Powerful magnetic forces are now being used to levitate, stir and dam the flow of molten metal in the production of steel and aluminium. Research at Cambridge and Oxford universities is allowing manufacturers to produce cleaner, higher quality metals and alloys in less polluting and cheaper processes.
One of the latest devices using magnetic manipulation acts as a barrier to the molten metal that could otherwise leak out from the sides of the rollers that compress the material into sheets. The magnetic field "dams" the molten metal in place, giving a quality edge to the sheet metal produced instead of the rough and jagged edges caused by leaks. Conventional mechanical edge "dams" are prone to erosion or failure, which reduce the quality of the final product and increases both the costs and production time.
Another new process developed at Cambridge uses magnetic fields to form a nozzle to "grab hold" of a liquid metal, producing a thin jet of material that is free from contamination for the sprayforming of titanium and nickel-based superalloys. Conventional pouring nozzles for producing the materials are highly polluting owing to the aggressive nature of these molten materials.
In another current project research is underway to investigate the full potential for using magnetic fields in reducing the cost of aluminium smelting. Magnetic fields are also being used as "teaspoons" to stir freshly poured ingots of metal to ensure that the ingot is properly formed.
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For further information or a full copy of the article please contact Andrew McLaughlin on tel: 0171 451 7395; fax: 0171 839 2289 or email: Andrew_Mclaughlin@materials.org.uk