8-252 BLACK BUNA 90D BACK-UP RING

APG stocks the HB90252, an AS568-252 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 5.234 in (132.94 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.512 in (140 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

The material holds up against water, many alcohols, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) is widely chosen for strong abrasion and tear resistance, an economical choice for high-volume maintenance programs. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). It should not be specified for service in ozone and direct sunlight or strong acids.

It sees regular use in construction equipment, fluid power, and general industrial maintenance.

Stocked as HB90252 and sold individually. Unit weight is approximately 1.9248 g. Check the compound against your process media, pressure and temperature before committing to a design.