||Tube hydroforming is a relatively new manufacturing approach for producing lightweight metal structure components. Profile tubes, which have different shape at different cross sections, are widely used in automotive parts, such as the supporting frames for dashboard, engine radiator, water tank and fan, etc. Many profile tubes can also be found in our daily life.|
In this study, a profile tube with rectangular and circular cross-sections at the both ends is formed by hydroforming and crushing processes. Carbon steel of SPFC590Y is used as the tube material. The flow stress of SPFC590Y steel tubes at room temperature is obtained by tensile tests. At first, a finite element simulation software DYNAFORM is adopted to analyze the plastic deformation of the steel tubes during the hydroforming and crushing processes. Then, effects of various loading paths on the formability and thickness distribution of the products are discussed. An appropriate loading schedule is designed and the corresponding loading path is found out to obtain products without defects and uniform thickness distribution. Finally, a profile die and rectangular punches are designed, and experiments of hydroforming and crushing processes using ERW steel tubes are conducted. Experimental results of the thickness distributions and shapes of the products are compared with the simulation results to verify the designed loading schedule and the validity of the finite element models.