Predictive integrated numerical approach for modeling spatio-temporal microstructure evolutions and grain size dependent phase transformations in steels

• Published in: International journal of plasticity Vol. 139; p. 102952
• Main Authors: Chen, Shuai-Feng, Bandyopadhyay, Kaushik, Basak, Shamik, Hwang, Byoungchul, Shim, Jae-Hyeok, Lee, Joonho, Lee, Myoung-Gyu
• Format: Journal Article
• Language: English
• Published: New York Elsevier Ltd 01.04.2021; Elsevier BV
• Subjects: Cellular automata; Cellular automaton; Cooling; Dislocation density; Dynamic recrystallization; Finite element method; Grain size; Hot rolling; Integrated modeling; Kinetics; Mathematical models; Mechanical properties; Metallurgy; Microstructure; Microstructure evolution; Morphology; Numerical prediction; Phase transformations; Phase transitions; Plastic deformation; Reinforcing steels; Simulation; Size distribution; Thermomechanical properties; Thermomechanical treatment; Yield strength; Finite element method; Cellular automaton; Integrated modeling; Phase transformations; Microstructure evolution
• ISSN: 0749-6419; 1879-2154
• DOI: 10.1016/j.ijplas.2021.102952

A computational modeling for predicting microstructure evolutions and mechanical properties of steels under thermo-mechanical-metallurgical process is established, for the first time, by integrating the finite element (FE) simulation, cellular automaton simulation (CA), and phase transformation kinetics. In this microstructural-integrated modeling, various recrystallization processes, such as dynamic recrystallization (DRX), meta-DRX, and static recrystallization (SRX), are formulated based on dislocation density based constitutive laws. With microstructure information provided by the CA modeling, the austenite grain size (AGS)-dependent phase kinetics in the form of continuous cooling transformation (CCT) diagram is applied for addressing the effect of AGS on transformations under various cooling conditions. The integrated numerical approach implemented in the FE software via user defined subroutines can simulate the morphology and size distribution of constituent grains, transformed fractions of various phases, hardness profiles and flow stresses after thermo-mechanical process with large plastic deformation. As a validation of the integrated modeling, the multiple oval-round pass hot rolling and subsequent cooling process are simulated for the seismic reinforcing steel bar and the predicted microstructure and mechanical properties are compared to those of experimental data. [Display omitted] •An integrated finite element (FE)-Cellular automaton (CA) model is proposed.•Spatio-temporal microstructure variation during thermo-mechanical process can be predicted by coupled FE-CA approach.•Fractions of various phases are accurately simulated with grain size-dependent phase transformation kinetics.•Predicted hardness profiles and fluctuations, and mechanical properties agree excellently with experiments.