Analysis of tapered preforms in cold upsetting

Gokler M., Darendeliler H., Elmaskaya N.

INTERNATIONAL JOURNAL OF MACHINE TOOLS & MANUFACTURE, vol.39, no.1, pp.1-16, 1999 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 39 Issue: 1
  • Publication Date: 1999
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.1-16
  • Middle East Technical University Affiliated: Yes


Upset forging is usually carried out with a sequence of stages and the tapered preforms are commonly used. The preforms should be free from flash formation and buckling injuries. :In this paper, the results that depend on elastic-plastic finite element analysis of taper upset forging are given. The buckling analysis was realized by using the Modified Riks method. For a given upset ratio which is the ratio of unsupported length to diameter of the initial billet, reduction in the height of the billet and the diameter ratio are the important design parameters in taper upsetting. For several values of the design parameters, the analysis has been carried out and the results have been compared with the results of the well-known Meyer's experiment and Gokler's suggestions. In the analysis, the perfectly square end (ideal billet case) and the end with face inclination angle were considered as two different end conditions of the billet. The results for the ideal billet case are in good-agreement with Meyer's results. The end-face inclination angle, which is a significant imperfection on the billet, reduces the limits of allowable upset ratio. It has been observed that although the tapered header dies designed at the limits suggested by Meyer produce flashless preforms, in some of the cases, injuries due to buckling are not eliminated. However, Gokler's suggested limits provide elimination of both flash formation and injuries due to buckling. (C) 1998 Elsevier Science Ltd. All rights reserved.