They are like rims which are used to strengthen the mechanical part or they are a means of attaching that part to another part or surface.

Flanges are available in round, square, and rectangular shapes.

Pipe Flanges are widely used as a popular category of pipe fittings.

A flange is used to mechanically connect two pipes together.

It can also be used to mechanically connect a pipe to a tee, valve, choke or any other piece of equipment.

In some cases, flanges are usually in the shape of a ring or a plate to form a rim at the end of a pipe when fastened to the pipe.

This is an example of closet flange.