Abstract To overcome the problems in high pressure tube hydroforming (HPTH), such as too high forming pressure, thickness thinning and low productivity, a new forming technology was put forward, named as tube hydro-forging(THFG). In THFG, hollow components were formed by cross-section compression, overturned the traditional idea about conventional tube hydroforming in which the tube was expanded into the desired shape. Compared with HPTH, the role of the internal pressure was translated into the function of supporting and the tube sidewall was subjected to compression deformation throughout the process. These changes permit the THFG process with lots of advantages, such as low required internal pressure, avoiding thickness thinning or crack defect, no need for axial feeding, and so on. In this study, an analytical model based on a rigid, perfectly plastic material model was developed to investigate the possibility and the main influencing factors of the THFG. The analytical solution developed was compared with the experimental results. Experimental results validate that the tube can be formed into the desired shape by cross-section compression under a certain internal pressure supporting. Through the analytical model combining FEM simulation, the critical support pressure was given. The critical support pressure increases gradually as the deformation going on and has great dependence on the materials properties, however has no dependence on the tube thickness. It is also validated that the required pressure in the THFG is much lower than that needed in the traditional tube hydroforming.

中文翻译：

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管材液压锻造——一种制造具有不同横截面周长的空心部件的方法

摘要 为克服高压管材液压成形(HPTH)中成形压力过高、厚度变薄、生产效率低等问题，提出了管材液压成形(THFG)的新型成形技术。在 THFG 中，中空部件是通过截面压缩形成的，颠覆了传统管材液压成形的传统观念，其中管材被膨胀成所需的形状。与HPTH相比，内压的作用转化为支撑作用，管壁在整个过程中受到压缩变形。这些变化使THFG工艺具有许多优点，例如所需的内压低、避免厚度变薄或裂纹缺陷、无需轴向进料等。在这项研究中，一个基于刚性的分析模型，开发完美塑性材料模型以研究THFG的可能性和主要影响因素。将开发的解析解与实验结果进行比较。实验结果验证了在一定的内压支撑下，通过截面压缩可以使管子成型为所需的形状。通过结合有限元模拟的解析模型，给出了临界支护压力。临界支撑压力随着变形的进行而逐渐增加，并且对材料特性有很大的依赖性，但与管子的厚度无关。还验证了 THFG 所需的压力远低于传统管材液压成形所需的压力。