Thermomechanical Rolling of Air-Cooled Thick Nb-Ti-V-Ni High Strength Structural Plate

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Abstract:

The effect of thermomechanical controlled processing (TMCP) strain and finishing temperature on the microstructure of as-rolled and air-cooled 50mm thick Nb-Ti-V-Ni microalloyed steel plate was investigated through laboratory simulations, incorporating variations in reheating, roughing and finishing practices. Laboratory simulations produced microstructures similar to those observed in industrial rolling owing to comparable total strain in the TMCP region. Larger total strains in the TMCP region promoted sub-grain formation and increased nucleation site density, leading to grain refinement. Recrystallisation was completely suppressed at the commencement of finishing in all TMCP schedules due to sufficiently lower starting temperatures. The extent of recrystallisation during finishing depended on the finishing temperature: i) partial softening after finishing above 910°C and ii) complete recrystallisation below 910°C due to substantial accumulated strain. Finishing below 910°C produced finer polygonal ferrite and pearlite microstructures. Microstructure and mechanical properties were fairly consistent when the finishing temperature was between 925 and 950°C. However, the sub-zero impact toughness can be significantly improved by employing lower finish temperatures or applying larger total TMCP strains. Interrupted accelerated cooling at 5°C/s after finishing significantly refined the microstructure.

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Materials Science Forum (Volume 1174)

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95-100

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January 2026

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© 2026 Trans Tech Publications Ltd. All Rights Reserved

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[1] K. Wang, A study of HSLA steels microalloyed with vanadium and titanium during simulated controlled rolling cycles, PhD. Thesis, Dept. of Mech. Eng., Univ. of Canterbury (2003).

Google Scholar

[2] A. Kundu, C. Davis, M. Strangwood, Grain size distributions after single hit deformation of segregated, commercial Nb-containing steel: Prediction and experiment, Metall. and Mater. Trans. A, 24A (2011) 2794-2806.

DOI: 10.1007/s11661-011-0712-1

Google Scholar

[3] L.J. Cuddy, Grain refinement of Nb steels by control of recrystallization during hot rolling, Metall. Trans. A 15A (1984) 87-98.

DOI: 10.1007/bf02644390

Google Scholar

[4] H. Baumgardt, H.F. de Boer, F. Heisterkamp, Review of microalloyed structural plate metallurgy – Alloying, Rolling, Heat Treatment, available online https://niobium.tech/.

Google Scholar

[5] D. G., Stalheim, Recrystallization behaviors in the production of structural steels, in Proceedings of the 2015 ABM 52nd Rolling Seminar, Rio de Janeiro, Brazil, August 2015.

DOI: 10.5151/1983-4764-26355

Google Scholar

[6] M. Jonsson, TM-Rolling of heavy plate and roll wear, Thesis, Dept. Applied physics and Mech Eng., (2006).

Google Scholar

[7] K.M. Banks, Internal offline one-dimensional heat transfer model. Univ. of Pretoria. (2017)

Google Scholar

[8] F. Fletcher, Meta-analysis of Tnr measurements: Determining new empirical models based on composition and strain; Proceedings of the Austenite Processing Symposium (Internal Company Presentation); Padua, Italy. 12 September 2008; p.1–14.

Google Scholar

[9] B.K. Show, R. Veerababu, R. Balamuralikrishnan, G. Malakondaiah, Effect of vanadium and titanium modification on the microstructure and mechanical properties of a microalloyed HSLA steel, Mater. Sci. & Eng. A 527 (2010) 1595-1604.

DOI: 10.1016/j.msea.2009.10.049

Google Scholar

[10] D.R.N. Maubane, K.M. Banks, V. Kurup., Influence of Hot Rolling Practice and Furnace Residence Time on the Strength and Toughness of Normalised Nb-Ti-V Structural Steel Plate, Mater. Sci. For. 1105 (2023) 111-1116.

DOI: 10.4028/p-k20ipd

Google Scholar

[11] S. Vervynckt, K. Verbeken, P. Thibaux, & Y. Houbaert, Evaluation of the austenite recrystallization by multideformation and double deformation, Steel Research International 82(2) (2011) 369-378.

DOI: 10.1002/srin.201000167

Google Scholar

[12] C.L. Miao, C.J. Shang, G.D. Zhang, S.V. Subramanian, Recrystallization and strain accumulation behaviours of high Nb-bearing line pipe steel in plate and steel rolling, Mater. Sci. and Eng. A 18–19 (2010) 4985-4992.

DOI: 10.1016/j.msea.2010.04.039

Google Scholar

[13] F. Siciliano Jr., J. Jonas, Mathematical Modeling of the Hot strip rolling of microalloyed Nb, Multiply alloyed Cr-Mo, and Plain C-Mn steels, Metall. & Mater. Trans. A, 31A (2000) 511-530.

DOI: 10.1007/s11661-000-0287-8

Google Scholar

[14] S. Shanmugama, N.K. Ramisetti, R.D.K. Misra, T. Mannering, D. Panda, S. Jansto, Effect of cooling rate on the microstructure and mechanical properties of Nb-microalloyed steels, Mater. Sci. and Eng. A 460–461 (2007) 335–343

DOI: 10.1016/j.msea.2007.01.054

Google Scholar

[15] X. Li, Z. Wang, X. Deng, G. Wang, R.D.K. Misra, The Determining Role of Finish Cooling Temperature on the Microstructural Evolution and Precipitation Behavior in an Nb-V-Ti Microalloyed Steel in the Context of Newly Developed Ultrafast Cooling, Metall. and Mater. Trans. A, 47A (2016) 1930-1938.

DOI: 10.1007/s11661-016-3424-8

Google Scholar

[16] J. Reiser, A. Hartmaier, Impact of grain size on toughness and the brittle-to-ductile transition: Elucidating the contradicting role of grain boundaries (obstacles vs. sources) by dislocation dynamics modelling, Submitted to Acta Mater.

DOI: 10.1038/s41598-020-59405-5

Google Scholar