Process for the production of flanges or collars on hollow parts by lateral extrusion

A process for producing a flange or collar on a hollow part having a bore which comprises:

• shaping said hollow part to produce said flange or collar using a technique wherein material forming said part flows at least in part radially outwardly from the bore;
• internally supporting said hollow part during said shaping so as to substantially prevent the formation of a lap in the region of said flange or collar and so as to be able to substantially constantly adjust to instantaneous geometrical requirements;
• and
• said supporting step comprising introducing a medium which produces a relatively high interior pressure and which is at least one of an elastic medium and a plastic medium into the bore.