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What is a Flange Plate?

Lori Kilchermann
Lori Kilchermann

A flange plate is a flat, circular disk that is welded onto the end of a pipe and allows it to be bolted to another pipe. Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them. The flange plate will have bolt holes all around the perimeter and will be used to create junctions, tees and joints.

When building a pipeline, the length of the pipes used are not always known. By manufacturing the pipe separate from the flange plate, the welders can cut the pipe to length and weld a flange plate in place to join the pipes at any needed length. The plates can also be welded to the pipe on a slight bias, allowing two pipes to be joined that may not be precisely lined up.

Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them.
Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them.

Flange plate designs are uniform in any given size regardless of materials used to create them. This allows a 6-inch (15 cm) black pipe flange to mate perfectly with a 6-inch stainless steel flange. The flange plates will have a serrated finish on the inside mating surface, which allows the plate to seat into the gasket material. This ensures a perfect seal between two joining pipes.

A blind flange refers to a disk that is used to block off a pipeline or to create a stop.
A blind flange refers to a disk that is used to block off a pipeline or to create a stop.

There are many different styles of flange plates that are used for different purposes. The blind plate acts as a cover or cap for a pipe and is used to seal or block off a pipe. The slip-on style of plate allows the plate to be slid onto a pipe and then welded in place. Using the socket weld-style of plate on the ends of two pipes allow them to be easily connected and disconnected.

Flange plates with chamfers and bevels are used to assist in lining up two pipes which are out of alignment. Plates with a studding outlet are plates that have studs inserted around the plate in place of bolt holes. This type of plate allows the pipes to be joined by sliding one flange plate over the studs on a second flange plate and then nuts are tightened to secure the two.

Flange plates make it possible to remove a section of pipe or to add onto a pipeline with ease. Without the flange plates, the pipes would require cutting and welding in order to be separated or added onto. This would be much more expensive and the pipe line would be out of service for a greater length of time.

Discussion Comments

kentuckycat

@TreeMan - I was interested by your question, so I tried to do some digging. As far as I know, the terms chamfer and bevel mean the same thing (even though I'm sure there is probably a subtle different).

In terms of piping, you can purchase both chamfering and beveling machines. Each one seems to put an angled edge on the pipe. Perhaps it helps the pipe to slide into the adjoining pipe and be connected. Maybe someone else will have some experience with this and can provide a better description.

jcraig

I don't know anything about construction or welding or the like, but is there ever any problem with welding a flange to two different types of metal?

For example, the article mentions a stainless steel plate flange connecting to a black pipe. If you were using a slip-on plate, would there be any sort of reaction between the two materials when you were welding, or does this not matter?

Also, several different flange plate types are mentioned. Are there special situations where each one is used, or is it basically up to the builders? Is there one that is stronger than another, or is one better for certain pipe materials or pipe uses?

titans62

Is there anyone here that has ever tried to replace a hydraulic flange?

I have a hydraulic wood splitter, and it started to leak fluid recently. I'm not sure if it is the flange or gasket that is causing the problem, but I think I could possibly fix it with the right information.

I have the original manual that describes the parts, and I think I know the right size I would need if I knew where to find one. Are these sold at hardware stores, or should I just call the company. Also, is this really something I could fix on my own, or am I just kidding myself?

TreeMan

I see flange plates every day and never knew what they were called. I never really thought about why they were there either.

Could someone explain to me what the chamfer and bevel system is? I understand that it connects pipes that are out of alignment, but how does it work? Also, is there any way that you can connect two pipes of different diameters together? It seems like that might be important in some cases.

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    • Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them.
      By: Jim Parkin
      Typically used in fuel and water pipelines, the two flange plates will be bolted together with a gasket in between them.
    • A blind flange refers to a disk that is used to block off a pipeline or to create a stop.
      By: chartcameraman
      A blind flange refers to a disk that is used to block off a pipeline or to create a stop.