Effect of Stress Reduction of Secondary Creep of Mild Steel

Abstract

The transient behavior of 0.14 per cent carbon steel, which appeared by a partial removal of applied stress at the stage of secondary creep, was studied at 450°C. The strain rate after the partial reduction of stress was found smaller than the true steady creep rate for the reduced stress, however it gradually increased with time and appeared to tend to the steady creep rate. It was also found that the higher was the applied stress before the stress reduction, the lower rate of strain appeared after the reduction at a given strain and the longer period was necessary before the strain rate reached the steady creep rate. These behaviors were ascertained to be well interpreted by the authors'theory of the plastic deformation of metais at high temperatures.