Deformation of annealed low carbon steel at high strain-rates

Abstract

The strain-time history of annealed low carbon steel is measured under constant stress loading conditions as a function of grain size, duration of loading, and position along a cylindrical specimen. The transition from elastic to plastic deformation is examined in terms of the elastic wave front attenuation, the delayed yielding time, and the macroscopic plastic deformation of the specimen. The experimental results are then compared with theoretical predictions. The theoretical model assumes that the deformation process can be separated into pre-yield and post-yield regimes separated by the advent of the delayed yielding. The agreement between the experimental results and theoretical predictions appears to be quite good. The results show that the effects of grain size cannot be neglected in certain loading regimes, that the upper and lower yield points can exist even under constant stress loading, and that it is unrealistic to treat the pre-yield and post-yield phenomena as being identical processes for metals which exhibit the yield-point phenomenon.