| 摘要 |
Molten steel or other electroconductive metal is treated with vacuum to remove dissolved gases therefrom. A rod of molten steel is drawn from a bath by applying vaccum to a vertical tube dipping into the molten bath. An electrical coil surrounding the tube applies an intense magnetic field to the steel rod by the passage of high frequency alternating current through the coil. The rod is compressed radially inwardly by the magnetic field exposing the whole of the external surface of the rod to vacuum. At the same time, the induced eddy currents superheat the steel rod. The large surface area of application of vacuum combined with the narrow dimension through which the gas must travel ensure rapid and efficient removal of the gases. The procedure is repeated until all the steel in the bath has been treated. Lack of contact of the steel rod with the tube surface eliminates loss of heat be convection and the superheating of the steel rod by the eddy currents ensures that the overall heat losses are minimal during processing of the molten metal bath.
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