Axial hydro-forging sequence is an emerging approach in forming the variable-diameter tubes without thinning. However, after the batch production, a barrelling defect occurs at the end of the maximum diameter zone during the process. To investigate the barrelling behavior of the tube in axial hydro-forging sequence, experiments and finite element simulation were carried out in the present work. It could be concluded that the barrelling formation is attribute to the non-uniform stress distribution and the geometric feature of the tube. Subsequently, the effect of expansion ratio, friction coefficient and transition form on barrelling behavior was investigated. It was found that the degree of the barrelling increased with increasing the expansion ratio, but decreased with reducing the friction coefficient. Moreover, the transition form had a significant effect on the barrelling degree, and the barrelling defect can be eliminated when the transition form with circular arc was employed.

轴向液压锻造工艺是在不变细的情况下形成变径管的一种新兴方法。但是，分批生产后，在此过程中，最大直径区域的末端会出现滚磨缺陷。为了研究管在轴向液压锻造过程中的桶身行为，在本工作中进行了实验和有限元模拟。可以得出的结论是，桶形形成是由于应力分布不均匀和管的几何特征引起的。随后，研究了膨胀比，摩擦系数和过渡形式对桶形行为的影响。可以发现，随着膨胀率的增加，桶形度增加，而随着摩擦系数的减小，桶度减小。此外，