Rubber Material Selection – For Gasket Applications

By Author: Abdullah Mohamed
Total Articles: 1
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Soft Gasket material is defined as the gasket material that is easily compressed under a low bolt load. A soft gasket material can be selected from a large variety of rubbers (neoprene, viton, SBR, EPDM, etc.), PTFE, graphite, and compressed non-asbestos sheet products. Soft gaskets are used in a wide range of applications from pipe flange, heat exchanger, compressor and bonnet valve gaskets to name just a few.
One of the more desirable properties of an effective gasket material in industrial applications is the ability to withstand high compressive loads. Most industrial gasket applications involve bolts exerting compression well into the 14 MPa (2000 psi) range or higher. This is why Non-asbestos gasket materials and especially Rubber materials are widely used in industrial gasket material applications.
However, it is always an issue when it comes to selecting the right rubber material for the intended application from the wide range that is available in the market. Selection should be in such a way that it should provide an effective and long standing seal at an optimum cost.
One should consider the following ...
... important parameters when selecting the right rubber material for the application:
Temperature Range; Compressibility; Recovery; Elongation; Tensile Range ; Chemical Compatibility; Hardness; Thickness
Once a right rubber material is chosen for the sealing application, that will provide the right start for the job on hand.
To make this task easier, we give below the rubber gasket material selection recommendations

Silicone:
Service temperature range: -80F to 550F ; Normal Durometer range: 10-85 Shore A
Recommended areas of usage: Flexibility, compression set resistance, UV, ozone, static applications ; Areas where it should not be used: Tear, abrasion and tensile strength, dynamic applications
Common applications: Electrical, fluid control, medical

Neoprene :
Service temperature range: -65F to 250F ; Normal Durometer range: 20-90 Shore A
Recommended areas of usage: Abrasion, ozone and flame retardant ; Areas where it should not be used: UV, heat, ketones and ester
Common applications: Industrial

EPDM : Ethylene Propylene Diene Monomer
Service temperature range: -60F to 300F ; Normal Durometer range: 25-95 Shore A
Recommended areas of usage: Weather, ozone and water ; Areas where it should not be used: Oils and corrosive environment
Common applications: Automotive, heating, ventilation and conditioning

Nitrile Rubber : Buna-N
Service temperature range: -40F to 250F ; Normal Durometer range: 30-95 Shore A
Recommended areas of usage: Oil, petroleum and high wear ; Areas where it should not be used: Ozone, tear, ketones and ester
Common applications: Industrial and automotive, in products such as fuel and oil handling hoses, seals grommets, hydraulic hoses, and o-rings.

Fluoro Elastomer ( Viton )
Service temperature range: -20F to 400F ; Normal Durometer range: 60-90 Shore A
Recommended areas of usage: Chemicals, heat, oil and petroleums ; Areas where it should not be used: Limited resistance to steam, hot water and methanol, low temperatures
Common applications: Aerospace, medical, chemical.

Fluoro Silicone :
Service temperature range: -65F to 450F ; Normal Durometer range: 40-70 Shore A
Recommended areas of usage: Heat, oils and fuels ; Areas where it should not be used: Tear, abrasion and tensile strength
Common applications: Chemical and hydrocarbon fuel seals.