A High-Temperature Strain-Compensated Arrhenius-Type Constitutive Model and an Improved Avrami-Type Dynamic Recrystallization Model of 40CrNiMo.

The flow stress of a metallic material is one of the important parameters to measure the plastic deformability of a material. The quality of the microstructure reflects the forming quality and reliability of a part. Therefore, a high-quality flow stress and microstructure models are very important for the optimization of the process parameters. The flow stress and dynamic recrystallization (DRX) law of the 40CrNiMo axle steel were obtained by performing a thermal simulation compression test and metallography examination. The effects of deformation temperatures, strain rates, and initial grain sizes on the DRX and flow curves were discussed. A strain-compensated Arrhenius-type flow stress equation was established. Considering the influence of the deformation temperatures, strain rates, and initial grain sizes on DRX, a kinetic model and an average grain size evolution model for DRX were established. Statistical and finite element (FE) simulation methods were used to verify the predictability and validity of the flow stress and the microstructure models, which provides an important basis for the study of hot forming of the 40CrNiMo steel. [ABSTRACT FROM AUTHOR]