Herein, two‐dimensional (2D) single‐action die compaction process of copper (Cu) powder was simulated by the multiparticle finite element method (MPFEM) at particulate scale. The initial packing structure, generated by the discrete element method (DEM), was used as an input for the FEM model, where the mesh division of each particle was discretized. The evolution of macro‐ and microscopic properties, such as relative density, stress distribution, particle deformation, void filling behavior, and force transmission, during compaction and pressure release processes have been systematically studied. The results revealed that the force is mainly concentrated on largely deformed regions of the particles during compaction and formed a contact force network, which hindered the densification process. In the compact, the shorter side of the large void edges rendered higher stress than the longer side. On the other hand, the stress distribution of small void edges remained uniform. After pressure release, large residual stress was observed at the contact area of the adjacent particles and the maximum stress was observed at the particles’ edges. Moreover, the residual stress did not proceed to the interior of the particles. Meanwhile, the stress of large void edges has been completely released but exhibited a nonuniform distribution. The smaller fraction of void filling resulted in a larger reduction of the released stress after pressure removal. Also, the particles closer to the upper die exhibited higher average equivalent von Mises stress inside the particles during compaction and pressure release processes.

The mixing efficiency of molten metal in a vessel is affected by the bottom blowing intensities and the positions of bottom nozzles. In this article, physical experiments and multiphase flow simulation models were used to investigate the effects that different distributions of bottom regiments have on the internal dynamic conditions of a molten bath. The results reveal that the configuration of the bottom regiments can overcome the drawback that a single blowing gas strand cannot effectively drive the rapid flow of liquid steel. When the outer regiments were kept on the circumference of a circle with a diameter ratio of 0.7 at the bottom of a furnace, the stirring force of blowing bubbles on molten steel was the strongest. Under a gas flowrate of 960 Nm³· h⁻¹, the minimum mixing time was 38 s, and the minimum proportion of inactive zone was 0.025. Also, from comparing the results of physical experiments and numerical simulations, it was found that the occurrence of coalescence in the bottom blowing gas streams is more beneficial for mixing the bath. Also, the range of the synergy of gas flow streams can be widened by increasing the distance between regiments and the bottom blowing flowrates.

The high content of aluminum in the steel reacts with the CaO-Si2O-based mold fluxes, resulting in deterioration of the mold slag physical and chemical properties, which cannot be applied to the continuous casting molten slag casting process of high-Mn high-Al steel Herein, the thermodynamic and structural properties of low-reactivity CaO-Al₂O₃-based mold fluxes were investigated. The thermodynamic properties were studied based on the first principles of quantum mechanics. The results show that the formation of stable structures of B-O and O-B-O in the mold fluxes was beneficial to reduce the probability of structural interconnection, degree of polymerization, and viscosity of the molten slag. The increase in the ratio of CaO/Al₂O₃=0.882 led to an increase in the O²⁻ concentration. O²⁻ entered the [AlO₄] structure to form a stable structure of [AlO₆] and [AlO₅], wherein [AlO₆] was more stable than [AlO₅], reducing the degree of polymerization of the network structure. When cosolvent content B₂O₃=210, a simple layered structure of [BO₃] was formed, and the particle migration resistance, break temperature, and viscous activation energy of the mold fluxes were reduced, while the corrected optical basicity of mold fluxes was gradually increased.

Since CaO-Al₂O₃-based mold fluxes are one of the most important mold flux systems in metallurgic processes, it is important to explore their structure characteristics and viscosity. Molecular dynamics simulation is performed to study the effect of w(CaO)/w(Al₂O₃) ratio on both the structural and viscosity properties of CaO-Al₂O₃-based mold fluxes. A systematic analysis of the structure and thermodynamics on CaO-Al₂O₃-based mold fluxes is carried out, and it is well known that the viscosity of mold fluxes is related to the structure. The results show that the formation of stable structures of Si-O in the mold fluxes was beneficial to reduce the probability of structural interconnection, degree of polymerization, and viscosity of the molten slag. In the cationic structure, the contents of Ca-O-Al and Ca-O-Si are more stable, the interconnection of the Ca-O-Al and Ca-O-Si network weakens, and the viscosity decreases. The tetrahedra [AlO₄] and [SiO₄] have similar structures, but they exhibit different thermodynamic and physical properties. Viscosity test shows that CaO/Al₂O₃=0.882 continuously increased, when the cosolvent content Li₂O=14, CaO-Al₂O₃-based mold flux viscosity decreased, the degree of network structure polymerization decreased, and the complex structure depolymerized. Increasing the water content in the cosolvent is beneficial to reduce the viscosity of the crystallizer.