Executive Summary

Flexible graphite sheet (also called exfoliated or expanded graphite sheet) provides an outstanding combination of high temperature resistance, chemical resilience, low gas permeability and conformability. Commonly supplied in plain sheet, laminated (metal-faced) or reinforced formats, it is a preferred choice for steam, exhaust, cokers and other high-temperature sealing challenges. This page offers engineers, procurement and maintenance teams a complete overview: grades, selection rules, specs, handling, case studies and downloadable technical documentation.

What is a Flexible Graphite Sheet?

Flexible graphite sheet is produced by high-temperature exfoliation of natural graphite flakes, then re-compacting into thin, flexible sheets. It is inherently layered, compressible, and can be produced with different densities and with optional metal/fiber facing for enhanced mechanical strength and blowout resistance. Key attributes include very wide temperature range, excellent chemical compatibility (in many media), and low permeation to gases. Typical formats: plain graphite sheet, stainless steel-faced graphite (SSFG), aluminum-faced graphite and reinforced graphite (glass fiber backing).

Classification — By Grade, Facing & Format

By Density / Grade

  • Low density (light, high compressibility) — better for low bolt load & conformability
  • Medium density — balanced compressibility and strength
  • High density (less compressible, higher crush strength) — for higher pressure applications

By Facing / Reinforcement

  • Unfaced (plain) graphite sheet — best for conforming to flange irregularities
  • Stainless steel foil-faced graphite (SSFG) — for coarse flanges and improved blowout resistance
  • Aluminum-faced graphite — lighter, for specific temperature/chemical needs
  • Reinforced (glass/aramid backing) — improved handling & tensile strength

By Application Format

  • Standard sheets (cut-to-size)
  • Die-cut gaskets and rings
  • Spiral-wound gaskets with graphite filler
  • Thermal pads & EMI shielding laminates

Selection Guide — How to Choose Flexible Graphite

  1. Identify service conditions: temperature, maximum pressure, media (oxidizing vs non-oxidizing), presence of steam, hydrocarbons or corrosive chemicals.
  2. Choose density: low density for excellent conformability and sealing on low bolt loads; high density for higher pressure and reduced extrusion.
  3. Decide on facing: use stainless steel or aluminum facing for coarse flange finishes or where blowout resistance is critical.
  4. Check mechanical constraints: consider reinforced backing for thin sheets used in handling/assembly-heavy operations.
  5. Regulatory & contamination: for food/pharma check for lubricant and contaminant controls; graphite is generally inert but verify filler/processing additives.
  6. Consider laminated options: metal-faced graphite laminates reduce gas permeation and increase structural stability for high-stress flanges.

Tip: For steam and high temperature oxidizing atmospheres, use grades with proper facing and confirm oxidation resistance with supplier test data.

Technical Parameters & Typical Specifications

Typical reference ranges.
Type / Grade Temp Range (°C) Max Pressure (bar) Typical Thickness (mm) Typical Applications
Plain flexible graphite (low density) -200 to 400 ≤ 100 0.5 / 1.0 / 1.5 / 2.0 Flange sealing at low bolt load, thermal gasketing
Plain graphite (medium / high density) -200 to 450 ≤ 250 1.0 / 2.0 / 3.0 Higher pressure flanges, heat exchangers
Stainless steel-faced graphite (SSFG) -200 to 450 ≤ 400 0.5 (face + core) Coarse flange surfaces, high blowout resistance
Reinforced graphite (glass/aramid backing) -200 to 400 ≤ 200 0.5 / 1.0 Improved handling, die-cut gaskets

Common Sheet Sizes

Sheet Size (mm) Thickness Options (mm) Typical Pack
1000 × 1000 0.5, 1.0, 1.5 Carton / pallet
1500 × 1500 1.0, 2.0, 3.0 Wood pallet
2000 × 1000 1.5, 3.0 Bulk / crates

Product Data & Technical Documents

Download datasheets, oxidation/aging reports, facing details and installation templates.

Cutting, Forming & Installation Guidelines

  1. Cutting: waterjet or CNC die-cutting is recommended for precision; mechanical shears for thicker sheets. For faced sheets, ensure the facing remains intact and edges are finished.
  2. Handling: faced and reinforced sheets have improved handling — plain graphite is fragile at thin gauges; store flat and avoid folding.
  3. Gasket assembly: when using faced graphite, orient the metal face toward the coarser flange to improve sealing and reduce extrusion.
  4. Tightening: follow a cross bolting pattern, incremental torque. Avoid overcompression which can damage thin sheets; use recommended seating stress from datasheet.
  5. Protection: in oxidizing atmospheres at elevated temperatures consider protective coatings or metal facing to limit oxidation.
  6. Inspection: inspect for signs of extrusion, oxidation, or facing delamination during scheduled maintenance intervals.
graphite gasket sheet
Typical workflow: cut → fit → torque → inspect. For faced sheets, face toward coarse flange.

Application Industries & Case Studies

  • Power generation — steam pipes, boilers, turbine auxiliaries
  • Petrochemical & refining — high temperature process lines
  • Automotive exhaust systems — seals and thermal gasketing
  • Chemical processing — non-oxidizing chemical services
  • Heat exchangers & furnaces — high temp sealing

Case Study — High-Temperature Steam Header Retrofit

Problem: Recurrent leakage at steam header flanges operating at 400 °C. Solution: Replaced aging compressed fiber gaskets with stainless steel-faced flexible graphite gaskets (SSFG) and re-profiled flange faces. Result: Achieved reliable sealing at elevated temperature with no leakage during 24-month follow up and reduced flange maintenance frequency.

Performance Comparison & Material Selection Matrix

Property Plain Graphite SSFG (stainless-faced) PTFE Sheet Aramid CNAS
High temperature tolerance Very high Very high Moderate Moderate
Gas permeability Low Very low (faced) Low Medium
Chemical resistance Good (some oxidizers caution) Good Excellent Good
Conformability Excellent Good Moderate Good
Blowout resistance Moderate High Low-Moderate Moderate

Common Failures & Troubleshooting

Graphite oxidation at high temperature
Cause: Exposure to oxidizing atmosphere (oxygen) at elevated temperatures. Action: Use metal-faced graphite or protective coatings; verify operating atmosphere and consult oxidation data.
Facing delamination
Cause: Improper bonding between facing and graphite core or mechanical damage. Action: Ensure proper facing bonding process and check for delamination before installation; avoid bending thin faced sheets.
Extrusion or blowout at high pressure
Cause: Incorrect density/grade or lack of facing for coarse flange. Action: Select higher density or faced laminate and verify seating stress and bolt load.
Edge fraying after cutting
Cause: Poor cutting method. Action: Use waterjet or precision die-cutting and deburr edges; for critical services apply edge sealing if recommended.

FAQ — For Purchasing / Engineering / Maintenance

Q: When should I use stainless steel-faced graphite instead of plain graphite?A: Use SSFG when flange surface is coarse or when improved blowout/gas-tightness is required. Facing increases mechanical strength and reduces permeation through the graphite core.
Q: How does graphite behave in oxidizing atmospheres at high temperature?A: Graphite can oxidize when exposed to oxygen at elevated temperatures. For oxidizing environments, use faced graphite or protective measures and consult supplier oxidation resistance data.
Q: What information is needed for a fast quote?A: Provide sheet type (plain / faced / reinforced), thickness, sheet size or gasket drawing, operating temperature and pressure, media description and required certifications.

Need help specifying flexible graphite for your equipment?

Contact our technical team for grade selection, oxidation test data, faced laminate options and sample gaskets.
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