Abstract: Production of a substantially constant wall thickness in every cross section on cylindrical tubular parts produced for example by extrusion and rolling. The process of the invention comprises determining, by means of a suitable apparatus, the position of the center of the internal contour of a cross section of the tubular part, then rotating one with respect to the other a machining tool and the part about the axis of said internal contour and moving the machining tool towards the part until, over the periphery of said cross section, a constant wall thickness which is equal at most to the minimum thickness is obtained, and then repeating those operations on the successive desired sections of the tube, which are parallel to the first section.

Abstract: Process and apparatus for expansion shaping of at least one localized region in a running portion of the wall of a tube of substantial length, wherein the distance between the expanded region and one of the ends of the tube is to be adjusted with precision; comprising disposing a die around the tube in the region to be shaped, the die comprising an expansion chamber between two cylindrical bearing surfaces, introducing a mandrel into the interior of the tube in the portion thereof which is within the die and delimiting an annular space between the mandrel and the tube, by two sealing regions disposed on respective sides of the expansion chamber at the location of the cylindrical bearing surfaces of the die, introducing a pressure fluid through the mandrel into the annular space, and increasing the pressure of the fluid until the tube becomes deformed against the walls of the expansion chamber.