Nosov Magnitogorsk State Technical University, Magnitogorsk, Russia

M. V. Chukin, Dr. Eng., Prof., Chief Researcher, Nanosteel Research Institute, e-mail: m.chukin@mail.ru
N. V. Koptseva, Dr. Eng., Prof., Dept. of Casting Processes and Materials Science, e-mail: kopceva1948@mail.ru
Yu. Yu. Efimova, Cand. Eng., Associate Prof., Dept. of Casting Processes and Materials Science, e-mail: jefimova78@mail.ru

A review of the available literature sources has shown that the use of thermoelectromotive force (TEF) as a method for monitoring the influence of the structural state and various types of defects on the properties of cold-rolled sheet steel is largely hindered by a lack of experimental research. The purpose of the research presented in this report was to investigate the relationship between TEF and the hardness distribution along the length and width of a cold-rolled strip using the developed methodology described in Report 1. The results showed that there is a weak to moderate positive correlation between the TEF values and the hardness of the recrystallized cold-rolled steel strip, indicating that as the hardness of the strip increases, the TEF values also increase. Conversely, higher TEF values are associated with higher hardness values. It has been established that the non-uniformity of the hardness distribution along the width of the strip is not related to microstructural non-uniformity, but is determined by the extent to which the initial cold-rolled strip was non-equilibrium and defective structure during recrystallization annealing and subsequent additional annealing. It has been revealed that there is a very strong positive correlation between the TEF values in the initial state and after additional annealing of the strip, which proves that the TEF values of the samples before annealing are always greater than the TEF values of the samples after additional annealing, and this relationship is close to linear. The prospects of using the TEF method to control the deformation irregularity and heterogeneity of the hardness distribution of cold-rolled steel strip, as well as to predict its behavior during further cold stamping, have been proven.
This work was supported by the Ministry of Science and Higher Education of the Russian Federation (project FZRU-2025-0003).

