Tula State University, Tula, Russia

S. N. Larin, Dr. Eng., Prof., Head of the Dept. of Mechanics and Plastic Forming Processes, e-mail: mpf-tula@rambler.ru
V. I. Tregubov, Dr. Eng., Prof., Dept. of Mechanics and Plastic Forming Processes
А. А. Pasynkov, Cand. Eng., Associate Prof., Dept. of Mechanics and Plastic Forming Processes, e-mail: sulee@mail.ru

Thin-walled steel cylindrical cups are usually produced using plastic forming methods from sheet or rods. When producing high cups using sheet blank drawing methods, it is necessary to implement several operations with intermediate annealing, which affects the efficiency of the technology. Extrusion processes make it possible to obtain deep cups in one stroke of the tool, but significant loads arise on the deforming tool, affecting its durability. In general, extrusion processes are more preferable in the manufacture of deep steel cups. In view of this, an important task is to reduce the loads on the working tool when extruding thin-walled cups from rods. One of the methods that allows for reducing forces is to provide active friction forces. The extrusion method with active friction and an additional deformation zone on the edge elements of the rod is considered, which allows for reducing force loads. The results of modeling the extrusion of the rod with active friction forces and pushing the end part of the rod are presented. The additional deformation zone during modeling was created by preliminary formation of a thickening at the end of the formed wall and its subsequent thinning on the die cone, due to which the rod was pushed. Based on the modeling results, studies were performed on the influence of high-speed deformation modes, deformation steps and tool geometry on the extrusion forces, pressure on the tool and rod contact surfaces, as well as the damageability of the rod material. Rational characteristics of the tool were established that ensure minimal pressures on the punch`s working surfaces.

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