What Is a Corrugated Metal Gasket?
A corrugated metal gasket is a semi-metallic sealing element formed by pressing concentric or sinusoidal grooves into a thin metal sheet, then bonding a soft facing material (flexible graphite, PTFE, or mica) to both sealing surfaces. The corrugations act as multiple concentric sealing lines and provide the spring-like resilience needed to maintain seal integrity during thermal cycling and pressure fluctuations.
| Feature | Specification |
|---|---|
| Type | Semi-metallic gasket |
| Core construction | Corrugated (grooved) metal sheet |
| Facing material | Flexible graphite, PTFE, or mica |
| Primary standard | ASME B16.20 (metallic gaskets), manufacturer specifications |
| Flange face | Raised face (RF) or flat face (FF) |
| Typical sizes | NPS 1/2 to NPS 60+ (including custom heat exchanger sizes) |
How Corrugated Metal Gaskets Work
The pressed corrugations create a series of concentric ridges on the metal sheet. Under bolt load, each ridge compresses the soft facing layer against the flange face, forming multiple independent seal lines. If one ridge fails to seal, adjacent ridges maintain the pressure barrier. This redundant sealing mechanism makes corrugated gaskets particularly effective for:
- Large-diameter heat exchanger flanges where bolt load distribution is uneven
- Low bolt load applications such as cast iron or fiberglass flanges
- Thermal cycling where expansion/contraction demands gasket elasticity
- Replacement of asbestos-containing gaskets in existing equipment
Material Options
| Metal Core | Facing | Max Temperature | Typical Service |
|---|---|---|---|
| SS 304 | Flexible graphite | 450 degC (842 degF) | General refinery service |
| SS 316L | Flexible graphite | 450 degC (842 degF) | Chemical, marine |
| SS 321 | Flexible graphite | 500 degC (932 degF) | High-temperature steam |
| Monel 400 | PTFE | 260 degC (500 degF) | Oxidizing acids |
| Inconel 600 | Mica | 850 degC (1,562 degF) | Exhaust, furnace applications |
| Titanium Gr.2 | PTFE | 260 degC (500 degF) | Aggressive chemical service |
The metal core thickness is typically 0.3-0.5 mm, which allows the corrugations to flex without permanent deformation. The facing layer is typically 0.25-0.50 mm per side, applied by adhesive bonding or mechanical interlocking during the forming process.
Corrugated vs Kammprofile Gaskets
Both corrugated and Kammprofile gaskets use a metal core with soft facing, but the core construction differs fundamentally:
| Feature | Corrugated Metal | Kammprofile |
|---|---|---|
| Core | Thin pressed sheet (0.3-0.5 mm) | Solid machined plate (2.5-4.5 mm) |
| Rigidity | Flexible, spring-like | Rigid |
| Bolt load required | Low to moderate | Moderate to high |
| Blowout resistance | Good | Excellent |
| Max pressure | Class 600 typical | Class 2500 |
| Reusability | No | Core reusable (re-face) |
| Cost | Moderate | Higher |
Corrugated vs Spiral Wound Gaskets
| Feature | Corrugated Metal | Spiral Wound |
|---|---|---|
| Construction | Pressed grooves + facing | Wound metal/filler strips |
| Best for | Large diameters, low bolt load | Standard piping flanges |
| Inner ring needed? | No | Yes, for certain services |
| Thermal cycling | Excellent | Good |
| Stock availability | Specialty | Widely stocked |
Apply controlled bolt torque using stud bolts per the flange bolt torque chart.
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