A Novel Approach in Manufacturing Two-Stepped Tubes using a Multi-Stage Die in Tube Hydroforming Process

Optimization of operating conditions is one of the most signicant issues concerning hydroforming the tubular components, including stepped tubes, conical tubes, box shape tubes, and etc. Obtaining a sharp corner without any defects such as thinning and rupturing is one of the main goals in the production of these components. In order to manufacture tubes with filled corners, it is common to increase the imposed pressure to the tubes. However, it may result in rupturing and thinning at the die corner radius, especially when it is too small. In this paper, a new multistage die has been proposed for producing two stepped tubes. Numerical modeling has been conducted using Abaqus/Explicit code. The results of simulation were afterwards checked against experiments in which it is shown that a better thickness distribution could be obtained employing the proposed die set. There is no thinning in the final workpiece, particularly at the copper tube corners. Moreover, it could be possible to produce two stepped tubes with complete filled corners. Finally, comparing to other well-established methods, a lower pressure profile is required and a better thickness distribution can be achieved.