Abstract
Two low-carbon high-strength bainitic steels with/without molybdenum (Mo) addition were designed to investigate the effect of Mo on bainitic transformation, microstructure and properties. The results show that during austempering, Mo addition increases the amount of isothermal bainite transformation and slightly accelerates the bainite transformation kinetics. It is mainly attributed to the fact that there is the ferrite transformation in Mo-free steel but not in Mo-added steel even cooled at a very high cooling rate before austempering. In Mo-free steel, the formation of ferrite leads to the higher carbon content in untransformed austenite with higher stability and thus retards the isothermal bainite transformation kinetics. The ferrite transformation controlled by carbon diffusion is strongly inhibited in the Mo-added steel because Mo addition decreases obviously the diffusion coefficient of carbon and grain boundaries energies. In addition, the promoted effect of Mo addition on isothermal bainite transformation is stronger at lower austempering temperature. Mo addition leads to the more and finer bainite plates and increases the strength of low-carbon bainitic steel. Moreover, the volume fraction of retained austenite first decreases and then increases in Mo-free steel with the increase in austempering temperature, whereas it presents the inverse trend in Mo-added steel. Similarly, during continuous cooling process, Mo addition effectively retards the formation of high-temperature products and thus improves the tensile properties of low-carbon steels.
Similar content being viewed by others
References
C. Garcia-Mateo, F.G. Caballero, and H.K.D.H. Bhadeshia, Acceleration of Low-Temperature Bainite, ISIJ Int., 2003, 43(11), p 1821–1825
J.Y. Tian, G. Xu, M.X. Zhou, H.J. Hu, and Z.L. Xue, Effects of Al Addition on Bainite Transformation and Properties of High-Strength Carbide-Free Bainitic Steels, J. Iron. Steel Res. Int., 2019, 26(8), p 846–855
K. Zhu, C. Oberbillig, C. Musik, D. Loison, and T. Iung, Effect of B and B + Nb on the Bainitic Transformation in Low Carbon Steels, Mater. Sci. Eng. A, 2011, 528(12), p 4222–4231
F.G. Caballero and H.K.D.H. Bhadeshia, Very Strong Bainite, Curr. Opin. Solid ST. Mater. Sci., 2004, 8, p 251–257
F.G. Caballero, H.K.D.H. Bhadeshia, K.J.A. Mawella, D.G. Jones, and P. Brown, Very Strong Low Temperature Bainite, Mater. Sci. Technol., 2002, 18(3), p 279–284
J. Kong and C. Xie, Effect of Molybdenum on Continuous Cooling Bainite Transformation of Low-Carbon Microalloyed Steel, Mater. Des., 2006, 27(10), p 1169–1173
H.J. Hu, G. Xu, M.X. Zhou, and Q. Yuan, Effect of Mo Content on Microstructure and Property of Low-Carbon Bainitic Steels, Metals, 2016, 6, p 173–182
J. Chen, S. Tang, Z.Y. Liu, and G.D. Wang, Influence of Molybdenum Content on Transformation Behavior of High Performance Bridge Steel During Continuous Cooling, Mater. Des., 2013, 49, p 465–470
T. Sourmail and V. Smanio, Low Temperature Kinetics of Bainite Formation in High Carbon Steels, Acta Mater., 2013, 61, p 2639–2648
J.Y. Chae, J.H. Jang, G.H. Zhang, K.H. Kim, J.S. Lee, H.K.D.H. Bhadeshia, and D.W. Suh, Dilatometric Analysis of Cementite Dissolution in Hypereutectoid Steels Containing Cr, Scr. Mater., 2011, 65, p 245–248
Y. Xia, G. Miyamoto, Z.G. Yang, C. Zhang, and T. Furuhara, Direct Measurement of Carbon Enrichment in the Incomplete Bainite Transformation in Mo Added Low Carbon Steels, Acta Mater., 2015, 91, p 10–18
J.Y. Tian, G. Xu, Z.Y. Jiang, Q. Yuan, G.H. Chen, and H.J. Hu, Effect of Austenisation Temperature on Bainite Transformation Below Martensite Starting Temperature, Mater. Sci. Technol., 2019, 35, p 1539–1550
M. Peet, H.K.D.H. Bhadeshia, MAP Program MAP_STEEL_MUCG83, Materials Algorithms Project (MAP), University of Cambridge, Cambridge.
