INTERACTION BETWEEN REFRACTORY MATERIAL AND STEEL, AND ITS EFFECT ON THE PURITY OF THE STEEL .2. NITROGEN, HYDROGEN AND CARBON CONTENT, AND THE EFFECT OF FLUSHING

The development of metallurgical process technology within the domains of secondary metallurgy and casting today makes it possible to produce highly pure steels containing ultralow concentrations of nitrogen, hydrogen and carbon. In order to ensure such low concentrations, there must be no influence exerted by way of the refractory material. The molten steel must be protected against contact with the atmosphere to avoid any nitrogen pickup. The sources of hydrogen and carbon in the refractory material must be kept as few as possible to minimize any hydrogen and carbon pickup. Efficient and reliable stirring systems are additionally required so as to accelerate the metal-slag reactions that take place.