How Do Corrugated Metal Gaskets Prevent Leakage in High Pressure Systems?

Corrugated metal gaskets prevent leakage in high-pressure systems by using a series of concentric ridges that concentrate sealing force into narrow contact lines, generating localized surface stress far exceeding the nominal bolt load. This mechanical advantage allows them to maintain a reliable seal at pressures exceeding 400 bar and temperatures above 600°C — conditions where soft gaskets fail outright. The sections below explain the engineering behind this performance, how to select the right material, and what installation practices protect the seal over the long service life these gaskets are designed to deliver.

The Engineering Mechanism Behind the Corrugated Seal

A metal corrugated sealing gasket works on a fundamentally different principle from flat soft gaskets. Rather than distributing bolt load across a wide surface area, the corrugated profile concentrates that load onto the peaks of each ridge. When bolts are tightened, those peaks plastically deform slightly and conform to microscopic surface irregularities on the flange face — filling voids that would otherwise become leak paths.

The key parameters that govern sealing performance are:

• Number of corrugations: More ridges provide more sealing lines and redundancy against leak propagation.
• Ridge pitch and height: Finer pitch increases contact line density; ridge height determines the elastic recovery available to compensate for thermal cycling and pressure fluctuation.
• Soft coating or filler: Most corrugated metal gaskets are faced with a thin layer of PTFE, graphite, or soft metal (silver, copper) that fills surface micro-defects and lowers the required seating stress.
• Base metal selection: The core material must be harder than the coating but soft enough to conform — stainless steel, carbon steel, Inconel, and titanium are common choices matched to the service medium.

This combination of metal resilience and soft facing is what allows corrugated metal gaskets to maintain a tight seal through repeated thermal cycles — a requirement that neither all-metal nor all-soft gaskets can satisfy alone.

Performance Comparison: Corrugated Metal vs Other Gasket Types

Understanding where corrugated metal gaskets outperform alternatives helps engineers make the right specification decision. The table below summarizes the operating envelope for each major gasket type:

Corrugated metal gaskets occupy a practical sweet spot: they outperform spiral wound designs in thermal cycling resistance while requiring lower seating stress than ring joint gaskets, making them compatible with a wider range of flange ratings and bolt patterns.

Why High Temperature Corrugated Gaskets Outperform Alternatives

In high-temperature service, most gasket materials lose seating stress as thermal expansion drives flange rotation and bolt relaxation. A high temperature corrugated gasket resists this because the corrugated metal core retains elastic recovery even at elevated temperatures — the ridges act as mechanical springs that maintain contact pressure as the joint expands and contracts.

The chart below illustrates how residual seating stress — the force keeping the seal intact — compares across gasket types as operating temperature rises:

At 500°C, a corrugated metal gasket retains approximately 78% of its initial seating stress, compared to roughly 40% for spiral wound and less than 15% for non-asbestos flat gaskets. This retention is the direct reason corrugated designs are specified in steam turbine, fired heater, and hydrogen process applications where thermal cycling is continuous and leak tolerance is zero.

Material Selection: Choosing the Right Stainless Steel Corrugated Sealing Ring

The base metal of a stainless steel corrugated sealing ring must be selected based on the corrosive properties of the process medium, the operating temperature, and the required mechanical strength. The following guide covers the most common material choices:

304 / 304L Stainless Steel

Suitable for general chemical service, water, steam, and mild acids up to approximately 450°C. The most widely used base material due to its broad availability and good corrosion resistance in non-chloride environments. 304L is preferred when welding is involved in the flange assembly, as the low carbon content reduces sensitization risk.

316 / 316L Stainless Steel

The addition of molybdenum improves resistance to chloride pitting and crevice corrosion, making 316 the standard choice for marine environments, coastal installations, pharmaceutical processes, and dilute halide acid service. Operating range extends to approximately 500°C in continuous service.

Inconel 625 / 825

Nickel-based superalloys are specified for service above 550°C or in highly aggressive media such as concentrated acids, sulfur compounds, or hydrogen sulfide. Inconel 625 maintains mechanical strength above 700°C and provides outstanding oxidation resistance in cyclic high-temperature applications.

