Semi-Metallic Gaskets

What Are Semi-Metallic Gaskets?
Semi-metallic gaskets are engineered sealing components that combine metallic and non-metallic materials to deliver reliable performance in demanding industrial environments. By pairing the structural strength of a metal core or winding with the conformability of softer sealing materials such as flexible graphite or PTFE, semi-metallic gaskets bridge the gap between fully metallic and non-metallic gasket types. This construction allows them to withstand high pressures, elevated temperatures, and thermal cycling conditions where conventional soft gaskets may fail.

Durlon® manufactures a range of semi-metallic gasket types, each engineered for specific operating conditions and flange configurations. The primary types include corrugated-faced gaskets (CFG), Durtec® gaskets, Kammprofile gaskets, and spiral-wound gaskets (SWG).

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Semi-Metallic Gasket Types
Corrugated Faced Gaskets (CFG)
Durlon® CFG gaskets feature a corrugated metal core with laminated flexible graphite facing on both sides. The corrugated profile acts as a spring element, providing bolt load retention and the ability to conform to flange surface irregularities. This makes CFG gaskets particularly effective in applications that involve thermal cycling, such as heat exchangers, processing pipes, and equipment subject to frequent start-up and shutdown cycles. The spring-like action of the corrugated core helps maintain seal integrity as flanges expand and contract under temperature changes.

Durtec® Gaskets
Durlon® Durtec® gaskets use a specially engineered, machined metal core bonded on both sides with soft covering layers, typically flexible graphite. This construction handles fluctuations in pressure and temperature while maintaining a consistent seal. Durtec® gaskets are suited to applications in chemical processing, steam systems, and hydrocarbon processing where sustained sealing reliability is required under variable operating conditions.

Kammprofile Gaskets
Durlon® Kammprofile gaskets consist of a solid metal core with concentrically serrated grooves machined into both faces, covered with a soft sealing material such as flexible graphite. The serrated profile provides high compressibility and recovery, allowing the gasket to seal effectively at relatively lower bolt loads than other semi-metallic types. Kammprofile gaskets are well-suited to heat exchangers, pressure vessels, and flanged joints operating under varying pressures and temperatures. They are reusable in many cases, as the metal core can be re-faced with new sealing material.

Spiral Wound Gaskets (SWG)
Durlon® Spiral Wound Gaskets are composed of a pre-formed metal strip and a softer filler material wound together in alternating layers. The V-shaped metal strip acts as a spring, providing resilience and the ability to adjust to irregularities in flange sealing surfaces. SWGs are available in multiple configurations, including Style D (centering ring only), Style DR (centering and inner ring), and Style DRI (centering ring, inner ring, and additional features). Spiral wound gaskets are widely used across the oil and gas, refining, petrochemical, and power generation industries for their versatility in handling thermal and mechanical stresses.

How to Select the Right Semi-Metallic Gasket
Selecting the appropriate semi-metallic gasket depends on several application-specific factors. Operating temperature and pressure ranges determine which gasket construction provides adequate sealing. Flange condition and bolt load capacity influence whether a lower-seating-stress option, such as a Kammprofile or CFG, is preferable over a spiral wound gasket. The chemical compatibility of the metal alloy and filler material with the process media must be verified. For applications involving thermal cycling, gaskets with high recovery characteristics, such as corrugated-faced or Kammprofile types, are generally recommended.

For application-specific recommendations, Durlon’s engineering team can assess operating conditions and recommend the optimal gasket type and material combination. Use the Gasket Application Data Form to submit your service parameters for a technical review.

Industries and Applications
Durlon® semi-metallic gaskets serve a range of critical industries, including oil and gas (upstream, midstream, and downstream), chemical processing, power generation, pulp and paper, mining, marine vessels, and primary metals processing. Common applications include flanged pipe joints, heat exchangers, pressure vessels, valves, pumps, and compressor housings. Each gasket type is matched to application demands based on temperature range, pressure class, media compatibility, and flange surface requirements.

Standards and Compliance
Durlon® semi-metallic gaskets are manufactured under rigorous quality control processes using computer-aided manufacturing. Gasket dimensions and construction adhere to applicable industry standards. Spiral wound gaskets are available in configurations conforming to ASME B16.20. For specific compliance documentation, including certificates of conformity, contact Durlon directly or visit the Product Data Sheets resource page.

Custom Semi-Metallic Gasket Solutions
In addition to standard sizes, Durlon® offers custom-fabricated semi-metallic gaskets for non-standard flanges, equipment-specific geometries, and unique operating conditions. Custom capabilities include CNC cutting, lathe cutting, and fabrication in a range of alloys and filler materials. For details on custom sizing and materials, refer to the Custom Capabilities resource page or submit a Gasket Application Data Form.

Get Reliable Semi-Metallic Gaskets for Your Application
Durlon® semi-metallic gaskets deliver durable sealing for industrial and custom applications. Choose from corrugated faced, Durtec®, Kammprofile, or spiral wound gaskets engineered for high-pressure, high-temperature, and thermally cycling environments.

Contact us today to request a quote or speak with a sealing solutions specialist.

FAQs About Semi-Metallic Gaskets
What is the Difference Between Semi-Metallic and Metallic Gaskets?
Semi-metallic gaskets combine a metal component (core, strip, or winding) with a non-metallic sealing material such as flexible graphite or PTFE. Metallic gaskets, such as ring-type joints (RTJs), are made entirely of metal and seal through metal-to-metal contact. Semi-metallic types generally require lower bolt loads and offer greater conformability to flange surfaces compared to fully metallic gaskets. Learn more in our Guide to Metallic and Semi-Metallic Gaskets.

What Materials Are Used in Durlon® Semi-Metallic Gaskets?
Durlon® semi-metallic gaskets are available in a range of metal alloys and filler materials. Common semi-metallic gasket materials include carbon steel, stainless steel (304, 316, 321, 347), and other alloys selected based on chemical compatibility and operating conditions. Flexible graphite is the most common filler and facing material. Specific material options vary by gasket type. See the Product Data Sheets for material specifications.

Which Semi-Metallic Gasket Type is Best for Heat Exchangers?
Kammprofile and corrugated faced gaskets (CFG) are commonly selected for heat exchanger applications due to their high recovery characteristics and ability to maintain seal integrity under thermal cycling. The appropriate choice depends on the specific operating conditions, including temperature range, pressure, and flange design. Submit a Gasket Application Data Form for an application-specific recommendation.

Can Semi-Metallic Gaskets Be Reused?
Kammprofile gaskets can be reused in many cases because the solid metal core is not permanently deformed during service. The soft facing material can be replaced, and the core reinstalled. Spiral wound gaskets, corrugated faced gaskets, and Durtec® gaskets are generally single-use components and should be replaced during maintenance.

What Standards Apply to Semi-Metallic Gaskets?
Spiral wound gaskets are commonly manufactured to ASME B16.20 dimensional standards. Other applicable standards may include ASME B16.5 (for flange pressure-temperature ratings) and API specifications for specific applications. Contact Durlon for compliance documentation relevant to your project requirements.