Part number H70251 is an AS568-251 black Buna-N (Nitrile) 70 Shore A O-Ring built to an inside diameter of 5.109 in (129.77 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.387 in (136.83 mm). An o-ring creates a positive seal at flange, piston and rod interfaces without added hardware.
As a material, Buna-N (Nitrile) offers strong abrasion and tear resistance, the most widely specified general-purpose sealing elastomer. Expect good resistance to propane and butane, hydraulic fluids, and many alcohols. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It should not be specified for service in ketones or polar solvents.
You will find this material specified across construction equipment, hydraulic and pneumatic systems, and agricultural equipment.
H70251 ships individually. Unit weight is approximately 5.07 g and nominal inside diameter is listed as 5 1/8 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.
description -251 BLACK BUNA 70D O-RING
uf_description2 0.139" (3.53MM) CS X 5.109" (129.77MM) ID
Actual_CS 0.139 inch (3.53 mm)
Actual_ID 5.109 inch (129.77 mm)
Actual_OD 5.387 inch (136.83 mm)
ProductCode Description O-Rings - Bulk - Commodity