1998 Volume 84 Issue 7 Pages 526-533
The Ω and a conventional methods were applied to analyze the short-term creep behavior of a Mod.9Cr-1Mo steel. The stress and temperatuer ranges investigated are from 107.9 to 196.1 MP and from 873 to 923K, respectively. Creep life, tr was related to the time to minimum creep (tm), the minimum creep rate (εm) and the imaginary initial creep rate (εo ) astm =0.22×tr1.03, ε m Z·tr KMG and εoY·tr= Ko, where the magnitudes of Z, KMG, Y, and Ko 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 εm = Am·σonm·exp (-Qm/RT) and εο= Ao·σono exp(-Qo/RT), where Am and Ao are structure factors, σo is the initial stress, nm and no are the stress exponents, and Nm, NoQm and Qο are the activation energies for the minimum creep rate and imaginary initial creep rate, respectively. The magnitudes of Am, Ao, NQm and Qo are 9.2 × 103/s, 1.08 × 108/s, 12.8 ±0.2, 13.0±0.2, 666 ± 5 kJ/mol and 751 ±5kJ/mol, respectively.