Investigation of dynamic recrystallization and grain size evolution behavior of 45CrNi steel processed by upsetting deformation by utilizing FE–CA method
摘要
A coupled method integrating physics-based finite element (FE) modeling and advanced cellular automata (CA) simulation (FE–CA method) were established to systematically investigate the dynamic recrystallization (DRX) behavior of 45CrNi steel during upsetting deformation. Uniaxial compression tests were firstly performed using a Gleeble-3800 thermal simulation machine with temperature ranging from 850 to 1200 ℃ and strain rate ranging from 0.01 to 1 s−1. Constitutive model and DRX kinetic model of the 45CrNi steel were developed based on the Arrhenius theory, and grain size model was established by utilizing linear regression method combined with metallographic analysis. A mesoscopic CA model composed of dislocation density model, nucleation model and grain growth model for the 45CrNi steel was further established, and a scaled-down upsetting experiment was conducted on a 100-ton hydraulic press to validate the reliability of the established FE–CA model by comparing the grain size distribution of parent austenite achieved through experiments with the simulation results obtained through calculation. Results indicate the DRX evolution discipline and grain size feature corresponding to the different deformation zones of the forging piece processed by upsetting deformation could be illuminated and characterized by the established FE–CA model, and the predicted volume fraction of DRX and average grain size obtained from the established FE–CA model show excellent agreement with the experimental results, with a maximum error margin of less than 8%, thereby confirming the high accuracy of the established model. The FE–CA method is expected to provide significant simulation and theoretical references for the optimization of hot processing technology for the other metal or alloys.