Papers by Keyword: Induction Melting

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Authors: Joaquim Barbosa, Orlando M.N.D. Teodoro, Augusto M.C. Moutinho, Sidney José Lima Ribeiro, Caetano Monteiro
Authors: Rui Run Chen, Feng Huang, Jing Jie Guo, Hong Sheng Ding, Yan Qing Su, Jie Ren Yang, Heng Zhi Fu
Abstract: The effects of technical parameters on initial silicon melting in cold crucible continuous casting were studied. These parameters include the materials, the shape and the position of the base, the mass of the silicon that set on the top of the base. Through experimental and theoretical analysis, the optimized parameters were finally given: the base graphite with obconical shaped should be put at the level of the second turn of the coil, and the initial silicon with 10g should be put on the base. The mechanism of these parameters affecting on the initial melting are discussed and revealed.
Authors: Ming Li, Guo Qiang Lv, Wen Hui Ma, Hua Wang, Xi Yang
Abstract: The temperature and velocity distribution of melting pool fields is very important effect to the silicon purification in vacuum induction furnace. A numerical model for the electromagnetic-thermal hydrodynamic coupling field has been developed by using the finite element method (FEM) and a two-dimension numerical simulation for temperature of metallurgical-grade silicon melting in vacuum induction furnace was carried out by using a software Multi-physics Comsol 4.2 in this paper. The results showed that the temperature field was dependent on induction heating times and melting pool position and the maximum temperature grads was 400K in constant temperature stage. With the silicon was molted gradually two vortexes were come into being for electromagnetic stirring in the smelting poor.
Authors: Il Ho Kim
Abstract: Sn-filled and Fe-doped CoSb3 skutterudites were synthesized by encapsulated induction melting. A single δ-phase was obtained by subsequent annealing, as confirmed by X-ray diffraction. The as-solidified ingot consisted of mixed phases of -CoSb, -CoSb2, δ-CoSb3 and elemental Sb. The phases could be transformed by annealing, and the phases of the as-solidified ingot annealed at 773 K for 24 h transformed to δ-CoSb3. The temperature dependence of the Seebeck coefficient, electrical resistivity and thermal conductivity were examined from 300 K to 700 K. The positive Seebeck coefficient confirmed p-type conduction. The electrical resistivity increased with increasing temperature, which showed that the SnzCo3FeSb12 skutterudite is highly degenerate. The thermal conductivity was reduced by Sn-filling because the filler atoms acted as phonon scattering centers in the skutterudite lattice. The thermoelectric figure of merit was enhanced by Sn filling and its optimum composition was considered to be Sn0.3Co3FeSb12.
Authors: Joaquim Barbosa, Carlos A. Silva Ribeiro, Caetano Monteiro
Authors: Jing Wei Liu, Fu Xue Zhang
Abstract: The method ofinduction cladding was adopted to make nickel-base layer on the surface ofsteel components in this test, and microstructure morphology, rigiditydistribution of the alloy layer made by cladding were analyzed and studied. Theresults shows that there is obvious bright white transition zone between thecladding alloy layer and the body, which forms an excellent metallurgicalbonding, microstructure of the alloy cladding layer is eutectic structure ofaustenite + carbide (austenite dendrite can be seen at individual parts), axialand radial rigidity are evenly distributed; bonding strength of cladding alloylayer is high without air hole and slag inclusion, with high flatness ofcylindrical surface, small machining allowance and low cost, etc.
Authors: Alexandr Shubin, Dmitriy Karpenkov, Andrey Stepashkin, Dmitriy Arkhipov, Sergey Taskaev, Toshiyuki Takagi, Vladimir Khovaylo
Abstract: We report on preparation of Mg2(Si,Ge,Sn)-based thermoelectric materials by a direct induction melting method in Al2O3 crucible. A 40 g ingot of Mg2Si0.8Sn0.1Ge0.1 was prepared after addition to the batch 10 wt% of Mg excess. Evolution of crystal structure of the induction melted sample upon annealing and spark plasma sintering (SPS) was tracked by room-temperature X-ray diffraction (XRD) and scanning electron microscopy (SEM) methods. An evidence for the formation of Mg2(Si,Ge,Sn) solid solution was obtained from the crystal lattice parameter of this phase which was found to be larger than that of undoped Mg2Si. XRD and SEM indicated that alongside with the main phase of the Mg2(Si,Ge,Sn) solid solution, an impurity phase of Mg2Sn exists in the sample. Amount of the Mg2Sn impurity phase is significantly reduced in spark plasma sintered sample.
Authors: Soon Chul Ur, Il Ho Kim
Abstract: Te-doped CoSb3 was prepared by the encapsulated induction melting, and its doping effects on the thermoelectric properties were investigated. Single phase d-CoSb3 was successfully obtained by the subsequent annealing at 773K for 24 hours. Tellurium atoms acted as electron donors by substituting antimony atoms. Thermoelectric properties were remarkably improved by the appropriate doping. Dimensionless figure of merit was obtained to be 0.83 at 700K for the CoSb2.8Te0.2 specimen.
Authors: Joaquim Barbosa, Carlos A. Silva Ribeiro, Caetano Monteiro
Authors: Shuang Shii Lian, I Hsuan Wang, Jen Jen Ke
Abstract: A study of thermal field in induction melting with cold crucible and dual induction frequencies is presented in this paper. Numerical simulation was done by finite element based software COMSOL with use of multi-physical modeling. A method of superposing of magnetic vector potential is proposed to solve the complexity of dual induction frequencies. Different conditions of high and low frequencies were given in the calculation to find the effects on distribution of thermal fields. The computed temperature distribution was compared with the macro etched section of solidified ingots and the results showed that the orientation of dendritic grain structures follow to the similar direction of heat flow. This indicates that proper set of induction coils could enable more uniform thermal field distribution and attaining controlled solidification morphology in the ingots.
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