Expanded Graphite Tape for Metal Spiral Wound Gaskets: High Carbon & Low Sulfur Solution

📅 Published: April 21, 2026 ✍️ By Engineering Team ⏱ 5 min read

When it comes to critical sealing applications in petrochemical, power generation, and industrial fluid systems, metal spiral wound gaskets rely heavily on the quality of their inner sealing layer. The filler material must withstand extreme temperatures, pressures, and corrosive media. Among the best choices, expanded graphite tape has proven itself as the gold standard for the sealing element — especially when carbon purity and low sulfur content are mandatory.

Our advanced expanded graphite tape (grade EGT-SW) is specifically engineered as the sealing layer for spiral wound gaskets. With carbon content ≥99%, sulfur ≤1200 ppm, and precision dimensions of 5.8mm width, 0.6mm thickness, density 1.1 g/cm³, this tape offers exceptional performance, superior tensile strength, anti-break properties, and outstanding compression & recovery rates.

Why Expanded Graphite Tape for Spiral Wound Gaskets?

Spiral wound gaskets consist of alternating layers of metal winding and filler material. The filler (or sealing element) must provide excellent deformability to fill flange irregularities while maintaining resilience under bolt load. Expanded graphite exhibits natural lubricity, chemical inertness, and thermal stability from cryogenic temperatures up to 450°C (in oxidizing atmospheres) and even higher in reducing conditions. But not all graphite tapes are equal — the precise formulation and physical properties define long-term reliability.

Product Name:

Expanded Graphite Tape (Sealing Layer Grade)

Carbon Content (C):

≥ 99%

Sulfur Content (S):

≤ 1200 ppm (ultra-low sulfur)

Width:

5.8 mm (±0.2 mm)

Thickness:

0.6 mm

Density:

1.1 g/cm³

Tensile Strength:

High (≥ 4 MPa) – excellent resistance to breakage

Compressibility (ASTM F36):

35% – 45% (outstanding)

Recovery Rate:

≥ 18% (superior resilience)

Key Advantages: High Carbon, Low Sulfur, Anti-Break Performance

🔷 High Carbon ≥99% Ensures maximum corrosion resistance, high thermal conductivity, and superior sealing integrity without carbon leaching.

🔷 Low Sulfur ≤1200 ppm Prevents stress corrosion cracking (SCC) of stainless steel flanges and metal windings, critical for sensitive media.

🔷 Excellent Tensile Strength The tape resists tearing and breaking during winding process, reduces production waste, and ensures uniform layer formation.

🔷 Superior Compressibility & Recovery Optimized density (1.1 g/cm³) allows the tape to adapt to flange surface irregularities while maintaining elastic recovery after load cycling.

🔷 Consistent Dimensions Precision 5.8mm width and 0.6mm thickness fit perfectly for standard spiral wound gasket inner/outer diameters.

🔷 Easy to Handle & Low Dust Enhanced mechanical strength reduces particle shedding and keeps production environment clean.

Technical Deep Dive: Why Density 1.1 g/cm³ Matters

The density of expanded graphite tape directly influences its sealing capability. A density of 1.1 g/cm³ provides the ideal balance between flexibility and compression strength. Lower densities (e.g., 0.9 g/cm³) may lead to excessive compression and loss of recovery, while higher densities become too rigid, reducing conformability. Our precisely controlled 1.1 g/cm³ ensures excellent gasket relaxation factor and maintains sealing stress even after thermal cycles. For spiral wound gaskets, this means consistent leak-tight performance under ANSI and DIN flange standards.

“In field tests, expanded graphite tape with C≥99% and S≤1200ppm reduced corrosion incidents on 316L stainless steel flanges by over 70% compared to conventional graphite grades.”

Anti-Break Property: Reliability in Automated Winding

When manufacturing spiral wound gaskets, the filler tape undergoes tension-controlled winding around a mandrel. Inferior graphite tapes often crack or break at edges, leading to inconsistent sealing gaps. Thanks to enhanced tensile strength and flexible reinforcement (proprietary process), our expanded graphite tape withstands winding stresses without fissures. The result: smooth, continuous sealing layers and reduced downtime in your gasket production line.

Compressibility & Recovery: The Dynamic Sealing Advantage

During bolted flange assembly, the gasket must compress sufficiently to fill microscopic surface irregularities but also recover to maintain contact pressure when internal pressure or temperature fluctuates. Our graphite tape demonstrates compressibility in the range of 35-45% and recovery over 18% (ASTM F36). This means the metal spiral wound gasket remains robust against bolt load relaxation, thermal cycling, and pressure surges. In high-risk applications like hydrogen service or steam systems, this dynamic performance prevents fugitive emissions.

Comparison vs. Conventional Graphite Tape

Standard expanded graphite tapes often have sulfur content exceeding 1800 ppm and carbon purity around 98%, which accelerates galvanic corrosion. Our low sulfur grade reduces sulfide-induced stress corrosion cracking (SCC) risks. Moreover, typical alternatives exhibit lower tensile strength and break easily. With our anti-break advantage, manufacturers achieve higher yield per roll.

Applications & Industry Use Cases

The 5.8mm x 0.6mm tape dimension is the most common specification for spiral wound gaskets used in ASME B16.20 compliant applications. Typical industries include:

Oil & Gas refineries (high-temperature hydrocarbon seals)
Chemical processing plants (aggressive media, acids)
Power generation (steam turbines, HRSG)
Pharmaceutical & food-grade (low sulfur prevents contamination)
Cryogenic services (LNG, liquid nitrogen)

Ordering & Customization

Our standard expanded graphite tape comes in 5.8mm width, 0.6mm thickness, density 1.1 g/cm³, with carbon≥99%, sulfur≤1200ppm. Available in continuous rolls (lengths up to 50m) or slit to custom widths. For special applications, we can adjust density, thickness, or provide adhesive backing upon request. Contact our technical support team for samples and bulk pricing.

Request Quotation →

* All data based on standard test methods. Performance may vary with application conditions. Consult our engineers for validation.