Dynamic tensile tests of auto-body steel sheets with the variation of temperature

Abstract

This paper is concerned with the thermo-mechanical behavior of steel sheet for an auto-body including the temperature dependent strain-rate sensitivity. Tensile tests have been carried out with the high strength steel sheets such-as SPRC35R, SPRC45E and TRIP60. The tensile tests were performed with the variation of the strain-rates from 0.001/s to 200/s and with the variation of environmental temperatures from -40 degrees C to 200 degrees C. The thermo-mechanical response at the quasi-static state is obtained with the static tensile test and the one at the intermediate strain-rate is obtained with the high speed tensile test. Both the strain-rate and the temperature sensitivity of the flow stress are calculated for the quantitative evaluation of thermo-mechanical behavior of steel sheets. The results demonstrate that as the strain-rate increases, the variation of the flow stress becomes more dependent on the temperature. The results also indicate that the material properties of SPRC35R are more sensitive to the strain-rate and the temperature than those of SPRC45E and TRIP60.