Abstract: A multilayer metallic high-pressure conduit for a high-pressure medium, particularly for a fuel injection system in motor vehicles, comprises a metallic inner tube, at least one metallic intermediate layer and a metallic outer tube. These metallic tubes or layers are connected to one another without soldering. At least one end connector element is welded to one end of the conduit.

Abstract: A pipe for pressurized-fluid feed systems, such as a diesel engine fuel pipe, has a wall of predetermined thickness with an internal surface and an external surface and an internal bore with a predetermined diameter for through-flow of the fluid. The internal surface and/or external surface are subjected to a nitriding or carbonitriding treatment, so as to obtain an increase in the hardness and/or the mechanical strength of the pipe, with regard to both stresses due to the pressure of the fluid and axial stresses due to flexing of the pipe.