568-387 FKM 75 SQUARE CUT RINGS

This square-cut ring is supplied in AS568-387 black Viton® (FKM) 70 Shore A measuring an inside diameter of 17.955 in (456.06 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 18.375 in (466.73 mm), catalogued under part number SV70387. It seals with a broad flat contact band instead of the line contact of a round-section ring.

Expect good resistance to aggressive chemicals, aromatic hydrocarbons, and engine and transmission fluids. That behavior comes from the compound itself: Viton® (FKM) is valued for the industry benchmark where nitrile reaches its thermal limit, excellent resistance to compression set and permeation. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with hot water and steam or ketones and esters. 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.

Maintenance and OEM teams specify it across automotive fuel systems, oil and gas, and chemical processing.

SV70387 ships individually. Application requirements vary, so validate compatibility with your process conditions prior to installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.