Creep deformation of low-alloy 1 Cr–Mo–V steel at 565°C

Creep tests on a 1Cr–Mo–V steel, in its tempered bainitic condition, for lives up to 3·3 × 104 h are reported. A transition in the plot of steady-state strain rate v. applied stress σ occurs at ∼230 MN m−2, yielding two values of stress exponent. Measurement of the friction stress σ0 as a function of applied stress has been carried out over a wide range of stress. Its variation is dissimilar to many precipitation-hardened materials in that its value diminishes at high applied stress levels. By plotting the steady-state strain rate v. the effective stress (σ−σ0) a single relationship is observed indicating that creep deformation is recovery controlled over the entire stress range. These observations are related to the structural stability of the alloy as determined by electron metallography.