Some features of the interaction between melts and the lining of an induction furnace

Abstract

Smelting steel in industrial furnaces has several technical, economic, health and hygiene, and ecological advantages over other steel-smelting methods. The widespread use of induction smelting of steel, particularly of alloyed steel, is hindered by the low resistance of the main lining, which is the result of ignoring the special features of the manufacture of the lining, its bringing on line, and operation. The consumption of refractories in induction smelting sometimes reaches 40 kg per ton of liquid steel.An important feature of induction furnaces is the presence of a large (up to 20-30=C/mm) temperature gradient between the working surface and the water-cooled inductor, which leads to the emergence of significant thermal and mechanical stresses in the lining as well as to intermittent working.The high working temperature of smelting and the intense electromagnetic perturbation of melts cause significant interaction to occur with the lining.The material of the lining should not be wetted by the molten metal and slag if one is to avoid migration of the melts into the depth of the lining. Corundum, fused magnesite, and composites of these in various compositions are most frequently used as the lining materials for induction furnaces, particularly vacuum furnaces; mineralizing and building components are added to the main refractory material in the batch for the manufacture of the lining.All the operations of preparing the crucible for the first standard smelting are directed to obtaining a crucible with the optimum material compositions and the optimum porosity of the structure. In order to reduce the wetting it is necessary to strive for a reduction in .•130