Abstract
Using a combination of high-resolution dilatometric measurements and microstructural analysis, this study investigated the bainitic transformation behavior in ultra-high strength 30CrNi3MoV steel after experiencing small deformation at 850 °C (in the nonrecrystallization austenite region). Under the influence of the small deformation in the nonrecrystallization austenite region, the bainite starting temperature (Bs) raised, the bainite finishing temperature (Bf) decreased, granular bainite was promoted to form, and intersections of differently oriented bainite laths became more common in the microstructure. The increase of Bs is owing to the stored energy in distorted austenite grain boundaries, which can serve as an extra mechanical driving force for bainitic transformation during continual cooling. The decrease of Bf can attributed to the more universal intersections of bainite laths with different orientations, which can decelerate the overall growth rate of bainite. The promoted formation of granular bainite is closely related to the increase of Bs because granular bainite usually forms at relatively high temperatures in the bainite range, above upper bainite and lower bainite.
Similar content being viewed by others
References
M.C. Zhao, K. Yang, and Y.Y. Shan: The effects of thermo-mechanical control process on microstructures and mechanical properties of a commercial pipeline steel. Mater. Sci. Eng., A 335, 14 (2002).
M. Knapinski, H. Dyja, A. Kawalek, T. Fraczek, and K. Laber: Analysis of the microstructure evolution during thermo-mechanical treatment of the steel plates in grade X80-X100. Metallurgy 52(2), 239 (2013).
S.Z. Qi, P.J. Zhang, L.X. Du, X-H. Liu, and G-D. Wang: Controlled rolling and controlled cooling technology of ultra-high strength steel with 700 MPa grade. J. Iron Steel Res. Int. 11(3), 27 (2004).
X.X. Xu, B.Z. Bai, D.Y. Liu, and Y. Yuan: Effect of thermomechanical treatment temperature on structure and properties of CFB/M ultra-high strength steel. J. Iron Steel Res. Int. 17(4), 66 (2010).
R. Kurahashi and I. Chikushi: Ultra fine grain steel production at nakayama hot strip and plate mill. Proceeding of the 4th Workshop on the Development of High Performance Structural Steels for 21st Century (Pohang Iron and Steel, Pohang, Korea, 2002) p. 217.
W. Yu, Y.J. Qian, H.B. Wu, and Y.H. Yang: Effect of heat treatment process on properties of 1000 MPa ultra-high strength steel. J. Iron Steel Res. Int. 18(2), 64 (2011).
V.M. Khlestov, E.V. Komopleva, and H.J. McQueen: Kinetics of austenite transformation during thermomechanical processes. Can. Metall. Q. 37, 75 (1998).
F. Boratto, R. Barbosa, S. Yue, and J.J. Jonas: Proc. of Int. Conf. on Phys. Metall. of Thermomechanical Processing of Steels and Other Metals (Thermec-88) (ISIJ, Tokyo, 1988), p. 383.
H.G. Lin and D.Z. Fu: Principles, Measurements and Applications of Transformation Curve of Austenite in Steels (Mechanical Industry Press, Beijing, 1988), p. 262.
Z.X. Qiao, Y.C. Liu, L.M. Yua, and Z.M. Gao: Incompleted bainitic transformation characteristics in an isochronally annealed 30CrNi3MoV steel. J. Alloys Compd. 478, 334 (2009).
H.K.D.H. Bhadeshia: Bainite in Steels, Transformations, Microstructure and Properties, 2nd ed. (IOM Communications, Ltd., UK, 2001), p. 136.
H.K.D.H. Bhadeshia: Bainite in Steels, Transformations, Microstructure and Properties, 2nd ed., (IOM Communications, Ltd., UK, 2001), p. 204.
Z.X. Qiao, Y.C. Liu, L.M. Yu, and Z.M. Gao: Formation mechanism of granular bainite in a 30CrNi3MoV steel. J. Alloys Compd. 475, 560 (2009).
Z.Y. Xu and S.K. Liu: Bainitic Transformation and Bainite (Scientific Press, Beijing, 1991).
H.K.D.H. Bhadeshia: Bainite in Steels, Transformations, Microstructure and Properties, 2nd ed. (IOM Communications, Ltd., UK, 2001), p. 129.
Author information
Authors and Affiliations
Additional information
Address all correspondence to this author.
Rights and permissions
About this article
Cite this article
Qiao, Z., Liu, Y., Ning, B. et al. Bainitic transformation behavior of ultra-high strength 30CrNi3MoV steel after experiencing small deformation in the nonrecrystallization austenite region. Journal of Materials Research 28, 2844–2851 (2013). https://doi.org/10.1557/jmr.2013.270
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1557/jmr.2013.270