Abstract
The current work focuses on a group of steels named KAB (kinetically activated bainite), with accelerated bainite formation kinetics. The bainite formed within the newly developed grades is very fine and exhibits a hardness of up to 66HRC upon oil quenching, which enables the obtainment of tensile strengths beyond 2800 MPa, and grades containing large amount of retained austenite achieve predominantly uniform elongations due to a pronounced TRIP effect, whereas those steels where the bainite reaction approaches completion do not exhibit poor impact properties which are commonly associated with carbide-free lower bainite. This contribution focuses on the microstructural characterization of these steels, using light microscopy, field emission scanning electron microscopy, high-resolution transmission electron microscopy, and the relationship between microstructure and mechanical properties.
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References
E.S. Davenport, E.C. Bain, Thermally hardening steel US Patent 1924099 A (1933)
D.V. Edmonds, The ‘Silicon Age’ of steel: how alloying with silicon is playing a crucial role in modern steel developments. Iron Steel Technol. 12(10), 157–176 (2015)
F.G. Caballero, H.K.D.H. Bhadeshia, Very strong bainite. Curr. Opin. Solid State Mater. Sci. 8(3–4), 251–257 (2004)
H.K.D.H. Bhadeshia, The first bulk nanostructured metal. Sci. Technol. Adv. Mater. 14(1), 1–7 (2013)
B.C. De Cooman, Structure-properties relationship in TRIP steels containing carbide-free bainite. Curr. Opin. Solid State Mater. Sci. 8(3–4), 285–303 (2004)
H.K.D.H. Bhadeshia, The first bulk nanostructured metal. Sci. Technol. Adv. Mater. 14(1), 014202 (2013)
C. Garcia-Mateo, F.G. Caballero, H.K.D.H. Bhadeshia, Acceleration of low-temperature bainite. ISIJ Int. 43(11), 1821–1825 (2003)
E. Kozeschnik, H.K.D.H. Bhadeshia, Influence of silicon on cementite precipitation in steels. Mater. Sci. Technol. 24(3), 343–347 (2008)
A.I. Kovalev, T.K. Sergeeva, D.A. Litvinenko, Segregation of impurities, temper brittleness, and hydrogen embrittlement of steeL 30KHnma with different concentrations of molybdenum. Met. Sci. Heat Treat. 37(5), 196–199 (1996)
T.N. Baker, Processes, microstructure and properties of vanadium microalloyed steels. J. Mater. Sci. Technol. 25(9), 1083–1107 (2009)
B.L. Bramfitt, A.O. Benscoter, Metallographer’s guide: practices and procedures for irons and steel (ASTM International, Ohio, 2012)
G.F. Vander Voort, Metallography, principles and practice (McGraw-Hill, New York, 1984)
A.K. De, J.G. Speer, D.K. Matlock, Color tint-etching for multiphase steels. Adv. Mater. Processes 161(2), 27–30 (2003)
G.F. Vander Voort, Etching isothermally treated steels. Heat Treat. Prog. 1, 1–8 (2001)
H.S. Zhao, X. Zhu, W. Li, X.J. Jin, L. Wang, H. Jiao, D.M. Jiang, Austenite stability for quenching and partitioning treated steel revealed by colour tint-etching method. Mater. Sci. Technol. 30(9), 1008–1013 (2014)
H. Zakerinia, A. Kermanpur, A. Najafizadeh, Color Metallography; a suitable method for characterization of martensite and bainite un multiphase steels. Int. J. ISSI 6(1), 14–18 (2009)
H.K.D.H. Bhadeshia, Nanostructured bainite. Proc. R. Soc. A Math. Phys. Eng. Sci. 466(2113), 3–18 (2010)
H.K.D.H. Bhadeshia, Lower Bainite transformation and the significance of carbide precipitation. Acta Metall. 28(8), 1103–1114 (1980)
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The authors would like to express their gratitude to Dr. Darja Jenko and Dr. Peter Majerič for their help with HRTEM and FESEM characterization, respectively.
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Kirbiš, P., Večko Pirtovšek, T., Anžel, I. et al. Metallographic Analysis of Kinetically Activated Bainite (KAB) Steels. Metallogr. Microstruct. Anal. 7, 643–649 (2018). https://doi.org/10.1007/s13632-018-0484-8
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DOI: https://doi.org/10.1007/s13632-018-0484-8