and liquids

� Flexibility, soft texture

� Resistance to most media

� Absence of health hazard;asbestos-free

� Environmental compatibility

� Suitability for use attemperatures ranging from -250°C up to approx. 3000°C depending oninstallation and serviceconditions:– in an inert atmosphere

up to approx. 800°C (limits imposed by metalreinforcement to beobserved)

– for applications in air at more than approx.400°C, users shouldrequest our advice

� Absence of binders meansno ageing or embrittlement

� Long-term stability ofcompressibility andrecovery over a widetemperature range

� No cold or warm flow up to maximum permissiblegasket pressure

� High residual stress

� Properties highlyanisotropic, particularly inrespect of electrical andthermal conductivity

� Resistance to radiation

� Very good resistance tothermal shock

� Ease of cutting or punching

250 µm

250 µm

Natural graphite flake

Expanded graphite “worm“

Flexible graphite foil


7

PRODUCTDESIGNATIONS

Type

Thicknessin hundredths of a mm

Bulk densityof graphite in tenths ofg/cm3

Ash content

Reinforcements(in V types only)

Upgrading

Typical product designation

S I G RA F L E X V 200 10 C 2 I

F FoilL SheetV Reinforced sheet

Z <_ 0.15 %E <_ 1.00 % C <_ 2.00 %D <_ 4.00 %APX <_ 2.00 % advanced

antioxidation technology

1 0.2 mm perforated steel sheet,DIN material no.1.0330

2 0.1 mm perforated stainlesssteel sheet, ASTM material no. 316 (L)

3 0.05 mm stainless steel foil, ASTM material no. 316 (L), unbonded

4 0.05 mm stainless steel foil,ASTM material no. 316 (L), bondedFor other reinforced materials, users should request our advice

E Sheet type EMAILI ImpregnationS Self-adhesive finishX Corrosion inhibitorI-P TA Luft (German Clean

Air Act) grades


8

Product Overview Table 1

Product Type Thickness Width Length Graphite[mm] [m] [m] bulk density

[g/cm3]

Rolls*)

F.....C 0.35 to 1.0 0.5/1.0 50/100 0.7 to 1.3 F.....D 0.35 to 1.0 0.5/1.0 50/100 0.7 to 1.3F.....E 0.35 to 1.0 0.5/1.0 50/100 0.7 to 1.3

SIGRAFLEX F.....APX 0.1 to 1.0 0.5/1.0 50/100 0.7 to 1.3FOIL F.....Z 0.1 to 1.0 0.5/1.0 50/100 0.7 to 1.3

F.....ZX 0.5 0.5 50 0.7F.....CS/ZS 0.5/1.0 0.5 25/50 1.0

Sheet L.....Z 1.0/1.5/2.0 1.0 1.0 1.0

SIGRAFLEX L.....C 1.0/1.5/2.0 1.0 1.0 1.0 BASIS

Homogeneous, free of adhesives and binders

Impregnated sheetL.....CI impregnated 1.0/1.5/2.0 1.0 1.0 1.0

SIGRAFLEXSTANDARD

Homogeneous, free of adhesives and binders

Reinforced sheets

SIGRAFLEX V.....C4 0.5 to 3.0 1.0 1.0 1.0 ECONOMY

Stainless steel foil reinforcement, 316 (L), 0.05 mm, bonded

SIGRAFLEX V.....C2I impregnated 1.5/2.0/3.0 1.0/1.5 1.0/1.5 1.0UNIVERSAL

Perforated stainless steel sheet reinforcement, 316 (L), 0.1 mm, unbonded

SIGRAFLEX V.....Z3I impregnated 1.0 to 4.0 1.0/1.5 1.0/1.5 1.1HOCHDRUCK

Multiple stainless steel foil reinforcement, 316 (L), 0.05 mm, unbonded

SIGRAFLEX V.....Z3E 2.0/3.0 1.0 1.0 1.1EMAIL

Two stainless steel foil reinforcements, 316 (L), 0.05 mm, unbonded

SIGRAFLEX V.....C2I-P impregnated 1.6/2.0/3.0 1.0/1.5 1.0/1.5 1.0UNIVERSALPRO Perforated stainless steel sheet reinforcement, 316 (L), 0.1 mm, unbonded

SIGRAFLEX V16010C3I 1.6 Gaskets with inner eyelet 1.1SELECT

Two stainless steel foil reinforcements, 316 (L), 0.05 mm, unbonded

SIGRAFLEX V.....Z3I-P impregnated 1.5 to 4.0 1.0/1.5 1.0/1.5 1.1HOCHDRUCKPRO Multiple stainless steel foil reinforcement, 316 (L), 0.05 mm, unbonded

SIGRAFLEX V.....Z2MF 1.6/2.0/3.0 1.0 1.0 1.1MF

Perforated stainless steel sheet reinforcement, 316 (L), 0.1 mm, unbonded

Other dimensions, densities and reinforcements on request *) Foil tapes are available at >_ 4.0 mm width

TALuft

TALuft

TALuft

TALuft


9

MECHANICAL ANDPHYSICAL PROPERTIESOF SIGRAFLEX FOILS

SIGRAFLEX products areavailable with standard bulkdensities of 0.7 to 1.3 g/cm3.The change in bulk density asa function of the pressureapplied in the compressionprocess is shown in Figure 1.Deformation consists of twodistinct components, namely:

• irreversible or plasticdeformation and

• reversible or elasticdeformation.

