Establishment of failure conditions for the cross-wedge rolling of hollow shafts

Manufacturing hollow products (i.e. transmission shafts) with the CWR process represents a significant opportunity for obtaining higher material utilization, better product quality, and lower production costs. Despite its potential benefits, little research has been performed to develop guidelines for manufacturing stepped hollow shafts with CWR. Although the authors have completed extensive studies on the acceptable operating conditions for the CWR rolling of solid products, preliminary results ‘have found these studies’ to be inapplicable to hollow parts. In order to establish fundamental manufacturing knowledge, the present manuscript utilizes experiments and the explicit finite element method to investigate the limits of forming hollow products with CWR. By varying billet wall thickness and material, area reduction, and tool geometry, a dimensionless crushing parameter is introduced for predicting operating conditions that lead to part failure.