Steel companies use a ladle furnace refining process. The main feature of this ladle technology exists in refining under non-oxidizing atmosphere and support of slag-metal reaction through stirring by Ar gas injection for a desired long time due to the temperature compensation by arc heating. A CCD camera, placed above the ladle, monitors the slag formation (so called eyes) that has a different temperature and therefore a different color than the metal. The automatic software capable of analyzing the homogeneity of the surface and characterizing features of the molten steel level such us presence of slag clusters is developed and presented in this chapter. The method for visual monitoring and automated retrieval of slag clusters taken from the CCD camera are described.
Top2. Ladle Furnace Refining Procedure
Ladle Furnace Refining process covers all functions in reduction period: deoxidation (Conejo, 2006), desulfurization, inclusion removal, temperature and molten steel chemistry adjustment, reduction of metal oxide in the slag, large quantity alloy addition and slag off (Yuasa, 1984). All of these operations can be achieved with easier handling, higher quality and better reproducibility than in usual melting (Yuasa, 1984).
The ladle furnace refining consists of a ladle with a porous brick at the bottom for Ar gas injection to induce molten steel stirring and accelerate slag-metal reaction, a lid for sealing the vessel chamber to keep the non-oxidizing atmosphere, and an electrode heating system in the upper part (Yuasa, 1984). The arc heating is usually applied in the form of slag submerged arc because it provides a better heating efficiency and a favorable protection of lining refractory, due to the absence of arc radiation.
Ladle refining furnace provide an ideal refining station with precise temperature control, stirring action for homogeneity, and ports for alloy addition and slag removal. Reheating steel in a ladle refining furnace is typically accomplished by electric arc heating.