The curve marked “pressurereduced“ in Figure 1 describesthe irreversible deformation ofSIGRAFLEX FOIL. The differencein density between the linesmarked “pressure applied“ and“pressure reduced“ is due tothe elastic deformation compo -nent. This component is ofoverriding importance in thesealing action of the graphitefoil, for example. As the de -gree of compression rises, theindividual graphite crystals areincreasingly oriented within theplane of the sheet. As a result,the anisotropy of the propertiesbecomes more pronounced:see Figures 2 to 5.

In Table 2, the properties of the high-purity foil F.....10Z areillustrated by way of examplefrom the large number of foiltypes available. A more detaileddescription is given in the datasheet SIGRAFLEX® FOIL.

The thermal stability of graphitefoil has a great impact on thereliability and service life ofseals made of it. Figure 10shows the im proved oxidationresistance of SIGRAFLEX APXfoil compared with commer -cially available graphite grades.

SIGRAFLEX FOIL Characteristic data for a graphite bulk density of 1.0 g/cm3

Table 2

Product type F.....10Z

Permeability coefficient for airthrough plane (DIN 51925) cm2/s < 5 · 10-5

Thermal stability Can be used from -250°Cup to approx. 3000°C(in protective gas)

Sublimation temperature °C > 3000

Ash content (DIN 51903) % <_ 0.15

Chloride content (DIN 28090-2) ppm <_ 10

Tensile strength N/mm2 >_ 4

Elongation at break % >_ 1

Residual stress (DIN 52913) N/mm2 >_ 48

Specific heat (20°C) k J/(kg · K) 0.7

Coefficient of thermal expansion (20 to 1000°C)

in plane 10–6/K approx. 1

through plane 10–6/K approx. 30

Shore hardness (D) approx. 30

Coefficient of friction at 20°C in airagainst steel, peak-to-valley height <_10 µm 0.1

Gasket pressure (N/mm )1

02 5 10 20 50 1000

1.0

1.5

2.0

2.5

Bulk

den

sity

(g/c

m )3

“pressure applied“

1002

500200

“pressure reduced“

Fig. 1:

Bulk density ofSIGRAFLEX with aninitial bulk density of 1.0 g/cm3 as afunction of the gasketpressure applied at a specific time(“pressure applied“)and that appliedpreviously (“pressurereduced“)


10

Temperature (°C) 1000 20000

100

1000

in plane10

Resis

tivity

(Ωμm

)

through plane

Temperature (°C) 1000 20000

100

150

Ther

mal

con

duct

ivity

(W/K

·m)

in plane

50

through plane

Fig. 2:

Resistivity as a function oftemperature, bulk density 1.0 g/cm3

Fig. 3:

Thermalconductivity asa function oftemperature, bulk density 1.0 g/cm3

OTHER PHYSICALPROPERTIES

Bulk density (g/cm ) 3

0.50 1.00 1.500

200

400

600

800

Resis

tivity

(Ωμm

)

through plane

in plane

Bulk density (g/cm3)0.50 1.00 1.500

100

200

300

400

Ther

mal

con

duct

ivity

(W/K

·m)

through plane

in plane

Fig. 4:

Resistivity as a function of bulk density

Fig. 5:

Thermalconductivity as a function of bulk density


11

MECHANICAL ANDPHYSICAL PROPERTIESOF UNREINFORCEDSIGRAFLEX SHEETS

The SIGRAFLEX BASIS sheetscontaining no additives or rein forcements and bearing the designations L.....C andL.....Z have the same propertiesas foils F.....C and F.....Z.Guideline material data onSIGRAFLEX BASIS andSIGRAFLEX STANDARD(impregnated) are contained in Table 3. Impregnated sheetsdiffer from unimpregnatedsheets in having better imper -mea bility, better handlingproperties and antistick surfaces.

Figure 6 shows the compressionbehavior of SIGRAFLEX BASISwith a bulk density of 1.0 g/cm3

and a material thickness of 2.0 mm. A distinction has to be drawn between the curvebranches “under pressure“ (line k) and “after reduction inpressure“ (linies r). Dependingon the pressure applied before -hand, the material recoversalong one of the “r“ lines afterthe pressure is reduced.

Typical levels of recovery are10 % of the residual thicknessafter previous compressivestress (for bulk density of 1.0 g/cm3). If the bulk densityis higher, the percentage re co very decreases.

The “recovery“ is synonymouswith the “elastic deformation“ of the material. The differencebetween the initial thickness ofthe material and its thicknessafter reduction in pressure is its “plastic deformation“. Bothvalues are plotted in Figure 7under conditions of increasinggasket pressure for a materialhaving a bulk density of 1.0 g/cm3 and containing noadditives.

Compared with other sealingmaterials, SIGRAFLEX is soft andrelatively easy to compress. Thisenables the material to adaptwell to the sealing surface, forinstance. Over long serviceperiods SIGRAFLEX displays nonotable changes in its propertiescompared with other sealingmaterials. Figure 8 shows thedecline in gasket pressure invarious sealing materials duringtheir service life. Figure 9 showstypical leakage rate curves ofvarious materials.

Disparities in compression have an effect on the material’simpermeability. The leakagerate declines at high gasketpressure when the installedSIGRAFLEX gaskets have a highbulk density in their compressedstate. One major advantage ofthis material is that the sealingeffect is retained even when thegasket pressure is reduced.


