Static and dynamic CCT curves of SC700D steel

The continuous cooling transformation (CCT) tests of static and dynamic undercooled austenite and the influencing factors of SC700D high strength steel were carried out by means of thermal dilatometer. The expansion curves, hardness and microstructure of SC700D steel at different cooling rates were analyzed, and the corresponding CCT curves of static and dynamic undercooled austenite were obtained. The results show that compared with the static CCT test at the same cooling rate, the grain size of ferrite and bainite in SC700D steel decreased, the hardness increased, and the cooling temperature range of bainite became larger after dynamic CCT test. In the CCT curve, the ferrite and pearlite range, the ferrite and bainite range, and the bainite temperature range all move to the upper right, and the phase transition time was prolonged, indicating that the plastic deformation caused the material to undergo ferrite, pearlite and bainite phase transformation.