4Cr5Mo2V钢贝氏体等温相变动力学

Bainite isothermal transformation kinetics of 4Cr5Mo2V steel

借助热膨胀相变仪测定压铸模具用钢4Cr5Mo2V在不同等温淬火温度下的贝氏体转变膨胀曲线,获得4Cr5Mo2V钢的贝氏体等温转变曲线。运用Johnson-Mehl-Avrami（J-M-A）和Arrhenius方程确定了等温相变动力学参数。结果表明：贝氏体相变激活能为160.35 kJ/mol,指前因子约为-12.59524,Avrami指数n的平均值为1.74758,通过这些相变参数确定的J-M-A动力学模型能够较为准确地预测贝氏体等温相变过程。

The dilatometric curves of bainite transformation of 4Cr5Mo2V die-cast mould steel at different isothermal quenching temperatures were measured by means of DIL-805 A dilatometer,and the transformatin-time-temperature（TTT） diagram of the bainite isothermal transformation of the 4Cr5Mo2V steel was obtained. The isothermal phase transformation kinetic parameters were determined by using Arrhenius and Johnson-Mehl-Avrami（JMA） equations. The results show that the activation energy of the bainite transformation,the pre-exponential factor and the local Avrami exponent n are 160. 35 k J/mol,-12. 59524 and 1. 74758,respectively. The J-M-A kinetic model determined by these transformation parameters can accurately predict the isothermal transformation process of bainite of the steel.