Titanium Grade 2

For highly oxidizing media — wet chlorine, chlorine dioxide, nitric acid — titanium offers corrosion resistance that stainless steel cannot match. Its lower density also makes it the preferred choice in weight-sensitive offshore or aerospace applications.

Facing Materials and Their Effect on Sealing Performance

The soft facing applied to both sides of a metal corrugated sealing gasket fills flange surface micro-defects and lowers the minimum required seating stress. Selecting the correct facing material is as important as selecting the correct base metal:

• Flexible graphite: Excellent conformability and chemical resistance across a wide pH range. Suitable up to 450°C in oxidizing atmospheres and up to 600°C in non-oxidizing or reducing media. The most common facing for steam and process piping.
• PTFE: Inert to virtually all chemicals except molten alkali metals and fluorine. Limited to approximately 230°C. Preferred in pharmaceutical, food processing, and strong acid service where contamination from graphite or metal particles is unacceptable.
• Silver or copper overlay: Used in extremely high-temperature service or where the process medium attacks graphite. Silver facing is common in hydrogen service above 500°C and in cryogenic applications.
• Non-asbestos compressed fiber: A lower-cost alternative for moderate-temperature service (up to 300°C) where chemical compatibility allows. Less conformable than graphite but adequate for standard water, air, and low-pressure steam applications.

Application Sectors: Where Corrugated Metal Gaskets Are Specified

The following chart shows the distribution of corrugated metal gasket applications across major industrial sectors, reflecting both the diversity of use cases and the relative demand intensity:

Petroleum and gas processing accounts for the largest share at 34%, driven by the prevalence of high-pressure, high-temperature flanged joints in refining and upstream production. Chemical processing follows at 27%, where corrosion resistance requirements often dictate the use of specialty alloy corrugated gaskets over simpler sealing solutions.

Installation Guidelines That Protect Long-Term Seal Integrity

A correctly specified corrugated metal gasket can fail prematurely if installation practices are poor. The following steps are critical to achieving full design-life performance:

1. Flange face inspection: Verify that flange faces meet the specified surface finish (typically 125–250 Ra µin for serrated finish, 63 Ra µin for smooth finish). Pits, radial scratches, or corrosion must be repaired before installation.
2. Gasket centering: Use alignment pins or temporary guides to ensure the gasket is concentric with the bolt circle. Off-center installation creates uneven seating stress and preferential leak paths.
3. Bolt lubrication: Apply an appropriate lubricant (never-seize compound or molybdenum disulfide paste) to threads and nut-bearing surfaces. Dry threads introduce up to 40% uncertainty in actual bolt load versus target torque.
4. Cross-pattern tightening: Tighten in three to four passes using a cross-bolt pattern at 30%, 70%, and 100% of target torque, then perform a final clockwise check pass. This ensures uniform compression across the gasket face.
5. No reuse: Corrugated metal gaskets are single-use items. The plastic deformation that creates the initial seal cannot be replicated on the second installation — always fit a new gasket when breaking a flanged joint.

About Ningbo Rilson Sealing Material Co., Ltd.

Ningbo Rilson Sealing Material Co., Ltd. was founded in 2007 and is located in Ningbo, Zhejiang Province. The manufacturing facility spans 20,000 square meters and is dedicated to ensuring the secure and dependable operation of fluid sealing systems. We operate numerous production lines for sealing products, specializing in the design and manufacture of sealing gaskets and other sealing materials for the petroleum, chemical, power, shipbuilding, and machinery manufacturing sectors.

Our primary products include spiral wound gaskets, ring joint gaskets, kammprofile gaskets, corrugated metal gaskets, insulation kit gaskets, and non-asbestos gaskets, among others. Our clientele hails from various parts of the globe, and through extensive industry experience, we have earned the trust and recognition of customers worldwide. We hold ISO 9001:2015 quality management system certification as well as the API 6A certificate.

As a professional corrugated metal gaskets manufacturer and supplier, we are dedicated to delivering value to customers, promoting health and wellbeing among workers, and producing positive social outcomes. We uphold the core principles of integrity, precision, innovation, and mutual success. With the aspiration of becoming the preferred brand in industrial gaskets, we are committed to establishing ourselves as a leading player in the fluid sealing industry.

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