Some units will consist of the main vacuum vessel into which there is the ladle of molten steel. The furnace will also be fitted with an electrical induction coil, which, when turned on, creates a stirring action within the liquid steel and, thus, agitates the steel within the ladle. This helps the homogeneity of the steel melt. The action will also help to release trapped gas particles within the molten-steel liquid and will ensure that the chemistry of the melt is homogenous.
This method of cleaning the steel will not remove all of the potential gaseous impurities present, but it will remove approximately 50% of the gaseous impurities down to a level of approximately 30 ppm of oxygen and down to approximately 2.5 ppm of hydrogen.
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