Friction welding is a process of welding two elements in the solid phase: one element is made to rotate at a high speed while the second is exerted at an axial force.
The friction between touching surfaces, produces frictional heat that allows welding without using sealing materials. The localized heating on the surfaces of the circular cross section, at temperatures lower than that of the melting point of the two components, causes a homogenization between the two micro structural elements thus obtaining a perfect weld, free of porosity, cracks, and surface imperfections.
The process, applied to the welding of carbon steels with stainless steels to obtain motor shafts, for example, for electric pumps, allows having the end of the shaft in contact with corrosive liquids in stainless steel, while the body of the shaft in carbon steel retains the ferromagnetic characteristics with a high performance of the rotor.
There are three advantages from this single process: resistance against corrosion, high motor efficiency, and low cost of the raw material.
Meva was a pioneer of this technology, and it uses its robotized and manual loading machines for shafts of large sizes and smaller series.