Their melting points are all around 1000 ☌ which can be achieved using a homemade furnace, however, due to their high thermal conductivity, they will cool rapidly, meaning you will have to heat them to higher temperature and pour them in the mold fast, before they solidify. While not ferrous metals, chromium and manganese have similar melting points, and can be cast in similar ways, though chromium metal is somewhat refractory, making it difficult to handle.Ĭopper, silver and gold are not very reactive and do not require protection against oxidation, nor do they fume in air. For casting, lost wax casting is widely employed. To melt these metals, an arc furnace is used, and the molten metal is added in a special mold made of refractory ceramic.įerrous metals (iron, cobalt, nickel) require high temperatures to melt, which can be achieved using coke or acetylene gas. Similar to magnesium, rare earth metals and lanthanides are difficult to cast in air, as they're very reactive and require inert atmosphere.ĭue to their very high melting point, these metals are impossible to melt using a gas burner and few crucibles can hold them in liquid form. A similar technique is used for the other metals. Magnesium is usually cast in an inert atmosphere, and the mold is covered with sand or magnesia to prevent it from catching fire as it's cooled. This process limits air contact.Īlkaline earth metals are also very reactive, but due to their high melting point, they cannot be melted and cast like the alkali metals. To pour them in a mold, a preheated metal or glass syringe is used to suck them and then inject the molten metal in the mold. They are best melted under inert atmosphere or in an inert solvent, like mineral oil or high-boiling point ethers, like dioxane. Metal casting conditions for each metal and alloy Alkaline metalsĪlkali metals are very reactive and can catch fire in molten state if exposed to air. There are other inconveniences, like fuming, flammability, corrosion of the crucible when casting metals.
Traditional techniques include lost-wax casting, plaster mold casting and sand casting. Metal casting depends on the type of metal you want to cast, and it's fairly easy to do for metals with a very low melting point like lead, tin, zinc, only needing the flame of a gas stove, while other metals like aluminium, copper and alloys like brass and bronze need a hotter flame to melt. Metal casting involves heating a metal or an alloy in a crucible until it melts, removing the floating dross then pouring the molten metal in a (preheated) mold, where is left to harden and cool. 2 Metal casting conditions for each metal and alloy.
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