High-Temperature Wear Properties of the Nitrided Alloys for Steam Turbine Valve System Parts
ASTM A355, SUS422 and Nimonic 901 steel were nitrided and their wear characteristics such as the wear coefficient, amount of wear, shape and composition of wear debris were evaluated. Fe3N and Fe4N were observed in the nitrided layer of ASTM A355. Fe3N, Fe4N and CrN were appeared in the nitride of SUS422. However, only CrN phase was observed in the layer of Nimonic 901. The amount of wear and wear coefficient for the nitride specimen decreased remarkably compared with non-nitrided specimens. Also, the surface hardness and ductility increased and small debris was formed in the nitrided specimen.
Z.Y. Zhong, H. Saka, T.H. Kim, E.A. Holm, Y.F. Han and X.S. Xie
I.S. Kim et al., "High-Temperature Wear Properties of the Nitrided Alloys for Steam Turbine Valve System Parts", Materials Science Forum, Vols. 475-479, pp. 4133-4136, 2005