Abstract: Process for deforming a piece of thin-walled metal tube, comprising the operations of bending the piece of tube with respect to its original axis, in which process the wall of the piece of tube is firstly provided, at least at the location where the bend is intended to be, with a deformation which extends substantially in the longitudinal direction of the piece of tube, and in which process wall material is moved closer to the neutral plane of bending, and the piece of tube is then bent, after which the ultimate shape of the piece of tube which is to be deformed is imposed by hydroforming.