The Role of Thermomechanical Processing in Creep Deformation Behavior of Modified 9Cr-1Mo Steel


In this study, to refine the microstructure and enhance the mechanical properties, thermomechanical treatment (TMT) was performed on modified 9Cr-1Mo steel. The creep deformation behavior of TMT processed steel and the steel in its normalized and tempered (NT) state were studied for different stress levels at 923 K (650 °C). Transient, secondary, and tertiary creep regimes were analyzed for both conditions of the steel based on the empirical equation \( \varepsilon = \varepsilon_{0} + \varepsilon_{\text{t}} \left( {1 - e^{ - rt} } \right) + \varepsilon_{\text{s}}^{ \cdot } t + \varepsilon_{\text{L}} e^{{p\left( {t_{\text{t}} - t_{\text{r}} } \right)}} \). The rate of exhaustion of primary creep (r), r with time to reach the minimum creep rate, minimum creep rate\( \left( {\varepsilon_{ \hbox{min} }^{ \cdot } } \right) \), \( \varepsilon_{ \hbox{min} }^{ \cdot } \) with time spent in the secondary creep regime, rate of acceleration of tertiary creep (p), p with time to reach the onset of tertiary creep, and creep rate with applied stress exhibited a proportional relationship in both conditions of the steel. This proportionality existence in the transient and tertiary creep deformation obeyed the first-order reaction rate kinetic theory. The enhanced MX (M = V, Nb; X = C, N) precipitation in the TMT steel significantly decreased the creep deformation rate and extended the secondary stages of deformation. TMT processing of modified 9Cr-1Mo steel led to a significant increase in the creep rupture strength through the stable microstructure.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15
Fig. 16
Fig. 17
Fig. 18
Fig. 19
Fig. 20
Fig. 21
Fig. 22
Fig. 23
Fig. 24
Fig. 25
Fig. 26
Fig. 27
Fig. 28
Fig. 29
Fig. 30
Fig. 31


  1. 1.

    K. Maruyama, K. Sawada, and J. Koike: Iron Steel Inst. Jpn. Int., 2001, vol. 41, pp. 641–53.

    CAS  Article  Google Scholar 

  2. 2.

    L. Tan, J.T. Busby, P.J. Maziasz, and Y. Yamamoto: J. Nucl. Mater., 2013, vol. 441, pp. 713–17.

    CAS  Article  Google Scholar 

  3. 3.

    R.L. Klueh, N. Hashimoto, and P.J. Maziasz: J. Nucl. Mater., 2007, vols. 367–370, pp. 48–53.

    Article  Google Scholar 

  4. 4.

    Abe F (2008) Sci. Technol. 9(2):15.

    Google Scholar 

  5. 5.

    M. Song, C. Sun, Z. Fan, Y. Chen, R. Zhu, K.Y. Yu, K.T. Hartwig, H. Wang, and X. Zhang: Acta Mater., 2016, vol. 112, pp. 361–77.

    CAS  Article  Google Scholar 

  6. 6.

    L. Tan, D.T. Hoelzer, J.T. Busby, M.A. Sokolov, and R.L. Klueh: J. Nucl. Mater., 2012, vol. 422, pp. 45–50.

    CAS  Article  Google Scholar 

  7. 7.

    L. Tan, Y. Yang, and J.T. Busby: J. Nucl. Mater., 2013, vol. 442, pp. S13–S17.

    CAS  Article  Google Scholar 

  8. 8.

    J. Pešička, R. Kužel, A. Dronhofer, and G. Eggeler: Acta Mater., 2003, vol. 51, pp. 4847–62.

    Article  Google Scholar 

  9. 9.

    E. Cerri, E. Evangelista, S. Spigarelli, and P. Bianchi: Mater. Sci. Eng. A, 1998, vol. 245, pp. 285–92.

    Article  Google Scholar 

  10. 10.

    K. Laha, K.S. Chandravathi, P. Parameswaran, K. B. S. Rao, and S.L. Mannan: Metall. Mater. Trans. A, 2007, vol. 38A, pp. 58–68

    CAS  Article  Google Scholar 

  11. 11.

