The Advantages of using SIGRAFLEX Universal and its Properties

 

Introduction:

SIGRAFLEX Universal is a high-performing gasket sheet that is popularly used in several industries, such as chemical, petrochemical, power generation, refinery, and ship building. This gasket is constructed of flexible graphite foil reinforced with stainless steel and coated to stop leakage and enhance operational handling. In this post, we will look at the benefits of utilizing SIGRAFLEX Universal and the characteristics that make it a popular sealing solution.

Advantages of using SIGRAFLEX Universal:

The below table shows different metrics of SIGRAFLEX Universal for several thicknesses and dimensions. The data are based on the technical data sheet provided by SGL Carbon.

Typical properties	Units	V10010C2I	V15010C2I	V20010C2I	V30010C2I
Thickness	mm	1	1.5	2	3
Dimensions	m	1.5 x 1.5	1.5 x 1.5	1.5 x 1.5	1.5 x 1.5
		1.0 x 1.0	1.0 x 1.0	1.0 x 1.0	1.0 x 1.0
Bulk density of graphite	g / cm³	1	1	1	1
Ash content of graphite (DIN 51903)	%	≤ 2.0	≤ 2.0	≤ 2.0	≤ 2.0
Purity	%	≥ 98	≥ 98	≥ 98	≥ 98
Total chloride content	ppm	≤ 25	≤ 25	≤ 25	≤ 25
Total halogen content (Cl, F, B, I)	ppm	≤ 70	≤ 70	≤ 70	≤ 70
Total sulphur content	ppm	< 300	< 300	< 300	< 300
Oxidation rate in air at 670 °C (TGA)	%/h	< 4	< 4	< 4	< 4
Oxidation inhibitor		yes	yes	yes	yes
Passive corrosion inhibitor (ASTM F 2168-13)		yes	yes	yes	yes
Reinforcing steel sheet details			Tanged stainless steel sheet
ASTM material number		316L	316L	316L	316L
Thickness	mm	0.1	0.1	0.1	0.1
Number of sheets		1	1	1	2
Residual stress (DIN 52913) {σD 16 h, 300 °C, 50 N/mm² }	N/mm²	≥ 45	≥ 45	≥ 45	≥ 45

 

The table shows that SIGRAFLEX Universal has a very consistent and high bulk density and purity of graphite, resulting in excellent thermal and chemical resistance. It also has very low ash and chloride levels, which make it, avoid corrosion and contamination effortlessly. It has mild compressible material and recovery, which allows it to quickly comply to the flange surface and effectively seal gaps.

High operational reliability and increased plant availability: SIGRAFLEX Universal offers exceptional resistance to corrosion, oxidation and medium, as well as superior blow-out resistance and mechanical strength, leading in enhanced plant availability and operational dependability. It can withstand temperatures from -269°C to 550°C and pressures up to 100 bar. It also has long-term compression and recovery stability, even under high temperature shifts. These features guarantee that SIGRAFLEX Universal can operate consistently and safely in a wide range of operating situations, reducing the likelihood of failures and downtime.

Good chemical resistance: SIGRAFLEX Universal has a low ash level and a high graphite purity, making it less likely to react with the majority of substances and chemicals. It can withstand acids, alkalis, oils, gasses, solvents, and steam, as well as corrosive mediums such as oxygen, propylene oxide, and ethylene oxide. It also has a low total chloride concentration, further reducing the possibility of cracking due to stress corrosion in stainless steel flanges.

Easy handling and assembly: SIGRAFLEX Universal is easy to handle and assemble because of its specific impermeability, which provides exceptional durability against scratches and anti-stick qualities. It also lacks significant cold or warm flow properties, therefore it does not distort or creep under pressure. It has no adhesives or binders, so it does not age or become brittle with time. These features make SIGRAFLEX Universal simple to cut, handle, and install, as well as remove and replace as needed.

Environmentally friendly and asbestos-free: SIGRAFLEX Universal is an adhesive-free and PFAS-free gasket sheet, which means it does not contain any harmful substances that could leach into the environment or pose health risks. It is also asbestos-free, which means it does not cause any respiratory problems or cancer. SIGRAFLEX Universal is a sustainable and safe sealing solution that complies with various environmental and health regulations.

