SIGRAFLEX® graphite sheets for gaskets made from flexible graphite

SIGRAFLEX unreinforced and reinforced graphite sheets

What are graphite gasket sheets?

Graphite gasket sheets are sealing sheets made from flexible graphite which provides a soft, highly adaptable surface.

The sheets can be unreinforced i. e. homogeneous and made from flexible graphite only or reinforced resulting in a multilayer sheet, which is sometimes also referred to as a graphite laminate. Common reinforcements are flat or tanged stainless steel, other metals like nickel or HASTELLOY^®, and polyester film.

The sheets are further processed into flat gaskets of different shapes by punching or cutting. Graphite soft cut gaskets are ideal for many applications due to their wide operating temperature range (-269 °C to max. 550 °C) and excellent media and corrosion resistance.

The portfolio of SIGRAFLEX graphite sheets made from flexible graphite provides a variety of solutions to all needs. We offer gasket sheets for flat gaskets in different variants e.g. unreinforced or reinforced, with or without impregnation, with adhesives or binders as well as adhesive-free. SIGRAFLEX graphite gasket sheets are manufactured exclusively at our two sites in Germany and the US.

Our reinforced SIGRAFLEX graphite gasket sheets made from flexible graphite are highly corrosion resistant. They considerably reduce the maintenance costs of equipment and extend its service life. Above all, the use of premium SIGRAFLEX materials significantly enhances gasket safety for employees and the environment – a high priority when operating equipment.

Sustainable high quality standard
High leak tightness
Excellent conformability to flange irregularities
Outstanding chemical and thermal resistance
Lower maintenance expenses thanks to the sealing materials’ long service life

Gaskets fill the space between flange surfaces to prevent leakage e. g. of fluids at pipework joints, flange connections, pump or compressors housings, heat exchangers etc.

Since no gasket material is 100% tight, all gaskets leak to a certain degree. Therefore, it is key to reduce the leakage to a minimum – under the given conditions like load/pressure, temperature, media aggressiveness or viscosity – by using a suitable, high-quality and leak tight gasket material for a certain application. Gasket leakage is given in tightness/leakage classes, e. g. L0.1 stands for a leakage rate of 0.1 mg/(s*m) of the test medium helium.

Leak tight flat gaskets can be made from metal reinforced SIGRAFLEX gasket sheets equipped with a special impregnation to improve leak tightness. For example, helium leakage of flat gaskets made from SIGRAFLEX HOCHDRUCK, HOCHDRUCK PRO, UNIVERSAL PRO or MF^® typically range from L0.01 to L0.000001 at the most common operating and surface pressures. Leakage in operation of most fluids is below that of helium.

Especially for equipment which has to meet the requirements of the “Technical Instructions on Air Quality Control” (TA Luft), our wide variety of reinforced and impregnated SIGRAFLEX graphite sheets provide the optimum sealing material – just like for stricter limit values for fugitive emissions.

Downtime is an extreme cost factor in any operation, so both planned and incidental maintenance are intended to be quick and kept to a minimum. Even graphite flat gaskets containing no binder or filler tend to stick to flanges. One thing is clear when it’s time for gasket replacement: The easier the gasket can be removed from the flange faces, the lower are time and effort for flange cleaning from gasket residues and the risk of flange damaging.

Flat gaskets made from SIGRAFLEX gasket sheets equipped with our anti-stick surface finish show excellent separating behavior: Adhesion to the flange faces is minimized, a clean gasket release is often possible. The materials are also favorable for partially inaccessible sealed joints, as the anti-stick effect facilitates disassembly.

Consequently, SIGRAFLEX flat gaskets with anti-stick properties allow for easier removability and save end users time and money: Resulting in reduced downtimes and total cost of ownership.

Our materials have been developed with an in-depth understanding of their use and application. Allow us to advise you – even on site. Together we will develop a sustainable solution tailored to your needs. Please just ask us. You may also use our SIGRAFLEX Product Finder to identify the ideal SIGRAFLEX sheet material for your needs e. g. extreme leak tight or anti-stick sheets.

We offer the graphite sheet for your individual application - no matter if you are e.g. looking for a gasket sheet material which is leak tight even under high pressure or which provides support to fulfill the requirements of TA Luft. Use our product finder to quickly and easily identify the optimum gasket material for your needs.

