Seam Welds in Hollow Profile Extrusion: Process Mechanics and Product Properties

In this paper a review of several papers published on seam weld formation also by the authors is presented and discussed: the process mechanics is deeply investigated and several experimental results are related to process parameters by means of FEM simulations. The relation between die design and local welding parameters, such as contact pressure, temperature, time of contact, strain and strain rate paths is analyzed. In particular, by testing profiles extruded in different conditions, it was found that it is possible to find optimum processing conditions for a welded profile to behave like a not welded one. The possibility to adopt criteria for assessing the welding quality is finally discussed, together with its implementation directly inside process FEM codes.