Simultaneous hydroforming of bulge- and T-zone in 304 stainless steel and 70/30 brass tubes

Hydroforming process is largely used for the production of tubular parts in various industries, and has advantages such as less weight, higher quality, more strength and fewer production cost compared to the conventional methods of production. The aim of this study is forming a tube-shaped part with a special geometry that has both bulge- and T-zones with tube hydroforming process. The forming operations were performed on 304 stainless steel and 70/30 brass tubes, and a finite element (FE) model was used to achieve the best forming conditions. To validate FE model, firstly, several experimental tests were performed with different process parameters, and then the results were compared with the FE model in terms of the formed profile and the distribution of thickness. After validation of FE model, various pressure paths were studied and the best one between them was chosen. Finally, the part was formed correctly by the selected pressure path without defects like wrinkling or tearing, and the desired geometry was fully filled.