Effect of microstructure on static and dynamic mechanical property of a dual phase steel studied by shear punch testing

Abstract

The high-speed deformation behavior of a dual phase steel was studied by means of dynamic Hopkinson bar shear punch testing, with an emphasis on the influence of microstructure. Dual phase microstructures with different fractions of martensite were obtained by changing heat treatment parameters during intercritical annealing. The effects of low temperature tempering (170°C, 235°C, and 300°C) and bake hardening treatment (5% pre-strain followed by holding at 170°C for 20 min) were also investigated for two selected microstructures containing 22% and 61 % martensite, respectively. Quasi-static shear punch property was also measured by a MTS hydraulic machine and compared with dynamic results. Additionally, quasi-static tensile tests for some specimens were also conducted for validating the shear punch data. © 2005 ISIJ.