改良 9Cr-1Mo 鋼の短時間クリープ挙動の解析

概要

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The Ω and a conventional methods were applied to analyze the short-term creep behavior of a Mod.9Cr-1Mo steel. The stress and temperature ranges investigated are from 107.9 to 196.1 MP and from 873 to 923K, respectively. Creep life, t_r was related to the time to minimum creep (t_m), the minimum creep rate (ε^^._m) and the imaginary initial creep rate (ε^^._o) as t_m=0.22×t_r^<1.03>, ε^^._m^Z・t_r=K_<MG> and ε^^._o^Y・t_r=K_o, where the magnitudes of Z, K_<MG>, Y, and K_o are 0.801, 0.332, 0.884 and 0.216, respectively. The constitutive equations for the minimum and imaginary initial creep rates are expressed as ε^^._m=A_m・σ_O^<n_m>・exp(-Q_m/RT) and ε^^._o=A_o・σ_o^<n_o>・exp(-Q_o/RT), where A_m and A_o are structure factors, σ_o is the initial stress, n_m and n_o are the stress exponents, and Q_m and Q_o are the activation energies for the minimum creep rate and imaginary initial creep rate, respectively. The magnitudes of A_m, A_o, n_m, n_o, Q_m and Q_o are 9.2×10^3/s, 1.08×10^8/s, 12.8±0.2, 13.0±0.2, 666±5 kJ/mol and 751±5kJ/mol, respectively.
社団法人日本鉄鋼協会の論文
1998-07-01