J.Y. Tian, G. Xu, M.X. Zhou, and H.J. Hu, Refined Bainite Microstructure and Mechanical Properties of a High-Strength Low-Carbon Bainitic Steel Treated by Austempering Below and Above MS, Steel Res. Int., 2018, 89, p 1–10
J.Y. Tian, G.H. Chen, Y.W. Xu, Z.Y. Jiang, and G. Xu, Comprehensive Analysis of the Effect of Ausforming on the Martensite Start Temperature in a Fe-C-Mn-Si Medium-Carbon High-Strength Bainite Steel, Metall. Mater. Trans. A, 2019, 50(10), p 4541–4549
J.Y. Tian, G. Xu, Z.Y. Jiang, H.J. Hu, Q. Yuan, and X.L. Wan, In-Situ Observation of Martensitic Transformation in a Fe-C-Mn-Si Bainitic Steel During Austempering, Met. Mater. Int., 2019, https://doi.org/10.1007/s12540-019-00370-8
H.K.D.H. Bhadeshia, Bainite in Steels, 2nd ed., The Institute of Materials, London, 2001, p 117–187
Z.Y. Chen, J.X. Li, J.J. Qi, L.Q. Chen, L. Sun, and G.D. Wang, Effects of Nb on Bainite Transformation Behavior and Mechanical Properties of Low-Carbon Bainitic Steels, Steel Res. Int., 2019, 90, p 1–10
B. Oztur, V.L. Fearing, J.A. Ruth, and G. Simkovich, The Diffusion Coefficient of Carbon in Cementite, Fe3C, at 450 °C, Solid State Ion., 1984, 12, p 145–151
E. Essadiqi and J.J. Jonas, Effect of Deformation on Ferrite Nucleation and Growth in a Plain Carbon and Two Microalloyed Steels, Metall. Mater. Trans. A, 1989, 20(6), p 987–998
G. Miyamoto, K. Yokoyama, and T. Furuhara, Quantitative Analysis of Mo Solute Drag Effect on Ferrite and Bainite Transformations in Fe-0.4C-0.5Mo Alloy, Acta Mater., 2019, 177, p 187–197
J.Y. Tian, G. Xu, L. Wang, M.X. Zhou, and H.J. Hu, In Situ Observation of the Lengthening Rate of Bainite Sheaves During Continuous Cooling Process in a Fe-C-Mn-Si Superbainitic Steel, Trans. Indian Inst. Met., 2018, 71(1), p 185–194
H.K.D.H. Bhadeshia, S.A. David, J.M. Vitek, and R.W. Reed, Stress Induced Transformation to Bainite in Fe-Cr-Mo-C Pressure Vessel Steel, Mater. Sci. Technol., 1991, 7, p 686–698
F.R. Xiao, B. Liao, Y.Y. Shan, and K. Yang, Isothermal Transformation of Low-Carbon Microalloyed Steels, Mater. Charact., 2005, 54, p 417–422
S.B. Singh and H.K.D.H. Bhadeshia, Estimation of Bainite Plate-Thickness in Low-Alloy Steels, Mater. Sci. Eng. A, 1998, 245(1), p 72–79
H.J. Hu, G. Xu, L. Wang, Z.L. Xue, Y.L. Zhang, and G.H. Liu, The Effects of Nb and Mo Addition on Transformation and Properties in Low Carbon Bainitic Steels, Mater. Des., 2015, 84, p 95–99
A. Morozova and R. Kaibyshev, Grain Refinement and Strengthening of a Cu-0.1Cr-0.06Zr Alloy Subjected to Equal Channel Angular Pressing, Philos. Mag., 2017, 97(24), p 2053–2076
S. Takeuchi, Solid-Solution Strengthening in Single Crystals of Iron Alloys, J. Phys. Soc. Jpn., 1969, 27(4), p 929–940
S.S. Babu, E.D. Specht, S.A. David, E. Karapetrova, P. Zschack, M. Peet, and H.K.D.H. Bhadeshia, In-Situ Observations of Lattice Parameter Fluctuations in Austenite and Transformation to Bainite, Metall. Mater. Trans. A, 2005, 36, p 3281–3289
C.Y. Wang, J. Shi, W.Q. Cao, and H. Dong, Characterization of Microstructure Obtained by Quenching and Partitioning Process in Low Alloy Martensitic Steel, Mater. Sci. Eng. A, 2010, 527, p 3442–3449
X.Y. Long, J. Kang, B. Lv, and F.C. Zhang, Carbide-Free Bainite in Medium Carbon Steel, Mater. Des., 2014, 64, p 237–245
J.Y. Tian, G. Xu, Z.Y. Jiang, H.J. Hu, and M.X. Zhou, Efect of Ni Addition on Bainite Transformation and Properties in a 2000 MPa Grade Ultrahigh Strength Bainitic Steel, Met. Mater. Int., 2018, 24, p 1202–1212
G. Mandal, C. Roy, S.K. Ghosh, and S. Chatterjee, Structure–Property Relationship in a 2 GPa Grade Micro-alloyed Ultrahigh Strength Steel, J. Alloys Compd., 2017, 705, p 817–827
R.K. Dutta, M. Amirthalingam, M.J.M. Hermans, and I.M. Richardson, Kinetics of Bainitic Transformation and Transformation Plasticity in a High Strength Quenched and Tempered Structural Steel, Mater. Sci. Eng. A, 2013, 559, p 86–95
Acknowledgments
The authors gratefully acknowledge the financial supports from Major Development Project of Hebei Province (18211019D), Project of “Three-three-three talents” in Hebei Province (A201803007) and Major Project of Science and Technology of HBIS GROUP (HG2018203).
Author information
Authors and Affiliations
Corresponding author
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Chen, Z., Qi, J., Liu, H. et al. Bainitic Transformation and Mechanical Properties of Low-Carbon High-Strength Bainitic Steels with Mo Addition. J. of Materi Eng and Perform 29, 2428–2439 (2020). https://doi.org/10.1007/s11665-020-04784-z
Received:
Revised:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11665-020-04784-z