Peter the Great St. Petersburg Polytechnic University:

A. A. Kazakov, Dr. Eng., Prof., Head of the Metallurgical Expertise Laboratory, e-mail: kazakov@thixomet.ru

Thixomet JSC (St. Petersburg, Russia):
D. V. Kiselev, Technical Director

National Research Centre “Kurchatov Institute” – Central Research Institute of Structural Materials “Prometey” (St. Petersburg, Russia):
O. V. Sych, Cand. Eng., Head of the Sector
E. I. Khlusova, Dr. Eng., Prof., Deputy Head of Scientific and Production Centre No. 3 (NPK-3), Head of the Laboratory

E. I. Kazakova participated in this work.

Microstructural inhomogeneity comparative automated complex analysis of plate low-alloy cold-resistant steels for Arctic application with a thickness of 25, 50 and 70 mm, produced by thermomechanical processing technology with various temperaturedeformation parameters, has been performed. The inhomogeneity of the microstructure over the plates thickness was estimated by the volume fraction of coarse packet-block regions of lath bainite and regions of bainite that does not have a developed internal subgrain structure (conventionally called “non-granular” bainite), as well as anisotropy of the microstructure at different dimensional levels: short and long distance neighborhoods. The obtained results of microstructural heterogeneity quantitative assessment over the plates thickness were used for its detailed interpretation, taking into account the metallurgical inheritance of the slab and special features of two-stage thermomechanical processing with accelerated cooling.

1. Kazakov A. A., Kiselev D. V., Sych O. V., Khlusova E. I. The technique for assessment of microstructural heterogeneity across thickness of plate made of cold-resistant low-alloy steel for Arctic applications. Chernye Metally. 2020. No. 9. pp. 11–19.
2. ND No. 2-020101-114. Rules for the classification and construction of sea-going ships. Part ХIII. Materials. St. Petersburg: Russian Maritime Register of Shipping, 2019. 241 p.
3. Filin V. Yu. Quality control of steels for large-sized welded structures of the Arctic shelf. Application of Russian and foreign requirements. Voprosy materialovedeniya. 2019. No. 2. pp. 136–153.
4. Bashaev V. K., Ilyin A. V., Filin V. Yu., Gusev M. A. On the determination of cold resistance of modern high-strength steels for Arctic structures. Nauchno-tekhnichesky sbornik Rossiyskogo morskogo registra sudokhodstva. 2015. No. 38–39. pp. 74–79.
5. Goly-Oglu E. A., Bokachev Yu. A. Thermomechanical treatment of plates with thickness of up to 100 mm from low-alloy structural steel at NLMK DanSteel. Stal. 2014. No. 9. pp. 71–78.
6. Goly-Oglu E. A., Bokachev Yu. A. Increasing the level of ductility in the Z-direction of rolled 150 mm thick low-carbon steels for critical welded structures. Metallurg. 2014. No. 9. pp. 71–76.
7. Bianchi J. G., Karialainen L. P. Modelling of dynamic and metadynamic recrystallization during bar rolling of a medium carbon spring steel. Journal of Materials Processing Technology. 2005. No. 160. pp. 267–277.
8. Gorelik S. S., Dobatkin S. V., Kaputkina L. М. Recrystallization of metals and alloys. Moscow: MISiS, 2005. 430 p.
9. Rybin V. V. Large plastic deformation and fracture of metals. Moscow: Metallurgiya, 1986. 224 p.
10. Kodzhaspirov G. E., Rudskoy A. I., Rybin V. V. Physical foundations and resource-saving technologies for the manufacture of products by plastic deformation. St. Petersburg: Nauka, 2006. 349 p.
11. Olasolo M., Uranga P., Rodriguez-Ibabe J. M., Lopez B. Effect of austenite microstructure and cooling rate on transformation characteristics in a low carbon Nb – V microalloyed steel. Materials Science and Engineering: A. 2011. Vol. 528, Iss. 6. pp. 2559–2569.
12. Miaoa C. L., Shang C. J., Zhang G. D., Subramanian S. V. Recrystallization and strain accumulation behaviors of high Nb-bearing line pipe steel in plate and strip rolling. Materials Science and Engineering: A. 2010. Vol. 527, Iss. 18-19. pp. 4985–4992.
13. Pereda B., Fernandez A. I., Lopez B. Effect of Mo on dynamic recrystallization behavior on Nb – Mo micro-alloyed steels. ISIJ International. 2007. Vol. 47, Iss. 6. pp. 860–868.
14. Fernandez A. I., Uranga P., Lopez B., Rodrigues-Ibabe J. M. Dynamic recrystallization behavior covering a wide austenite grain size range in Nb and Nb – Ti Microalloyed steels. Materials Science and Engineering: A. 2001. Vol. 361. pp. 367–376.
15. Hodgson P. D., Zahiri S. H., Whale J. J. The static and metadynamic recrystallization behavior of an X60 Nb microalloyed steel. ISIJ International. 2004. Vol. 44, Iss. 7. pp. 1224–1229.
16. Dehgan-Manshadi A., Barnett M., Hodgson P. Hot deformation and recrystallization of austenitic stainless steel: Part 1. Dynamic recrystallization. Metal. Mater. Trans. 2008. Vol. 39A. pp. 1359–1370.
17. Sych O. V. Scientific and technological foundations for the creation of cold-resistant steels with a guaranteed yield point of 315-750 MPa for the Arctic. Part 2. Production technology, structure and performance characteristics of sheet metal. Voprosy materialovedeniya. 2018. No. 4. pp. 14–41.
18. Kazakov A. A., Kiselev D. Industrial application of Thixomet image analyzer for quantitative description of steel and alloys microstructure. Metallography, Microstructure, and Analysis. 2016. Vol. 5. Iss. 4. pp. 294–301.
19. Kazakov A. A., Kazakova E. I., Kiselev D. V., Kurochkina O. V. Investigation method of structure of tube steels. Patent RF No. 2449055. Applied: 18.10.2010. Published: 27.04.2012. Bulletin No. 12.
20. Orlov V. V., Malyshevsky V. A., Khlusova E. I., Golosienko S. A. Development of technologies for the production of structural steels for marine equipment and trunk pipelines intended for operation in the Arctic. Stal. 2014. No. 9. pp. 79–88.
21. Sych O. V. Scientific and technological foundations for the creation of cold-resistant steels with a guaranteed yield point of 315-750 MPa for the Arctic. Part 1. Alloying principles and requirements for the sheet metal structure. Voprosy materialovedeniya. 2018. No. 3. pp. 22–47.
22. GOST R 52927–2015. Rolled of normal, increased and high-strength steel for shipbuilding. Specifications. Introduced: 01.04.2016.