Sevastopol State University, Sevastopol, Russia
S. M. Bratan, Dr. Eng., Prof., Head of the Dept. of Automation and Technology of Mechanical Engineering, e-mail: serg.bratan@gmail.com
N. I. Pokintelitsa, Dr. Eng., Prof., Dept. of Automation and Technology of Mechanical Engineering, e-mail: NIPokintelitsa@sevsu.ru
A. S. Chasovitina, Cand. Eng., Associate Prof., Dept. of Automation and Technology of Mechanical Engineering, e-mail: aschasovitina@mail.sevsu.ru
Ch. F. Yakubov, Cand. Eng., Doctoral Student, Dept. of Automation and Technology of Mechanical Engineering, e-mail: yakubov_chingiz@mail.ru

Accurately constructing a material’s hardening curve is a key factor influencing the reliability of numerical simulations of technological processes. This is particularly true in cold die forging, where the material is subjected to large plastic deformations. However, standard compression tests on cylindrical specimens reduce the reliability of the results due to friction on the contact surfaces. Contact friction with the tool surface causes a “barreling” effect, leading to uneven strain distribution and an overestimation of the calculated stress value. As a result, the hardening curve loses reliability for logarithmic strain values greater than 0.6. This article proposes an improved method for compressing cylindrical specimens using soft inserts, aimed at actively controlling material flow. The method is based on a basic cylindrical specimen (grade 10 steel) with inserts inside the ends made of a softer, highly deformable material (A5M aluminum), placed in recesses on the end surfaces. The mechanism of action is as follows: significant transverse expansion of the soft inserts under a compressive load creates localized tensile forces acting radially along the end face of the main specimen, effectively compensating for frictional resistance. This ensures high radial deformation uniformity, eliminates the “barreling” effect, and achieves conditions of near-uniaxial compression. Using computer modeling, this study conducted a numerical selection process to determine the optimal geometric parameters of the inserts, ensuring the required equilibrium of compensating forces. Analysis revealed that the use of A5M aluminum inserts with a diameter of 12 mm and a thickness of 2.9 mm is the optimal configuration for true strain near unity. This configuration demonstrated the ability to provide a virtually uniform distribution of logarithmic strain intensity across the entire specimen cross-section, significantly reducing strain fluctuations compared to traditional methods.

1. Bannikov A. I., Bannikov A. A., Kurchenko A. I., Dyatlov N. A., Permyakov I. L. Improving the efficiency of thermofriction cutting of rolled pipes. STIN. 2010. No. 10. pp. 34–37.
2. Nasad T. G., Ignatiev A. A. High-speed machining of difficult-to-cut materials with additional energy flows in the cutting zone. Saratov: Izdatelstvo Saratovskogo gosudarstvennogo tekhnicheskogo universiteta, 2002. 110 p.
3. Gik L. A. Rotary cutting of metals. Kaliningrad: Knizhnoe izdatelstvo, 1990. 254 p.
4. Zarubitsky E. U. Thermofriction treatment of flat steel surfaces. Kuybyshev: Kuybyshevskoe knizhnoe izdatelstvo, 1988. 42 p.
5. Sherov K., Kuanov I., Imanbaev Ye., Mussayev M., Karsakova N., Mardonov B., Makhmudov L. The investigation and improvement of the hardness of the clad surface by thermal friction milling methods. International Journal of Mechanical Engineering and Robotics Research. 2022. Vol. 11. No. 10. pp. 784–792. DOI: 10.18178/ijmerr.11.10.784-792
6. Zahaf M. Z., Benghersallah M., Amirat A. Surface roughness and vibration analysis in end milling of annealed and hardened bearing steel. The International Journal of Advanced Manufacturing Technology. 2020. Vol. 111. pp. 525–535. DOI: 10.1016/j.measen.2020.100035
7. Momeni A., Arabi H., Rezaei A., Badri H., Abbasi S. M. Hot deformation behavior of austenite in HSLA-100 microalloyed steel. Materials Science and Engineering: A. 2011. Vol. 528, Iss. 4-5. pp. 2158–2163. DOI: 10.1016/j.msea.2010.11.062
8. Volkov O. A. Study of the influence of TFP on the stress state in 15Kh11MF steel. Vestnik NTU "KhPI". 2005. Vol. 12. pp. 84–88.
9. Nasad T. G. Surface quality after high-speed heat treatment. Mechanical engineering technology. 2004. Vol. 3, Iss. 27. pp. 11–13.
10. Volkov O. A. Study of heat-deformation influence during surface hardening of steels by thermofriction processing. VEZhPT. 2016. No. 5 (80). pp. 38–44.
11. Nasad T. G., Nasad I. P., Sherov K. T. Methods of analytical determination of temperatures in the cutting zone during processing of difficult-to-machine materials. Vestnik SGTU. 2021. No. 4 (91). pp. 71–78.
12. Bratan S. M., Pokintelitsa N. I., Kharchenko A. O., Yakubov Ch. F. Improvement of the thermofriction processing quality by introducing additional dynamic damping devices into the technological system. Chernye Metally. 2023. No. 12. pp. 96-103.
13. Yakubov Ch. F., Pokintelitsa N. I., Bratan S. M., Skakun V. V. Disc for friction cutting with cooling system. Patent RF, No. 2834739. Applied: 24.06.2024. Published: 13.02.2025
14. Yakubov Ch. F., Pokintelitsa N. I., Bratan S. M., Skakun V. V. Cutting disc with helical grooves Patent RF, No. 231132. Applied: 24.06.2024. Published: 13.01.2025
15. Kim V. A., Yakubov Ch. F., Samar E. V. Dissipative processes of contact interaction and chip formation during metal cutting. Vestnik mashinostroeniya. 2019. No. 7. pp. 65–69.