纵向内筋薄壁筒反向滚珠旋压成形机理研究

Study of deformation mechanism of backward ball spinning of thin-walled tube with longitudinal inner ribs

作为一种连续局部塑性成形工艺,反向滚珠旋压被应用于成形带有纵向内筋的薄壁筒形件。反向滚珠旋压使变形区金属处于三向压应力状态,有利于内筋的形成。以塑性屈服准则、最小阻力定律和局部塑性成形理论为基础,将筒坯沿周向变形区分为接触区和前区,通过滚珠沿周向运动的4个阶段,给出了接触区和前区的应力应变状态,分析了内筋的成形过程,最后揭示了旋压件内筋的成形机理。

As a successively and locally plastic deformation process, backward ball spinning was applied to forming thin walled tubular part with longitudinal inner ribs. During backward ball spinning, the metal in the deformable zone was caused to be in a three-compressive stress state which contributed to formability of the inner ribs. Based on plastic yield criterion, minimum resistance law and local plastic forming theory, the deformation zone along the circumferential direction of the tubular blank was divided into the contact zone and the front zone in which the stress and strain state was given, and the forming process of the inner ribs was analyzed by means of four stages where ball moved along the circumferential direction. In the end, deformation mechanism of the inner ribs of the spun part was revealed.