The exhaustion of creep ductility in 1CrMoV steel

The calculation of creep damage due to secondary (self equilibrating) stresses for the lifetime assessment of critical locations in components subject to creep-fatigue loading at high temperatures may be determined in terms of ductility exhaustion. A new Spindler type stress-modified creep ductility exhaustion model has been developed for 1CrMoV steel in which the rupture ductility is dependent not only on creep strain rate, stress and temperature, but also on a material pedigree function. The paper covers the background to the development of the new model and demonstrates its capability for predicting the creep rupture ductility characteristics of heats of 1CrMoV at different positions in the alloy scatterband.