Abstract: A graphite block for an induction furnace in the form of a right prism formed from a plurality of plates associated along adjacent end faces parallel to the axis of the prism. Each plate includes a longitudinal recess opening into its top face adjacent a first end and a longitudinal recess opening into its bottom face adjacent an opposite end. Each end face is provided with a flexible graphite joint. The association of plates results from a partial interfitting of a top face longitudinal recess of one plate with a bottom face longitudinal recess of a second plate, the recesses being adapted to leave a void of polygonal section between the plates. This void is occupied by a graphite key of similar section divided over its length into two parts meeting along an oblique surface.

Abstract: An arc furnace comprising a furnace vessel having a transverse axis and a central axis, electrodes disposed on a graduated circle, the electrodes projecting into the furnace vessel parallel to the central vertical axis, the electrodes are mounted on an electrode holding device of three supporting columns and three supporting arms, the center is located on the transverse axis at a predetermined distance from the center, the transverse axis being collinear with the middle one of the supporting arms, an electrode is disposed closest to the supporting columns at the intersection of the transverse axis and the graduated circle, and the other electrodes are disposed on the graduated circle an angle .alpha.=<110.degree. with the electrode at the center of the circle.

Abstract: A direct current arc furnace, includes a graphite cathode; and a container forming a hearth with a hearth base surface and having a container bottom acting as anode. The container bottom includes a supporting copper-plated sheet steel base consisting of a steel sheet and a copper plating plated on the steel sheet; electrical connection means extending through the steel sheet to contact the copper plating to supply an anode current to the copper plating; and a refractory brick lining having a graphite content above the copper-plated sheet steel base with the copper-plated layer adjacent the brick lining. In a preferred embodiment the graphite content in the brick lining decreases from the vicinity of the copper-plated sheet steel base to the vicinity of the hearth base surface.

Abstract: A roof structure for an electric arc smelting furnace includes a spider frame for supporting a plurality of independent removable coolant coil sections. An inner coil section is generally annular in shape and includes a coolant pipe which spirals completely around a central opening in the roof structure. An intermediate coil section is also generally annular in shape, but includes a coolant pipe which extends around the circumference of the inner section, reverses itself around the circumference of the first pipe of the intermediate section, and then reverses itself once again around the circumference of the second coolant pipe of the intermediate section, to form a generally serpentine pattern. A plurality of semi-annular outer coil sections are supported radially outwardly from the intermediate coil section. Each outer section includes a first pipe located generally centrally within the semi-annular section and extending from end to end.

Abstract: A wall electrode includes a metal bar adapted to extend through the wall of the furnace, a water-cooled sleeve composed of a material which is a good conductor of heat and electricity, an end member composed of a material which is a good conductor of heat and electricity, and an annular member such as a ring composed of a metal which is heavy and has a low melting point surrounding the bar so that the heavy metal in the liquid state spreads in the space between the bar and the sleeve when the annular member is made to melt during use of the electrode.

Abstract: A refractory is laid on a base plate provided with a connector for the connection of a power source apparatus. Many electrode pins are inserted through the refractory and fixed in the base plate at their lower ends. The base plate is made of a steel upper plate member and a copper lower plate member overlapped one on the other and the lower end portions of the many electrode pins are electrically connected to the lower plate member through the upper plate member. When a DC electric arc furnace is operated, the electric current supplied to the connector reaches all the electrode pins mainly through the lower plate member in the base plate and flows from there homogeneously through the pins into the molten metal pool in the furnace.

Abstract: The present invention has been devised to obtain a metallurgical effect by introducing refining gas into a molten metal in a metallurgical vessel and stirring the molten metal sufficiently by convection, and to improve durability of one nozzle or a few nozzles for introducing the refining gas. At a predetermined position of a furnace bottom onto which a ramming mass is provided, a few cylindrical refractory sleeves are disposed close to the upper face of the furnace bottom from the lower portion thereof. In each cylindrical refractory sleeve a gas introducing nozzle, which introduces the refining gas, is disposed in such a manner that it can be drawn out downwardly for replacement.

Abstract: An electric arc furnace has a dished hearth, vertical side walls, and a relatively flat roof consisting of a center portion, a relatively planar outer portion and a cylindrical skirt which abuts the side wall to define a space above and around the expected surface of the furnace charge wherein CO containing waste gases can be oxidized to minimize CO and promote heat transfer to the furnace charge. The roof center portion is refractory having holes for receiving electrodes and the outer portion is formed of water-cooled pipes which define sections of the annulus. The upper end of the side walls is also formed of water-cooled panels.

