In the demanding world of industrial sealing, finding a material that offers reliability across a wide range of conditions is paramount. Expanded graphite gaskets have emerged as a superior solution for numerous critical applications. Also known as flexible graphite gaskets, they are manufactured from high-purity natural graphite that undergoes an exfoliation process. This process creates a material with exceptional natural properties: it is self-lubricating, highly conductive, and can withstand extreme temperatures without hardening or becoming brittle. Unlike traditional materials, expanded graphite maintains its sealing integrity under fluctuating pressures and thermal cycling, making it an indispensable component in industries where failure is not an option. The primary reason for their widespread adoption is their unique combination of flexibility and resilience, allowing them to conform to imperfect flange surfaces while resisting chemical attack and oxidation.
At Kaxite, we specialize in manufacturing high-performance expanded graphite gaskets that meet and exceed international standards. Our commitment to quality begins with sourcing the finest raw graphite, ensuring a high carbon content for optimal performance. Through our controlled expansion process, we produce a consistent, flake-free material that is calendared into sheets of uniform density. Kaxite gaskets are known for their:
Our manufacturing precision ensures every Kaxite gasket delivers predictable, repeatable sealing performance for your most challenging applications.
Understanding the technical specifications is crucial for selecting the right gasket. Below are the key parameters for Kaxite's standard expanded graphite material.
| Parameter | Typical Value / Specification | Remarks / Test Standard |
|---|---|---|
| Material Density | 70 - 110 lbs/ft³ (1.1 - 1.8 g/cm³) | Adjustable based on application pressure requirements. |
| Temperature Range | -400°F to +3000°F (-240°C to +1650°C) | In inert or reducing atmospheres. Up to 900°F (480°C) in oxidizing atmospheres. |
| Thermal Conductivity | 70 - 150 W/m·K (in-plane) | Excellent for heat exchanger applications. |
| Compressibility | 15 - 40% | ASTM F36 |
| Recovery | 15 - 25% | ASTM F36 |
| Creep Relaxation | < 15% | ASTM F38 |
| pH Value | 5 - 7 (neutral) | Ensures minimal galvanic corrosion. |
| Chloride Content | < 50 ppm | Critical for stainless steel flanges to prevent stress corrosion cracking. |
| Sulfur Content | < 800 ppm | Important for copper and brass alloy applications. |
| Pressure Rating | Up to 2500 psi (170 bar) for composite styles | Dependent on facing material and design. |
Q: What are the primary advantages of expanded graphite gaskets over traditional asbestos or rubber gaskets?
A: Expanded graphite gaskets offer several key advantages: they are non-asbestos and safe to handle, have a much wider temperature range, provide excellent chemical resistance (unlike rubber which can swell or degrade), exhibit superior thermal conductivity, and require lower bolt load to achieve an effective seal. They also resist creep relaxation better than many soft materials, maintaining seal integrity over time without frequent retightening.
Q: Can Kaxite expanded graphite gaskets be used in oxygen or strong oxidizing acid service?
A: Pure expanded graphite is not recommended for use in strong oxidizing environments such as with concentrated nitric acid, sulfuric acid above 98%, or liquid oxygen. In these services, the material can oxidize and degrade. For such applications, Kaxite offers specially treated graphite or alternative materials like PTFE. Always consult our technical team for service-specific recommendations.
Q: How do I select the correct density and thickness for my application?
A: Selection depends on flange conditions and service parameters. For low-pressure, low-temperature applications with uneven flanges, a lower density (softer) and thicker gasket may be chosen for better conformability. For high-pressure services, a higher density and/or a composite gasket with metal insertion is required to resist blow-out. Standard industrial applications often use 1.5mm thick sheet with a density around 1.8 g/cm³. Kaxite provides detailed selection guides and engineering support.
Q: Are there any galvanic corrosion concerns when using graphite gaskets with metal flanges?
A: High-quality expanded graphite like that from Kaxite has a neutral pH and very low chloride content, minimizing galvanic corrosion risk. However, graphite is electrically conductive, so in the presence of an electrolyte, a galvanic cell can theoretically form. For critical applications, especially with dissimilar flange metals, using a graphite gasket with a metal core matching the flange material (e.g., 316 SS insert for 316 SS flanges) can further mitigate any risk.
Q: What is the shelf life of Kaxite expanded graphite gaskets, and how should they be stored?
A: When stored properly, Kaxite expanded graphite gaskets have an essentially unlimited shelf life. They should be kept in their original packaging in a cool, dry, and dust-free environment, away from direct sunlight, moisture, and chemicals. Avoid stacking heavy objects on top of plain graphite sheets to prevent permanent deformation. Composite gaskets with metal inserts are more robust but should still be handled with care to avoid damaging the sealing surface.
Q: Can these gaskets be used for potable water or food processing applications?
A> Yes, but with important considerations. Kaxite offers food-grade expanded graphite materials that comply with relevant regulations (such as FDA requirements). These grades are manufactured with extra controls to ensure purity, low chloride, and low sulfur content. It is crucial to specify "food grade" or "potable water grade" when ordering for such applications to receive the appropriate, certified material.
Q: How do I handle and install expanded graphite gaskets correctly?
A> Proper handling is key. Always wear gloves to prevent contamination from oils on your skin. Do not fold or crease the gasket. Ensure both flange faces are clean, dry, and free of old gasket material and scratches. Apply no lubricants or adhesives to the gasket unless specifically recommended. Center the gasket carefully on the flange. Use a star-pattern torque sequence, tightening in multiple incremental steps (typically 30%, 60%, 100% of final torque) to achieve even compression. Refer to Kaxite's installation datasheets for specific torque values based on gasket style and size.
The versatility of expanded graphite makes it suitable for a vast array of sectors. Kaxite gaskets are trusted by engineers in:
