Abstract: The protective coating consists of three layers. As alloying additives in the first and second layer or only in the second layer are used, nickel and iron or their oxides whereby the nickel content is from 0.05 to 0.95% and the iron content is, respectively, from 0.1 to 15% with regard to the total amount of aluminum. Both layers are submitted to heat treatment with surface density of the heat flow from 8 to 16.10.sup.6 W/m.sup.2. The third layer consists of aluminum with technical grade purity.The thus described graphitic electrodes are used in arc furnaces.

Abstract: Method of and apparatus for treating and refining liquid metal alloys by direct current arc heating. On at least a part of the melt surface there is performed an electrolysis whereby the melt across a layer of liquid slag-electrolyte is connected as an anode or a cathode, and the connection with the other pole--cathode or anode--is effected by means of one or more direct current arcs. Depending upon the desired direction of the electrolysis process, it is possible to change the polarity of the metal melt or the slag-electrolyte. The apparatus for performing the method comprises a vessel equipped with a mechanism for pouring, a movable cover and movable electrodes. The centers of the electrodes are disposed symmetrically one to the other in a vertical plane. As a source of direct current there are used two or more rectifiers operating independently.

Abstract: An apparatus and a method of operating an apparatus for the refining of a ferrous melt make use of a ladle with a removable cover provided with a porous plug at its bottom through which an inert gas is introduced. A direct current source is connected to an electrode means comprising at least three electrodes in electrical contact with the melt.

Abstract: A method of and an apparatus for the refining of a ferrous melt makes use of a ladle with a removable cover provided with a porous plug at its bottom through which an inert gas is introduced. A direct current source is connected to a carbon electrode in contact with the melt and at least one electrode above the melt.

Abstract: A method for steelmaking with direct current in which, during melting in an arc furnace, the contact anodes are connected by contact to the iron material, and the electric arc is formed between the latter and the movable cathodes. After the contact anodes attain the slag, the further burning of the electric arc between the molten metal and the movable cathodes is effected so that the working ends of the contact anodes remain immersed in the slag.