12

Gasket pressure (N/mm )2

2000

10

Com

pres

sibili

ty a

nd re

cove

ry (%

)

1

20

30

40

50

2 5 10 20 50 100

Compressibility

Recovery

Field ofplasticdeformation

Gasket pressure (N/mm )2 1000

k

1.0

Gas

ket t

hick

ness

(mm

) 2.0

10

r1.2

1.4

1.6

1.8

20 30 40 50 60 70 80 90

50

100

60

70

80

90

Thic

knes

s re

lativ

e to

the

initi

al th

ickn

ess

(%) Fig. 6:

Compressioncurve k andrecovery curves r as determined on gaskets*)

Fig. 7:

Recovery as apercentage of theinitial thickness of SIGRAFLEXgaskets*) plottedagainst precedinggasket pressure(plastic defor ma -tion = compres -sibility - recovery)

*) SIGRAFLEX BASIS L20010Z

Unreinforced SIGRAFLEX sheets. Characteristic data for 2.0 mm thick sheets Table 3

Product type

Graphite, bulk density g/cm3

Graphite, ash content (DIN 51903) %Chloride content (DIN 28090-2) ppm

Compression factors (1), (2) (DIN 28090-2)

• Compressibility at 20°C �KSW %• Recovery at 20°C �KRW %• Hot creep during operation �WSW %• Recovery at 300°C �WRW %

Compressibility (ASTM F36A-66) %Recovery (ASTM F36A-66) %

STANDARDL20010CI

1.0<_ 2.0<_ 50

40 to 503 to 5< 4

3 to 4

40 to 5010 to 15

BASISL20010Z

1.0<_ 0.15<_ 20

40 to 503 to 4< 3

3 to 4

40 to 5010 to 15

(1) �KSW Gasket compression set under a pressure of 35 N/mm2

�KRW Gasket recovery after reduction in pressure from 35 N/mm2 to 1 N/mm2

�WSW Gasket creep compression under a pressure of 50 N/mm2 at 300°C after 16 h�WRW Recovery after reduction in pressure from 50 N/mm2 to 1 N/mm2

The percentage changes in thickness of �KSW, �KRW, �WSW and �WRW are relative to the initial thickness of the gasket

(2) Gasket factors in accordance with DIN E 2505, DIN 28090, DIN 52913 and DIN EN 13555 for the various sheet materials can be found in our separate product data sheets


13

Duration of test (h)

Leak

age

rate

l

10

Flexible graphite (200°C)

1 100 1000 10 000

Elastomer-bondedfiber gasket (200°C)

Standard PTFE (150°C)

Fig. 9:

Change in the leakage rate of varioussealing materials in long-term testing,measured in accordance with DIN 28090-1 and -2 in flange PN 40DN 40. The testing temperature for thismaterial was set at only 150°C owingto the hot flow of PTFE

Fig. 10:

Comparison between the thermalstability of a commercially availablegraphite foil and that of SIGRAFLEXAPX foil with advanced oxidationresistance

Duration of test (h)

0

Gas

ket p

ress

ure

(%)

10

Flexible graphite (200°C)

20

40

60

80

100

1 100 1000 10 000

Elastomer-bonded fiber gasket (200°C)

Standard PTFE (150°C)

Fig. 8:

Change in the gasket pressure ofvarious sealing materials during long-term testing, measured in accordancewith DIN 28090-1 in flange PN 40DN 40. The testing temperature for this material was set at only 150°C. The flexible graphite retains its highresidual stress even after exposure toload for approximately 1 year

Temperature in °C

Mas

s lo

ss in

air

(%/h

)

Commercially available grade

APX grade

Type: F05010Ash content: ≤ 2 %

~150°C

400 500 600 700 8000.001

0.01

0.1

1

10

100


14

MECHANICAL ANDPHYSICAL PROPERTIESOF REINFORCEDSIGRAFLEX SHEETS

Reinforced sheets of variousversions are illustrated in Figure14. Typical data on these sheetsare compared in Table 4. Theminimum requirements specifiedin DIN 28091-4 are surpassedby sheets with metal reinforce -ment. Detailed particulars aregiven in the relevant data sheets.The maximum permissible gasketpressures on reinforced sheetsare illustrated in Figure 13.With gaskets it is important tonote the width-to-thickness ratio;as it increases, so too does themaximum permitted pressure.The curves shown by way ofexample are for materials 2 mmthick.

Figure 11 shows the typicalcom pressibility and recovery of SIGRAFLEX HOCHDRUCK for reinforced sheet types in comparison with those ofunreinforced sheets.

SIGRAFLEX has an extra -ordinary stability in vibratingmachinery. This is illustrated by the following example:A gasket pressure of 50 N/mm2

reduces the initial thickness ofSIGRAFLEX UNIVERSAL byabout 60 %. After this pre limi -nary stress the material issubjected to vibrating stressesranging from 10 to 50 N/mm2.Its power of recovery is retainedeven after 107 stress alternationcycles, when no more than very slight creep compression is observed (see Figure 12).

Gasket pressure (N/mm )2100 2000

k

1.1

Gas

ket t

hick

ness

(mm

)

1.2

1.3

1.4

1.5

1.6

1.7

1.8

1.9

2.0

1.050 150

r

r

j

Fig. 11:

Compression curve k and variousrecovery curves r as determined ongaskets fabricated from SIGRAFLEX HOCHDRUCK V20011Z3I.For purposes of comparison, thecompression line j for SIGRAFLEX BASISis included from Figure 6

Fig. 13:

Max. permissible gasket pressure forgaskets made from reinforcedSIGRAFLEX sheets of 2 mm thickness,as determined at 300°C in accordancewith DIN 28090-1

Max

. per

miss

ible

gas

ket p

ress

ure

@N/m

m2 #

Width-thickness ratio

50

100

150

200

250

300

0 2 4 6 8 10 12 14

SIGRAFLEXSELECT

SIGRAFLEX MF

SIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSAL PRO

SIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCK PRO

Graphite gasket with high adhesive and /or binder content

Number of stress cycles 100

Recovery

0

60

65

70

Resid

ual t

hick

ness

as

a pe

rcen

tage

of i

nitia

l thi

ckne

ss

102 104 106 108

stress reduced to 10 N/mm2

stress increased to 50 N/mm2

Stress cycles

f = 50 Hzs max = 50 N/mm2

s min = 10 N/mm2

Fig. 12:

