Forming Mechanism of Hollow Shafts With Heavy Section Shrinkage by Multi-Roll Tandem Skew Rolling

Abstract

Abstract Hollow shafts with heavy section shrinkage have the advantages of material saving, weight reduction, easy maintenance and flaw detection, so they are widely used in automobile, aerospace and other fields. However, it is difficult to break through the bottleneck of 75% section shrinkage when forming hollow shaft by traditional rolling process, which limits its application. Therefore, a new process for short process flexible forming of hollow shafts with heavy section shrinkage, namely the multi-roll tandem skew rolling (MRTSR) process, has been proposed. In order to analyze the feasibility of forming hollow shafts with heavy section shrinkage by MRTSR, theoretical and simulation studies are conducted on the forming process. Firstly, the forming principle of hollow shaft by MRTSR is introduced, and the technological characteristics of multi-roll and single-roll skew rolling are compared. Then, the kinematic analysis of the rolling process is carried out to obtain the pitch of the roller pushing the rolling piece forward. Based on this, the stable rolling condition of the hollow shaft by MRTSR is deduced. Finally, a finite element model was established to simulate the forming process of a hollow shaft with heavy section shrinkage by MRTSR, and the distribution of the equivalent stress and strain in a hollow rolling piece with 81% section shrinkage was analyzed. The results show that it is feasible to form hollow shaft with heavy section shrinkage by MRTSR.