SAWICKI Sylwester Czestochowa University of Technology

Spoluautoři GALKIN M. Alexander, DYJA Henryk, OZHMEGOV V. Kirill, KAWAŁEK Anna

The first technological operation of the cycle of chipless shaping of tubes and rods of zirconium alloy is multipass forging of the ingots on hydraulic press in the conditions of hot deformation. Taking into account the tension pattern and active gas saturation of the surface layers of the deformed metal in the forging process, the most important role is played by the correct choice of the thermomechanical schedules of hot deformation. On the one hand, for the cast structure crushing and decrease in the metal physical-mechanical inhomogeneity increased unit and sum drafting of the blanks is necessary. On the other hand, a increase in drafting leads to penetration of the gas saturated and oxidized surface layers of the metal into the ingot. It has a very negative effect on quality of zirconium alloy blanks produced during the further processes of extrusion, rolling and drawing. That is why during the schedule design for zirconium alloy ingots forging the most important role is played by the right choice of the thermomechanical parameters of this process: initial and final forging temperature, strain rate, the unit and sum drafting value, the length of the pauses between stressing. The best way to reproduce the influence and interaction of these parameters is to use the physical modelling of the fractional deformation process on modern plastometric devices. This paper presents results of plastometric modeling of the forging process of zirconium alloy Zr-Nb-Sn blanks. The results were obtained by test on plastometric simulator “Gleeble 3800” in hot conditions.

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