Application

For special steel grades, the processes of primary and secondary metallurgy are not sufficient. In such cases, tertiary treatment by remelting and controlled crystallization is necessary. These processes include the electroslag remelting (ESR) process, in which remelting of the steel takes place under a protective, metallurgically active slag layer. The heat required to melt the steel is supplied by the electrical resistance of the slag in the energized state. As the molten steel droplets sink through the slag, interfacial reactions such as desulfurization, diffusion deoxidation and deposition of already formed nonmetallic inclusions are promoted due to the large surface area. A largely defect-free microstructure with significantly improved technological properties is produced, while block segregation and non-metallic inclusions are minimized. AKF is normally used in the so-called cold start, with a specific consumption of about 20 kg/ton of steel.