568-137 BUNA 70 SQUARE CUT RINGS

This square-cut ring is supplied in AS568-137 black Buna-N (Nitrile) 70 Shore A supplied with an inside diameter of 2.05 in (52.07 mm), a cross section of 0.103 in (2.62 mm), and an outside diameter of 2.256 in (57.3 mm), catalogued under part number SH70137. It resists the spiral failure that affects round rings on long reciprocating strokes.

The compound resists greases and lubricants, petroleum-based oils, and propane and butane. Buna-N (Nitrile) is widely chosen for low compression set under sustained load and the most widely specified general-purpose sealing elastomer. The material carries a published service range of -40°F (-40°C) to 250°F (121.1°C). Applications involving ketones or polar solvents call for a different compound. The profile itself contributes simple lathe-cut manufacture at low tooling cost and a rectangular section that will not roll in the groove. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

It sees regular use in hydraulic and pneumatic systems, general industrial maintenance, and fluid power.

Stocked as SH70137 and sold individually. Unit weight is approximately 1.147 g and nominal inside diameter is listed as 2 1/16 inch. Check the compound against your process media, pressure and temperature before committing to a design.