	Scope of application	STANDARD	ECONOMY	UNIVERSAL	UNIVERSAL PRO	iNXT	SELECT	HOCHDRUCK	HOCHDRUCK PRO	APX2 HOCHDRUCK	MF	EMAIL	SIGRASEAL	BSSC	BTCSS
Gaskets	Kammprofile and corrugated gaskets	○
	PTFE envelope gaskets											●
	Gaskets for pumps and valve bodies	○	●	○	○	●		●	●	●			○	●	○
	One-piece gaskets up to Ø 1500 mm (59.1")			●	●			●	●	●		●	●	●	●
Flange design	Flanges with sealing strips	○	●	●	●	●	●	●	●	●	●		●	●	●
	Tongue-and-groove flanges/ highly stressed sealed joints							●	○	●
	Unstable flanges with low gasket stress		●			●					●
	Vessel and equipment flanges	○		●	●	●		●	●	●	●		○	●	●
	Emergency repairs, complex dimensions	●	○			●		●	●	●				●
Operations under pressure	Low internal pressure up to 40 bar	●	●			●								●
	Internal pressures vacuum up to 100 bar			●	●	●	●	●	●	●	●		○		○
	Internal pressures vacuum up to 250 bar							●	●	●
Operating temperatures	−269 °C to 300 °C (-452 °F to 572 °F)	●	●	●	●	●	●	●	●	●	●		●	●	●
Operating temperatures	−269 °C to ~550 °C (-452 °F to ~1022 °F)¹⁾	●	●	●	●	●	●	●	●	●	●		○	●	●
Leak tightness	Max. requirements acc. to the emission protection regulation TA Luft²⁾				●	●	●	○	●		●	●

Typical properties	Unit	HOCHDRUCK PRO 2–9 inserts	APX2 HOCHDRUCK 1–5 inserts	MF 3–7 inserts	UNIVERSAL PRO 1–2 inserts	SELECT¹⁾ 2 inserts
Metal reinforcement: Stainless steel sheet 316L	mm in	0.05 0.002	0.05 0.002	0.05 0.002		0.05 0.002
Metal reinforcement: Perforated stainless steel sheet 316L	mm in			0.1 0.004	0.1 0.004
Thickness	mm in	1.0-4.0 0.04-0.16	1.0-3.0 0.04-0.12	2.0/3.0 0.08/0.12	1.6/2.0/3.0 0.06/0.08/0.12	1.6 0.06
Width	mm in	1000/1500 39.4/59.1	1500 59.1	1000 39.4	1000/1500 39.4/59.1
Length	mm in	1000/1500 39.4/59.1	1500 59.1	1000 39.4	1000/1500 39.4/59.1
Purity	%	≥ 99.85	≥ 98	≥ 99.85	≥ 98	≥ 98
Ash content	%	≤ 0.15	≤ 2.0	≤ 0.15	≤ 2.0	≤ 2.0
Chloride content	ppm	≤ 10	≤ 25	≤ 10	≤ 25	≤ 25

Typical properties	Unit	iNXT 1 insert	ECONOMY¹⁾ 1–2 inserts	BSSC 1 insert	BTCSS 1 insert	BSC 1 insert	BMY
Metal reinforcement: Stainless steel sheet 316L	mm in	0.05 0.002	0.05 0.002
Metal reinforcement: Perforated stainless steel sheet 316L	mm in				0.1 0.004
Wire mesh reinforcement: Stainless steel 316, wire diameter	mm in					0.19 0.0075
Polyester film							0.127 0.005
Bonded/adhesive-free		adhesive-free	bonded	bonded	adhesive-free	bonded	bonded
Thickness	mm in	2.0 0.08	0.55-3.0 0.02-0.12	0.76-3.05 0.03-0.12	0.76-3.05 0.03-0.12	0.76-3.05 0.03-0.12	0.38-3.05 0.015-0.12
Width	m in	1.0 39.4	1.0 39.4	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1
Length	m in	1.0 39.4	1.0	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1	1.0 / 1.5 39.4 / 59.1
Purity	%	≥ 98	≥ 98	≥ 98	≥ 98	≥ 98	≥ 98
Ash content	%	≤ 2.0	≤ 2.0	≤ 2.0	≤ 2.0	≤ 2.0	≤ 2.0
Chloride content	ppm	≤ 50	≤ 25	≤ 50	≤ 50	≤ 50	≤ 50