JSC Vyksa Steel Works, Vyksa, Russia¹ ; Vyksa branch of NUST MISIS, Vyksa, Russia²:

D. V. Kudashov, Cand. Eng., Chief Innovation Specialist, Engineering and Technology Center (ETC)¹, Director², e-mail: kudashov_dv@vsw.ru

Vyksa branch of NUST MISIS, Vyksa, Russia:

E. A. Volkova, Senior Lecturer, e-mail: eavolk@yandex.ru

JSC Vyksa Steel Works, Vyksa, Russia:

L. I. Efron, Dr. Eng., Scientific Supervisor of ETC, e-mail: LEFron@omk.ru
K. S. Smetanin, Chief Specialist, ETC, e-mail: smetanin_ks@vsw.ru

The paper presents the results of studies of the structural features of plate rolled products of low-carbon pipe steels 04KhNDB, 05KhGB and 06GNFB differing in the basic composition and content of microalloying elements. In the production of industrial rolled products for each steel under study, the choice of rolling temperatures was made individually, but in the same way from the point of view of structure formation. The completion of the finishing stage of rolling was carried out in the austenite region near the temperature of the beginning of the phase transformation, the beginning of cooling - from the austenite region, in order to form a homogeneous structure and exclude the formation of structural banding. The steels have a similar microstructure after rolling, but the structure of the axial zone, which is basically the weak point in tests in hydrogen sulfide, is different. The microstructure of steel 04KhNDB is almost uniform in thickness and a slight segregation of manganese has little effect on the hardness of the axial zone. In steels 05KhGB and 06GNFB, segregation of manganese and an increase in the proportion of intermediate transformation products in the axial zone leads to the formation of elongated regions with increased hardness. This is most pronounced in steel 06GNFB, in which cracks were revealed after testing for hydrogen cracking in accordance with the NACE TM0284 method. It has been established that with a homogeneous microstructure in the axial zone of rolled products without areas of increased hardness and in the absence of manganese sulfides in it, large inclusions of titanium and niobium carbonitrides do not adversely affect the resistance to hydrogen cracking.

1. Shabalov I. P., Matrosov Yu. I., Kholodny А. А., Matrosov М. Yu., Velikodnev V. Ya. Steel for oil and gas pipes resistant to destruction in hydrogen sulfide environments: monograph. Moscow: Metallurgizdat, 2017. 322 p.
2. Efron L. I. Metal science in "big" metallurgy. Pipe steels. Moscow: Metallurgizdat, 2012. 696 p.
3. Kudashov D. V., Mursenkov E. S., Stepanov P. P. et al. Assimilation of pipe steel extra-furnace treatment and casting technology with specification for resistance to H2S media under casting and rolling complex conditions. Metallurgist. 2017. Vol. 61. No. 7-8. pp. 656–665.
4. Matrosov М. Yu., Talanov O. P., Kholodny А. А. Development of pipe steels with a ferrite-bainite structure resistant to hydrogen cracking and hydrogen sulfide stress cracking. International scientific and technical congress “Metal Forming 2014. Fundamental problems. Innovative materials and technologies”: Proceedings. Moscow: NITU «MISiS», 2014. Vol. 2. pp. 481–490.
5. Steklov О. I., Bodrikhin N. G., Kushnarenko V. М., Perunov B. V. Testing of steels and welded joints in hydrogen-rich environments. Moscow: Metallurgiya. 1992. 128 p.
6. Gray J. M. Ultra low-manganese, high-viscosity tubular HTT steel for sour service. Microalloyed pipe steels for the oil and gas industry: Proceedings of the international conference. Moscow: Metallurgizdat, 2018. pp. 175–181.
7. Williams J. G. New Alloy Design Perspectives for High Strength Steels. Paper presented at the 3^rd Int. Conf. on Thermomechanical Processing of Steels. 2008.
8. Patent 5993570 US. Linepipe and Structural Steel Produced by High Speed Continuous Casting. J. M. Gray; 30 Nov. 1999.
9. Gray J. M. Low manganese sour service linepipe steel, microalloyed steels for sour service. International Seminar. Sao Paulo, Brazil. 2012.
10. GOST 1778–70. Steel. Metallographic methods for the determination on nonmetallic inclusions. Introduced: 01.01.1972.
11. Efron L. I., Volkova Е. А., Kudashov D. V. et al. Structure formation during heating for rolling of niobium microalloyed pipe steels. Problemy chernoy metallurgii i materialovedeniya. 2020. No. 4. pp. 24–33.
12. Stalheim D. Strategy for production of plate steels requiring resistance to hydrogen induced cracking. The 2^nd International Symposium on the Recent Developments in Plate Steels, Orlando, USA, 2018. pp. 275–286.
13. Naumenko V. V., Bagmet О. А., Mursenkov Е. S. Resistance of low-carbon microalloyed pipe steels to cracking in hydrogen sulfide environment. Chernaya metallurgiya. Byulleten nauchnotekhnicheskoy i ekonomicheskoy informatsii. 2018. No. 7. pp. 56–64.
14. Naumenko V. V., Muntin А. V., Mursenkov Е. S. et al. Ensuring the resistance against hydrogen induced cracking of pipes welded from structural steel using high-frequency currents. Chernye Metally. 2021. No. 6. pp. 32–37.
15. Efron L. I., Volkova Е. А., Kudashov D. V., Ringinen D. А., Bagmet О. А., Smetanin К. S. Formation of the structure and properties of low-carbon pipe steel with an ultra-low manganese content during thermomechanical treatment. Metallurg. 2021. No. 3. pp. 34–47.