Journal of Materials Engineering and Performance

, Volume 27, Issue 4, pp 1494–1504 | Cite as

Microstructural Evolution and the Precipitation Behavior in X90 Linepipe Steel During Isothermal Processing

  • Y. Tian
  • H. T. Wang
  • Z. D. Wang
  • R. D. K. Misra
  • G. D. Wang


Thermomechanical controlled processing of 560-MPa (X90) linepipe steel was simulated in the laboratory using a thermomechanical simulator to study the microstructural evolution and precipitation behavior during isothermal holding. The results indicated that martensite was obtained when the steels were isothermally held for 5 s at 700 °C. Subsequently, granular bainite and acicular ferrite transformation occurred with increased holding time. Different amount of polygonal ferrite formed after isothermally holding for 600-3600 s. Pearlite nucleated after isothermally holding for 3600 s. Precipitation occurred after isothermal holding for 5 s and continuous precipitation occurred at grain boundaries after isothermally holding for 600 s. After isothermally holding for 3600 s, large Nb/Ti carbide precipitated. The presence of MX-type precipitates was confirmed by diffraction pattern. The interphase precipitation (IP) occurred between 5 and 30 s. Maximum hardness was obtained after isothermally holding for 600 s when IP occurred and rapidly decreased to a low value, mainly because polygonal ferrite dominated the microstructure after isothermally holding for 3600 s.


linepipe steel isothermal transformation precipitation the hardness 



The authors acknowledge support from the National Key R&D Program of China (Grant No. 2016YFB0300701). R.D.K. Misra also acknowledges continued collaboration with the Northeastern University as an Honorary Professor by providing guidance to students in research.


