Abstract: The present invention includes a system and a method for attaching the end of a tube of a plastically deformable material such as titanium to a hard metal fitting in a manner that can provide the resulting tube joint with increased strength and fatigue resistance. In the method the tube and fitting are assembled by inserting the tube into the end of a bore in the fitting. A radial force is exerted against a predetermined axial length of the tube wall, and thus also against the fitting, to plastically deform the tube wall radially into plural, axially spaced, circumferential grooves in the fitting bore. While this radial force is being exerted, a die restrains the fitting, causing it to deform elastically more near the end of the fitting bore than near the end of the tube. In the resulting tube joint the fitting applies residual circumferential stresses to the tube that are larger near the end of the fitting bore, and this stress distribution increases the fatigue resistance of the tube joint.