A type of metal washer used to provide a seal around a screw or bolt
This design came about in order to solve seal problems that copper washers presented in high-pressure applications where they ended up bursting. The bonded seal was then invented, a static seal formed by an elastomeric lip seal/ring to which a metal washer was added.
What are the advantages of a bonded seal?
Bonded seals are produced by vulcanising the rubber ring to a zinc plated steel washer with heat and pressure. A simple process that brings many advantages to the finished product:
- Good seal for both low and high pressure.
- Able to withstand both high and low temperatures.
- Cost effective and very versatile solution for threaded bolts.
- Wide range of elastomers and metals available.
- Metal washer prevents over-compression, limits the elastomeric ring from deforming and can be used for overhead installations.
- Its design prevents excess compression and extrusion.
- Easy installation, seals flat surfaces that holds the lip seal in place.
- The self-centring bonded washers also prevent the possibility of leakage and ensure correct centring during installation.
Types of metal washers
The metal part of bonded seals can be made of different metals (copper, aluminium, steel...), but we only sell steel ones at JIOrings.
Zinc-plated carbon steel: Carbon steel (also known as mild steel) is a common machine steel with a low carbon content that is neither extremely brittle nor ductile. With the zinc plating process, a layer of zinc is bonded to the steel to protect it from corrosion when it is exposed to air and moisture.
Stainless steel: These ferrous alloys are highly corrosion-resistant alloys that contain chromium and/or nickel.
Types of elastomeric lip seals/rings
Elastomeric part of bonded seals can be made of different materials (NBR, FPM, HNBR, copolymers...). The choice will depend on its intended use. In our case, most of our bonded seals are made of NBR lip seal, although we also have some in FPM.
NBR: Acrylonitrile-butadiene rubber (NBR) is the most widely used material due to its good mechanical properties, high abrasion resistance, low gas permeability and high resistance to oils and mineral oil based-greases.
Check the size chart at https://jiorings.com/metal-buna-medidas/