  1. 1.
    S.S. Sohn, S.Y. Han, S.Y. Shin, J.H. Bae, and S. Lee, Effects of Microstructure and Pre-strain on Bauschinger Effect in API, X70 and X80 Linepipe Steels, Met. Mater. Int., 2013, 19, p 423–431CrossRefGoogle Scholar
  2. 2.
    H. Zhao, B.P. Wynne, and E.J. Palmiere, Effect of Austenite Grain Size on the Bainitic Ferrite Morphology and Grain Refinement of a Pipeline Steel After Continuous Cooling, Mater. Charact., 2017, 123, p 128–136CrossRefGoogle Scholar
  3. 3.
    C. Zhang and Y.F. Cheng, Corrosion of Welded X100 Pipeline Steel in a Near-Neutral PH Solution, J. Mater. Eng. Perform., 2010, 19, p 834–840CrossRefGoogle Scholar
  4. 4.
    M. Rakhshkhorshid and S.H. Hashemi, Experimental Study of Hot Deformation Behavior in API, X65 Steel, Mater. Sci. Eng., A, 2013, 573, p 37–44CrossRefGoogle Scholar
  5. 5.
    P. Cizek, B.P. Wynne, C.H.J. Davies, and P.D. Hodgson, The Effect of Simulated Thermomechanical Processing on the Transformation Behavior and Microstructure of a Low-Carbon Mo-Nb Linepipe Steel, Metall. Mater. Trans. A, 2015, 46, p 407–425CrossRefGoogle Scholar
  6. 6.
    P.S. Bandyopadhyay, S.K. Ghosh, S. Kundu, and S. Chatterjee, Evolution of Microstructure and Mechanical Properties of Thermomechanically Processed Ultrahigh-Strength Steel, Metall. Mater. Trans. A, 2011, 42, p 2742–2752CrossRefGoogle Scholar
  7. 7.
    M. Rakhshkhorshid, H.M. Zadeh, and S.H. Hashemi, Thermomechanical Processing of a Nb-Ti-V Pipeline Steel, Int. J. Adv. Manuf. Technol., 2015, 79, p 1623–1631CrossRefGoogle Scholar
  8. 8.
    G.K. Andrii, O.M. Olexandra, R.K. Chris, and V.P. Elena, Strengthening Mechanisms in Thermomechanically Processed Nb-Ti-Microalloyed Steel, Metall. Mater. Trans. A, 2015, 46A, p 3470–3480Google Scholar
  9. 9.
    G. Peng, P.J. Eric, and W.M. Rainforth, Characterisation of Strain-induced Precipitation Behaviour in Microalloyed Steels during Thermomechanical Controlled Processing, Mater. Charact., 2017, 124, p 83–89CrossRefGoogle Scholar
  10. 10.
    L. Sanz, B. Pereda, and B. López, Effect of Thermomechanical Treatment and Coiling Temperature on the Strengthening Mechanisms of Low Carbon Steels Microalloyed with Nb, Mater. Sci. Eng., A, 2017, 685, p 377–390CrossRefGoogle Scholar
  11. 11.
    F.Z. Bu, X.M. Wang, L. Chen, S.W. Yang, C.J. Shang, and R.D.K. Misra, Influence of Cooling Rate on the Precipitation Behavior in Ti-Nb-Mo Microalloyed Steels during Continuous Cooling and Relationship to Strength, Mater. Charact., 2015, 102, p 146–155CrossRefGoogle Scholar
  12. 12.
    S. Liu, V.S.A. Challa, V.V. Natarajan, and R.D.K. Misra, D.M. Sidorenko, M.D. Mulholland, M. Manohar, J.E. Hartmann, Significant Influence of Carbon and Niobium on the Precipitation Behavior and Microstructural Evolution and Their Consequent Impact on Mechanical Properties in Microalloyed Steels, Mater. Sci. Eng. A, 2017, 683, p 70–82CrossRefGoogle Scholar
  13. 13.
    H.J. Kestenbach, S.S. Campos, and E.V. Morales, Role of Interphase Precipitation in Microalloyed Hot Strip Steels, Mater. Sci. Technol., 2006, 22, p 615–626CrossRefGoogle Scholar
  14. 14.
    H.W. Yen, P.Y. Chen, C.Y. Huang, and J.R. Yang, Interphase Precipitation of Nanometer-sized Carbides in a Titanium-Molybdenum-Bearing Low-Carbon Steel, Acta Mater., 2011, 59, p 6264–6274CrossRefGoogle Scholar
  15. 15.
    M. Goro, H. Ryota, P. Behrang, and F. Tadashi, Interphase Precipitation of VC and Resultant Hardening in V-added Medium Carbon Steels, ISIJ Int., 2011, 51, p 1733–1739CrossRefGoogle Scholar
  16. 16.
    I. Timokhina, M.K. Miller, J.T. Wang, H. Beladi, P. Cizek, and P.D. Hodgson, On the Ti-Mo-Fe-C Atomic Clustering During Interphase Precipitation in the Ti-Mo Steel Studied by Advanced Microscopic Techniques, Mater. Des., 2016, 111, p 222–229CrossRefGoogle Scholar
  17. 17.
    S. Mukherjee, I.B. Timokhina, C. Zhu, S.P. Ringer, and P.D. Hodgson, Three-Dimensional Atom Probe Microscopy Study of Interphase Precipitation and Nanoclusters in Thermomechanically Treated Titanium-Molybdenum Steels, Acta Mater., 2013, 61, p 2521–2530CrossRefGoogle Scholar
  18. 18.
    E. Girault, P. Jacques, P. Harlet, K. Mols, J.V. Humbeek, E. Aernoudt, and F. Delannay, Metallographic Methods for Revealing the Multiphase Microstructure of TRIP-Assisted Steels, Mater. Charact., 1998, 40, p 111–118CrossRefGoogle Scholar
  19. 19.
    H.K. Sung, S.Y. Shin, B. Hwang, C.G. Chang, and S. Lee, Effects of Cooling Conditions on Microstructure, Tensile Properties, and Charpy Impact Toughness of Low-Carbon High-Strength Bainitic Steels, Metall. Mater. Trans. A, 2013, 44, p 294–302CrossRefGoogle Scholar
  20. 20.
    Y. Tian, Q. Li, Z.D. Wang, and G.D. Wang, Effects of Ultra Fast Cooling on Microstructure and Mechanical Properties of Pipeline Steels, J. Mater. Eng. Perform., 2015, 24, p 3307–3314CrossRefGoogle Scholar
  21. 21.
    S.S. Sohn, S.Y. Han, J.H. Bae, H.S. Kim, and S. Lee, Effects of Microstructure and Pipe Forming Strain on Yield Strength Before and After Spiral Pipe Forming of API, X70 and X80 Linepipe Steel Sheets, Mater. Sci. Eng., A, 2013, 573, p 18–26CrossRefGoogle Scholar
  22. 22.
    L.V. Amin, M. Reza, and A.Z. Amir, The Mutual Effects of Hydrogen and Microstructure on Hardness and Impact Energy of SMA Welds in X65 Steel, Mater. Sci. Eng., A, 2017, 679, p 87–94CrossRefGoogle Scholar
  23. 23.
    P. Gong, E.J. Palmiere, and W.M. Rainforth, Thermomechanical Processing Route to Achieve Ultrafine Grains in Low Carbon Microalloyed Steels, Acta Mater., 2016, 119, p 43–54CrossRefGoogle Scholar
  24. 24.
    S.F. Medina and A.D.A. Gregorio, From Heterogeneous to Homogeneous Nucleation for Precipitation in Austenite of Microalloyed Steels, Acta Mater., 2015, 84, p 202–207CrossRefGoogle Scholar
  25. 25.
    D.P. Dunne, Interaction of Precipitation with Recrystallisation and Phase Transformation in Low Alloy Steels, Mater. Sci. Technol., 2010, 26, p 410–420CrossRefGoogle Scholar
  26. 26.
    Z.W. Hu, G. Xu, H.L. Yang, C. Zhang, and R. Yu, The Effects of Cooling Mode on Precipitation and Mechanical Properties of a Ti-Nb Microalloyed Steel, J. Mater. Eng. Perform., 2014, 23, p 4216–4222CrossRefGoogle Scholar

Copyright information

© ASM International 2018

Authors and Affiliations

  • Y. Tian
    • 1
  • H. T. Wang
    • 1
  • Z. D. Wang
    • 1
  • R. D. K. Misra
    • 2
  • G. D. Wang
    • 1
  1. 1.State Key Laboratory of Rolling and AutomationNortheastern UniversityShenyangChina
  2. 2.Laboratory for Excellence in Advanced Steel Research, Department of Metallurgical, Materials and Biomedical EngineeringUniversity of Texas at El PasoEl PasoUSA

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