基于相变产物构建DP1180相变动力学方程研究

摘要：DP1180钢相变动力学方程的构建，有利于其力学性能的精准调控。利用Gleeble 3500对DP1180钢进行相变点测定，结合切线法、金相 硬度法研究了DP1180钢在冷却过程中的显微组织演变规律，绘制连续冷却转变曲线(CCT)，并基于相变产物对相变动力学方程（JMAK方程）进行了修正。结果表明：冷速为0.5~1℃/s时，组织为铁素体(F)和贝氏体(B)；冷速为2℃/s时，有马氏体(M)出现；冷速为10℃/s时，组织为贝氏体(B)和马氏体(M)；冷速大于20℃/s时，组织以马氏体(M)为主；显微硬度随冷速的增加而升高；基于不同相变产物对n值的影响规律，对传统JMAK方程进行修正，构建了基于相变产物的相变动力学方程，预测精度得到提升。

Investigation of phase transition kinetic equation of DP1180 based on phase transition production

Abstract： The construction of kinetic equation of phase transformation of DP1180 steel is beneficial to the precise control of its mechanical properties. Gleeble 3500 was used to measure the transformation point of DP1180 steel. The microstructure evolution of DP1180 steel during cooling was studied by tangent method and metallographic hardness method. The continuous cooling transformation curve (CCT) was drawn, and the phase transformation kinetic equation (JMAK equation) was modified based on the phase transformation production. The results show that the microstructure is composed of ferrite (F) and bainite (B) with the cooling rate of 0.5-1℃/s. And the martensite (M) appears with the cooling rate increasing to 2℃/s. With the cooling rate increasing to 10℃/s, the bainite (B) and martensite (M) are dominant. The microstructure is composed of M with the cooling rate over 20℃/s. The microhardness increases with the increase of the cooling rate. Based on the influence of phase transition production on the value of n, the traditional JMAK equation was corrected, and a phase change kinetic equation based on the phase transition production was constructed, and the prediction accuracy was improved.