Tube-hydroforming experiments on an Al 7003 extruded tube

Tube hydroforming (THF) is a valid alternative technique for the production of parts with enhanced performances in terms of resistance and feasibility of complex shapes. Automotive industry is the most important field of THF application [1], but in the last years also bicycle and motorbike companies started to produce hydroformed parts. In Brescia University Lab an experimental equipment able to run THF experiments is available. This equipment is the result of a cooperation between our research group and Officine Meccaniche Sangrato (Italy), a motorbike supplier of alluminum components. In a previous research [2] hydroforming of an Al7003 extruded tube has been studied by means of FE analysis made with PAM STAMP 2G 2003® code. The results of those simulations allowed the definition of the process parameters window. The present paper shows the results of the first experimental tests run at the Brescia University Lab. These tests have been used to validate the correct process parameters derived from simulations in order to obtain defect-free parts. An experimental thinning evaluation coupled with a metallurgical analysis have been carried out to evaluate the FE predictions. From this research it is clear that, in order to run a successful THF operation, it is very important to characterize the material behaviour since THF is a material depending process. Without this information the knowledge of process parameters like pressure curve or axial feeding amount could be not enough to obtain safe parts. The results presented in this paper match with the FE predictions confirming that FE analysis could be a valid tool for virtual prototyping of new processes like THF.