Water Vapor Oxidation Behavior under High-Temperature and Pressure Conditions of the Nitrided Alloys for Steam Turbine Valve System Parts

Abstract:

Article Preview

Mechanical and corrosion properties were evaluated in the nitrided and non-nitrided specimens of ASTM 355 and SUS422 steels. The oxides formed on the specimen were analyzed using by XRD and the weight change was measured after oxidation test at high temperature, high pressure, and steam conditions. The oxidation behaviors and rates between two alloys and nitrided/non-nitrided specimens were clearly different. XRD analysis showed that the nitrides formed on the nitrided specimen were composed of CrN, Fe4N, and Fe2-3N. Also, it was found that the hardness on the nitrided specimen at 283°C decreased from Hv 1150 of room temperature to Hv 425.

Info:

Periodical:

Materials Science Forum (Volumes 475-479)

Main Theme:

Edited by:

Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie

Pages:

4129-4132

Citation:

J.H. Yoon et al., "Water Vapor Oxidation Behavior under High-Temperature and Pressure Conditions of the Nitrided Alloys for Steam Turbine Valve System Parts", Materials Science Forum, Vols. 475-479, pp. 4129-4132, 2005

Online since:

January 2005

Export:

Price:

$38.00

[1] C. D. Walker. Search for an Improved Steam Material for Fossil Fired Steam Turbine, TR79MPL3158, 1/14 /(1980).

[2] C. D. Walker. Oxidation of LST-GValve Steam Bushing Materials-A Progress Report, TR81MPL378, 5/7/(1981).

[3] J. A. Board, British Nuclear Energy Society Technical Journal, Vol. 13 (1974) p.211.

[4] A. A. Korhonen and E. H. Sirvio, Thin Solid Films, Vol. 96 (1982) p.103.

[5] D. B. Williams : Practical Surface analysis, John Wiley and Sons Inc., New York, (1983).

[6] J. H. Cuturilo, An Investigation of the Reaction Zone Formed During the Oxidation of Chromium Bearing Steels, TR81MPL382, 5/13/82.

[7] Z. L. Zhang and T. Bell, Surf. Eng., Vol. 1 (1985) p.131.

[8] Y. D. Jang, Met. Mater. -Int. Vol. 8 (2002) p.503. Fig. 10 XRD patterns of gas-nitrided SUS422 obtained after high-temperature oxidation at 283o C. Fig. 9 XRD patterns of non-nitrided SUS422 obtained after high-temperature oxidation at 283o C.