A Graphite Sheet, often referred to as flexible graphite or expanded graphite sheet, is a high-performance sealing and thermal management material manufactured from pure natural graphite flake. Through a chemical and thermal expansion process, the graphite flakes are exfoliated and then compressed into cohesive, flexible sheets without the use of binders. This unique structure gives graphite sheets an exceptional combination of properties: high thermal conductivity, excellent compressibility, reliable sealing under low bolt loads, and outstanding chemical resistance. They are indispensable in demanding industrial applications where temperature extremes, aggressive media, and long-term reliability are critical factors.
At Kaxite Sealing, we engineer our graphite sheets to meet the highest industrial standards. Our products stand out due to several key advantages:
Our graphite sheets are available in various grades and specifications to suit specific application needs. Below are the standard parameters for our flagship industrial-grade series.
| Property | Test Method | Standard Grade | High-Density Grade | Reinforced Grade |
|---|---|---|---|---|
| Density (g/cm³) | ASTM D3800 | 1.0 - 1.1 | 1.5 - 1.6 | 1.8 - 2.0 |
| Tensile Strength (MPa) | ASTM F152 | 4.0 min | 7.0 min | 10.0 min |
| Compressibility (%) | ASTM F36 | 40 - 60 | 25 - 40 | 15 - 30 |
| Recovery (%) | ASTM F36 | 15 - 25 | 10 - 18 | 8 - 15 |
| Thermal Conductivity (W/m·K) | ASTM E1461 | 80 - 120 (in-plane) | 100 - 140 (in-plane) | 50 - 80 (through-plane) |
| Maximum Temperature (Oxidizing) | - | 450°C (842°F) | 480°C (896°F) | 500°C (932°F) |
| pH Range | - | 0 - 14 | 0 - 14 | 0 - 14 |
| Thickness (mm) | Standard Width (mm) | Standard Roll Length (m) | Sheet Size (mm) |
|---|---|---|---|
| 0.15, 0.20, 0.25, 0.40, 0.50 | 500, 1000, 1500 | 10, 20, 30 | 1000 x 1000, 1500 x 1500 |
| 0.75, 1.0, 1.5, 2.0, 3.0 | 500, 1000 | 5, 10 | 1000 x 1000, 1200 x 1200 |
Note: Custom dimensions, thicknesses, and die-cut shapes are available upon request from Kaxite Sealing.
The versatility of graphite sheets makes them suitable for a broad spectrum of industries. Key applications include:
What is the main difference between a graphite sheet and a traditional compressed non-asbestos (CNA) gasket?
Graphite sheets offer significantly higher temperature resistance, better chemical inertness, and superior thermal conductivity compared to CNA materials. While CNA gaskets are often limited to around 400°C (752°F) and can be affected by certain chemicals, graphite sheets can function in much hotter and more corrosive environments. Additionally, graphite maintains its sealing properties over a wider load range and has a longer service life without embrittlement.
Can Kaxite Sealing graphite sheets be used in oxidizing atmospheres above 450°C?
Continuous use in oxidizing atmospheres above 450°C is not recommended for standard grades as it leads to gradual oxidation and loss of mass. For such applications, we offer specially treated oxidation-resistant grades or recommend our composite sheets with stainless steel or Inconel inserts, which can extend the upper temperature limit in air up to 800°C (1472°F) or higher.
How do I select the correct density and thickness for my application?
Selection depends on flange conditions and media. For uneven or damaged flanges, a lower density (softer) sheet with higher compressibility (e.g., 1.0 g/cm³) is better for conformability. For high-pressure sealing or as a thermal pad, a higher density sheet (1.5 g/cm³ or above) offers better blowout resistance and thermal transfer. Thickness is typically chosen based on flange gap and required recovery; standard gasket applications often use 0.5mm to 1.5mm thickness. Our Kaxite Sealing engineering team can provide specific recommendations.
Are graphite sheets electrically conductive?
Yes, graphite sheets are electrically conductive in the plane of the sheet. This property is beneficial for applications requiring static dissipation or electrical current carrying, such as in fuel cell bipolar plates. However, it also means insulation is required if electrical isolation between components is necessary.
How should I store and handle graphite sheets?
Store sheets in a dry, cool environment away from direct sunlight and moisture. Handle with clean gloves or tools to prevent contamination from oils and dirt. While flexible, sheets should not be folded sharply or creased, as this can cause cracks. Use sharp knives or die-cutting for shaping. Always follow the specific Material Safety Data Sheet (MSDS) provided by Kaxite Sealing.
Can your graphite sheets be combined with other materials?
Absolutely. Kaxite Sealing specializes in manufacturing composite gaskets. Our graphite sheets are often laminated with metallic foils (stainless steel, aluminum) for added strength, punched with metal inserts for bolt hole reinforcement, or sandwiched between steel shells to create spiral wound gasket filler material. These combinations enhance mechanical properties and extend application ranges.
What quality certifications does Kaxite Sealing hold for its graphite sheet products?
Kaxite Sealing is committed to quality. Our manufacturing process and products comply with international standards such as ISO 9001:2015 for quality management. Our materials are tested to meet ASTM standards for gasket properties. Furthermore, we can provide material certifications (Mill Test Certificates) and support compliance with industry-specific requirements like API, ASME, and DIN standards upon request.
