Failure Analysis of T12 Boiler Re-Heater Tubes During Short-Term Service
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The failure of T12 re-heater tubes that had been in service only for 3000 h was investigated. The wall thickness of the tubes was visibly reduced by heavy oxidation corrosion on the outer and inner walls. The original pearlite substrate completely decomposed. Uniform oxide scale appearance on the inner wall shows obvious vapor oxidation corrosion characteristics. Corrosion originated in the grain boundary, and selective oxidation occurred due to ion diffusion in the substrate. The layered oxide scale formed on the inner wall is related to the different diffusion rates for different cations. Exposure to high temperature corrosive flux accelerated the corrosion on the outer wall. The microstructure degradation and corrosion characteristics of the tubes indicate that the tubes failed primarily because of overheating, as evidenced by calculations.
KeywordsSteel High temperature corrosion Oxidation Microstructure
The author would like to acknowledge the support provided by the National Science Foundation of China (50760176) for this correlative research project.
- 1.F. Gabrielli, Overview of water related tube failures in industrial boilers. Mater. Perform. 27, 51–56 (1988)Google Scholar
- 2.M. Mobin, A.U. Malik, I.N. Andijani, F. Al-Muaili, M. Al-Hajri, Premature waterside corrosion of furnace wall tubes in a high pressure boiler. Mater. Perform. 62, 44–49 (2006)Google Scholar
- 4.J.N. Liu, Y.F. Zhao, B. Geng, Z.P. Wang, Y.H. Yao, C.Z. Shi, Research on the microstructure of the oxidation film of T91 steel tube under the high temperature and high pressure water vapor. Foundry Technol. 26(3), 202–204 (2005)Google Scholar
- 7.ECCC Recommendations, Residual life assessment and micro-structure, in ECCC, vol. 6, no. 1 (2005)Google Scholar
- 11.Y. Ikeda, K. Nii, Mechanism of accelerated oxidation on Fe-Cr alloys in water vapor containing atmospheres. Trans. Natl. Res. Inst. Met. 26(1), 52–62 (1984)Google Scholar
- 15.D.N. French, Metallurgical Failures in Fossil Fired Boilers (Wiley, New York, 2000)Google Scholar