1. Averkiev A. Yu. Evaluation of stampability of sheet and tubular rolled products. Kuznechnoshtampovochnoe proizvodstvo. 1990. No. 2. pp. 19-24.
2. Shevelev V. V., Yakovlev S. P. Anisotropy of sheet materials and its influence on drawing. Moscow : Mashinostroenie, 1972. 133 p.
3. Grechnikov F. V., Kargin V. R. Theory of plastic deformation of metals: textbook. Samara : Izdatelstvo Samarskogo universiteta, 2021. 448 p.
4. Rodionova I. G., Mishnev P. A., Adigamov R. R. et al. Features of the formation of the structure and properties of cold-rolled low-carbon steels for the automotive industry depending on the degree of reduction during cold rolling. Tekhnologiya kolesnykh i gusechnykh mashin. 2013. No. 2 (6). pp. 20-28.
5. Salikhov T. Sh. Factors of non-uniformity of sheet steel quality and methods of assessment thereof: Dissertation ... of Candidate of Engineering Sciences. Moscow, 2009. 120 p.
6. Matyuk V. F. State of non-destructive testing of mechanical properties and stampability of sheet steel in the production flow. Nerazrushayushchiy control i diagnostika. 2012. No. 3. pp. 3-24.
7. Ferrajolo A. Method and device for continuous evaluation of mechanical and microstructural properties of metal material, in particular steel, during cold deformation. Applicant: Marsegaglia Carbon Steel S.P.A. Patent RF, No. 2765768. Applied: 02.02.2022. Published: 29.03.2018.
8. Kutanov S. V. Experimental determination of deformations and mechanical properties of parts obtained by plastic forming methods. Vestnik mashinostroeniya. 2011. No. 12. pp. 78-80.
9. Sonmez F. O., Demir A. Analytical relations between hardness and strain for cold formed parts. Journal of materials processing technology. 2007. Vol. 186. No. 1-3. pp. 163-173.
10. Del G. D. Determination of stresses in the plastic region by hardness distribution. Moscow : Mashinostroenie, 1971. 200 p.
11. Fedash G. M., Surovova V. I. Study of thermoelectromotive force arising in a circuit of deformed and undeformed metals. FMM. 1960. Vol. 10. Iss. 1. pp. 20-23.
12. Physical metallurgy: In 3 volumes. Vol. 3: Physical and mechanical properties of metals and alloys. Edited by R. W. Cahn, P. Haazen. Translated from English by O. V. Abramov. 3rd edition, revised and enlarged. Moscow : Metallurgiya, 1987. 661 p.
13. Belenkiy A. M., Dmitrieva E. E., Khadzaragova E. A. et al. Thermoelectric effect in the sensors of iron and steel industry. Chernye Metally. 2024. No. 5. pp. 63-73.
14. Soldatov A. I., Soldatov A. A., Sorokin P. V. et al. Thermoelectric method of plastic deformation detection. Materials Science Forum. 2018. Vol. 938. pp. 112-118.
15. Kuznetsov E. E. Plastic deformation and thermoelectric effect in alloys. Yekaterinburg: UrO RAN, 2021. 280 p.
16. Vasiliev A. P. The influence of dislocations on the thermoelectric properties of metals. Moscow : Fizmatlit, 2017. 224 p.
17. Kochkin Yu. P., Chernega A. Kh., Shevchenko S. G. Change in thermoelectromotive force caused by elastic deformation of steel wire under tension. Vestnik Magnitogorskogo gosudarstvennogo tekhnicheskogo universiteta imeni G. I. Nosova. 2006. No. 3 (15). pp. 49-50.
18. Kochkin Yu. P., Solntsev A. Yu. The nature of changes in thermoelectric power during small elastic deformation of carbon steel. Teoriya i tekhnologiya metallurgicheskogo proizvodstva. 2016. No. 1 (18). pp. 54-56.
19. Soldatov A. A., Soldatov A. I., Haskova E. S. Experimental studies of thermoelectric characteristics of plastically deformed St3, 08kp, and 12Kh18N10T steels. Kontrol. Diagnostika. 2014. No. 13. pp. 149-151.
20. Demmel P., Pazureck A., Golle R. et al. Characterization of the thermoelectric behavior of plastically deformed steels. Journal of Electronic Materials. 2013. Vol. 42. No. 7. pp. 2371-2375.
21. Milicevic I., Popovic M., Ducic N. et al. Experimental identification of the degree of deformation of a wire subjected to bending. Science of Sintering. 2018. Vol. 50. pp. 183-191.
22. Demmel P., Tröber P., Kopp T. et al. Characterization of the Thermoelectric Behavior of Plastically Deformed Steels by Means of Relative Seebeck Coefficient. Materials Science Forum. 2013. Vol. 755. pp. 1-7.
23. Korndorf S. F., Nogacheva T. I., Melnik E. E. Thermoelectric method testing inhomogeneity of metals and alloys. Patent RF, No. 2229703. Applicant: Oryol State Technical University. Applied: 17.10.2002. Published: 27.05.2004
24. Tupikin D. A. Thermoelectric method to test metallic materials. Patent RF, No. 2229117. Applicant: Oryol State Technical University. Applied: 10.02.2003. Published: 20.05.2004.
25. Lukhvich A. A., Sharando V. I. Thermoelectric method to test metallic materials. Copyright certificate SU 1548732 A1 No. 4400979. Applied: 04.01.1988. Published: 07.03.1990. Bulletin No. 9. 2 p.
26. Wu Y., Chen C., Wang C. et al. Influence of the sheet metal Seebeck coefficient on wear detection based on thermoelectric measurement. DOI: 10.25518/esaform21.2019.ESAFORM2021
27. Schrepfer A., Welm M., Tröber P. et al. Temperature measurement during blanking with enhanced speeds. Materials Research Proceedings. 2023. Vol. 25. pp. 3-10.
28. Karolik A. S., Kopylov V. I., Sharando V. I. Study of the recovery of microcrystalline copper based on the results of measuring hardness, electrical resistance and thermoelectric power. Deformatsiya i razrushenie materialov. 2008. No. 12. pp. 22-28.
29. Karolik A. S., Kopylov V. I., Sharando V. I. Recovery of copper microstructure on thermoelectric power measurements. Current problems of strength. Proceedings of the XLVI International Conference. Vitebsk, 2007. pp. 265-269.
30. Mucsi A., Dévényi L. Recrystallization of boron containing and boron-free low carbon steels investigated by thermoelectric power and hardness measurements. Materials Science Forum. 2015. Vol. 812. pp. 195-199.
31. Mucsi A. Thermoelectric Power Study of Nitride Precipitation and Recrystallization in Continuously-heated Low Carbon Al-killed Steels. Acta Polytechnica Hungarica. 2014. Vol. 11. No. 8. pp. 87-102.
32. Chukin M. V., Koptseva N. V., Efimova Yu. Yu. et al. Thermal EMF hysteresis depending on the heating and cooling conditions of thermocouples from different manufacturers of platinumrhodium wire. Tsvetnye Metally. 2025. No. 3. pp. 17-23.
33. Chukin M. V., Koptseva N. V., Linkov S. A. et al. Determination of the recrystallization onset temperatures of platinum-rhodium thermocouples using differential scanning calorimetry and thermal EMF methods. Tsvetnye Metally. 2025. No. 3. pp. 24-31.
34. Chukin M. V., Efimova Yu. Yu., Koptseva N. V. Determination of the heterogeneity of cold-rolled strip properties by thermo-EMF. Report 1. Development of a research methodology. Chernye Metally. 2026. No. 2. pp. 60-66.
35. GOST 5639–82. Steels and alloys. Methods for detection and determination of grain size. Introduced: 01.01.1983.
36. GOST R ISO 6507–1–2007. Metals and alloys. Vickers hardness test. Part 1. Test method. Introduced: 01.08.2008.