Friction or vibration welding belongs to the class of solid-state welding processes.This process utilizes the heat generated by friction between the work pieces.Among the work pieces one is kept constant while the other is rubbed against it.This rubbing generates friction and hence heat is produced which melts the surface of the work pieces.Only the surface of the work pieces melt and in real sense no actual melting takes place and therefore this procedure is actually a forging technique.
There are three types of Friction Welding
- Friction Surfacing
- Spin Welding
- Linear Friction Welding
Friction Surfacing is a process in which a coating material is applied to the base material’s surface.In this process a rod which is composed of the material to be coated is rotated upon the surface of the base material and simultaneously pressure is applied resulting a thin layer of the coating material which is deposited on the base material’s surface due to the friction in between them.
In Spin Welding one of the work pieces is kept constant while the other spins at a very high speed against it thereby producing friction and hence heat which melts the surfaces of the work pieces. The work pieces fuse together and cool down to produce a joint.Only circular or spherical materials can be joined by this process.
The overall process of Linear Friction Welding is similar to Spin Welding with a difference that one of the work pieces oscillates instead of spinning.A lower speed is required than spin welding and pieces of any shape or size can be joined by this process.