Friction welding

Known since the end of the last century, but rarely used, friction welding was developed in its industrial form in the Soviet Union around 1956, then in Great Britain and the USA a few years later.

Friction welding is used to produce butt joints between two parts, at least one of which is rotationally symmetrical. It uses the thermal effect generated in the joint plane by rapid rotation of the parts under pressure, or by friction. The heating power results from the resistive torque and the rotation speed, which is kept constant in principle. This is an all-round joining process, which is classified as a forging process. Due to material creep during friction and forging, the melting temperature is never reached.

It is difficult to use on materials whose characteristics are not conducive to friction, particularly highly electrically conductive materials such as copper and its alloys.

In a given application, it can compete favorably with the other processes that can be used, namely and essentially: resistance or flash butt welding, ring projection welding, electron beam welding and brazing. Its strength lies in its mechanical heat source –– which, thanks to its natural stability, is particularly easy to produce and control. The result for machines is a very simple morphology and interesting advantages: no high current draw, no spattering, wear-free tooling, no costly metal input, easy control, etc., appreciated in mechanical engineering workshops.

Insofar as appropriate tightenings can be applied to the transmission of friction torque and forging force, it takes first place over the others.

Readers may also wish to refer to the article for different welding processes.