Behavior ofSIGRAFLEXUNIVERSAL undervibrating stress


15

Fig. 14:

Sketches showingthe construction ofsheets reinforcedwith metal foils

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SIGRAFLEX HOCHDRUCKHigh-integrity multilayer laminate,impregnated graphite, s/s foilsSIGRAFLEX HOCHDRUCK PROalso for applications subject to TA Luft

SIGRAFLEX MFHigh-integrity laminate made ofgraphite, stainless steel and PTFE; max. requirements for sealability (TA Luft), safety, chemical resistance and process hygiene

SIGRAFLEX ECONOMYReinforced with bonded s/s foil

SIGRAFLEX SELECTHigh-integrity s/s foil reinforcement,impregnated gasket with inner eyeletfor applications subject to the German TA Luft (Clean Air Act)

SIGRAFLEX UNIVERSALPerforated s/s sheet reinforcement,impregnatedSIGRAFLEX UNIVERSAL PROalso for applications subject to the German TA Luft (Clean Air Act)

The flexible graphite is shown in white color.The metal foilsare shown ashatched surfaces.The PTFE foils areshown as dottedsurfaces.


16

Reinforced SIGRAFLEX sheets. Characteristic data for 2.0 mm thick sheets*)

Product type

Graphite, bulk density g/cm3

Graphite, ash content (DIN 51903) %Chloride content (DIN 28090-2) ppm

Reinforcing sheet, numberReinforcing sheet, thickness mmReinforcing sheet, type

Reinforcing sheet, ASTM material no.

Compression factors (1), (2) (DIN 28090-2)

• Compressibilty at 20°C �KSW %• Recovery at 20°C �KRW %• Hot dreep during operation �WSW %• Recovery at 300°C �WRW %

Compressibility (ASTM F36A-66) %Recovery (ASTM F36A-66) %

ECONOMYV20010C4

1.0<_ 2.0<_ 50

10.05

smooth

316(L)

35 to 453.5 to 4.5

< 53 to 4

40 to 5010 to 15

UNIVERSALV20010C2IUNIVERSAL

PROV20010C2I-P

1.0<_ 2.0<_ 50

10.1

perforated

316(L)

35 to 454 to 6< 5

3 to 6

30 to 4515 to 25

SELECTV16010C3I

1.0<_ 2.0<_ 50

20.05

smooth

316(L)

30 to 403 to 5< 2

2 to 4

30 to 4010 to 15

HOCHDRUCKV20011Z3I

HOCHDRUCKPRO

V20011Z3I-P

1.1<_ 0.15<_ 20

30.05

smooth

316(L)

30 to 404 to 5< 4

3 to 4

30 to 4015 to 20

MFV20011Z2MF

1.1<_ 0.15<_ 20

10.1

perforated

316(L)

25 to 353 to 5< 4

3 to 5

25 to 3515 to 20

(1) �KSW Gasket compression set under a pressure of 35 N/mm2

�KRW Gasket recovery after reduction in pressure from 35 N/mm2 to 1 N/mm2

�WSW Gasket creep compression under a pressure of 50 N/mm2 at 300°C after 16 h�WRW Recovery after reduction in pressure from 50 N/mm2 to 1 N/mm2

The percentage changes in thickness of �KSW, �KRW, �WSW and �WRW are relative to the initial thickness of the gasket(2) Gasket factors in accordance with DIN E 2505, DIN 28090, DIN 52913 and DIN EN13555 for the various sheet materials

can be found in our separate product data sheets*) SIGRAFLEX SELECT in 1.6 mm thickness

Table 4


17

The technical world we live in isgrowing increasingly complex.To minimize risks, standards arebeing agreed on both nationaland international levels andstatutory regulations issued.

For many years our materialshave been subjected to wide-ranging tests as specified in the current regulations. Therespective product reports,approvals and certificates arelisted below. SIGRAFLEXmaterials comply with manydifferent standards and statutory regulations. Thisrepresents a safeguard for our customers.

• BAM1) reports on testsconducted to determinereactivity with gaseous and liquid oxygen. SIGRAFLEX FOILSIGRAFLEX STANDARD SIGRAFLEX ECONOMYSIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSALPROSIGRAFLEX SELECTSIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCKPROSIGRAFLEX MF

• BAM reportson tests conducted todetermine the chemicalstability of ethylene oxide and propylene oxide.SIGRAFLEX UNIVERSALSIGRAFLEX HOCHDRUCK

• Blow-out resistance (TÜV)SIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSALPROSIGRAFLEX SELECTSIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCKPROSIGRAFLEX MF

• DVGW2) registration reports for gas supplySIGRAFLEX FOILSIGRAFLEX STANDARDSIGRAFLEX ECONOMYSIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSALPROSIGRAFLEX SELECTSIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCKPROSIGRAFLEX MF

• DVGW test certificates fordrinking waterin accordance with KTW3)

SIGRAFLEX FOILSIGRAFLEX STANDARD

• Fire safety (API 607 and/or BS 6755-2)SIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSALPROSIGRAFLEX SELECTSIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCKPROSIGRAFLEX MF

• Germanischer LloydSIGRAFLEX UNIVERSALSIGRAFLEX HOCHDRUCK

• TA Luft (VDI 2440)(German Clean Air Act)SIGRAFLEX UNIVERSALPROSIGRAFLEX SELECTSIGRAFLEX HOCHDRUCK*)

