Technical Information

On this page you will find an overview of the standard materials used for our metal seals, typical heat treatments, and the different plating options we can apply.

The selection of these parameters is highly application-dependent and is influenced by factors such as operating media, pressure, temperature, flange movement, available bolt load, and groove geometry. The information provided here serves as a technical reference to support early design and feasibility discussions.

As every application is unique, Provecta works closely with its customers to translate operating conditions into a fully optimized sealing solution. For project-specific guidance or further technical support, please do not hesitate to contact us.

Base Materials

For our metallic seals, we exclusively select high-quality base materials that must comply with strict purchasing specifications defined by Provecta. This ensures long service life as well as reproducible and consistent performance when the same seal type is reproduced or applied in a different application.

Seal Materials

Inconel® 718 (AMS 5596)
Developed after Inconel X-750, this nickel-chromium superalloy has become the industry standard for high-performance seals.

Very high strength, even at elevated temperatures
Excellent oxidation and corrosion resistance

Inconel® X-750 (AMS 5598)
Often reselected without discussion, as this material, the seal design and the application were already qualified decades ago.

High creep and fatigue resistance
Good weldability

Stainless steels (SS304 / SS316L – AMS 5507 & 5511)
For specific industrial or less extreme applications, stainless steel can be a suitable choice.

Good general corrosion resistance
Suitable for medium pressure and temperature processes
Often selected without plating depending on the process medium

Spring Materials

For spring-energised seals, the selection of the spring material is critical to achieve accurate and repeatable compression behaviour.

Inconel® 718 (AMS 5962)
The most widely used alloy for spring systems in metallic seals.

Inconel® X-750 (AMS 5699)
Frequently reselected without discussion, as the material, seal and application were already qualified in historical qualification programmes.

Nimonic® 90 (AMS 5829)
A nickel-chromium-cobalt superalloy developed for high-temperature spring applications, offering excellent performance.

Elgiloy® (Co-Cr-Ni alloy)
A spring alloy with unique properties for chemically aggressive environments and flat spring applications.

Why these materials?

The listed base materials represent the very top tier of the industry and provide:

High mechanical strength over a wide temperature range
Stable spring characteristics, crucial for high-performance C-seals
Superior corrosion and oxidation resistance, even in aggressive media
Reliable performance under thermal and mechanical cycling
Long service life in critical applications

These alloys and purchasing requirements are essential to consistently serve high-end markets.

Speed, control and traceability

By performing all heat treatments in-house, Provecta is able to:

Reduce lead times by days to weeks
Precisely fine-tune cycles according to the application
Guarantee full traceability (temperature profiles, time records, certification)
Iterate faster in R&D programmes
Ensure consistency across multiple batches

1. “SP” Annealing + Precipitation Hardening (long cycle for maximum performance)

The most comprehensive and technically demanding cycle, delivering the highest mechanical performance.
Properties: optimal strength after full annealing, excellent resilience and long-term stability under load.
Drawback: longer processing time → higher cost.

2. “NA” Annealing + Precipitation Hardening (NACE – HRC < 40)

For oil & gas applications, compliance with NACE MR0175 / ISO 15156 is required.

Hardness: < HRC 40, strictly controlled.
Application: corrosive environments, H₂S-sensitive systems.
Properties: controlled strength and ductility, maximum resistance to stress corrosion cracking.

3. “SC” Precipitation Hardening

Some applications require material that has already been annealed and only needs a precipitation hardening step.

Advantage: shorter lead time, increased strength without full heat treatment, lower cost.

4. “AN” Pure Annealing

Application: thin-walled seals, complex geometries or intermediate annealing steps.
Advantage: softer material and optimal formability.

In-house Plating

Provecta operates a fully equipped in-house plating department, enabling us to apply high-quality technical platings to our metallic seals.

The importance of a soft outer layer

Most of our metallic seals are finished with a soft outer layer, typically applied via electroplating. Depending on the application, a PTFE coating may also be used, for example in cryogenic or chemically inert environments.

This soft layer fulfils a critical function:

During compression, the material flows in a controlled manner under high contact pressure
It fills micro-grooves, scratches and other surface irregularities of the mating surface
Microscopic leakage paths are sealed

The result is a drastic improvement in sealing performance. Leak testing often shows that two identical metallic seals, one plated and one unplated, can differ by a factor of 1,000 to 10,000 in leak tightness, clearly demonstrating the decisive role of the outer layer.

Available plating materials and applications

Provecta offers a carefully selected range of plating materials, each with specific properties suited to different technical requirements.

Zilver (Ag)

One of the most commonly used soft metallic platings.

Advantages: excellent deformability, low friction, excellent thermal conductivity

Applications: aerospace, cryogenic systems, vacuum applications, ultra-low leakage requirements

Gold (Au)

Gold is fully inert and does not oxidise, even in extremely corrosive environments.

Advantages: very soft, excellent flow behaviour, perfect corrosion resistance
Applications: critical instrumentation, corrosive media

Tin (Sn)

Tin is a very soft plating, particularly suitable for low-temperature applications.

Advantages: extremely soft, flows easily into surface irregularities even at low contact loads
Applications: cryogenic systems, CO₂ lasers, cryocoolers

Nickel (Ni)

Nickel is often used at very high temperatures.

Advantages: high temperature resistance, high hardness, wear resistance, chemical and corrosion resistance
Applications: wear- or corrosion-loaded environments, high temperatures, and as an underlayer to improve adhesion of other platings