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For further lowering inclusions and improving the quality of steel, a new electromagnetic steel-teeming technology based on electromagnetic induction heating was proposed. To assess the proposed technology, an experimental platform that imitates the actual production condition of steelmakers was established. High temperature experiments were performed to investigate the melting length of Fe-C alloy under different power and frequency conditions. The heating effect was analyzed, and the method of magnetic shielding to reduce the power loss of power supply was put forward. The results show that when the power is 40 kW and frequency is 25 kHz, the melting length of the Fe-C alloy is 89.2 mm in 120 s, which meets the requirements of steel teeming. In addition, when magnetic shielding material is installed under the induction coil, the power loss is reduced by about 64 %, effectively improving the heating effect of power supply.

In this paper, the effect of an annealing treatment on the microstructure, mechanical properties and electrical conductivity of a deformed Cu-12.8 wt%Fe composite prepared by the “casting/cold working” process is investigated. The Fe filaments exhibit the shape characteristic in the as-drawn composite as the annealing temperature is lower than 500 °C. When the annealing temperature is above 500 °C, the Fe filaments undergo the instability process in terms of boundary splitting, coarsening and breakup gradually. The tensile strength gradually decreases with increasing annealing temperature due to the coarsening of filament spacing. The work hardening for the composite annealed above 600 °C is slower than that annealed at a lower temperature. The electrical conductivity reaches a maximum of 60%IACS at a temperature of 450 °C for one hour of annealing, and it further increases with increasing annealing time at 450 °C to reach a plateau of 68% IACS. The curve between the tensile strength and electrical conductivity under different annealing processes indicates that the optimum annealing temperature for the Cu-Fe composite is 450 °C.

The nanocrystalline Fe64Ni36thin films were prepared by molecular-beam-vapor deposition under different magnetic flux densities. The microstructure and magnetic properties of thin films were examined by AFM, TEM, HRTEM and VSM. The results show that with the increase of magnetic flux densities, the changing trend of the average particle size is the same as the coercive force except 6 T. Under 6 T condition, the thin film became the mixture of bcc and fcc phases, which leads to slight increase of the coercive force. In addition, the HRTEM result shows the short-range ordered clusters (embryos) or nucleation rate of thin films increase with increasing magnetic flux densities.

The size, number, morphology and type of inclusion particles are the key factors to estimate the quality of steel product. Although considerable efforts have been made in the mathematical modeling of inclusion growth, few papers were involved in inclusion''s nucleation and collision-growth, and all the existing researches about the behaviors of magnesia inclusion were based on the experiments. Thus, a mathematical model was developed to investigate the nucleation, Ostwald ripening and collision-growth of magnesia inclusion in the molten steel. Numerical results showed that the predicted particle size distributions are consistent with the previous experimental data. For the magnesia inclusions smaller than 100 nm, Brownian collision is the main collision modes. For the inclusions ranging from 0.1 to 10 μm, Brownian collision and turbulent collision are the main collision modes. For the inclusions ranging from 10 to 100 μm, turbulent collision and Stokes collision are the main collision modes. Thus, the strong turbulent flow can decrease the peak-value diameter of the magnesia inclusion effectively. [Copyright &y& Elsevier]

Based on the annual production data collected by the Statistic Center of the Ministry of Railways of the People’s Republic of China, we calculated the energy saving and direct emission reductions of CO2, soot, SO2, CO, NOxand CnHmof electrified railways, and analyzed their dynamic characteristics during the period of 1975–2007. The results show that during this period, the annual mean values of energy saving is 1.23×106tce, and direct emission reduction of CO2, soot, SO2, CO, NOxand CnHm are 4.267×106t, 20.5×103t, 3.0×103t, 9.6×103t, 67.9×103t, and 6.9×103t per year, respectively. The annual average increasing rates of energy saving is 139×103tce, and direct emission reduction of CO2, soot, SO2, CO, NOxand CnHm are 483×103t, 2.3×103t, 0.34×103t, 1.1×103t, 7.7×103t and 0.78×103t per year, respectively. The electrified railways have played an important role in decreasing the energy consumption and air pollutant emissions of China’s railway system. The results of this study could provide some reference knowledge for future reductions of energy consumption and waste gas emission in China’s railway transportation.