SIGRAFLEX HOCHDRUCKPROSIGRAFLEX MF

• Test report of the Baden-Württemberg Department of IndustryOffice for Chemical andTechnical Testing: Contact ofSIGRAFLEX graphite foil withfoodstuffs

• TRD 401 (manhole gaskets)SIGRAFLEX HOCHDRUCK

• United States Coast GuardSIGRAFLEX UNIVERSALSIGRAFLEX HOCHDRUCK

1) BAM = Bundesanstalt für Ma terial prüfung (Federal Institute for Materials Testing), Berlin

2) DVGW = Deutscher Verein der Gas- und Wasserfachmänner(German Association of Gas andWater Operatives)

3) KTW = Kunststoff-Trinkwasser -empfehlung des Bundesgesundheits -ministeriums (Federal GermanMinistry of Health recommendationfor max. levels of plastics in drinkingwater)

*) For raised-face flanges with inner eyelet, for tonque-and-groove flanges without inner eyelet

APPROVALS ANDCERTIFICATES


18

CHEMICAL RESISTANCE OFSIGRAFLEX

Based on natural graphite,SIGRAFLEX products areresistant to most media up tohigh temperatures.

Unreinforced SIGRAFLEX isresistant to inorganic andorganic acids and bases,solvents, waxes and oils, butnot to agents with a powerfuloxidizing action, such as highly concentrated nitric acid,highly concentrated sulfuricacid (oleum), nitrating acid and chloric acid, or molten saltswith a powerful oxidizingaction. Where no details ofconcentration and temperaturesare given for the media listed, it can be assumed that theconcentration is 100 % andthat the temperature is boilingpoint or melting point.

The data given in Table 5should always be checked bythe user since the limits to theuse of SIGRAFLEX seals alsodepend on the design features,internal pressure, temperatureand the gasket pressure.Resistance to highly aggressivesubstances not listed needs tobe ascertained. SIGRAFLEXusers should request advicefrom us in such circumstances.

The resistance of reinforcedSIGRAFLEX gaskets is usuallygoverned by the reinforcingmetal sheets or foils used.Table 5 makes no reference tothe stability values for steel orPTFE. The stainless steel withASTM material no. 316 (L)used in unbonded SIGRAFLEXsheets (UNIVERSAL, UNIVERSALPRO, SELECT, HOCHDRUCK, HOCHDRUCKPRO and EMAIL)has proved very successful inthe chemical industry becauseof its good stability. Uponrequest we also provide a listof chemical media showing the resistance of graphite foil,stainless steel and PTFE. Onbonded sheets (ECONOMY)particular attention must bepaid to the stability of the ad -hesive, especially at elevatedtem peratures.

As is the case with other gas ket materials, it is essentialfor chemical stability tests onSIGRAFLEX to be carried outwith the material in a com press - ed state (see DIN 28090-3).


19

Table 5Chemical resistance of SIGRAFLEX FOIL (pure graphite)***)

Alcohols

e.g. � Ethyl alcohol� Glycol� Isopropyl alcohol� Methyl alcohol

Aldehydes

e.g. � Acetaldehyde� Benzaldehyde� Formaldehyde

Ethers

e.g. � Diethyl ether� Dioxane� Diphenyl ether� Methyl ethyl ether

Esters

e.g. � Acetic acid amyl ester� Acrylic acid ethyl ester� Ethyl butyl ester

Amines

e.g. � Aniline� Diethylamine� Triethylaminoethanol

Oxidizing molten salts

� Potassium chlorate� Potassium nitrate� Sodium peroxide

Ketones

e.g. � Acetone� Ethyl methyl ketone� Methyl isobutyl ketone

Hydrocarbons

e.g. � Benzene� Ethylene� Iso-octane� Propane� Propylene� Styrene� Xylene

Alkalis

e.g. � Ammonia solution� Caustic potash solution� Caustic soda solution� Potassium hydroxide up to

400°C� Sodium hydroxide up to

400°C

Other inorganic media

� Bleach liquor� Hydrazine� Sulfur

Technical mixtures

e.g. � Heat transfer oils� Hydraulic oils� Motor oils� Paint thinner� Paraffin oil (kerosene)� Petrol (gasoline)� Transformer oil

Other organic media

e.g. � Acrylonitrile� Carbon disulfide� Dimethyl sulfoxide� Epichlorohydrine� Mercaptans� Nitrobenzene� Phenol� Silicones� Siloxanes� Thionyl chloride

� Potassium up to 350°C� Silver� Tin� Wood’s alloy� Zinc

Organic acids

e.g. � Acetic acid� Acrylic acid� Formic acid� Hexachlorphenyl acetic

acid� Maleic acid� Monochloroacetic acid� Phenylacetic acid� Phthalic acid� Stearic acid� Sulfonic acid� Tartaric acid� Trichloroacetic acid

Acids

e.g. � Aqua regia� Boric acid� Bromic acid� Chromosulfuric acid

up to 20 %� Hydrochloric acid � Hydrofluoric acid� Nitrating acid� Nitric acid

up to 65 %� Nitric acid

> 65 %� Oleum� Perchloric acid

up to 20 % � Phosphoric acid� Sulfuric acid

up to 70 %� Sulfuric acid

70-100 %up to 100°C

� Sulfurous acid

Gases/vapors

e.g. � Air, at more than 400°Csubject to prior consultation

� Ammonia� Bromine� Carbon dioxide up to

approx. 600°C� Carbon monoxide� Chlorine dioxide� Chlorine, dry� Chlorine, moist at > 30°C� Fluorine� Hydrogen bromide� Hydrogen chloride� Hydrogen fluoride� Hydrogen sulfide� Nitrogen� Nitrogen dioxide up to

approx. 600°C**)

