Effects of Constant Engineering and True Strain Rates on the Mechanical Behavior of 304 Stainless Steel

Abstract

Kolsky bar (split Hopkinson pressure bar) with a pulse shaping technique was utilized to study the dynamic behavior of 304 stainless steel at high constant engineering and true strain rates. To show the differences between the strain rates, equations were presented for the engineering strain rate and strain as a function of true strain rate. To deform the specimen at constant true strain rates at 600–2500 s−1, a bi-linear incident pulse was necessary. Furthermore, a trapezoidal incident wave was required to deform the specimen at a constant true strain rate of 7000 s−1. The results show that the dynamic flow stresses of the specimens increased with increasing strain rates. At the highest strain rate of 7000 s−1, the flow stress of specimen deforming at constant engineering strain rate was clearly higher than the flow stress obtained at a similar constant true strain rate.