This is a sealing ring made by bonding and vulcanizing a rubber ring with a metal ring, used for sealing threaded and flanged connections. The ring consists of a metal ring and a rubber sealing washer.
Metallic rings are treated for rust prevention, and rubber rings are generally made of oil-resistant nitrile rubber or fluororubber. The combined gaskets come in both metric and imperial sizes, adhering to the standard JB982-77 for the combination of metal and rubber in gaskets. Combination sealing washers are used for threaded pipe fittings and plugs, often used alongside sleeve-type pipe fittings to seal oil ports. They are primarily used for static sealing at the end faces of hydraulic valve pipe fitting threaded connections, suitable for both British and American standard imperial threads and French and German standard metric threads. Combination sealing washers can be categorized into Type A and Type B based on their structural forms; and into full-jacketed and half-jacketed based on the rubber covering.