Ural Federal University (Ekaterinburg, Russia):

G. V. Shimov, Cand. Eng., g.v.shimov@urfu.ru
M. V. Erpalov, Cand. Eng., m.v.erpalov@urfu.ru
D. A. Pavlov, Cand. Eng., d.a.pavlov@urfu.ru

The article deals with the problem of non-accuracy of classical methods of calculation of technological parameters, associated with not taking into account the actual rheological properties of the material during deformation. The differences of the stress-strain state in the deformation zone during pipe drawing are shown for three different material models: rigid plastic model with softening, ideal plastic model and rigid plastic model with hardening. The difference between the standard deviation of the strain intensity on the elements of the hearth was found, which confirms the fact of the strain state gradient for the three models considered. This effect allows us to say that even in such a simple process of cold drawing, without taking into account the speed, temperature and elastic dependencies, it is possible to trace the influence of the character of the hardening curve on the deformed state in the hearth. Also, in the course of solving the problems, differences in the value of non-focal deformation depending on the material model were found. Conclusions are drawn and the necessity of considering the effects in the design of metal forming processes for each specific case of technology implementation is shown.
The study was made within the base part of State assignment in the field of scientific activity № 11.9538.2017/8.9, supported by the Program 211 of the RF Government (agreement № 02.A03.21.0006).

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