Tula State University, Tula, Russia

V. I. Platonov, Associate Professor of Department of Mechanics and Processes of Plastic Forming, e-mail: pvi_1@rambler.ru

Russian University of Transport (MIIT), Moscow, Russia

V. N. Chudin, Professor of Department of Materials Resistance and Construction Mechanics

The paper proposes relations for calculating the deformation and force regimes of the expansion process with heating of pipeline elements under conditions of viscoplastic deformation. The calculation of the expansion operation was carried out for billets made from the light and strong alloys based on aluminum and titanium. Technological processes of expansion are used to increase the diametrical size of the end part of a tube cylindrical billet. Products made of high-strength materials can be used as adapters for the pipeline systems with the different diameters, the fuel tank elements, the various containers, the casings in the aerospace, chemical and other branches of technics, where it is necessary to ensure the operability of constructions at the extreme temperatures and pressures, at the vibration and force loads in the aggressive environments. The observance of special conditions, regulating the temperature and velocity parameters of shaping, allows plastically to treat billets from the high-strength alloys with the high degrees of deformation and forecast mechanical characteristics. The use of heating technology only for the part of the pipe billet, undergoing plastic deformation, leads to significant savings in energy resources and the timerequir ed to raise the temperature. The material of the billets is assumed to be anisotropic, viscoplastic and relaxation under specified temperature and speed deformation conditions. The energy method of calculation, based on the kinematics of deformation, is used. The relations for calculating the pressure value and the loss of continuity of the initial billet’s material on the degree of shape changing of the billet, the velocity of operation and the anisotropy of mechanical properties are given. It is shown that the velocity of deformation has a significant influence on the magnitude of deformations, pressure and damage of billet’s material, i.e. on the product’s quality. The calculated results and product samples are presented.

1. Yakovlev S. S. (ed.) Forging and stamping: Handbook. Vol. 4. Sheet stamping. Moscow : Mashinostroenie, 2010. 732 p.
2. Popov E. A. Fundamentals of the theory of sheet stamping. Moscow : Mashinostroenie, 1977. 278 p.
3. Yakovlev S. S., Yakovlev S. P., Chudin V. N. et al. Isothermal shaping of anisotropic materials by rigid tool in the regime of preliminary creepage. Moscow : Mashinostroenie, 2009. 412 p.
4. Malinin N. N. Creepage in metal processing. Moscow : Yurait, 2023. 221 p.
5. Golenkov V. A., Yakovlev S. P., Golovin S. A., Yakovlev S. S., Kukhar V. D. Theory of metal forming by pressure. Moscow : Mashinostroenie, 2009. 442 p.

6. Chudin V. N. The process of hot expansion during viscoplastic deformation. Zagotovitel'nye Proizvodstva v Mashinostroenii. 2017. No. 5. pp. 217–219.
7. Yakovlev S. P., Yakovlev S. S., Andreichenko V. A. Pressure treatment of anisotropic materials. Kishinev : Kvant, 1997. 331 p.
8. Platonov V. I. To the calculation of stresses during distribution under conditions of viscoplasticity. Izvestija Tul'skogo Gosudarstvennogo Universiteta. Tehnicheskie Nauki. 2022. No. 8. pp. 497–500.
9. Platonov V. I., Chudin V. N. Power regime of swaging with heating. Zagotovitelnye Proizvodstva v Mashinostroenii. 2022. Vol. 20, No. 7. pp. 311–314.
10. Ji H., Li Y., Huang X., Dong S., Li Y., Xiao W. Study on formability of duplex steel expansion pipe and its threaded joints. Measurement. 2023. Vol. 206, No. 1. 112308.
11. Tan B., Yao S., Zhang L., Xu P., Che Q. A novel deformation mode of expansion tubes accounting for extra contact. International Journal of Mechanical Sciences. 2023. Vol. 242, No. 3. 108024.
12. Shinkin V. N. Simple analytical dependence of elastic modulus on high temperatures for some steels and alloys. CIS Iron and Steel Review. 2018. Vol. 15. pp. 32–38.
13. Paul S. K. The effect of deformation gradient on necking and failure in hole expansion test. Manufacturing Letters. 2019. Vol. 21, No. 8. pp. 50–55.
14. Lu R., Zheng S., Teng J., Hu J., Fu D., Chen J., Zhao G., Jiang F., Zhang H. Microstructure, mechanical properties and deformation characteristics of Al – Mg – Si alloys processed by a continuous expansion extrusion approach. Journal of Materials Science and Technology. 2021. Vol. 80, No. 7. pp. 150–162.
15. Shinkin V. N. Direct and inverse non-linear approximation of hardening zone of steel. Chernye Metally. 2019. No. 3. pp. 32–37.
16. Wu M. Z., Zhang X. W., Zhang Q. M. A new model for the expansion tube considering the stress coupling: Theory, experiments and simulations. Defence Technology. 2022. Vol. 18, No. 7. pp. 1190–1204.
17. Li J., Xie Z., Yu Y., Gong X., Gao G. Experimental and numerical study on the crashworthiness performance of a hybrid energy absorber with expanding-splitting-bending process. Thin-Wall Structures. 2022. Vol. 181, No. 12. 110122.
18. Shinkin V. N. Springback coefficient of round steel beam under elastoplastic torsion. CIS Iron and Steel Review. 2018. Vol. 15. pp. 23–27.
19. Moreno C., Beaumont R., Hughes D. J., Williams T., Dashwood R. Quasi-static and dynamic testing of splitting, expansion and expansion-splitting hybrid tubes under oblique loading. International Journal of Impact Engineering. 2017. Vol. 100, No. 2. pp. 117–130.
20. Li J., Gao G., Dong H., Xie S., Guan W. Study on the energy absorption of the expanding-splitting circular tube by experimental investigations and numerical simulations. Thin-Wall Structures. 2016. Vol. 103, No. 6. pp. 105–114.
21. Demin V. A., Chernyaev A. V., Platonov V. I., Korotkov V. A. Experimental technique for determining the mechanical properties of metal under stretching at high temperature. Tsvetnye Metally. 2019. No. 5. pp. 66–73.
22. Chernyaev A. V., Usenko N. A., Korotkov V. A., Platonov V. I. Understanding how deformation rate influences the resistance to deformation under static tension at high temperature. Tsvetnye Metally. 2019. No. 5. pp. 60–65.