Based on annual statistical data collected by the Chinese Railway Statistic Center, the CO2emissions of locomotives during 1975–2005 were calculated and the emission intensity and its dynamic characteristics were analyzed. The results show that the CO2emissions of steam locomotives decreased while that of diesel locomotives increased with time, due to the continuous shift from steam to diesel and electric locomotives. The total CO2emissions of steam and diesel locomotives in China decreased from 42.23 Mt in 1975 to 16.40 Mt in 2005. The emission intensity of CO2from the two kinds of locomotives decreased at an average rate of 2.4 g (converted t km)-1per year. The percentage of the CO2emissions of locomotives to the total CO2emissions in the sector of transportation, storage and post in China also decreased persistently from 1980 to 2005.

Abstract: A mechanical analysis is done to find the evolution of the interface profile between binary immiscible fluids induced by a three-dimensional orthogonal magnetic field gradient. In the experiments, the changes of the interface profile between four groups of binary immiscible fluids are investigated under the same horizontal magnetic field gradients. The binary immiscible fluids are made of benzene and other liquids, like CuSO4, Fecl3, FeSO4 or Cucl2 aqueous solutions. In addition, the interface profile between the benzene and CuSO4 aqueous solution is examined under different horizontal magnetic field gradients. The experimental results are consistent with the theoretical analysis. This study explains the enhanced Moses effect from a mechanics standpoint. Furthermore, a new method for susceptibility measurement is proposed based on this enhanced Moses effect.

The carbide precipitation nature of an automobile gear material, i.e. Fe-C-Mn-Si-Cr-Mo alloy, during carburization and element addition process are investigated through PE+PA+LR prediction. Results show that, carburization process greatly increases the amount of cementite as well as the hardness index at the surface part. Besides, the addition of Ti and V helps to formation of TiC and (V, Mo)C carbides but suppress the precipitation of cementite, which contributes equivalent hardness at surface and lighter weight to the alloy.

A coupled Cellular Automaton - Finite Volume (CA-FV) model is developed for the prediction of macrosegregation and solidification microstructure of an Al-Si binary alloy under unidirectional solidification. The enthalpy, concentration and velocities are calculated at FV scale following macroscopic fluid flow, heat and solute transfer equations. The temperature and solid fraction are updated at CA scale from both the energy balance and the nucleation, grain growth under fluid flow and entrapment procedure with the help of microsegregation approximation. The variables at FV and CA sites exchange information through topological relations. The recalescence and the inter- and intra-granular segregation during solidification are predicted. The effects of thermal/solutal buoyancy and the grain structure on molten natural convection and the segregation pattern are also analyzed. Verification of the model has been done using the previous experimental solidification morphologies by other researchers.

A multiphase microsegregation model for the solidification of multicomponent alloys that experience a peritectic transformation is developed. It is based on a volume averaging method. Coupling is achieved among the conservation equations for total mass, solute mass and energy. The diffusion in extradendritic and several interdendritic liquid and solid phases, the growth kinetics of the dendritic and peritectic solidifying microstructures, as well as the velocities of the solid/liquid and solid/solid phase interfaces are considered in the model. The model is applied to the dendritic and peritectic solidification of a Fe-C-Cr alloy. Equilibrium between phases at the interface is taken into account and computed using a thermodynamic software. The occurrence of several recalescences due to the growth of the microstructure and the peritectic transformation are predicted and the solidification behaviors near recalescence are evaluated. By adjusting the parameters, the lever rule (LR), Gulliver-Scheil (GS) and partial equilibrium (PE) approximations are retrieved.