568-318 BUNA 70 SQUARE CUT RINGS

This square-cut ring is supplied in AS568-318 black Buna-N (Nitrile) 70 Shore A built to an inside diameter of 0.975 in (24.77 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.395 in (35.43 mm), catalogued under part number SH70318. It resists the spiral failure that affects round rings on long reciprocating strokes.

This material stands up to many alcohols, greases and lubricants, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) delivers strong abrasion and tear resistance, low compression set under sustained load. Service temperature is rated from -40°F (-40°C) through 250°F (121.1°C). The profile itself contributes greater resistance to extrusion than a round section of the same size and a flat contact band that spreads sealing load across a wider area. Note that a square section is less suited to high-speed rotary service, where the larger contact area raises friction and heat.

Maintenance and OEM teams specify it across general industrial maintenance, agricultural equipment, and fluid power.

This item is sold individually under part number SH70318. Nominal inside diameter is listed as 1 inch. Check the compound against your process media, pressure and temperature before committing to a design. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.