Tula State University, Tula, Russia

A. A. Pasynkov, Associate Professor at the Department of Plastic Forming Mechanics, Candidate of Technical Sciences, e-mail: sulee@mail.ru
P. V. Romanov, Postgraduate Student at the Department of Plastic Forming Mechanics

Tekhpolikom Research & Production Company, Moscow, Russia
G. A. Nuzhdin, Deputy General Director, Candidate of Technical Sciences, e-mail: nuzhdin.65@mail.ru

This paper considers the process of upsetting applied to a section of barstock that helps achieve a considerable difference in cross-sections in relation to the vertical axis. This forming operation is quite widespread finding real application in the production of adapters for various machines. The process is not complicated and does not require any full-fledged substantiation. However, when making certain parts for special-purpose machinery one may face difficulties associated with the mechanical properties of the workpiece material used. They are either titanium or aluminium superalloys that are usually used for parts of special-purpose machinery. Theoretical substantiation is required to justify the process of upsetting workpieces made of superalloys. Such materials should usually be hot stamped. And deformation rates produce a considerable impact on the stamping force and the stress-strain state. The upsetting process can be adequately described with the upperbound theorem of plasticity. In view of the above statement, the authors simulated the upsetting of a titanium alloy VT6 pipe on the basis of the solution of the external and internal forces equilibrium equation. We shall consider an axisymmetric strain pattern and a non-stationary velocity field. Simulation of the upsetting operation resulted in expressions for assessing the pressure and continuity of the workpiece material. The authors used the quantitative results of mathematical modelling to perform a regression estimate of the pressure and continuity values. Natural values of regression equations were obtained to analyze the influence of the key process parameters on the force and failure rate during upsetting. The obtained results could be used for assigning upsetting modes when dealing with titanium alloys.
Support for this research was provided under Grant 23-29-00470 by the Russian Science Foundation.

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