Investigations on carburizing mechanisms of Cr35Ni45Nb subjected to different service conditions in a high-temperature vacuum environment


The carburizing behaviors and mechanisms for Cr35Ni45Nb alloy subjected to different service conditions were studied in a high-temperature vacuum environment. Generally, the carburizing process of an alloy is always accompanied by diffusional heterogeneous reactions regardless of the service condition of the alloy. For a carburized original tube, there is a layered structure at the inner wall of the tube, which is comprised of a M7C3 zone, a M7C3–M23C6 mixed zone, and a M23C6 zone with different morphologies. However, for a 6-year tube (short for a tube serviced for 6 years), the composite oxide layers formed previously act as effective barriers to carbon infiltration. Moreover, the Cr2O3 scale tended to be carbonized to form carbide scale to spall from the surface in a reducing environment, while the SiO2 kept stable all along. Once the oxide layers were removed or carbonized enough, inconceivable internal carburization occurred widely.

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  1. 1.

    S. Yancheshmeh, S. Seifzadeh Haghighi, M. Gholipour, O. Dehghani, M. Rahimpour, and S. Raeissi: Modeling of ethane pyrolysis process: A study on effects of steam and carbon dioxide on ethylene and hydrogen productions. Chem. Eng. J. 215, 550 (2013).

    Article  Google Scholar 

  2. 2.

    G. Zhang and B. Evans: Progress of modern pyrolysis furnace technology. Adv. Mater. Phys. Chem. 2, 169 (2013).

    Article  Google Scholar 

  3. 3.

    H. Grabke and I. Wolf: Carburization and oxidation. Mater. Sci. Eng. 87, 23 (1987).

    CAS  Article  Google Scholar 

  4. 4.

    A. Ul-Hamid, H.M. Tawancy, A-R.I. Mohammed, and N.M. Abbas: Failure analysis of furnace radiant tubes exposed to excessive temperature. Eng. Failure Anal. 13, 1005 (2006).

    CAS  Article  Google Scholar 

  5. 5.

    J. Lee, W. Yang, W. Yoo, and K. Cho: Microstructural and mechanical property changes in HK40 reformer tubes after long term use. Eng. Failure Anal. 16, 1883 (2009).

    CAS  Article  Google Scholar 

  6. 6.

    A.A. Kaya: Microstructure of HK40 alloy after high-temperature service in oxidizing/carburizing environment: II. Carburization and carbide transformations. Mater. Charact. 49, 23 (2002).

    CAS  Article  Google Scholar 

  7. 7.

    T. Ramanarayanan, R. Petkovic, J. Mumford, and A. Ozekcin: Carburization of high chromium alloys. Mater. Corros. 49, 226 (1998).

    CAS  Article  Google Scholar 

  8. 8.

    A. Rahmel, H. Grabke, and W. Steinkusch: Carburization–introductory survey. Mater. Corros. 49, 221 (1998).

    CAS  Article  Google Scholar 

  9. 9.

    R. Petkovic-Luton and T. Ramanarayanan: Mixed-oxidant attack of high-temperature alloys in carbon-and oxygen-containing environments. Oxid. Met. 34, 381 (1990).

    CAS  Article  Google Scholar 

  10. 10.

    S. Ling, T. Ramanarayanan, and R. Petkovic-Luton: Computational modeling of mixed oxidation-carburization processes: Part 1. Oxid. Met. 40, 179 (1993).

    CAS  Article  Google Scholar 

  11. 11.

    D. Mitchell, D. Young, and W. Kleemann: Caburisation of heat-resistant steels. Mater. Corros. 49, 231 (1998).

    CAS  Article  Google Scholar 

  12. 12.

    H. Evans and R. Lobb: Conditions for the initiation of oxide-scale cracking and spallation. Corros. Sci. 24, 209 (1984).

    CAS  Article  Google Scholar 

  13. 13.

    A. Huntz and M. Schütze: Stresses generated during oxidation sequences and high temperature fracture. Mater. High Temp. 12, 151 (1994).

    CAS  Article  Google Scholar 

  14. 14.

    I. Wolf, H. Grabke, and P. Schmidt: Carbon transport through oxide scales on Fe-Cr alloys. Oxid. Met. 29, 289 (1988).

    CAS  Article  Google Scholar 

  15. 15.

    C. Li, Y. Yang, and X. Wu: Analysis of coking and caburizing of HP heat-resistant steel. J. Chin. Soc. Corros. Prot. 22, 289 (2002).

    Google Scholar 

  16. 16.

    J-W. Snoeck, G. Froment, and M. Fowles: Filamentous carbon formation and gasification: Thermodynamics, driving force, nucleation, and steady-state growth. J. Catal. 169, 240 (1997).

    CAS  Article  Google Scholar 

  17. 17.

    S.H. Khodamorad, D. Haghshenas Fatmehsari, H. Rezaie, and A. Sadeghipour: Analysis of ethylene cracking furnace tubes. Eng. Failure Anal. 21, 1 (2012).

    CAS  Article  Google Scholar 

  18. 18.

    H. Tawancy and N. Abbas: Mechanism of carburization of high-temperature alloys. J. Mater. Sci. 27, 1061 (1992).

    CAS  Article  Google Scholar 

  19. 19.

    V. Tari, A. Najafizadeh, M. Aghaei, and M. Mazloumi: Failure analysis of ethylene cracking tube. J. Fail. Anal. Prev. 9, 316 (2009).

    Article  Google Scholar 

  20. 20.

    N. Ryzhov, A. Smirnov, R. Fakhurtdinov, L. Mulyakaev, and V. Gromov: Special features of vacuum carburizing of heat-resistant steel in acetylene. Met. Sci. Heat Treat. 46, 230 (2004).

    CAS  Article  Google Scholar 

  21. 21.

    N. Ryzhov, A. Smirnov, and R. Fakhurtdinov: Control of carbon saturation of the diffusion layer in vacuum carburizing of heat-resistant steels. Met. Sci. Heat Treat. 46, 340 (2004).

    CAS  Article  Google Scholar 

  22. 22.

    D. Farkas and K. Ohla: Modeling of diffusion processes during carburization of alloys. Oxid. Met. 19, 99 (1983).

    CAS  Article  Google Scholar 

  23. 23.

    A. Borgenstam, L. Höglund, J. Ågren, and A. Engström: DICTRA, a tool for simulation of diffusional transformations in alloys. J. Phase Equilib. 21, 269 (2000).

    CAS  Article  Google Scholar 

  24. 24.

    A. Kaya, P. Krauklis, and D. Young: Microstructure of HK40 alloy after high temperature service in oxidizing/carburizing environment: I. Oxidation phenomena and propagation of a crack. Mater. Charact. 49, 11 (2002).

    CAS  Article  Google Scholar 

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The authors are grateful for the financial support and facilities provided by China Special Equipment Inspection and Research Institute and Beijing Institute of Aeronautical Materials, respectively.

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Correspondence to Maicang Zhang.

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Peng, Y., Zhang, M., Xiao, J. et al. Investigations on carburizing mechanisms of Cr35Ni45Nb subjected to different service conditions in a high-temperature vacuum environment. Journal of Materials Research 30, 841–851 (2015).

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