Abstract: It is demonstrated by the new theory of the document[1] that there necessarily exist such serious drawbacks as the internal stress state not good and the deformation non-homogeneous when a cylinder upset between flat platens. The boundary condition should be started with so as to change the bad stress state. In this paper, a new sort of cone upsetting platen is proposed. With the tool used to compress a blank, the internal stress state can be changed, it is advantageous to weld the defects in the blank and it is disadvantageous to sprout the internal crackle. As is full testified by the mechanical model which has been built and the physical simulation experiments.

Key words: Cone upsetting platen, Upsetting