National University of Science and Technology “MISiS” (Moscow, Russia):

V. N. Shinkin, Dr. Phys.-Math., Prof., e-mail: shinkin-korolev@yandex.ru

To calculate the power parameters of metallurgical machines in the production of pipes from steel sheet, it is extremely necessary to know the analytical dependence of the elastic-plastic hardening curve of steel and the numerical value of bending moment of steel sheet depending on the curvature’s radius of its neutral plane during bending. Otherwise, the power characteristics of links of metallurgical machines (driving mechanisms of punches, torsion shafts, power frames and so on) may exceed the permissible values, which will lead to their breakage. To obtain the mechanical characteristics of steel, a round or flat steel sample of standard dimensions is usually stretched and the stretching diagram is obtained in the coordinates “normal stress σ – relative elongation ε”, which is given as a graph. In the experimental stretching diagram, the yield strength σ_y (or σ_0.5), the ultimate strength σ_u, the relative elongation at break δ and the relative narrowing ψ (not always determined experimentally) of the neck of the round sample at break are usually found (determined). The stretching curve has the maximum at the moment of the beginning of the neck formation in the round steel sample (at the relative deformation ε_u). For a number of steels (for example, for the low-carbon steels), the deformation curve may have the yield area, where the normal stress σ is practically unchanged when the relative longitudinal deformations ε change. At this moment, the internal restructuring of the steel microstructure occurs at the level of the steel grains — sliding at the grains’ boundary and changing the orientation of the grains relative to each other. The size of the yield area is significantly smaller than the steel hardening zone. Therefore, the yield area is usually neglected in the analytical and numerical calculations.

1. Buhan P., Bleyer J., Hassen G. Elastic, plastic and yield design of reinforced structures. Elsevier Science, 2017. 342 p.
2. Starovoitov E. I., Naghiyev F. B. Foundations of the theory of elasticity, plasticity and viscoelasticity. Apple Academic Press, 2012. 320 p.
3. 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.
4. Shinkin V. N. Springback coefficient of round steel beam under elastoplastic torsion. CIS Iron and Steel Review. 2018. Vol. 15. pp. 23–27.
5. Bazant Z. P., Cedolin L. Stability of structures: Elastic, inelastic, fracture and damage theories. World Scientific Publishing, 2010. 1040 p.
6. Del Piero G. A variational approach to fracture and other inelastic phenomena. Springer, 2014. 90 p.
7. Belskiy S. M., Pimenov V. A., Shkarin A. N. Analysis of geometrical parameters of hot-rolled rolling. IOP Conference Series: Materials Science and Engineering. 2020. Vol. 971. 022074.
8. Belskiy S. M., Pimenov V. A., Shkarin A. N. Profiles’ classifier of hot-rolled rolling. IOP Conference Series: Materials Science and Engineering. 2020. Vol. 971. 022075.
9. Barenblatt G. I. Flow, deformation and fracture. Cambridge Academ, 2014. 276 p.
10. Silberschmidt V. V. Dynamic deformation, damage and fracture in composite materials and structures. Elsevier Science, 2016. 810 p.
11. Shinkin V. N. Elastoplastic flexure of round steel beams. 1. Springback coefficient. Steel in Translation. 2018. Vol. 48. No. 3. pp. 149–153.
12. Shinkin V. N. Elastoplastic flexure of round steel beams. 2. Residual stress. Steel in Translation. 2018. Vol. 48. No. 11. pp. 718–723.
13. Fedorov V. A., Ushakov I. V., Permyakova I. E. Mechanical properties and crystallization of an annealed cobalt-based amorphous alloy. Russian Metallurgy (Metally). 2004. No. 3. pp. 293–297.
14. Simonov Yu. V., Ushakov I. V. Methodology of mechanical testing for experimental detection of microdestruction viscosity in local regions of thin ribbons of amorpho-nanocrystalline material. Advanced Materials and Technologies. 2018. No. 2. pp. 52–59.
15. Alkazraji D. A quick guide to pipeline engineering. Woodhead Publishing, 2008. 176 p.
16. Butazzo G., Galdi G. P., Lanconelli E., Pucci P. Nonlinear analysis and continuum mechanics. Springer, 2011. 148 p.
17. Cowin S. C. Continuum mechanics of anisotropic materials. Springer, 2013. 438 p.