8-439 BLACK FKM 90D BACK-UP RING

This back-up ring is supplied in AS568-439 black Viton® (FKM) 90 Shore A built to an inside diameter of 6.475 in (164.47 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.025 in (178.44 mm), catalogued under part number VBU90439. It installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Viton® (FKM) is widely chosen for the industry benchmark where nitrile reaches its thermal limit and long service life in hot, chemically aggressive environments. The material holds up against aromatic hydrocarbons, petroleum oils and fuels, and engine and transmission fluids. Continuous operating temperature is published at -15°F (-26.1°C) to 400°F (204.4°C).

Common environments for this compound include oil and gas, chemical processing, and aerospace.

Stocked as VBU90439 and sold individually. Unit weight is approximately 15.307 g and nominal inside diameter is listed as 6 1/2 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.