568-442 FKM 75 SQUARE CUT RINGS

This square-cut ring is supplied in AS568-442 black Viton® (FKM) 70 Shore A built to an inside diameter of 7.225 in (183.52 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 7.775 in (197.49 mm), catalogued under part number SV70442. It resists the spiral failure that affects round rings on long reciprocating strokes.

As a material, Viton® (FKM) is valued for the industry benchmark where nitrile reaches its thermal limit, excellent resistance to compression set and permeation. Expect good resistance to engine and transmission fluids, many acids, and petroleum oils and fuels. Rated temperature range runs from -15°F (-26.1°C) to 400°F (204.4°C) in continuous service. It is not the right choice where amines or ketones and esters are present. The profile itself contributes a flat contact band that spreads sealing load across a wider area 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.

Typical settings include aerospace, oil and gas, and automotive fuel systems.

Stocked as SV70442 and sold individually. Nominal inside diameter is listed as 7 1/4 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application.