PECULIARITIES OF REFINING AND HARDENING OF METAL DURING ELECTROSLAG REMELTING,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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The mechanisms of the steel refining in electroslag melting were investigated. The desulfurizing process occurs during the period in which the electrode is melted and drops of the metal are formed. Non-metallic impurities are separated from the metal by adsorption of the slag, and not by rising to the surface during metal crystallization. Corundum in an acid slag provided little purification. CaF2 significantly reduced impurities. More pure metal was obtained with ANF-6 slag. Work was done to determine favorable conditions for metal crystallization in the water cooled crystallizer to obtain ingot with minimum number of defects. The depth of the metal bath and rate of melting of the ingot affect the crystal growth experiments confirmed earlier works that with slow melting and low bath depths, crystal growth is almost axial, and with increase in these factors, radial growth and formation of cavities arises. An extensive study was conducted of the heat flow in the melt and crystallizer. There is a direct relationship between the temperature of the slag and the depth of the metal bath the heat losses through the tray, in the water-cooling system and by heat accumulation in the ingot are very small most of the heat flow is through the walls. There is almost a direct relationship between the depth of the metal bath and the flow of heat introduced into the bath by the metal drops. Isotherms were drawn showing the difference in heat distributions in the electroslag melted ingots resulting from heat from the slag only, and from heat introduced by the metal drops.
- Metallurgy and Metallography