Abstract: A furnace lining is formed by a plurality of lining bricks. The bricks have surfaces defining an internal surface of the lining that is to face the interior of the furnace and to receive therefrom radiant heat. At least one depression is formed in the lining and opens onto the surface through an opening. The depression has internal wall surfaces that are geometrically configured to cause radiant heat from the furnace interior that impinges on a first internal wall surface to be reflected thereby and to impinge therefrom onto a second internal wall surface. Thus, the heat will be absorbed by the bricks of the lining, and such heat will be emitted thereby from the inner surface thereof.

Abstract: A lining for a direct-current electric-arc furnace, in which at least part of that regions of said furnace which receives the melt is provided on the inside with an electrically conductive, refractory brick lining and a ring-shaped current conductor, on its outside, constitutes the opposite pole to the upper electrode centrally extending into said surface. The entire bottom area is covered with a refractory, insulating brick lining and a brick lining of graphite bricks is applied onto that brick lining in the radially outer wall region of the furnace. Located adjacent thereto in radially inward manner is an annular zone, comprising an electrically conductive, refractory brick lining. The central bottom area above said insulating brick lining is consittuted by a monolithic ramming mass. Furthermore, the material of the wall of said furnace above said brick lining of graphite bricks largely corresponds to that of said insulating brick lining at the hearth bottom.

Abstract: A furnace bottom structure of a direct current electric furnace has at least one furnace bottom electrode and at least one gas injection tuyere provided in the furnace bottom refractory of the direct current electric furnace. Preferably, the furnace bottom electrodes and the gas injection tuyere are embedded in a substantially cylindrical refractory body with downwardly diverging tapered upper portion. The refractory body, the furnace bottom electrodes and the gas injection tuyere form an integral furnace bottom block which is detachably attached to the bottom of the electric furnace so as to close a bottom opening of the furnace.

Abstract: In a direct-current electric-arc furnace, the bottom contact, that is the hearth electrode, must be insulated from the metallic shell of the furnace vessel by insulating material. For this purpose, the bottom plate carrying the bottom contact essentially forms the bottom of the furnace vessel. This bottom contact, with an insulating material, or a material which is at least a poor electrical conductor, inbetween, rests on a part, projecting radially inward, of the metallic vessel shell.

Abstract: The service life of a bottom electrode for a direct current arc furnace for producing steel is prolonged by using ZrB.sub.2 type sintered bodies for a contacting pins which constitutes a major part of the bottom electrode wherein the ZrB.sub.2 type sintered bodies have a corrosion-resistance to molten steel and slag. Further, the number of contacting pins to be used is reduced by forming each of the pins into a form of pillar with a through hole at the axis, or by assembling a plurality of longitudinally divided pin portions to form a contacting pin, whereby the diameter of the contacting pin can be made large. Then the space between contacting pins is made broad, and brick having good corrosion-resistance are filled in the space so that the service life of the bottom electrode is brought closer to that of the refractory lining of the direct current arc furnace.

Abstract: A cover for a vessel handling heated substances, such as a furnace, in which the cover comprises an outer segment defining an opening in which a removable inner cover segment (delta) is seated and wherein said inner cover segment comprises spaced apart walls defining an enclosed space that contains coolant spray means adapted for spraying coolant onto the wall that is closest to the interior of the vessel.

Abstract: The present invention relates to an arrangement for gas collection in electrolytic aluminium reduction furnaces equipped with Soderberg anode. The arrangement comprises a plurality of liftable cover plates 8-11 which cover the complete area between the sidewalls of the furnace and the anode casing 2. The cover plates 8-11 are gas tight sealed against the circumference of the anode casing 2 and against the furnace sidewalls 7. The cover plates 8-11 are on their upper side equipped with a plurality of ribs 12. A channel 13 comprising of a lower plate 14, and inclined plate 15 and an upper plate 16 is inserted in recesses in the ribs 12.

Abstract: An improved electric arc furnace provides increased capacity and reduced operating costs. The furnace has an ob-round shape which locates sidewalls further from the source of heat. The improved furnace can accept a larger scrap charge and provides a larger surface area for slag reactions to take place. All of these advantages are obtained without the need for building new foundations or ancillary equipment.

Abstract: Process and apparatus for the continuous melting of scrap in an electric D.C. furnace, in which the D.C. source (23) supplies vault electrodes (4) and hearth electrodes (8) by means of respective feed conductors (7) and return conductors (9). The scrap is fed through an orifice (12). The vault electrode or electrodes (4) are arranged on the other side of the axis of the shaft (1) in relation to the orifice (12). The hearth electrode or electrodes (8) are offset towards the orifice (12), and the return conductor or conductors (9) connected to the hearth electrode or electrodes (8) are led under the bottom (2) of the shaft (1) and as near as possible to the latter, being directed towards the opposite zone of the furnace where the vault electrodes (4) are located, as to generate magnetic fields capable of deflecting the arc or arcs towards a zone set apart from the vault electrodes (4) and located substantially below the scrap feed orifice (12 ).

