Korean Journal of Metals and Materials (대한금속재료학회지)

The Korean Institute of Metals and Materials (대한금속재료학회)
권호 표지
DOI QR코드

DOI QR Code

Premature Failure Analysis of Servovalve Components for a Thermal Power Plant

  • Chang, Sung-Yong (Power Integrity Group, Korea Electric Power Research Institute (KEPRI)) ;
  • Chang, Joong-Chel (Power Integrity Group, Korea Electric Power Research Institute (KEPRI)) ;
  • Kim, Bum-Soo (Power Integrity Group, Korea Electric Power Research Institute (KEPRI)) ;
  • Seo, Min-Woo (School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center (SPRC), Chonbuk National University) ;
  • Choi, Chel-Jong (School of Semiconductor and Chemical Engineering, Semiconductor Physics Research Center (SPRC), Chonbuk National University)
  • Published : 2011.09.25
⟨ Previous Next ⟩

Abstract

The premature failure of a servovalve used for six months in a thermal power plant has been analyzed. The servovalve was made of stainless steel, containing 16Cr-0.44Mo, along with other elements. An overload of oil-supply pumping and an abnormal increase in the oil flux were observed during operation. A study revealed that erosion and corrosion could be the main causes of the failure. The visual examination of the servovalve did not show any appreciable damage. However, corrosion and erosion of the servovalve were observed using scanning electron microscopy (SEM). Upon examination of the servovalve, the corrosion was found to have occurred throughout the bushing and spool; however, erosion occurred at only the edge-side. In addition, the condition of the electrohydraulic control system (EHC) oil was investigated with respect to its satisfaction of the management standard.

Keywords

Acknowledgement

Grant : Human Resource Development program

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

References

  1. W. J. Thayer, Transfer function for Moog servovalves, Moog Technical Bulletin 103, Moog Inc., New York (1958).
  2. W. J. Thayer, Specification standards for electrohydraulic flow control servovalves, Moog Technical Bulletin 117, Moog Inc., New York (1962).
  3. D. H. Kim and T. Tsao, J. Dyn. Sys. Meas. Control 122, 179 (2000). https://doi.org/10.1115/1.482440
  4. H.S. Lee, J. S. Jung, K.B. Yoo, and E.H. Kim, J. Kor. Inst. Met. & Mater. 49, 277 (2010).
  5. J. R. Davis, ASM Specialty Handbook: Stainless Steels, p.174, Materials Park, Ohio (1994).
  6. D. Martinez, R. Gonzalez, K Montemayor, A. Juarez- Hernandez, G. Fajardo, and M. A. L. Hernandez-Rodriguez, Wear 267, 255 (2009). https://doi.org/10.1016/j.wear.2008.12.056
  7. Outi M. Zacheus, Eila K. Iivanainen, Tarja K. Nissinen, Markku J. Lehtola, and Pertti J. Martikainen, Water Res. 34, 63 (2000). https://doi.org/10.1016/S0043-1354(99)00113-X
  8. P.C. Pistorius and G.T. Burstein, Corros. Sci. 33, 1885 (1992). https://doi.org/10.1016/0010-938X(92)90191-5
  9. M. Suresh Kumar, M. Sujata, M.A. Venkataswamy, and S.K. Bhaumik, Eng. Fail. Anal. 15, 497 (2008). https://doi.org/10.1016/j.engfailanal.2007.05.002
  10. G. Bolelli, V. Cannillo, R. Giovanardi, and L. Lusvarghi, Int. J. Surf. Sci. Eng. 2, 222 (2008). https://doi.org/10.1504/IJSURFSE.2008.020495
  11. B. Sibul and P.K. Trygstad, Power Eng. 103, 41 (1999).
  12. T Christopher Dickenson, Filters and Filtration Handbook, 4th ed., p.39-40, Elsevier Science Inc., New York (1997).