    Triratna Shrestha, Mehdi Basirat, Indrajit Charit, Gabriel P. Potirniche, and Karl K. Rink: Mater. Sci. Eng. A, 2013, vol. 565, pp. 382–91.

    CAS  Article  Google Scholar 

  12. 12.

    S. Hollner, B. Fournier, J. Le Pendu, T. Cozzika, I. Tournié, J.-C. Brachet, and A. Pineau: J. Nucl. Mater., 2010, vol. 405, pp. 101–08.

    CAS  Article  Google Scholar 

  13. 13.

    D.V.V. Satyanarayana, G. Malakondaiah, C. Phaniraj, and D.S. Sarma: Mater. Sci. Technol., 2009, vol. 25 (8), pp. 953–59.

    CAS  Article  Google Scholar 

  14. 14.

    C. Phaniraj, M. Nandagopal, S.L. Mannan, and P. Rodriguez: Acta Metall. Mater., 1991, vol. 39 (7), pp. 1651–56.

    CAS  Article  Google Scholar 

  15. 15.

    T.C. Totemeier, H. Tian, and J.A. Simpson: Metall. Mater. Trans. A, 2006, vol. 37A, pp. 1519–25.

    CAS  Article  Google Scholar 

  16. 16.

    Sakthivel T, Shruti P, Parameswaran P, Rao GVSN, Laha K, and Rao TS (2016): Trans. Ind. Inst. Met., 1:23

    Article  Google Scholar 

  17. 17.

    Irina Fedorova, Alla Kipelova, Andrey Belyakov, and Rustam Kaibyshev: Metall. Mater. Trans. A, 2013, vol. 44A, pp. 128–35.

    Article  Google Scholar 

  18. 18.

    T. Sakthivel, S. P. Selvi, and K. Laha: Mater. Sci. Eng. A, 2015, vol. 640, pp. 61–71.

    CAS  Article  Google Scholar 

  19. 19.

    P.G. McVetty: Mech. Eng., 1934, vol. 56, p. 149.

    Google Scholar 

  20. 20.

    F. Garofalo: Fundamentals of Creep and Creep Rupture in Metals, Macmillan, New York, NY, 1965.

    Google Scholar 

  21. 21.

    J.B. Conway: Numerical Methods for Creep and Rupture Analysis, Gordon & Breach, New York, NY, 1968.

    Google Scholar 

  22. 22.

    J.B. Conway and M.J. Mullikin: Trans. TMS-AIME, 1966, 242, p. 1496.

    Google Scholar 

  23. 23.

    W.J. Evans and B. Wilshire: Trans. TMS-AIME, 1968, 242, p. 2514.

    Google Scholar 

  24. 24.

    G.A. Webster, A.P.D. Cox, and J.E. Dorn: Met. Sci. J., 1969, vol. 3, p. 221.

    Article  Google Scholar 

  25. 25.

    P.W. Davies, W.J. Evans, K.R. Williams, and B. Wilshire: Scripta Metall., 1969, vol. 3, pp. 671–74.

    CAS  Article  Google Scholar 

  26. 26.

    P.W. Davies and K.R. Williams: Acta Metall., 1969, vol. 17, pp. 897–903.

    CAS  Article  Google Scholar 

  27. 27.

    F. Dobes and J. Cadek: Kov. Mater., 1981, vol. 19, p. 31.

    CAS  Google Scholar 

Download references


The authors wish to thank Dr. A. K. Bhaduri, Director, Indira Gandhi Centre for Atomic Research, Kalpakkam, for his keen interest in the work and encouragement. The authors acknowledge the Board of Research in Nuclear Sciences (BRNS), Department of Atomic Energy (DAE), Government of India, for providing financial support (Project No. 36(2)/14/42/2014-BRNS) to carry out this work. The authors also acknowledge Dr. N. Srinivasan, Head, Metal Working Group, DMRL, Hyderabad, for extending the hot-rolling facility.

Author information



Corresponding author

Correspondence to T. Sakthivel.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Manuscript submitted June 7, 2017.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Shruti, P., Sakthivel, T., Rao, G.V.S.N. et al. The Role of Thermomechanical Processing in Creep Deformation Behavior of Modified 9Cr-1Mo Steel. Metall Mater Trans A 50, 4582–4593 (2019).

Download citation