The Difference Between NBR Seal and FKM Seal of the Bearing

Sep 08, 2021

The NBR and FKM are the commen bearing sealing ring material. 

The differences are as follows:

1. Heat resistance

FKM seal: FKM sealing ring heat resistance characteristics and silica gel, can be said to be the stage of vulcanized rubber polyurethane elastomer stronger, the basic type of fluorine rubber number FKM or FPM, its product output can be long-term in 200℃ application, and perfluoroether vulcanized rubber FKM high can continue to be applied at 330℃.

NBR seal: higher 100℃ application, from the heat resistance of NBR sealing ring.

2. Physical performance

FKM seal: FKM seal has high quality physical and physical properties, has advantages in elastic compressive strength and tensile elongation level.

NBR seal: NBR seal has excellent physical reflectivity and production characteristics.

3. Reliability

FKM seal: FKM seal has smooth organic chemical characteristics, it is also at the present stage of all vulcanized rubber polyurethane elastomers in a variety of substances with stronger characteristics. Fluorine rubber oil resistant silicon ether, magnesium chloride oil, crude oil, base oil, double ester oil, resistant to most of the organic chemistry, inorganic organic solvent, resistance to strong oxidizer, drugs, etc., in which fluorine rubber resistance of the material not only to the following categories: low substructure of the ether, ester, ketone, and all of the ammonia, amines, chlorosulfonic acid, hydrochloric acid, ammonium sulfate type of gear oil.

NBR seal: poor cold resistance, poor resistance to reactive oxygen species, poor dielectric strength, low ductility.

4. Anti-aging characteristics

FKM seal: FKM seal has good resistance to weather embrittlement and reactive oxygen species. The yield of fluoro glue products is still satisfactory after five years of storage.

NBR seal: NBR seal anti-aging performance of is a little poor, general nitrile rubber product output can be stored for ten years.

5. Ultra-low temperature characteristics

FKM seal: because the organic chemical structure of FKM itself causes the cold resistance of FKM is not very excellent.

In the specific application of fluorine rubber ultra-low temperature characteristics are also general, unless the addition of a unique preservative can make fluorine rubber cold do minus 30 degrees, otherwise the general fluorine rubber only do minus 10 degrees.

NBR seal: Generally NBR adhesives can be cold resistant -30℃, and with extremely super cold resistance nitrile adhesives can be cold resistant -50℃.

Therefore, in the selection of sealing, it should be decided according to the working condition of the bearing.