Nickel-based superalloy thin-walled components have been used in aerospace equipments requiring high reliability and durability at high-temperature condition. To overcome the problem of severe thinning occurs in conventional one-step hydroforming, this paper proposes an innovative multi-step hydroforming process for manufacturing complex T-shaped tubular parts of nickel-based superalloy. The appropriate process parameters in every step for preventing undesirable wrinkling and splitting defects, including internal pressure, axial feeding length, axial feeding ratio, and retreating displacement of middle punch, have been determined through a detailed numerical simulation investigation. The results show that manufacturing of a GH4169 T-shaped tubular part with expanded diameter can be successfully implemented using a four-step hydroforming. Moreover, the four-step hydroforming process, as well as the forming defects and the thickness distribution of several typical sections on the hydroformed GH4169 T-shaped tubular part, are all discussed. Finally, the complex GH4169 T-shaped tubular part with a thickness more than 3 mm can be obtained successfully after the top of the side branch is removed. These results provide insights for the manufacturing of T-shaped tubular part with expanded diameter, and contribute to the development of superalloy tube forming process at room temperature.

镍基超合金薄壁部件已用于航空设备，要求在高温条件下具有较高的可靠性和耐用性。为了克服常规单步液压成形中严重变薄的问题，本文提出了一种创新的多步液压成形工艺，用于制造镍基高温合金的复杂T形管状零件。通过详细的数值模拟研究，已经确定了用于防止不希望的起皱和开裂缺陷的每个步骤的适当工艺参数，包括内部压力，轴向进给长度，轴向进给比和中间冲头的后退位移。结果表明，使用四步液压成形可以成功地实现直径扩大的GH4169 T形管状零件的制造。而且，讨论了四步液压成形工艺，以及液压成形GH4169 T形管状零件上几个典型部分的成形缺陷和厚度分布。最后，厚度大于3的复杂GH4169 T形管状零件 除去侧分支的顶部后，可以成功获得mm。这些结果为扩大直径的T形管状零件的制造提供了见识，并为室温下高温合金管成形工艺的发展做出了贡献。