up to +900°C
up to 75,000 psi
|down to 10-12 mbar
including hydrogen, grease and residues from diesel exhaust
By minimizing leakage, and hence increasing power and efficiency, they improve the performance of both existing and developing fueled systems. This enhancement is welcomed by OEMs, Tier 1 suppliers and tuning kit providers. It allows systems to be pushed to new levels, without fear of the increasingly demanding conditions this creates.
Essentially, a metal seal has the properties of a spring, holding a continuous line of contact with the cavity to prevent or restrict leakage. Under a sufficient seal contact load, it deforms to conform with the shape of the contacting surface.
Importantly, metal seals are less flexible than polymer alternatives. In most cases, the metal seal undergoes plastic as well as elastic deformation – ultimately becoming permanently reshaped to fit tightly against the sealed assembly. This is the reason why metal seals are not reusable. Once a sealed joint has been disconnected, its seal must be replaced with a new one.
In most applications, Resilient Metal Seals are static – except perhaps for a little movement due to vibration. When we speak of a dynamic metal seal application, we are usually talking about slow and limited motion. Typically, this might mean:
Metal seals with relatively large amounts of movement – 0.100” (2.54 mm) or more – tend to be regarded as ‘flow restrictors’ rather than true seals. However, we will be happy to work with you to create much more dynamic metal seals, with extremely low leakage, if your application requires them.
Resilient Metal Seals can be broadly divided into two types: face seals and radial (axial) seals. Face seals generate a seal contact load by being compressed. Radial seals generate their load through interference between the contacting surfaces of the bore and shaft. In each case, the seal contact load results in deformations of the seal or its plating which enable it to fill any imperfections in the mating hardware.
The metal seal’s effectiveness in preventing leakage depends on factors including:
• Size of the contact load
• Quality of the seal’s surface finish
• Quality of the cavity’s surface finish
• Degree of conformity of the seal contact line to the cavity surface
• Choice of plating material
At Saint-Gobain, we can vary the factors above, and other parameters, to achieve the best result for you. We offer a range of Resilient Metal Seal types, shapes and structures to suit the nature of the application and the conditions faced. As with any Saint-Gobain product, our design engineers will co-operate with you to develop a tailored solution meeting your precise needs. They draw upon deep technological experience in fields such as aviation, space and energy, as well as automotive engineering.
The seal’s size, shape and other characteristics will be optimized for your use, and it will be produced with tight tolerances. Crucially, our simulation programs and testing facilities will ensure full confidence in its behavior under real-life conditions.
Our Resilient Metal Seals were initially developed for internal combustion engine vehicle (ICE) and hydrogen mobility applications, but their properties offer other great opportunities both within and beyond the automotive sector. Examples include:
• Fueling noses (diesel and gas)
• CO2 compressors
• Hydrogen tanks
The key automotive applications of our Resilient Metal Seals, relating to medium-duty and heavy-duty vehicles, are:
|turbocharger and exhaust manifold interfaces
|butterfly and wastegate valves incl. EGR* valves
|Challenge: hot exhaust gas temperatures; thermal movement
|Challenge: non-uniform joint separation
|Challenge: extreme temperatures; thermal movement
|Challenge: high cost of welded bellows; thermal movement
|Solution: external dynamic resilient metal lip seals
Solution: metal turbo seal (internal pressure type) with or without retainer plate
|Solution: axial V-seal
Solution: assembly including two external dynamic resilient metal lip seals and a machined tube
The base materials for our Resilient Metal Seals are usually high-temperature metals like INCONEL 718 steel and stainless steel. Optional plating with gold, silver or other coatings can be applied to adjust seal properties as required for specific applications. Heat treatment increases the seals’ strength and durability.
Most of our metal seals are produced by die-forming (stamping) or roll-forming processes. We can supply any quantity, however large or small. Depending on the volume needed, and the cost considerations, we manufacture them on manual or fully automated lines.
Tailored to your needs
Like all our products, our Metal Seals will be custom-designed, configured and manufactured according to the requirements of your individual application and order.
Our engineers will work closely with you at all stages to understand and meet those needs precisely. Discuss your challenges with us, engineer to engineer.
January 26th, 2023