Using molten Pb-Sn-Bi alloy, the meniscus shape under high frequency magnetic field of φ100 mm round billet caster was investigated. The effect of some parameters on meniscus shape was studied. The results show that ...Using molten Pb-Sn-Bi alloy, the meniscus shape under high frequency magnetic field of φ100 mm round billet caster was investigated. The effect of some parameters on meniscus shape was studied. The results show that for a mold with 12 segments, the meniscus shape is relatively stable. With increasing power input, the menis- cus height increases with intensification of fluctuation. For the given caster, the reasonable power input is about 70 kW. The coil should be near to the top of mold and/or the initial meniscus should be near to the center of the coil. The lower the frequency, the higher is the meniscus height. With increasing frequency, the free surface is more flattened and meniscus becomes more stable. In practice, the power input should be increased simultaneously with frequency. The optimal frequency is about 20 kHz.展开更多
With miniaturization and complication of the shape of electronic devices in recent years, powder injection molding (PIM) seems to be a suitable process for fabricating the higher performance soft magnetic components. ...With miniaturization and complication of the shape of electronic devices in recent years, powder injection molding (PIM) seems to be a suitable process for fabricating the higher performance soft magnetic components. In this paper, high quality Fe-50Ni soft magnetic alloy was fabricated by PIM with carbonyl iron and nickel, and the effect of sintering process on its microstructure and magnetic properties were investigated. The mechanical and magnetic properties can be obviously improved by increasing the sintering temperature or using the hydrogen atmosphere instead of high vacuum, which causes by the increase of grain size and the densification. At the optimum sintering conditions, the PIM Fe-50Ni soft magnetic alloy with high properties are obtained, whose relative density, tensile strength, Bm, Hc, μm are 97%, 465 MPa, 1.52 T, 16.62 A·m-1, 42.5 mH·m-1, respectively.展开更多
The distribution of the magnetic flux density in a soft-contact electromagnetic continuous casting （EMCC） rectangular mold was investigated. The experimental results show that with an increase in electric power, the...The distribution of the magnetic flux density in a soft-contact electromagnetic continuous casting （EMCC） rectangular mold was investigated. The experimental results show that with an increase in electric power, the magnetic flux density increases. The position where the maximum magnetic flux density appears will shift up when the coil moves to the top of the mold. At the same time, the maximum magnetic flux density will increase and the effective acting range of electromagnetic pressure will widen. As a result, in practice, the coil should be placed near the top part of the mold. The meniscus should be controlled near the top part of the coil, as this not only remarkably improves the billet surface quality but also saves energy. With the same electric power input, the higher the frequency, the lower the magnetic flux density.展开更多
Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromag...Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field （20 kHz）, the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux de- creases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.展开更多
文摘Using molten Pb-Sn-Bi alloy, the meniscus shape under high frequency magnetic field of φ100 mm round billet caster was investigated. The effect of some parameters on meniscus shape was studied. The results show that for a mold with 12 segments, the meniscus shape is relatively stable. With increasing power input, the menis- cus height increases with intensification of fluctuation. For the given caster, the reasonable power input is about 70 kW. The coil should be near to the top of mold and/or the initial meniscus should be near to the center of the coil. The lower the frequency, the higher is the meniscus height. With increasing frequency, the free surface is more flattened and meniscus becomes more stable. In practice, the power input should be increased simultaneously with frequency. The optimal frequency is about 20 kHz.
基金This work was financially supported by the National 863 Program (No.2001AA337075).
文摘With miniaturization and complication of the shape of electronic devices in recent years, powder injection molding (PIM) seems to be a suitable process for fabricating the higher performance soft magnetic components. In this paper, high quality Fe-50Ni soft magnetic alloy was fabricated by PIM with carbonyl iron and nickel, and the effect of sintering process on its microstructure and magnetic properties were investigated. The mechanical and magnetic properties can be obviously improved by increasing the sintering temperature or using the hydrogen atmosphere instead of high vacuum, which causes by the increase of grain size and the densification. At the optimum sintering conditions, the PIM Fe-50Ni soft magnetic alloy with high properties are obtained, whose relative density, tensile strength, Bm, Hc, μm are 97%, 465 MPa, 1.52 T, 16.62 A·m-1, 42.5 mH·m-1, respectively.
基金ItemSponsored by National Natural Science Foundation of China (50274203) , National High Technology Research andDevelopment Programof China (2001AA337040) and National Fundamental Research and Development Plan of China(G1998061510)
文摘The distribution of the magnetic flux density in a soft-contact electromagnetic continuous casting （EMCC） rectangular mold was investigated. The experimental results show that with an increase in electric power, the magnetic flux density increases. The position where the maximum magnetic flux density appears will shift up when the coil moves to the top of the mold. At the same time, the maximum magnetic flux density will increase and the effective acting range of electromagnetic pressure will widen. As a result, in practice, the coil should be placed near the top part of the mold. The meniscus should be controlled near the top part of the coil, as this not only remarkably improves the billet surface quality but also saves energy. With the same electric power input, the higher the frequency, the lower the magnetic flux density.
基金Item Sponsored by National Natural Science Foundation of China (59734080)
文摘Heat transfer and deformation of initial solidification shell in soft contact continuous casting mold under high frequency electromagnetic field were analyzed using numerical simulation method; the relative electromagnetic parameters were obtained from the previous studies. Owing to the induction heating of a high frequency electromagnetic field （20 kHz）, the thickness of initial solidification shell decreases, and the temperature of strand surface and slit copper mold increases when compared with the case without the electromagnetic filed. The viscosity of flux de- creases because of the induction heating of the high frequency electromagnetic field, and the dimension of the flux channel increases with electromagnetic pressure; thus, the deformation behavior of initial solidification shell was different before and after the action of high frequency electromagnetic field. Furthermore, the abatement mechanism of oscillation marks under high frequency electromagnetic field was explained.
