KEPCO Journal on Electric Power and Energy

Korea Electric Power Corporation (한국전력공사)
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Study on the Microstructural Degradation of the Boiler Tubes for Coal-Fired Power Plants

  • Yoo, Keun-Bong (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • He, Yinsheng (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Lee, Han-Sang (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Bae, Si-Yeon (KEPCO Research Institute, Korea Electric Power Corporation) ;
  • Kim, Doo-Soo (KEPCO Research Institute, Korea Electric Power Corporation)
  • Received : 2017.09.08
  • Accepted : 2018.06.05
  • Published : 2018.06.30
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Abstract

A boiler system transforms water to pressured supercritical steam which drives the running of the turbine to rotate in the generator to produce electricity in power plants. Materials for building the tube system face challenges from high temperature creep damage, thermal fatigue/expansion, fireside and steam corrosion, etc. A database on the creep resistance strength and steam oxidation of the materials is important to the long-term reliable operation of the boiler system. Generally, the ferritic steels, i.e., grade 1, grade 2, grade 9, and X20, are extensively used as the superheater (SH) and reheater (RH) in supercritical (SC) and ultra supercritcal (USC) power plants. Currently, advanced austenitic steel, such as TP347H (FG), Super304H and HR3C, are beginning to replace the traditional ferritic steels as they allow an increase in steam temperature to meet the demands for increased plant efficiency. The purpose of this paper is to provide the state-of-the-art knowledge on boiler tube materials, including the strengthening, metallurgy, property/microstructural degradation, oxidation, and oxidation property improvement and then describe the modern microstructural characterization methods to assess and control the properties of these alloys. The paper covers the limited experience and experiment results with the alloys and presents important information on microstructural strengthening, degradation, and oxidation mechanisms.

Keywords

Acknowledgement

Supported by : Korea Institute of Energy Technology Evaluation and Planning (KETEP)

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