Developpment of a hydroforming method taking advantage of friction

对小口径（外径不超过10mm）油管液压成形新工艺的可行性进行了评价。该技术利用管状试样（外径8mm，厚度0.8 ~ 0.5mm）与成型模具之间的摩擦来控制铜管和铝管试样的变形行为。采用化学镀（0.01mm厚）改变十字形成形模和三字形成形模的摩擦表面状况。在本实验研究中，表面镀镀对钢管变形的影响不明显。这取决于成形的形状。此外，这取决于电镀的位置。然而，接触压力和镀层厚度对管材变形的影响可能并不明显。

Feasibility of a new hydroforming technique for small diameter (at most 10-mm-outer-diameter) tubing was evaluated. The technique uses the friction between the tubular specimen (8 mm outer-diameter, 0.8 & 0.5mm thick) and the forming die to control the deformation behavior of the specimens made of copper tubing and aluminum tubing. Electroless plating (0.01mm thick) was adopted to change the frictional surface condition of a cross-shaped forming die and a tee-shaped die.Effect of the surface-plating on the tube deformation weakly appeared in this experimental study. It depended on the forming shape. Besides, it depended on the location of the plating. However, there might have been unclear effect of the contact pressure and plating thickness on the tube deformation.