Premelted Slag for ESR

The quality of steel and of nickel alloys depends mainly on their degree of purity and their micro-structure. In order to optimize these two properties, steels and alloys are refined by the electro-slag remelting process (ESR process) with the assistance of electro-remelt slags (ESR slags). Cast ingots act as electrode. The electrodes dip into an electrically heated molten slag bath, and the submerged electrode metal melts. As the molten droplets sink through the liquid slag, impurities and mineral inclusions migrate from the droplets into the slag, ie, a refining process occurs. The refined metal droplets collect in the metal sump at the top of the remelt ingo, and the molten metal solidifies under controlled conditions as it gives up heat to the cooling water in the surrounding copper mould. ESR metals are free from shrink-holes, are isotropic, and exhibit a very high level of purity. It is thus only logical that these metals are exceptionally strong, with parts made from them boasting a long service life and superior reliability. The homogeneity of ESR ingots with regard to purity and microstructure produces significantly higher yields than are obtained from steel cast in moulds.