Zinc and zinc alloys are mainly smelted in orange worm furnaces, and furnaces for smelting aluminum alloys, including coke ovens, gas furnaces, resistance furnaces, and induction furnaces, are generally suitable for smelting zinc alloys. Due to the low smelting humidity of zinc alloy, the erosion of furnace lining or crucible is greatly reduced, so the service life is long. Since lead and tin have an adverse effect on the corrosion resistance of zinc alloys, the smelting of zinc alloys and smelting copper alloys should be strictly separated. In addition, the zinc alloy reacts with iron at the usual melting temperature. In order to avoid the contamination of the alloy by iron, cast iron tapu should not be used. The tools used should be brushed with appropriate refractory paint, or the outer surface of the collapse should form a layer when the vortex is produced. Protective layer against iron oxidation, graphite burnout and phase transformation. There are zinc-rich and aluminum-rich phases in zinc-aluminum alloys. Due to their different relative densities, element segregation occurs during melting. Therefore, the melt should have better stirring measures when pouring. Coreless induction furnace melting has the function of automatically stirring the melt; for coreless induction furnaces, it needs a little stirring before pouring; for reverberatory furnaces, the liquid melted in electric resistance orange worm furnaces needs to be stirred as a whole before pouring. In addition, small pouring spoons, large pouring spoons, bell jars, sampling spoons, slag scraping spoons and ladles need to be prepared during melting.
Before smelting, the chemical composition of all metal charges must meet the requirements, the appearance is clean, and there is no oil pollution and sediment. It should be preheated to 200-300 ℃ before the furnace. New graphite crucibles should be slowly heated to 900°C for calcination before use. Old crucibles should first be inspected for damage and then cleaned of slag and metal adhering to the crucible walls. It should be preheated to 500-600 ℃ before charging. All tools in contact with zinc alloy sprinklers must be thoroughly cleaned, sprayed with paint, and fully dried before use. The melting process is simple and easy to implement, and no special ballast and degassing treatment is required, and no special covering agent is required. The melting speed is fast, the melting efficiency is high, and the energy consumption is small. In order to limit the introduction of harmful impurities, the purity of the raw materials is required to be high, and the charge should be isolated from titanium alloys and copper alloys when preparing materials. The melting process should be stirred up and down to avoid specific gravity segregation. The melting should be rapid, and it should not be overheated.
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