A bonded seal is a type of washer used to provide a seal around a screw or bolt. The Bonded Seal comprises a metal washer and an elastomeric ring bonded inside the diameter. A bonded seal consists of an outer annular ring of a hard material, (typically stainless steel SS316, SS304, aluminum, brass, etc) and an inner annular ring of an elastomeric material that acts as a gasket. It is the compression of the elastomeric part between the faces of the parts on either side of the bonded seal that provides the sealing action. The elastomeric material, typically NBR， HNBR， FKM， EPDM, is bonded by heat and pressure to the outer ring, which holds it in place. The metal washer prevents over-compression and limits deformation of the elastomeric ring. This structure increases resistance to bursting, increasing the pressure rating of the seal. Because the bonded seal itself acts to retain the gasket material, there is no need for the parts to be sealed to be shaped to retain the gasket. This results in simplified machining and greater ease of use as compared to some other seals, such as O-rings. Some designs come with an additional flap of rubber on the internal diameter to locate the bonded seal at the center of the hole, these are called self-centring bonded washers.
1. Versatile, applicable to all threaded bolts, studs, and clearance holes.
2. Sealing washers are available for metric, Whitworth, and BSP threads.
3. Reliable and suitable for high and low-pressure sealing.
4. Available in different temperature ranges.
5. Easy installation.
6. The rubber and metal combination prevents over-compression and extrusion.
7. cost-efficient solution for bolt/thread sealing.
Type of Bonded Seal
/ GM500 / U-Seal
Can be used to seal clearance or tapped holes in general engineering using a
wide range of different bolts
- Can be used on flat flanges or with recessed bolt holes
/ GM500 self-centering
Ability to pre-assemble
Ease of assembly
All European thread sizes available
· GM1000 Sealing Ring
- Good sealing function with a low tightening moment - No need of a countersink to center the seal, this is achieved thanks to the design of the sealing lip
Mostly used together with metric bolts with hexagonal headsasper DIN
On request GM 1000 can also be made for inch threadsaswellasfor special bolt
· GM2000 Sealing Ring
Rubber to metal bonded seal with specially designed sealing lip for threads and
No need of a countersink to center the seal, this is achieved thanks to the
design of the sealing lip
The seal prevents leakage by sealing in the thread
The three contact lips of the rubber body seal the thread to nut and machine
Mostly used together with hexagonal nuts as per DIN specification as well as
for threaded connectors and adjusting screws
· KDS Sealing Ring
Rubber and metal bondeding, EO-3 soft sealing ring for Banjo Fitting.
EO-3 is an innovative Parker flareless fitting for metric tubing similar to the
EO and EO-2 series.
EO3 flareless fitting system utilizes a visual indicator to prevent leakage due
or over-tightening, allowing the user more control to make high-quality, fast connections.
Max pressure is dependent of design, material choice and dimensions. Bonded Seals can be designed to withstand from 25 to 200 MPa max pressure.
Please contact us for further information.
-30 °C to + 100 °C NBR 70 Shore A
-20 °C to + 100 °C NBR 90 Shore A
-18 °C to + 200 °C FKM 70 Shore A / FKM 75 Shore
-50 °C to + 120 °C EPDM 70 Shore A / EPDM 75 Shore
-10 °C to + 80 °C NBR/PVC blend 60 Shore A
Mineral oils, water, water-oil emulsion, gases
Bonded seals are available in a choice of materials including:
Rubber Material: NBR, FKM, EPDM, HNBR, SILICONE, NEOP, ACM.
Metal Material: Carbon Steel, SS304, SS316, Aluminum#5052, Copper, AISI#1050.
Surface Treatment: CR3, ZnNi, Phosphate, Anodizing, Cobalt Plating, Tinne Plating.