� Nitrous oxide**)

� Oxygen up to approx.350°C

� Phosgene� Sulfur dioxide� Sulfur hexafluoride� Sulfur trioxide

Aqueous salt solutions

e.g. � Borates� Bromides� Carbonates� Chlorides� Chromates,

20 % conc.� Fluorides� Iodides� Nitrates� Nitrites� Phosphates� Sulfates

Metal melts

e.g. � Aluminum� Copper� Gold� Iron� Lead� Magnesium� Mercury

Halogenated hydrocarbons

e.g. � Carbon tetrachloride� Chlorobenzene� Chloroform� Frigen products

Non-oxidizing molten salts

� Borate, soda, potash � Calcium chloride� Potassium hydrogen sulfate

� resistant� not resistant� reservedly resistant

*) without oxygen ingress**) dry gases only***) The resistance of

reinforced SIGRAFLEXgaskets can be check edin our TechnicalInformation “SIGRAFLEXGaskets – Resistance toChemical Media”


20

Seals and Sheetsmade fromSIGRAFLEX®

Technical Trader

SIGRAFLEX®

FoilsSheetsSealings

Seals and Sheets made fromSIGRAFLEX®

LegislationStandardization

Regulation

SealManufacturer

WholesaleTrader

MARKET APPROACH AND CUSTOMER SERVICE

R & DTest Facilities

Product Quality

Product Availability

Customer Service

Technical Support & Advice

Training

END USERS AND PLANT CONTRACTORS IN THE PROCESS INDUSTRIES:

Chemical and Petrochemical Industries,Power Stations, Pulp & Paper, Gas, Machine Construction

Expanded Graphite


21

OUR EXPERTISE IS YOUR ADVANTAGE

High Performance and Safety in Sealing Systems

Our Expertise

Analytical Lab• R & D in sealing systems• Comprehensive seal testing• Continuous product

improvement

Excellent Product Quality• Selected raw materials • Low leakage rates• High blow-out resistance• Superior oxidation resistance• Fire safety

Worldwide Product Availability• Available from stock

in various dimensions • For universal use over a

wide range of applications

Service• Technical support in sealing

selection and installation• Training on fluid sealing-

related issues • Worldwide sales offices• Advice on seal design

and calculation

Your Advantage

• Outstanding productreliability

• Long service life

• Skilled maintenance staff

• Less downtimes

• Saving of resources

• Reduced total costs of ownership

� EnvironmentalProtection

� Safety and PlantAvailability

� Cost Savings

Enhances


22

PROCESSING OFSIGRAFLEX FOILS

Our semi-finished SIGRAFLEXproducts are processed invarious branches of industryinto a wide variety of seals and other components by the

techniques summarized below.The soft material is easy topunch and cut with standardtools.

Packing rings

Crinkle tapes

Spiral-wound graphite gaskets

Gaskets

Graphite outer layers forKammprofile gaskets

ElectrodesHeating elementsLinings

Self-adhesive gaskets

Universalsealing tapes,self-adhesive

Foil tapes

Cutting

Cutting andcorrugating

Windingandpressing

Crinkling

Winding

Punching

Punching andbonding

Cutting andpunching

Punching

SIGRAFLEX foils

SIGRAFLEX self-adhesive foil withrelease paper

Coating

Semi-finished product Processing technique End product


23

PROCESSING OFSIGRAFLEX SHEETS

Simple gaskets

Smooth stainless steel ring gas -kets with graphite outer layers

Corrugated stainless steel ringgaskets with graphite outerlayers

Gaskets for pumps and fittings

Gaskets for pipeworkUNIVERSAL PRO: Forapplications subject to theGerman TA Luft (Clean Air Act)

Gaskets with s/s inner eyeletsfor raised-face flanges, inapplications subject to theGerman TA Luft (Clean Air Act)

High-quality gasketswith metal eyelets for universal applicationsHOCHDRUCK PRO: Forapplications subject to theGerman TA Luft (Clean Air Act)

Superior-quality gaskets with s/s inner eyelets for maximum sealability and safety

Unr

einf

orce

d sh

eets

Rein

forc

ed s

heet

s

Typi

cal

gask

et s

ectio

ns

SIGRAFLEX product Processing technique End product

Typi

cal

gask

et s

ectio

n

SIGRAFLEX BASIS +SIGRAFLEX STANDARD

SIGRAFLEX SELECT

SIGRAFLEX ECONOMY

SIGRAFLEX UNIVERSALSIGRAFLEX UNIVERSAL PRO

SIGRAFLEX HOCHDRUCKSIGRAFLEX HOCHDRUCK PRO

The flexible graphite is shown in white color. The metal foils are shown as hatched surfaces. The PTFE foils are shown as dotted surfaces

PunchingCuttingScarf cuttingBonding

PunchingCutting




SIGRAFLEX MF

PunchingCutting

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24

ADVICE ONAPPLICATION FORSTUFFING BOXPACKINGS

Key words

Maintenance

Shaft wear

Friction coefficients

Packing height

Packing structure

Leakage rate

Heat dissipation

Fire safety test

Results of using SIGRAFLEX in practical situations

Low maintenance expenditure due to longservice life and hence short downtimes.

Low; SIGRAFLEX is soft and self-lubricating.

Between 0.08 and 0.25 against steel withsliding speeds of up to 30 m/sec and in thepresence of small quantities of moisture.

Low, owing to high density. Individual rings canbe subsequently added to a packing if the glandcannot be tightened further.

Marked improvement in service behaviorobtained with braided carbon fiber packingrings.

Low, even with short packings and high pressuredifferentials.

Very good owing to high thermal conductivityup to 400 W/(K·m).

