Friction welding is a special type of press welding in which
the two surfaces to be welded are rotated relative to each other,
and compressed with appropriate pressure.
On the contact surfaces, the metal heats up due to friction,
becomes ductile and then thanks to the influence of heat and pressure a
cohesive, atomic-level bonding emerges. With friction welding, complex geometry
parts can be assembled from simple elements. Within a part
also substances with different chemical composition and mechanical properties can be found which wouldn’t be possible to combine with other procedures.
The use of expensive materials can be limited to the justified place of the workpiece.
The technology is mainly used in series production, such as in the automotive industry,
in the manufacture of hydraulic components, in the manufacture of tractors and agricultural machinery.
It provides benefits in general mechanical engineering and many other areas
Examples of friction welding economics:
- The tractor planetary housing consists of a relatively heavy head and and a long stem.
The traditional manufacturing technology is casting or forging.
Both procedures are labor and energy intensive.
The relatively long shaft is also a problem when forging and casting. For friction welding, the part can be divided into a unit: the housing and the shaft.
The housing is made of well-forged carbon steel, the shaft is made of alloy steel due to the higher stress load.
After welding, the planetary house is normalized and finished.
The planetary house made in this way is equivalent to a forged part in terms of service life, but its production is 45% cheaper.
- Prefabrication of the crankshaft is also usually made by casting or forging. It can be divided into three parts and they can be made quickly by cutting.Crankshafts produced by friction welding mean cost savings of 60% compared to cast and 48% compared to forged.
- The working head of cutting tools is made of tool steel, the shank is made of refractory carbon steel by friction welding.
- The stems of engine valves are made of wear-resistant alloy, while the head is made of heat-resistant alloy. The uniaxiality provided by friction welding is particularly important for these components
- In the case of pump shafts, only one half of the shaft is exposed to the risk of corrosion and diameter changes are frequent, so it is a significant saving to friction weld a stainless steel alloy with a different diameter.