Temperature Sensitivity of BH Steel Sheet Tensile Property for Automobile

Uniaxile tensile tests of BH220 bake hardening steel sheet used for the automobile parel were carried out at different temperatures (room temperature-180 ℃). The effect of deformation temperature on tensile properties of the BH220 steel was studied. The results show that the tensile properties of BH220 steel had obviously temperature sensitivity. With the increase of temperature, the yield strength, tensile strength and yield ratio decreased first and then increased, and the critical temperature was about 120 ℃. The strength coefficient K decreased with the increase of temperature, the hardening exponent n decreased first, then increased and decreased again at last. The strain rate sensitivity exponent increased first and then decreased with increasing the temperature, and the critical temperature was about 60 ℃.