4. Refining of liquid steel by conversion processes

The first liquid steel produced by melting was probably designed by Huntsmann, who in 1740 devised a furnace in which the fuel was separated from the metal charge. The cast iron was charged and melted in a refractory crucible heated in a blown coke furnace, then refined by air blowing. This is the origin of crucible steel, also known as molten steel, as opposed to "natural" steel obtained in a pasty state. But this process was not very productive, and only interested very small quantities.

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