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http://dx.doi.org/10.3365/KJMM.2011.49.9.708

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)
Publication Information
Korean Journal of Metals and Materials / v.49, no.9, 2011 , pp. 708-714 More about this Journal
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
alloys; deformation; corrosion; scanning electron microscopy (SEM); servovalve;
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  • Reference
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).   DOI   ScienceOn
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).   DOI   ScienceOn
7 Outi M. Zacheus, Eila K. Iivanainen, Tarja K. Nissinen, Markku J. Lehtola, and Pertti J. Martikainen, Water Res. 34, 63 (2000).   DOI   ScienceOn
8 P.C. Pistorius and G.T. Burstein, Corros. Sci. 33, 1885 (1992).   DOI   ScienceOn
9 M. Suresh Kumar, M. Sujata, M.A. Venkataswamy, and S.K. Bhaumik, Eng. Fail. Anal. 15, 497 (2008).   DOI   ScienceOn
10 G. Bolelli, V. Cannillo, R. Giovanardi, and L. Lusvarghi, Int. J. Surf. Sci. Eng. 2, 222 (2008).   DOI   ScienceOn
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).