Research on Phase Transformation Behavior of 07MnNiMoVDR Steel during Continuous Cooling

The dynamic CCT curves of 07MnNiMoVDR steel were determined by means of MMS-200 thermomechanical simulator.The phase transformation behavior and microstructure were investigated during continuous cooling.The results showed that with the cooling rate increase,the microstructure transformed gradually from ferrite and pearlite to bainite;and with different cooling rate,two phase transitions existed in the CCT diagram,that is,the pro-eutectoid ferrite and pearlite transformation area at low cooling rate and the bainite transformation area at middle cooling rate.