Q-258 BUNA 70 Q RING

This quad-ring is supplied in AS568-258 black Buna-N (Nitrile) 70 Shore A measuring an inside diameter of 5.984 in (151.99 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 6.262 in (159.05 mm), catalogued under part number QH70258. It resists spiral failure in reciprocating service thanks to its multi-lobe geometry.

Buna-N (Nitrile) is specified here for low compression set under sustained load, strong abrasion and tear resistance. The material holds up against propane and butane, water, and hydraulic fluids. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). Exposure to polar solvents or automotive brake fluid will shorten service life. The profile itself contributes a parting line located away from the sealing surface and two sealing bands per contact face rather than one.

Common environments for this compound include hydraulic and pneumatic systems, general industrial maintenance, and automotive.

Order part number QH70258, sold individually. Unit weight is approximately 5.5776 g and nominal inside diameter is listed as 6 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.