Abstract: A process to improve electric arc furnace steelmaking. The efficiency increase is due to the metal-slag stirring that is produced by bottom gas injection through gas permeable ceramic elements. The permeable elements are not penetrated by the liquid metal, which does not stop the gas flow.The process is carried out in combination with a furnace charging door stopper device. The device avoids liquid ejections through the furnace charging door during the injection periods. The electric arc furnace steelmaking generalized practices are more effective when the molten metal is being stirred by gas injection, by increasing the metal-slag and the slag-atmosphere interphase area. When the stirring gas is natural gas, the process conditions, oxidizing or reducing, are reinforced according to the slag in the bath.

Abstract: A furnace vessel (301) of a metallurgical furnace, in particular an electric arc furnace, in which the tap hole (305) is arranged within a lower vessel (303) which is oval or circular in plan view, in the vicinity of the wall of the vessel, and the upper vessel (309), above the tap hole (305), includes a vessel portion (320) which is displaced or is displaceable relative to the lower vessel towards the center of the vessel and in which there is provided a maintenance opening (327) for the tap hole (305) (FIG. 11).

Abstract: An arc furnace is provided with a variable-capacity ring which is placed at the top of a furnace body and which is split into a plurality of circumferential sections which in turn define in combination a top furnace wall portion, and a driving mechanism for causing the ring to move horizontally. As the ring is moved radially outwardly or inwardly of the furnace body, the height of the furnace body is varied and consequently the capacity or the volume of the furnace body can be varied. As a result, the overcharging of the charge (scrap) is much facilitated; that is, the number of back charges can be reduced. Furthermore, when the pile of the charge in the furnace body is lowered, the capacity or volume of the arc furnace is decreased so that unwanted thermal losses and oxidation and resulting wear of electrodes can be reduced to a minimum.

Abstract: A characteristic feature of the furnace disclosed in the present invention is the presence therein of additional current-carrying elements with the free end thereof sunk relative to the effective area of the furnace brickwork. The elements are connected with the terminals of a power source of the opposite polarity with respect to the connection of the main current-carrying elements of a corresponding operating area.

Abstract: The combination of an electric furnace and a slag retaining pouring spout thereon in registry with a modified tap hole is disclosed. The tap hole located in one end of the electric furnace communicates with the interior thereof and the slag retaining pouring spout is positioned on the electric furnace and in communication with the tap hole. The slag retaining pouring spout is angled upwardly and outwardly with respect to the tap hole and positioned above of the molten metal and slag in the operating electric furnace and receives molten metal from the electric furance when the same is tilted to pour the molten metal through the tap hole. The slag retaining pouring spout has a secondary tap hole therein normally closed with a consumable plug during the operation of the electric furnace and the early tap of the molten metal therefrom into the slag retaining pouring spout.

Abstract: A DC arc furnace electrically conductive hearth brickwork wear lining has metal electrical conductors extending through it which are molten for their upper portions when working and by electromagnetic flowing can erode the bricks of the brickwork. To prevent this erosion resistant refractory shields are positioned so as to shield the bricks from such flows.

Abstract: In order to move a furnace body (1) and a furnace lid (2) relative to one another by approximately one furnace body width, the separating surfaces of the furnace body (1) and furnace lid (2) are inclined relative to the horizontal.The direction of movement when the furnace body (1) is moved then runs in the direction of the angle opening and, when the furnace lid (2) is moved, the movement is in the opposite direction.In order to reduce the frictional forces between the separating surfaces (4, 5) of the furnace body (1) and furnace lid (2) and to ensure that the relative movement of the furnace body (1) and the furnace lid (2) occurs under defined conditions, the furnace lid (2) is supported on at least two support points on the furnace body (1) on which roller tracks (6) are arranged together with support rollers (7) which roll on the tracks for a certain travel.

Abstract: The present invention relates to a reduction furnace with a split furnace body, particularly suited for production of ferro alloys, pig iron or calcium carbide. Furnaces of such types are provided with a furnace pot equipped with an internal refractory lining anchored to the furnace wall by means of anchoring elements. According to the present invention the refractory lining of at least the upper section of the split furnace body comprises a plurality of individual, pre-fabricated elements which are removably arranged at least on the upper section. Each unit comprises preferably a rear plate of steel, pig iron or similar material and one or more anchoring ribs or bolts extending horizontally out from and rigidly secured to the rear plate. The anchoring ribs provide a hold for the refractory lining on the rear plate. The separate units are suspended at least from the upper segment by means of simple support means.

Abstract: Electric arc furnace, of the type having metallic walls (2) and an at least partly metallic roof (1), and provided with radiation detection apparatuses (8) for their controlled operation. Differential water circulation transducers (8) are positioned in the intrados of the metallic part (7) of the roof (1); they project with respect to the inner surface of the roof and their end faces (16) facing the interior of the furnace are concave.