Fittings with packings manufactured by ourcustomers from SIGRAFLEX material have provedsatisfactory in this test.


25

ADVICE ONAPPLICATION FORGASKETS

Key words

Gasket pressure

Maximum gasket pressure

Bolt forces

Service pressure

Cold and warm flow

Service lives

Microsealing andmacrosealing

Leaking flange joint

Fire safety test

Gaskets of large andcomplicated design

Release agents

Wet or moisture

Dismantling

Disposal

Results of using SIGRAFLEX in practical situations

Owing to their high compressibility, SIGRAFLEXgaskets are useful for sensitive and/or unevenflanges, e.g. those made of glass, enamel orgraphite. The homogeneous distribution of thegasket pressures ensures an optimum sealing effect.

High gasket pressures are permissible even at hightemperatures. The selected SIGRAFLEX type shouldbe suitable for the specified width-thickness ratio.

As a rule, the bolt forces should be used to the full.

Very high service pressures can be accommodatedreliably by using a properly selected SIGRAFLEXtype (e.g. HOCHDRUCK).

None detected up to maximum permissible gasket pressure; hence no need for retightening the bolts while plant or equipment is in use.

Very high in comparison with conventional material(e.g. longer lives due to very good oxidationresistance).

SIGRAFLEX adapts very well to ultrafine or coarsesurface irregularities. Hence, no special demandsneed be imposed on the flange surfaces.

In the case of liquids, never retighten flange bolts – always replace the gasket.

BS 6755-2 and API 607 certificates have been issued for a number of high-qualitySIGRAFLEX materials.

Can be assembled from segments.

Never pretreat gaskets with oil or grease.

Moist gaskets must not be fitted (drying allowed).

SIGRAFLEX gaskets are easy to remove and involve no health risk.

Uncontaminated material can be disposed ofwithout any problems.


26

SIGRAFLEX type

STANDARD

ECONOMY

UNIVERSALUNIVERSAL PRO

HOCHDRUCKHOCHDRUCK PRO

EMAIL

Unreinforced,impregnated

Reinforced withperforated s/s sheet,impregnated

High-integritymultilayerlaminate,impregnated,reinforced with s/s foil

PTFE-envelopegasket withSIGRAFLEX EMAILcore

Reinforced withbonded stainlesssteel foil

Cross-section Characteristics

High-quality SIGRAFLEX gasket systems and fields of application

Field of application

Glass/enamelled flanges,complicated designs, highlycorrosive media (e.g. HCI)

Gas technology; pumps and fittings; offshore

For pipework and vessels in thechemical and petro chemicalindustries and in power stations;UNIVERSAL PRO: For appli -cations subject to the GermanTA Luft (Clean Air Act)

Universal problem-solvinggasket material for the processindustries to meet demandingrequirements for sealability andsafety (e.g. tongue-and-grooveflanges); ease of pro cessingand assem bly. HOCHDRUCKPRO: For applications subjectto the German TA Luft (CleanAir Act)

MF High-integritylaminate made of graphite,stainless steel and PTFE

Maximum requirements forsealability, safety, chemicalresistance and process hygiene; sealed joints in thechemical, petro chemical,pharmaceutical and foodindustries

SELECT High-integrity s/s foilreinforcement,impregnated

For applications subject to theGerman TA Luft (Clean AirAct); raised-face flanges;pipework in the chemical andpetrochemical industries

For enamelled flanges,exacting demands for seal -ability and process hygiene in the pharmaceuticalindustry, aggressive media

Table 6


27

Exhaust systemsCylinder-head gasketsStandard flangesTongue-and-groove flangesVessel/equipment flangesGaskets up to 1500 mm diam.Glass/plastic/enamel surfacesHighly corrosive media*)

High gasket pressuresMechanical shear movements

Fittings Vessels/equipmentPipeworkInspection glassesWaste gas purification

recommendedsuitable**)

*) to which the metal reinforcements (ASTM material no. 316 (L)) are not resistant**) each individual case needs to be considered separately

