Thermodynamic coupling simulation of forging process is the basic work for the formulation of deformation parameters, subsequent recrystallization process, and phase transformation process. Whether the selection of simulation algorithms, elements, and grids can accurately reflect the engineering process has become a work with certain skills. In this paper, the forging upsetting process was simulated by Abaqus software, and the influence of different simulation parameters on the results was discussed. The different simulation results were verified by surface temperature measurement and shape measurement, which provided some simulation technical guidance for the actual forging process.

A multi-fluid volume of fluid (VOF) model for compressible oxygen flow in a 260t top blown converter was established. The energy transfer efficiency of the top blown gas to the molten pool was analyzed. A user-defined function was used to calculate splash energy consumption. The energy conservation equation of 'jet attenuationcavity formationbath stirringmolten steel splashing' was established. The results show that more than 75% of the total energy is wasted in jet attenuation. The energy used stirring bath and used for molten steel splashing are less than 1.5% and 3% of the total energy, respectively. Approximately 15%-20% of the energy is used to form cavity and maintain its shape. As the lance position decreases from 2.2 to 1.8 m, the energy used for stirring molten pool increases by 13.3%, while the energy used for splashing and cavity formation decreases by 7.7% and 5.22%, respectively.

In order to study the metadynamic recrystallization behavior of 34CrNi3MoV steel, a double-pass isothermal compression experiment and a single-pass thermal interval experiment were designed and conducted to obtain the stress–strain curves under different deformation conditions and to explore the action law of deformation parameters during the compression process. The softening rate was calculated by the compensation method, and the grain size in the recrystallization region was measured. Based on the obtained data, the effects of deformation temperature (T), interval time (t), and strain rate (ε˙) on the softening rate and grain size of 34CrNi3MoV steel during metadynamic recrystallization were analyzed. The results show that increasing the deformation temperature, extending the interval time, and increasing the strain rate are all beneficial to the improvement of the metadynamic recrystallization softening rate and that fine and uniform new grains can be obtained under a high strain rate. However, in high-temperature conditions, mixed crystallization can easily occur, which is not conducive to grain refinement. Based on the true stress–strain data and experimental data on the grain size, a relevant model for metadynamic recrystallization of 34CrNi3MoV steel was established using mathematical analysis of regression equations. The average relative error AARE between the constructed dynamic model and the grain size model and the experimental results are 6.48% and 1.30%, respectively. This indicates that the model has high predictability.