2008 Volume 94 Issue 3 Pages 99-105
Ω method is effective for an assessment of creep life time. In this study, creep curves of 9Cr ferritic heat-resistant steels were analyzed by the Ω method. Samples were four types of 9Cr steel, which were fundamental 9Cr steel, solid solution hardened steel containing W, precipitation hardened steel with MX and precipitation hardened steel with MX and Laves phase. The comparison between rupture time in creep tests and creep life time assessed by the Ω method indicated that the life assessment of the Ω method was sufficiently effective in the 9Cr steels. In addition, we investigated the dependence of Ω value on stress applied in creep test. In the case of the precipitation hardened steels, Ω value had the strong dependence on stress. This dependence indicated that Ω value has relevance to creep deformation mechanism.
