On-Site Corrosion Behavior of T91 Steel after Long-Term Service in Power Plant

  • He, Yinsheng (School of Nano & Advanced Materials Engineering, Changwon National University) ;
  • Chang, Jungchel (Technology Policy and Planning Department, Korea Electric Power Corporation) ;
  • Lee, Je-Hyun (School of Nano & Advanced Materials Engineering, Changwon National University) ;
  • Shin, Keesam (School of Nano & Advanced Materials Engineering, Changwon National University)
  • Received : 2015.07.27
  • Accepted : 2015.10.01
  • Published : 2015.11.27


In this work, on-site corrosion behavior of heat resistant tubes of T91, used as components of a superheater in a power plant for up to 25,762 h, has been investigated using scanning electron microscopy(SEM), energy dispersive X-ray spectroscopy (EDS), and electron backscattered diffraction(EBSD), with the objectives of studying the composition, phase distribution, and evolution during service. A multi-layer structure of oxide scale was found on both the steamside and the fireside of the tube surface; the phase distribution was in the order of hematite/magnetite/spinel from the outer to the inner matrix on the steamside, and in the order of slag/magnetite/spinel from the outer to the inner matrix on the fireside. The magnetite layer was found to be rich in pores and cracks. The absence of a hematite layer on the fireside was considered to be due to the low oxygen partial pressure in the corrosion environment. The thicknesses of the hematite and of the slag-deposit layer were found to exhibit no significant change with the increase of the service time.


Supported by : National Research Foundation of Korea(NRF)


  1. L. Tan, X. Ren and T. R. Allen, Corro. Sci., 52, 1520 (2010).
  2. K. Natesan and J. H. Park, Int. J. Hydrogen Energy, 32, 3689 (2007).
  3. S. R. J. Saunders, M. Monteiro and F. Rizzo, Prog. Mater. Sci., 53, 775 (2008).
  4. P. Ampornrat and G. S. Was, J. Nucl. Mater., 371, 1 (2007).
  5. S. C. Srivastava and K. M. Godiwalla, J. Mater. Sci., 32, 835 (1997).
  6. K. Song, T. Y. Cho, J. H. Yoon, C. G. Lee, K. Shin, S. H. Lee, K. W. Urm, J. W. Lee and I. S. Kim, Met. Mater. Int., 14, 721 (2008).
  7. Y. Chen, K. Sridharan and T. Allen, Corro. Sci., 48, 2843 (2006).
  8. K. Yin, S. Qiu, R. Tang, Q. Zhang and L. Zhang, J. Supercrit. Fluids, 50, 235 (2009).
  9. L. Tan, Y. Yang and T. R. Allen, Corro. Sci., 48, 3123 (2006).
  10. X. Ren, K. Sridharan and T. R. Allen, J. Nucl. Mater., 358, 227 (2006).
  11. X. Zhong, X. Wu and E. H. Han, J. Supercrit. Fluids, 72, 68 (2012).
  12. Y. He, J. Chang, J. Dong and K. Shin, Adv. Sci. Lett., 4, 1416 (2011).
  13. C. G. Panait, W. Bendick, A. Fuchsmann, A.-F. Gourgues-Lorenzon and J. Besson, Int. J. Pres. Ves. Pip., 87, 326 (2010).