Flange connection is to fix two pipes, pipe fittings or equipment on a flange plate, add flange pads between the two flange plates, and fasten them together with bolts to complete the connection. Some pipe fittings and equipment already come with flanges, which are also flange connections. Flange connection is an important connection method in pipeline construction. Flange connection is easy to use and can withstand large pressure.

Common flanges

Special flanges

Blind Flanges
Blind Flanges are round plates which have all relevant boltholes but lack a center hole and thus are used to close off the ends of a piping system or a pressure vessel opening.

Forged Steel Blind Flanges conform to ASTM A105 while Stainless Steel Flanges conform to ASTM A182.
Stocked in sizes from 1/2″ to 24″.
Available both with a flat face and a raised face.
Flanges of Class 150#, 300#, 600#, 900#, and 1500# are stocked.
Available in Carbon Steel as well as Stainless in grades 304L and 316L (L=low carbon).
Carbon Steel Flanges are available in both domestic and less expensive Imported versions. All Stainless Blind Flanges that we stock are imported.

Lap Joint Flanges
Lap Joint Flanges slide directly over a pipe and are used with Stub Ends. Typically, a pipe is welded to the Stub End leaving the Lap Joint Flange to rotate freely around the stub end, simplifying bolt hole alignment.

Lap Joint Flanges are forged steel and conform to ASTM A105.
Stocked in sizes from 1.50″ to 20″.
Forged Steel Lap Joint Flanges are available in both domestic and less expensive Imported versions.
Stub Ends are sold separately.

Slip On Flanges
Slip On Flanges are manufactured with an inside diameter that is slightly larger than the pipe’s outside diameter and are connected to the pipe via fillet weld at the top and bottom of the flange.

Stocked in sizes from 1/2″ to 24″, depending on the material.
Aluminum Flanges conform to ASM 6061 T6.
Carbon Steel Slip On Flanges conform to ASTM A105.
Stainless Steel Slip On Flanges conform to ASTM A182. Both 304L and 316L available.
Available with both a Raised Face and a Flat Face.

Socket Weld Flanges
Socket Weld Flanges are often used on smaller sizes of high pressure pipe and are attached to that pipe by inserting the pipe into the socket end and applying fillet weld around the top. This results in a smooth bore with excellent flow characteristics.