Strain Rate and Strain Rate History Effects in Two Mild Steels.

Results are presented of a series of experiments performed with two steels to investigate the dependence of flow stress on strain rate and its history. For this purpose quasi-static, dynamic and incremental strain rate tests were conducted on SAE 1020 hot-rolled steel and SAE 1018 cold-rolled steel at room temperature. It is shown that while the flow stress of both steels exhibits a significant strain rate sensitivity, the effect of strain rate history is relatively small in comparison with that generally found in fcc and hcp metals. A comparison is made with results of the work of other investigators. (Author)