2026, 47(1): 1-9.
doi: 10.7513/j.issn.1004-7638.2026.01.001
Abstract:
Aiming at solving the problems of temperature control in molten bath, iron loss, and grade reduction of vanadium slag caused by O2 injection in the traditional process of vanadium extraction from hot metal, a new technology using iron oxides (Fe2O3) for vanadium extraction from hot metal was proposed in this study, taking advantage of the characteristics of mild indirect oxidation reaction and controllable process. Thermodynamic calculations identified Fe2O3 as the optimal oxidizer with recommended addition ranges of 1.5%–6.0%. A systematic investigation was conducted on the effects of Fe2O3 addition ratio, particle size, and bath temperature, revealing the enhancement mechanisms of particle size reduction and temperature elevation on vanadium oxidation. The study further developed a “CaO-Fe2O3” oxidizer system that improves reaction efficiency by lowering the melting temperature. Through process parameter optimization, the optimal conditions were determined as: reaction temperature 1350 °C, 4.5% of 0.074–0.5 mm Fe2O3 with n(CaO): n(Fe2O3) = 0.75. Under these conditions, the reaction reached equilibrium within 2 min, achieving a final V content in the hot metal of 0.016%, oxidation rate of 95.12%, with vanadium slag containing 7.15% V and 1.93% P. This “CaO-Fe2O3” system demonstrates efficient vanadium extraction from hot metal and provides new insights for the development of vanadium extraction technologies.
Aiming at solving the problems of temperature control in molten bath, iron loss, and grade reduction of vanadium slag caused by O2 injection in the traditional process of vanadium extraction from hot metal, a new technology using iron oxides (Fe2O3) for vanadium extraction from hot metal was proposed in this study, taking advantage of the characteristics of mild indirect oxidation reaction and controllable process. Thermodynamic calculations identified Fe2O3 as the optimal oxidizer with recommended addition ranges of 1.5%–6.0%. A systematic investigation was conducted on the effects of Fe2O3 addition ratio, particle size, and bath temperature, revealing the enhancement mechanisms of particle size reduction and temperature elevation on vanadium oxidation. The study further developed a “CaO-Fe2O3” oxidizer system that improves reaction efficiency by lowering the melting temperature. Through process parameter optimization, the optimal conditions were determined as: reaction temperature 1350 °C, 4.5% of 0.074–0.5 mm Fe2O3 with n(CaO): n(Fe2O3) = 0.75. Under these conditions, the reaction reached equilibrium within 2 min, achieving a final V content in the hot metal of 0.016%, oxidation rate of 95.12%, with vanadium slag containing 7.15% V and 1.93% P. This “CaO-Fe2O3” system demonstrates efficient vanadium extraction from hot metal and provides new insights for the development of vanadium extraction technologies.
2026, 47(1): 36-48.
doi: 10.7513/j.issn.1004-7638.2026.01.005
Abstract:
Electron Beam Melting (EBM) is an ideal forming method for additive manufacturing (AM) of brittle TiAl alloy components, enabling the formation of complex structures and the achievement of superior performance in TiAl alloys. Compared to other additive manufacturing techniques, EBM offers advantages such as high preheating temperatures, resistance to cracking, and low oxygen content, making it widely researched, especially for the Ti-48Al-2Cr-2Nb (4822) alloy. The average grain size of 4822 alloy prepared by EBM is typically less than 20 μm, significantly smaller than that of traditionally cast alloys. The room-temperature strength of 4822 alloy prepared by EBM can reach over 600 MPa, but it exhibits poor ductility and defects. Hot isostatic pressing (HIP) and high-temperature heat treatment (HT) are important post-processing methods to enhance mechanical properties, increasing the room-temperature elongation to 1.3%. However, there are still many issues with the EBM process and HT of TiAl alloys. This paper reviews the recent research progress in EBM additive manufacturing of TiAl alloys and their HT processes, analyzes and summarizes the current problems and countermeasures, and provides an outlook on the future development direction of additive manufacturing of TiAl alloys.
Electron Beam Melting (EBM) is an ideal forming method for additive manufacturing (AM) of brittle TiAl alloy components, enabling the formation of complex structures and the achievement of superior performance in TiAl alloys. Compared to other additive manufacturing techniques, EBM offers advantages such as high preheating temperatures, resistance to cracking, and low oxygen content, making it widely researched, especially for the Ti-48Al-2Cr-2Nb (4822) alloy. The average grain size of 4822 alloy prepared by EBM is typically less than 20 μm, significantly smaller than that of traditionally cast alloys. The room-temperature strength of 4822 alloy prepared by EBM can reach over 600 MPa, but it exhibits poor ductility and defects. Hot isostatic pressing (HIP) and high-temperature heat treatment (HT) are important post-processing methods to enhance mechanical properties, increasing the room-temperature elongation to 1.3%. However, there are still many issues with the EBM process and HT of TiAl alloys. This paper reviews the recent research progress in EBM additive manufacturing of TiAl alloys and their HT processes, analyzes and summarizes the current problems and countermeasures, and provides an outlook on the future development direction of additive manufacturing of TiAl alloys.
