8-438 BLACK FKM 90D BACK-UP RING

This back-up ring is supplied in AS568-438 black Viton® (FKM) 90 Shore A with an inside diameter of 6.225 in (158.12 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 6.775 in (172.09 mm), catalogued under part number VBU90438. It bridges the extrusion gap so the primary seal holds its shape under load.

It resists aromatic hydrocarbons, petroleum oils and fuels, and engine and transmission fluids. Viton® (FKM) delivers long service life in hot, chemically aggressive environments and very low compression set at elevated temperature. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C).

You will find this material specified across automotive fuel systems, oil and gas, and aerospace.

VBU90438 ships individually. Unit weight is approximately 15.087 g and nominal inside diameter is listed as 6 1/4 inch. Check the compound against your process media, pressure and temperature before committing to a design.