Properties of SIGRAFLEX Universal:

●             High operational reliability, increased plant availability

●             Excellent oxidation resistance

●             High blow-out resistance and mechanical strength

●             Very high fault tolerance during assembly and operation

●             Good chemical resistance

●             Long-term stability of compressibility and recovery, even under fluctuating temperatures

●             Good scratch resistance and antistick properties due to special impregnation

●             No measurable cold or warm flow characteristics up to the maximum permissible gasket stress

●             No aging or embrittlement (no adhesives or binders)

●             Asbestos-free (no associated health risks)

Material data of SIGRAFLEX® UNIVERSAL
Gasket factors (DIN E 2505 / DIN 28090-1)
Gasket width bD = 20 mm at an internal pressure of
σVU/0,1	10 bar	N/mm²		10		10		12		18
	16 bar	N/mm²		14		14		15		23
	25 bar	N/mm²		17		17		18		30
	40 bar	N/mm²		20		20		22		35
m				1.3		1.3		1.3		1.3
σVO		N/mm²		200		180		160		140
	σBO at 300 °C	N/mm²		180		160		140		120
Gasket factors (DIN EN 13555)		Compression factors (DIN 28090-2)
Compressibility	sKSW	%		35		40		40		40
Recovery at 20 °C	sKRW	%		5		5		5		5
Hot creep	sWSW	%		< 4		< 4		< 4		< 4
Recovery at 300 °C	sWRW	%		4		4		4		4
E-Modul at 20 N/mm² (DIN 28090-1)		N/mm²		850		850		850		850
ASTM	„m“-factor			2.5		2.5		2.5		2.5
	„y“-factor	psi		2000		2000		2000		2000
Compressibility (ASTM F36)	%			37		42		42		42
Recovery (ASTM F36)	%			15		14		14		14

 

 

k0 x KD = σVU x bD k1 = m x bD

σVU/0.1               Minimum gasket assembly stress needed to comply with leakage class L 0.1 (according to DIN 28090-1)

Recommended gasket assembly stress: ≥ 20 N/mm² up to σBO

σBU       Minimum gasket assembly stress in service, where σBU is the product

of internal pressure pi and gasket factor m for test and in service (σBU = pi x m)

σVO       Maximum permissible gasket stress at 20 °C σBO at 300 °C           Maximum permissible gasket stress in service m                m = σBU /pi

„m“-factor Similar to m, but defined acc. to ASTM, hence different value

„y“-factor  Minimum gasket stress in psi

k0           in mm, factor for gasket assembly stress

k1           in mm, factor for gasket stress in service

KD          in N/mm², max. gasket stress-bearing capacity under assembly conditions

sKSW     Compression set under a gasket stress of 35 N/mm²

sKRW    Gasket recovery after reduction in gasket stress from 35 N/mm² to 1 N/mm²

sWSW   Gasket creep compression under a gasket stress of 50 N/mm² at 300 °C after 16 h

sWRW   Recovery after reduction in gasket stress from 50 N/mm² to 1 N/mm²

The percentage changes in thickness of sKSW, sKRW, sWSW und sWRW

are relative to the initial thickness.

Conclusion:

SIGRAFLEX Universal is a versatile and reliable gasket sheet that offers many advantages and properties for various sealing applications. It is suitable for all common pipework and vessel flange designs, and can handle high temperatures, pressures, and corrosive media. It is also easy to handle and assemble, and environmentally friendly and asbestos-free. SIGRAFLEX Universal is a superior sealing solution that can improve the operational reliability and efficiency of your plant.

FAQ:

1.       What temperature and pressure can Sigraflex Universal withstand?

It can withstand temperatures ranging from -269°C to 550°C and pressures up to 100 bar.

2.       Why Sigraflex Universal is popular for operational reliability?

Sigraflex Universal demonstrates long-term compression and recovery stability, even after significant temperature fluctuations. These characteristics ensure that SIGRAFLEX Universal performs consistently and safely across a wide variety of operating conditions, lowering the chance of failures and downtime, making it popular for operational reliability.

3.       In which industries, Sigraflex Universal is used widely?

Sigraflex Universal is popularly used in several industries, such as chemical, petrochemical, power generation, refinery, and ship building.

4.       What is the environmental effects of SIGRAFLEX Universal?

SIGRAFLEX Universal is an adhesive-free and PFAS-free gasket sheet, which means it does not contain any harmful substances that could leach into the environment or pose health risks.