Exploring forming mechanism of a part with transverse inner rib during power spinning

In order to reveal the forming mechanism of a part with a transverse inner rib during power spinning, a 3D finite element model for the process was established based on ABAQUS/Explicit in this study. With this model,the rib characteristics and the metal flow rules during the filling process were researched. The results and their analysis show preliminarily that: the filling of metal to the rib groove along the hoop direction is homogeneous while it is non-homogeneous along the tangential direction. Besides this, there is an obvious depression in the outer wall in the middle zone of the rib. The forming mechanism of this depression explored by us, we believe, consists of: (1) this depression results from the thinning effect due to axial tensile stress during the middle stage of rib filling and the closing to the mandrel as a result of the bending of the non-rib part of the workpiece at the end of rib filling; (2) as the filling process goes on, the flow of metal along the radial direction is larger than that along the tangential direction in the earlier stage, while the former becomes smaller than the latter at the end of the filling process.