Microstructural evolution of dynamic recrystallization in 30CrNiMoVW steel during hot Compression: Constitutive modeling, kinetic model optimization, and multiscale FEM coupled CA simulation
Wang Li, Junwei Qin, Pengyun Zhai, Haohan Jia, Min Li, Yuzhi Zhu, Kaixuan Chen, Xiaohua Chen, Yanlin Wang, Zidong Wang
Abstract
Process of dynamic recrystallization (DRX) plays a crucial role in altering the microstructure and enhancing the mechanical characteristics of CrNiMoVW steel. However, its initiation mechanism, deformation conditions, and predictive models remain insufficiently understood, requiring further research to optimize the processing technology. In the present study, hot compression experiments were carried out on 30CrNiMoVW steel under deformation conditions with temperatures ranging from 950 to 1,250 °C and strain rates from 0.001 to 1 s −1 , during which true stress–strain curves were obtained. Based on friction and temperature corrections applied to these curves, a constitutive equation for 30CrNiMoVW steel was established, and its accuracy was verified through fitting analysis. Simultaneously, the study identified limitations in the initial volume fraction model, prompting the development of a modified recrystallization volume fraction model that was validated via correlation analysis between experimental data and model predictions. Furthermore, building upon the modified recrystallization volume fraction model, a novel recrystallization rate model was developed, and three characteristic strain points were determined. These points segmented the rate curve into three stages: a slow initiation stage (0, ε 1), a rapid growth stage (1, ε 3), and a slow equilibrium stage ( ε 3, 0.9). Notably, the value of ε 3 was considered the most economical, ensuring the formation of fine and uniform grains during production while optimizing the process, reducing energy consumption and costs, and enhancing overall material performance. Finally, based on the physical constitutive relationships and kinetic models, a multiscale simulation approach combining the finite element method (FEM) and cellular automata (CA) was employed to predict the microstructural evolution of 30CrNiMoVW steel. The simulation results demonstrate that the FEM&CA approach can accurately reproduce the dynamic recrystallization behavior and microstructural evolution observed experimentally. This work provides critical guidance for the development of forging processes for 30CrNiMoVW steel.