568-245 BUNA 70 SQUARE CUT RINGS

APG stocks the SH70245, an AS568-245 black Buna-N (Nitrile) 70 Shore A Square-Cut Ring built to an inside diameter of 4.359 in (110.72 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 4.637 in (117.78 mm). A square-cut ring resists the spiral failure that affects round rings on long reciprocating strokes.

As a material, Buna-N (Nitrile) is widely chosen for low compression set under sustained load and the most widely specified general-purpose sealing elastomer. Expect good resistance to many alcohols, propane and butane, and greases and lubricants. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). It is not the right choice where polar solvents or ozone and direct sunlight are present. The profile itself contributes a flat contact band that spreads sealing load across a wider area and greater resistance to extrusion than a round section of the same size. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

Typical settings include agricultural equipment, fluid power, and general industrial maintenance.

Order part number SH70245, sold individually. Unit weight is approximately 4.059 g and nominal inside diameter is listed as 4 3/8 inch. Check the compound against your process media, pressure and temperature before committing to a design. For a size or compound outside the standard catalog, APG can quote from a print or sample.