Flow-forming

Using a long-established principle – similar to the potter's technique – mechanized since the 1950s, fluotournage consists in plastically deforming metals by point extrusion, with the material flowing between a rotating mandrel and one or more rollers exerting high pressure. The metal flows as it rotates, hence the name given to the process.

It enables an axisymmetric preform to be elongated by reducing its thickness. This reduction in thickness is characteristic of the process, and the name "repoussage" is reserved for shaping with a constant thickness.

Depending on the material, flow forming can be carried out cold (i.e. without heating the blanks), or hot (450 to 1,050°C depending on the metal).

English-speaking countries use several equivalent terms: spinning, flow-spinning, flow-forming, flow-turning, shear spinning.