Dynamic mechanical behaviour of Q345 steel at elevated temperatures: experimental study

摘要

The quasi-static compression and impact experiment of Q345 steel by the MTS material testing machine and SHPB (Split-Hopkinson Pressure Bar) testing technique has been carried out. It aims to study the Q345 steel's mechanical properties at elevated temperatures under different strain rates. The experimental results show that, at normal temperature, the dynamic strength of the Q345 steel is markedly higher than that under the quasi-static state. It displays an obvious strain rate strengthening effect. With the ambient temperature rising, the plastic stress decreases below 400°C but increases between 450 and 600°C, while it displays a strain rate strengthening effect below 400°C and strain rate softening effect between 450 and 600°C. Based on the experimental data, a constitutive model used for structure analysis under impact loading was determined.