PSI - Issue 65

D.S. Bezverkhy et al. / Procedia Structural Integrity 65 (2024) 17–24 D. S. Bezverkhy and N. S. Kondratev / Structural Integrity Procedia 00 (2024) 000–000

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driving force of which is the energy difference stored on the defects formed during inelastic deformation (Huang K. E. & Logé R. E. (2016), Alaneme K. K. & Okotete E. A. (2019)). This value depends on the history of previous deformation, which differs significantly for the considered material points (Fig. 5 (b)). Elevated temperatures ensure the growth of new recrystallized grains. Figure 7 (a) shows the average grain size evolution for the considered material points. Figure 7 (b) shows the average dislocation density for the considered material points at different stages of the hot upsetting process. The results obtained show that the hot upsetting process, in which dynamic recrystallization is realized, leads to a decrease in grain size and an increase in defect density. Figure 8 shows the resulting pole figures of the selected points at the end of the workpiece deformation. ATEX software (Beausir B. & Fundenberger J. J. (2017)) was used to obtain the pole figures. The resulting material texture corresponds to the typical texture of uniaxial compression, which is best seen for point B; for other points deviations from the characteristic compression texture are observed.

(a)

(b)

Fig. 7. Evolution of the average grain size (a) and change in the average dislocation density (b) for the considered material points

Fig. 8. Polycrystal textures of the considered points at the workpiece processing end.

5. Conclusion

Increasing performance requirements of modern parts and constructions determines interest in the problems of designing products that are best adapted to specific operating conditions. This paper discusses the use of a multilevel modeling method to clarify the material inelastic deformation, taking into account the dynamic recrystallization, of the multistage upsetting technological process. This method allows to quantify the most important material characteristics and structural evolution for the most loaded workpiece areas. Its advantage is reduced computational costs compared to the direct use of a complex multilevel material model in engineering calculations in a finite element software. To study the influence of the dynamic recrystallization process on the multistage technological