An investigation is made of the radial upsetting of metallic circular tubes into a die cavity, of different contours, in which an axial collar is produced. A clew to the metal flow mode is given, the physical plane model of deformation is suggested and the corresponding triangular velocity field is constructed. An upper bound solution is utilized for finding the upsetting load. The theoretical predicted load values are compared with those obtained experimentally. Pressure rating tests of the produced articles are performed. Distribution of wall thickness strain and hardness values are determined and discussed.