Abstract: An electric arc furnace for melting metal, especially steel, includes a container having an upper open ended substantially cylindrical wall portion and a lower cylindrical wall portion extending downwardly therefrom and being closed at the bottom and receiving during operation of the furnace a bath of molten material having an upper level at a predetermined maximum elevation above the bottom of the container. The container includes an outer metal shell and refractory material covering at least the lower wall portion of the shell and the closed bottom. In order to increase the charging volume of the container without essentially changing the height thereof, the upper wall portion has, at a distance of at least 300 mm above the level the bath of molten metal, an inner diameter which is greater than the outer diameter of the metal shell of the lower wall portion.

Abstract: A box-shaped shallow, water-cooled element of steel plate for the construction of a wall portion of a melting furnace above the melt in the furnace, has a front wall adapted to face the interior of said furnace. This front wall is provided with a plurality of recesses of equal cross-section equally spaced from each other in the form of elongated grooves or bores to facilitate adhesion of a layer of refractory material to be applied thereto, wherein the recesses are machined in the surface of the front wall adapted to be directed to the interior of the furnace in such a manner that the area of recesses at this surface is smaller than the area of the remaining non-machined surface to thus enhance heat conduction from the interior of the furnace to the cooling water passing through the wall element and to prevent damage of the front wall when the protective layer is missing completely or in part.

Abstract: The opposite ends of at least one pair of tubular members, for instance steel tubes, are closed by inserts which have radial portions overlying end faces about the open ends of the tubular members. The tubular members are then axially aligned with each other while maintaining the radial portions of the inserts spaced from each other, whereafter the tubular members and the spacing therebetween are covered with a jacket of plastic material. Subsequently thereto, the jacket is severed intermediate the annular portions of the inserts to thereby obtain two discrete tubular elements.