Strain rate behaviour of multi-phase and complex-phase steels for automotive applications

A combined study on the mechanical behaviour of multi-phase 800 high yield strength steel (MP800HY) and complex-phase 800 steel (CP800) is carried out under tensile loads in the strain rate range from 0.001s−1 to 750s−1. Quasi-static (0.001s−1) tests are performed on electromechanical machine, whereas, medium (5s−1 and 25s−1) and high strain rate (250s−1, 500s−1 and 750s−1) experiments are conducted on hydro-pneumatic machine (HPM) and modified Hopkinson bar (MHB) setup respectively. The thermal softening behaviors of the materials are investigated at quasi-static condition and the materials’ m-parameters of the existing Johnson-Cook model are imposed in authors’ previous work. Thereafter, the predicted flow stress by Johnson-Cook model has been compared with the experimental results