The flange, also known as a plate due to its shape, is a piece whose function is to join one tubing to another in piping systems. In the same way, it is also used to connect two different tubular devices (tubing to valves, or tubing to equipment).

The connection between two tubing can be made by welding directly across a seam, but connecting two tubing together without welding is a difficult task. Furthermore, when this type of connection presents problems, it becomes difficult to repair them. The same problems can appear between a tubing and a valve connection. Generally, flanges are used to connect pipes or valves, so the above-mentioned problems can be easily solved.