Table 7 Recommended SIGRAFLEX products for various applications

TA LuftAutomotiveindustryChemical industry

Gas technologyPower stationtechnology

Engine buildingFood industryWater supply

ProductsComponentsIndustries

SIG

RAFL

EX S

TAN

DA

RD

SIG

RAFL

EX E

CO

NO

MY

SIG

RAFL

EX U

NIV

ERSA

LSI

GRA

FLEX

UN

IVER

SALPRO

SIG

RAFL

EX S

ELEC

T

SIG

RAFL

EX H

OC

HD

RUC

KSI

GRA

FLEX

HO

CH

DRU

CKPRO

SIG

RAFL

EX M

F

SIG

RAFL

EX E

MA

ILin

PTF

E en

velo

pes


28

Weight Units

1kg = 2.2046 lb = 35.274 oz1lb = 16 oz = 0.45359 kg

COMMONLY USEDCONVERSION FACTORS

mmcmminchfootyard

mm

110100025.4304.8914.4

cm

0.111002.5430.4891.44

m

1·10–3

0.0110.02540.30480.914

inch

0.03940.393739.3711236

foot

3.281·10–3

0.032813.2810.083313

yard

1.094·10–3

1.094·10–2

1.0942778·10–2

0.331

Units of Length

mm2

cm2

m2

inch2

foot2

yard2

mm2

1102

106

645.29.29·10–4

8.36·105

cm2

10–2

1104

6.4529298.36·103

m2

10–6

10–4

16.452·10–4

9.29·10–2

0.836

inch2

1.55·10–3

0.155155011441296

foot2

1.076·10–5

1.076·10–3

10.7646.94·10–3

19.009

yard2

1.196·10–6

1.196·10–4

1.1967.716·10–4

0.1111

Units of Area

Units of Volume

cm3

literm3

inch3

foot3

gallon

cm3

11000105

16.392.83·104

3785

liter

10–3

110000.0163928.323.785

m3

10–6

0.00111.64·10–5

0.028323.785·10–3

inch3

0.0610261.026.1·104

11728231

foot3

3.53·10–5

0.0353235.325.79·10–4

10.1337

gallon

2.64·10–4

0.2642264.24.33·10–3

7.4811


29

l/sgal/minft3/sft3/min

l/s

10.063128.320.4719

gal/min

15.851448.87.481

ft3/s

0.035320.0022310.01667

ft3/min

2.1190.1337601

Units of Force

Units of Pressure and Stress

Units of Density

1 kg/l = 1g/cm3 = 62.42 lb/ft3 = 9271.1 lb/in3

1 lb/ft3 = 5.787·10-4 lb/in3 = 0.01602 g/cm3

1 lb/in3 = 1728 lb/ft3 = 107.86 g/cm3

1 N/m2 = 1 Pa = 10-6 N/mm2 = 1.45037·10-4 lbf/in2 (psi)1 MPa = 1 N/mm2 = 10.2 bar = 145.037 lbf/in2 (psi)

1 bar = 760 mm Hg = 29.92 inch Hg = 14.5 psi

1 psi = 144 lbf/ft2 = 6.895 kPa = 6.895·10-3 N/mm2

= 6.895·103 N/m2 = 6.895·10-2 bar1 mm Hg = 0.03937 inch Hg = 0.01934 psi = 0.001315 bar1 inch Hg = 0.4912 psi = 1.133 ft water

1 N = 0.2248 lbf1 lbf = 4.448 N

Units of Energy, Moment

Units of Flow Rate

1 Ws = Nm = 1 Joule = 0.948 BTU = 0.738 lbf · ft1 lbf · ft = 1.356 Nm = 1.3558 Joule = 1.285 BTU



30

Units of Temperature

Units of Thermal Conductivity

tC = 5/9(tF - 32) °C tF = (1.8·tC) + 32 °F

1 BTU/(hr °F) · ft2/ft = 1.731 W/(K·m) 1 W/(K·m) = 0.578 BTU/(hr °F) · ft2/ft

Unit of Resistivity

1 Ohm in = 25.4 · 103 Ohm µm 1 Ohm µm = 39.4·10–6 Ohm in

Units of Gas Permeability

Gas permeability (DIN 3535-4): ___ in ___

Gas permeability (DIN 28090-1): �= ___ _____ in ___

Conversion DIN 3535 into DIN 28090: 1= ___ = 0.094 ____

� in mg/cm3 Density of test gas under normal conditionsdD in m Mean efficient gasket diameter (0.07 m)

Conversion of leakage rates for nitrogen:1 mbar·l/s = 1.19 mg/s = 0.952 cm3/s = 57.12 cm3/min

tV

tV

s·mmg

s·mmg

mincm3

mincm3

�·dD

�

°C

-100- 90- 80- 70- 60- 50- 40- 30- 20- 10

°F

-148-130-112- 94- 76- 58- 40- 22- 4

14

°C

010203040506070809

°F

32506886

104122140158176194

°C

100110120130140150160170180190

°F

212230248266284302320338356374

°C

200250300350400450500550600

1000

°F

392482572662752842932

102211121832

·



31

DEFINITIONS OF GASKET FACTORS

Definitions of gasket factors used in old and new regulations

bD

bD bD�

DIN EN 13555 DIN 28090 Explanation

QMIN(L) �VU/L Minimum level of surface pressure required for leakage rate class L on assembly [MPa]

�BU Minimum gasket pressure under serviceconditions, where �BU is the product of internalpressure p and gasket factor m for test and service conditions [�BU = p · m]

QS MIN(L) �BU/L Minimum level of surface pressure rate class Lafter off-loading [MPa]

QS MAX �BO Maximum surface pressure that can be safely imposed upon the gasket at service temperature without damage [MPa]

�VO Maximum permissible gasket pressure at RT [MPa]EG Secant unloading modulus of the gasket [MPa] PQR Ratio of gasket surface pressure before and

after relaxationLN LN Leakage rate class – subscript N indicates the

max. specific leakage rate for that leakage rate class [mg s-1 m-1]

The definitions of the older gasket factors (DIN V 2505 of 1964, AD Merkblatt B7of 1977) are as follows:

k0 in mm Factor for gasket assembly pressurek1 in mm Factor for gasket pressure under

service conditions k2 in mm Factor for max. stress-bearing capacity under

service conditionsKD in N/mm2 Max. gasket stress-bearing capacity under

assembly conditionsKD� in N/mm2 Creep strength under compressive stress at

service temperaturebD in mm Gasket width

The following conversion formulas are used:

�VU = Qmin = k0 ·KD

m = k1 / bD

�VO = Qmax = V k0 ·KD

�BO = Qmax = V k2 ·KD�

Graphite Specialties

SGL CARBON GmbH

Werner-von-Siemens-Straße 1886405 Meitingen/GermanyPhone +49 8271 83-2276Fax +49 8271 [email protected]

www.sglgroup.com

® registered trademark of SGL Group companies 01 2011/0 8NÄ Printed in Germany

This information is based on our present state of knowledge and is intended to provide general notes on our products and their uses. It should therefore not be construed as guaranteeing specific properties of the products described or their suitability for a particular application. Any exis tingindustrial property rights must be observed. The quality of our products is guaranteed under our “General Conditions of Sale“.

products manufactured from flexible graphite...

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