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In demanding industrial sealing applications, reliability is non-negotiable. For decades, professionals have sought a material that combines superior sealing performance with exceptional resilience against extreme conditions. The answer lies in a unique, flexible form of carbon. Expanded graphite gaskets represent a pinnacle of sealing technology, engineered to address the shortcomings of traditional materials like compressed non-asbestos, PTFE, and rubber. Manufactured from pure, exfoliated graphite, these gaskets are renowned for their outstanding thermal conductivity, chemical inertness to a wide range of media, and a natural ability to conform to flange surfaces, creating a robust, leak-tight seal. At Kaxite, we have refined this technology, producing expanded graphite gaskets that set the benchmark for performance in industries ranging from chemical processing and power generation to oil & gas and pharmaceuticals.
Selecting the right gasket material is a critical decision impacting safety, efficiency, and operational costs. Kaxite expanded graphite gaskets offer a compelling array of advantages:
To ensure proper selection and application, understanding the technical specifications of Kaxite expanded graphite gaskets is essential. Below are the key parameters that define our product range.
| Property | Test Method | Typical Value (Kaxite Standard Grade) | Units |
|---|---|---|---|
| Density | ASTM F1315 | 90 - 110 | lbs/ft³ (1.45 - 1.75 g/cm³) |
| Tensile Strength | ASTM F152 | ≥ 1200 | psi |
| Compressibility | ASTM F36 | 25 - 45 | % |
| Recovery | ASTM F36 | ≥ 40 | % |
| Creep Relaxation | ASTM F38 | ≤ 15 | % |
| Thermal Conductivity | ASTM D5470 | 40 - 150 (in-plane) | W/m·K |
| Maximum Service Temperature (Oxidizing) | - | 850°F - 900°F | °F |
| Maximum Service Temperature (Non-Oxidizing) | - | 3000°F | °F |
| pH Range | - | 0 - 14 | - |
Kaxite expanded graphite is available in multiple forms to suit various application needs:
| Flange Type | Standard Size Range (NPS) | Pressure Class (ANSI/ASME) | Recommended Gasket Thickness |
|---|---|---|---|
| Weld Neck / Slip-On / Blind | 1/2" to 48" | 150, 300, 600, 900 | 1.5mm (1/16") |
| Flat Face / Raised Face | 1/2" to 60" | 150, 300 | 1.5mm or 3.0mm |
| Heat Exchanger (TEMA) | Per TEMA specifications | All Classes | 1.5mm or as per design |
| Spiral Wound Gasket Filler | All standard sizes | Up to 2500 | As per winding |
Q: What are the primary applications for expanded graphite gaskets?
A: Kaxite expanded graphite gaskets are exceptionally versatile. Key applications include: heat exchangers and boilers, chemical and petrochemical processing equipment (pumps, valves, reactors), power plant flue gas desulfurization systems, exhaust and high-temperature ducting, pharmaceutical and food processing where purity is critical, and any application involving extreme temperatures, aggressive chemicals, or requiring superior fire safety.
Q: How do I select the right thickness for my application?
A: The standard thickness for most raised face flange applications is 1.5mm (1/16"). For flat face flanges or surfaces with significant irregularities, a thicker 3.0mm (1/8") gasket may be recommended to ensure proper conformance and sealing. For high-pressure applications or with a reinforced/laminated design, the standard 1.5mm is typically sufficient. Always consult Kaxite engineering support for non-standard conditions.
Q: Can expanded graphite gaskets be used with oxidizing agents?
A: While expanded graphite has excellent chemical resistance, its one vulnerability is strong oxidizing agents (e.g., concentrated nitric acid, sulfuric acid above 98%, hydrogen peroxide, chlorine gas). In such environments, prolonged exposure at high temperatures can lead to oxidation of the graphite. For these services, Kaxite offers specially treated or laminated versions with enhanced oxidation resistance, or we may recommend an alternative material.
Q: What is the difference between "expanded graphite" and "flexible graphite"?
A: They are essentially the same material. "Expanded graphite" refers to the process where natural graphite flakes are treated with acid and heat, causing them to exfoliate or expand volumetrically. This exfoliated material is then compressed without a binder into sheets or forms, resulting in a "flexible graphite" product. The terms are often used interchangeably in the industry.
Q: How should I store and handle Kaxite expanded graphite gaskets?
A: Store in a cool, dry place away from direct sunlight and moisture. Keep in original packaging until use. Handle with clean gloves or tools to avoid contamination from oils or dirt. While the material is robust, avoid excessive bending or creasing of thin sheets. For laminated gaskets with metal cores, take care to avoid bending the metal insert.
Q: What flange surface finish is recommended for optimal sealing with expanded graphite?
A: Expanded graphite is very forgiving and can seal effectively on a range of finishes. An ideal surface finish is between 125 and 250 microinches Ra (3.2 - 6.3 µm Ra). It can also perform well on smoother or slightly rougher finishes. The key is that the flange faces must be parallel, undamaged, and free of old gasket material, deep scratches, or warping.
Q: Are there any safety or environmental concerns with expanded graphite?
A: Kaxite expanded graphite is a safe, non-toxic material. It contains no asbestos, chloride, or heavy metals, making it safe for use in potable water and food processing applications. It is chemically inert and does not leach harmful substances. From an environmental standpoint, it is made from natural graphite, a sustainable resource, and the production process is designed to minimize environmental impact.
Q: Can Kaxite provide custom-shaped gaskets or special sizes?
A: Absolutely. Kaxite specializes in manufacturing custom expanded graphite gaskets to exact customer specifications. We can produce virtually any shape—oval, square, rectangular, or complex geometries—using precision CNC cutting, laser cutting, or waterjet cutting. We also produce large-diameter gaskets and composite designs with various inserts or laminates. Provide us with a drawing or sample, and our team will manufacture a solution tailored to your needs.
