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Pipe Flanges

A pipe flange is a disc, collar or ring that attaches to pipe with the purpose of providing increased support for strength, blocking off a pipeline or implementing the attachment of more items. They are usually welded or screwed to the pipe end and are connected with bolts. A gasket is inserted between the two mating flanges to provide a tighter seal. These flanges are either custom with dimensions provided by the customer or they are manufactured according to published specifications. Several organizations and associations have published specifications that provide dimensional information as well as pressure specifications at different temperatures. Our company manufactures custom designs and stocks six basic types of these products. Although, these are the six most common types, we are a custom manufacturer as well and are able to create just about any type of flange necessary for your requirements. Please click on one of the following pictures for a more detailed description of the item you are interested in. Each page also has a video that provides a better understanding of the installation process.



Slip-on pipe flanges actually slide over the pipe. They are typically machined with an inside diameter slightly larger than the outside diameter of the pipe. This allows the flange to slide over the pipe but to still have a somewhat snug fit. Slip-ons are secured to the pipe with a fillet weld at the top and the bottom of the flange. These are further catagorized as a ring or a hub. Rings and hubs are both considered slip on flanges because they both fit over the pipe.

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Weld Neck

Weld neck pipe flanges are installed by welding the pipe to the neck of the flange. This allows for the transfer of stress from the flange to the pipe itself. This also reduces high stress concentration at the base of the hub. Weld necks are often used for high pressure applications. The inside diameter of this attachment is machined to match the inside diameter of the pipe.

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Blind pipe flanges are used to seal the end of a piping system or pressure vessel openings to prevent flow. They are commonly used for pressure testing the flow of liquid or gas through a pipe or vessel. They also allow easy access to the pipe in the event that work must be done inside the line. Blind pipe flanges are often used for high pressure applications.

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Lap Joint

Lap joint pipe flanges fit over the pipe and are most commonly used with Stub End Fittings. A pipe is typically welded to the Stub End and the Lap Joint is free to rotate around the stub end. The benefit of this is that there will not be any issues with bolt hole alignment. These are often used for applications that require frequent dismantling.

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Threaded pipe flanges are similar to slip-ons except the bore of threaded pipe flange has tapered threads. They are used with pipes that have external threads. The benefit of these is that it can be attached without welding. Threaded pipe flanges are often used for small diameter, high pressure requirements.

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Socket-weld pipe flanges are typically used on smaller sizes of high pressure pipes. These flanges are attached by inserting the pipe into the socket end and applying fillet weld around the top. This allows for a smooth bore and better flow of the fluid or gas inside of the pipe.

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