UBA analysis of the process of pipe extrusion through a porthole die
UBA analysis of the process of pipe extrusion through a porthole die
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DOI：
10.1016/0924-0136(94)01582-l
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发表时间：
1995-02
影响因子：
6.3
通讯作者：
J. X. Xie;K. Ikeda;T. Murakami
中科院分区：
文献类型：
--
作者：
J. X. Xie;K. Ikeda;T. Murakami
通过上限方法（UBA）分析了通过分流模挤压管材时的变形行为，并将结果与实验结果进行了比较。所提出的模型具有到塑性区域的平滑边界和连续的速度场。发现预测的挤压载荷比实验记录的载荷大不到 10%。分析结果表明，对于挤压力而言，存在一个最佳的焊接室深度。分析还表明，焊接室直径与容器直径之比越大，压力越大，压力随孔口数量的变化趋势受孔口外接圆是否固定的影响。当保留在容器中的坯料的长度小于容器的半径时，塑性区域在整个坯料上延伸。对于流速分布以及死金属区的形状和体积，预测结果与实验结果存在一定差异。
The deformation behavior in the extrusion of pipes through a porthole die has been analyzed by means of the upper-bound approach (UBA) and the results compared with experimental ones. The proposed model has a smooth boundary to the plastic region and a continuous velocity field. The predicted extrusion loads were found to be less than 10% greater than the experimentally recorded loads. The results of the analysis show that there exists an optimum depth of the welding chamber with regard to the extrusion pressure. The analysis suggests also that the pressure is greater with a larger ratio of the diameter of the welding chamber to that of the container, and that the variation tendency of the pressure with the number of portholes is effected by whether the circumcircle of portholes is fixed or not. When the length of the billet remaining in the container is smaller than the radius of the container, the plastic region extends over the whole of the billet. For the distribution of the flow velocity and the shape and volume of the dead-metal zone, there exist some differences between the predicted and the experimental results.