Creep Deformation Behaviour and its Effect on Creep Life and Rupture Ductility of W-Mo-balanced 9Cr Steels.

The creep deformation behaviour and its effect on the creep life and rupture ductility are investigated for W-Mo-balanced 9Cr steels at 600 °C to 700 °C. The creep life is described as tr = 1.5/[ ε ˙ min (dln ε ˙ /d ε)], where ε ˙ min and dln ε ˙ /d ε reflect the creep deformation behaviour in the transient and acceleration creep regions, respectively. The creep life is also correlated with the time to minimum creep rate tm as tr = gtm, where g slightly increases with decreasing stress. The logarithm of creep rate linearly increases with strain in the initial stage of acceleration creep region. This is followed by a decrease in dln ε ˙ d ε with strain at high stresses, resulting in ductile failure at large strains, while it is followed by an increase in dln ε ˙ /d ε with strain at low stresses, resulting in rupture at small strains. [ABSTRACT FROM AUTHOR]