Square-rings are square cross-section seals designed to be interchangeable with standard AS568 O-Rings. Complete interchangeability within standard glands is assured in most applications. 6" ID and larger may be vulcanized.
With flat edges on all four sides, square-profile O-rings cover more surface than round-profile O-rings for a better seal in static applications, such as hose, pipe, and faucet connections. They are made of Buna-N, which is resilient and offers excellent tear resistance. They resist hydraulic oils and motor oil.
A Square ring is an elastic part placed between two parts and then squeezed to fill up the gap between the two parts. After installation the ring is slightly compressed to seal at low pressures. When a square o-ring is pressurised, it's forced to a flow within the groove toward the clearance gap. In comparison to O-rings, the square shape allows the sealing solution to be exposed to higher pressures without the use of a Back-Up ring.
Buna-N o-rings also referred to as NBR o-rings and Nitrile o-rings are the most widely used o-ring material in the word because of low cost, good mechanical performance with resistance to water, most basic oils, lubricants and some fuels, many pneumatic, hydraulic systems, and the default choice for basic applications.