Nosov Magnitogorsk State Technical University (Magnitogorsk, Russia):

P. P. Poletskov, Dr. Eng., Prof., Materials Processing Dept.
O. A. Nikitenko, Cand. Eng., Scientific Researcher., R&D Center
A. S. Kuznetsova, Junior Scientific Researcher, Engineering Center, E-mail: allakuznetsova.mgtu@mail.ru
V. M. Salganik, Dr. Eng., Prof., Materials Processing Dept.

Strategic importance of creation of the new competitive materials providing efficient operation of the machine-building complex in the extremal Arctic and High North conditions is substantiated. The complex of requirements to the new materials is determined; it is based on their operating features such as σ_0.2 ≥ 600 N/mm², σ_v = 700–1100 N/mm², with δ₅ ≥ 17%, KCV^–60 ≥ 50 J/cm² and С_eqv ≤ 0.53. Chemical composition of the newly developed steel 20G2SMRA (20Г2СМРА) is presented. Critical points A_c1 – 725 and A_c3 – 814 °C are determined for this new steel, as well as the effect of cooling rate on structural and phase transformations, qualitative structural parameters and properties for continuous transformation of overcooled austenite are researched. Thermal kinetic diagram is also built. The obtained results can be also used in development of the new cold-resistant steels as well as in choice of routes and procedures of their heat treatment.

The research was executed under financial support of the RF Ministry of Education and Science within the framework of realization of RF President’s grant (Agreement No. 075-15-2020-205 dated 17.03.2020 (int. No. МК-1979.2020.8)).

1. Khlusova E. I., Sych O. V. Development of cold-resistant structural materials for the Arctic region. History, experience, current state. Innovatsii. 2018. No. 11(241). pp. 85–92.
2. Stolyarov V. I., Nikitin V. N., Efron L. I., Lazko V. G. State and development prospects of the technology and composition of high-strength weldable steels with yield strength 700 N/mm². Stal. 1993. No. 6. pp. 61–67.
3. Chukin M. V., Poletskov P. P., Nabatchikov D. G. et al. Analysis of technical requirements for ultra cold-resistant rolled sheets. Vestnik Yuzhno-Uralskogo gosudarstvennogo universiteta. Seriya: Metallurgiya. 2017. Vol. 17. No. 2. pp. 52–60.
4. Chukin M. V., Poletskov P. P., Gushchina M. S. et al. Development of the import replacing technology for production of rolled sheet metal made of high-strength structural steel of north modification. Proizvodstvo prokata. 2019. No. 4. pp. 5–11.
5. Solntsev Yu. P., Titova T. I. Steels for North and Siberia. St. Petersburg : Khimizdat. 2002. 352 p.
6. Solntsev Yu. P. Cold-resistant steels and alloys : A manual for high schools. St. Petersburg : Khimizdat. 2005. 480 p.
7. Poletskov P. P., Denisov S. V., Nikitenko O. A. et al. Study of decomposition of overcooled austenite of low-carbon tube steel using Gleeble 3500 complex. Izvestiya vysshikh uchebnykh zavedeniy. Chernaya metallurgiya. 2019. Vol. 62. No. 3. pp. 235–240.
8. Poletskov P. P., Nikitenko O. A., Kuznetsova A. S., Efimova Y. Y. Investigation of the effect of nickel content on the structural and phase transformation and properties of high-strength cold-resistant complex-alloyed steel. Journal of Chemical Technology and Metallurgy. 2019. Vol. 54(6). pp. 1291–1297.
9. Jech Ya.Heat treatment of steel. Reference book. 3rd edition. Translated from Czech. Moscow : Metallurgiya. 1979. 264 p.
10. Koptseva N. V., Chukin M. V., Nikitenko O. A. Use of the Thixomet PRO software for Quantitative Analysis of the Ultrafine-Grain Structure of low-and medium-carbon Steels Subjected to equal Channel Angular Pressing. Metal Science and Heat Treatment. 2012. Vol. 54. No. 7-8. pp. 387–392.
11. Mirzaev D. A., Okishev K. Yu., Schastlivtsev V. M., Yakovleva I. L. Kinetics of forming of bainite and massive martensite. I. Account of massive structure. Fizika metallov i metallovedenie. 2000. Vol. 90. No. 5. pp. 55–65.
12. Juna H. J., Kanga J. S., Seob D. H., Kangb K. B., Park C. G. Effects of deformation and boron on microstructure and continuous cooling transformation in low carbon HSLA steels. Materials Science and Engineering. 2006. A 422. pp. 157–162.
13. ASM Handbook: Metallography and Microstructures. ASM Int. 2004. Vol. 9. 1184 p.
14. Smirnov M. A., Pyshmintsev I. Yu., Boryakova A. N. On the problem of classification of microstructure of low-carbon tube steels. Metallurg. 2010. No. 7. pp. 45–51.
15. Thompson S. W., Colvin D. J., Krauss G. Continuous Cooling Transformations and Microstructure in a Low-Carbon High-Strength Low-Alloy Plate Steel. Met. Trans. 1990. Vol. 21A. No. 4. pp. 1493–1507.
16. Bramfitt B. L., Speer J. G. A Perspective on the Morphology of Bainite. Met. Trans. 1990. Vol. 21A. No. 4. pp. 817–829.