2026, 47(1): 94-101.
doi: 10.7513/j.issn.1004-7638.2026.01.011
Abstract:
Carbonaceous materials are one of the essential components in mold flux, mainly serving to regulate its melting behavior. Under the background of the “dual carbon” strategy, conventional carbon materials exhibit high contents of fixed carbon, nitrogen, and sulfur, resulting in excessive emissions of CO2, NOx, and SO2, which pose serious environmental concerns. Moreover, their non-renewability and high cost further limit their sustainable application. Therefore, it is urgent to explore the renewable and environmentally friendly alternatives. The research proposed a “carbon-neutral”, renewable and abundant solid waste, straw charcoal, as a new type of carbon source for protective slag. The respective basic physical properties of carbon black C611 and straw charcoal were investigated, and the influence of carbon types and contents on the melting behavior of mold fluxes were systematically analyzed. The results indicate that straw charcoal possesses a higher specific surface area and larger average particle size than carbon black C611, though its fixed carbon content is relatively lower. With increasing straw charcoal content, the softening temperature, melting temperature, and flowing temperature of mold flux increase noticeably, with the melting temperature being the most affected. As the carbon content of straw increases, the melting rate of the mold flux decreases. When the carbon content is 8%, the control effect of straw charcoal on the melting rate of the protective residue is the same as that of carbon black C611.
Carbonaceous materials are one of the essential components in mold flux, mainly serving to regulate its melting behavior. Under the background of the “dual carbon” strategy, conventional carbon materials exhibit high contents of fixed carbon, nitrogen, and sulfur, resulting in excessive emissions of CO2, NOx, and SO2, which pose serious environmental concerns. Moreover, their non-renewability and high cost further limit their sustainable application. Therefore, it is urgent to explore the renewable and environmentally friendly alternatives. The research proposed a “carbon-neutral”, renewable and abundant solid waste, straw charcoal, as a new type of carbon source for protective slag. The respective basic physical properties of carbon black C611 and straw charcoal were investigated, and the influence of carbon types and contents on the melting behavior of mold fluxes were systematically analyzed. The results indicate that straw charcoal possesses a higher specific surface area and larger average particle size than carbon black C611, though its fixed carbon content is relatively lower. With increasing straw charcoal content, the softening temperature, melting temperature, and flowing temperature of mold flux increase noticeably, with the melting temperature being the most affected. As the carbon content of straw increases, the melting rate of the mold flux decreases. When the carbon content is 8%, the control effect of straw charcoal on the melting rate of the protective residue is the same as that of carbon black C611.
2026, 47(1): 130-139.
doi: 10.7513/j.issn.1004-7638.2026.01.015
Abstract:
Two 45# carbon steel ingots with dimensions of 300 mm × 300 mm × 400 mm were prepared by the lost foam casting method, with rare earth ferrosilicon additions of 0.15% and 0.35% respectively. A quarter section of each ingot was sampled along the Y-axis from the center to the bottom. SEM observations shows the microstructure of ingots consist primarily of ferrite and pearlite. From the core to the bottom, the ferrite volume gradually increases while the pearlite decreases, accompanied by a progressive reduction in ferrite size. Additionally, when the rare earth ferrosilicon additions is increased from 0.15% to 0.35%, the overall solute element (Mn,Si) content in the ingots increases, which significantly increases ferrite volume and improves pronounced structural refinement. Mechanical property test results indicates a gradual decrease in both properties from the center to the bottom in both ingots, demonstrating a positive correlation between hardness/tensile properties and pearlite content. Further analysis reveals that compared to the 0.15% addition, the 0.35% rare earth ferrosilicon addition enhances the hardness and tensile properties of the ingot while increasing the solute element content. Consequently, the increase in solute element content resulting from the higher rare earth ferrosilicon addition exerts an important influence on hardness and tensile properties.
Two 45# carbon steel ingots with dimensions of 300 mm × 300 mm × 400 mm were prepared by the lost foam casting method, with rare earth ferrosilicon additions of 0.15% and 0.35% respectively. A quarter section of each ingot was sampled along the Y-axis from the center to the bottom. SEM observations shows the microstructure of ingots consist primarily of ferrite and pearlite. From the core to the bottom, the ferrite volume gradually increases while the pearlite decreases, accompanied by a progressive reduction in ferrite size. Additionally, when the rare earth ferrosilicon additions is increased from 0.15% to 0.35%, the overall solute element (Mn,Si) content in the ingots increases, which significantly increases ferrite volume and improves pronounced structural refinement. Mechanical property test results indicates a gradual decrease in both properties from the center to the bottom in both ingots, demonstrating a positive correlation between hardness/tensile properties and pearlite content. Further analysis reveals that compared to the 0.15% addition, the 0.35% rare earth ferrosilicon addition enhances the hardness and tensile properties of the ingot while increasing the solute element content. Consequently, the increase in solute element content resulting from the higher rare earth ferrosilicon addition exerts an important influence on hardness and tensile properties.
2021, 42(5): 54-61.
doi: 10.7513/j.issn.1004-7638.2021.05.009
Abstract:
2023, 44(3): 1-8.
doi: 10.7513/j.issn.1004-7638.2023.03.001
Abstract:
