Effects of Prior Plasticity on Subsequent Creep of Type 316 Stainless Steel at Elevated Temperature

Interaction between creep and plastic deformation was studied experimentally for type 316 stainless steel at 650°C, with special emphasis on creep behavior subsequent to plastic prestraining. In combined creep-plasticity experiments, thin-walled tubular specimens were first prestrained plastically in the axial tensile direction, and were subsequently subjected to constant stress creep under various multiaxial stress states with an identical effective stress. Furthermore, the variation in creep resistance due to the plastic prestrain was compared with that due to the same amount of creep prestrain. From the experimental results, it was found that creep resistance was markedly enhanced by the plastic prestrain and that the increase in the creep resistance depended on the amount and relative direction of the plastic prestrain. The creep resistance was increased more markedly by creep prestrain than the same amount of plastic strain.