Abstract: An optimized thread profile (140) for joining composite materials is presented. This thread profile (140) maintains a certain material strength when used as part of a composite threaded joint (101). The thread profile (140) comprises a repeating pattern of four components: a crest region (150), a first flank (162), a root region (170) and a second flank (164). The thread profile (140) is symmetrical, that is, the dimensions of the four components do not change throughout the length of the thread profile. The crest (152) has a flat profile and the root (172) has a rounded profile. When a shaft (120) is affixed to a joining shaft (110) using this optimized thread profile (140), the flat profiles of the crest (152) of the shaft (120) and corresponding rounded profiles of the root (172) of the joining shaft (110) create a gap to accommodate a substance such as an adhesive or a lubricant.

Abstract: A lift plug for lifting a graphite electrode includes a main body and an insert coupled to one end of the main body, with the insert configured to mate with a graphite electrode to secure the lift plug to the graphite electrode. The lift plug also includes a lifting component coupled to the main body opposite the insert to lift the graphite electrode. The insert comprises a non-graphite material with a coefficient of thermal expansion (CTE) similar to graphite, such that the lift plug expands at a similar rate as the graphite electrode when heated so as to prevent locking at a joint between the lift plug and the graphite electrode.

Abstract: A carbon-containing nipple has a nipple thread for carbon-containing electrodes. The nipple has an inlet formed in the nipple thread and the inlet is suitable for receiving an adhesive container filled with a curable adhesive. Preferably, the inlet is a groove which runs through the nipple thread in a transverse manner and is undercut at least in sections. A nipple kit contains such a nipple and the adhesive container containing the adhesive for securing a nipple/electrode connection, wherein the adhesive container is disposed in the inlet. The nipple kit can be used in conjunction with a carbon-containing electrode for use in arc furnaces.

Abstract: An electrode joining apparatus for joining a first electrode and a second electrode includes an electrode holder configured to receive the first electrode and a torque device positioned above the electrode holder. The torque device is configured to engage and rotate the second electrode relative to the first electrode. A lift is disposed on the apparatus to move the torque device relative to the electrode holder. In some embodiments, the lift includes a mechanism such as a powered actuator operable to raise the torque device above the electrode holder. In additional embodiments, the lift includes a carriage that is vertically moveable relative to the electrode holder, and the torque device is attached to the carriage.

Abstract: An electrode joining apparatus for joining a free electrode to a fixed electrode. The electrode joining apparatus includes an electrode holder configured to selectively hold the fixed electrode and a torque device positioned above the electrode holder, the torque device configured to grip and spin the free electrode to join the electrodes. The electrode joining apparatus can include an axial passage defined through the electrode holder and the torque device. A retractable spacer can be movably connected to the electrode joining apparatus, the retractable spacer configured to selectively move into the axial passage. The retractable spacer can be used to form a gap between the free electrode and the fixed electrode before the joining process is initiated. Electrode joining apparatus can also include a spacer drive mechanism coupled to the retractable spacer, the spacer drive mechanism configured to selectively move the retractable spacer into the axial passage.

Abstract: An embodiment disclosed herein includes a monolithic graphite electrode. The electrode has a main body having a length of more than 3050 mm. Another embodiment disclosed herein includes an electrode column comprising a plurality of monolithic graphite electrodes. The column has a length of more than 3050 mm of electrode per joint. A further embodiment discussed herein is the practice of increasing the length of the electrode to minimize the occurrence of an electrode joint in the electrode column for a given length. This practice will improve efficiencies for both electrode manufacturers as well as electric arc furnace operators.

Abstract: A sealing device is arranged around a rod electrode extending vertically through an aperture made in the ceiling of an arc furnace and being vertically movable inside the furnace to prevent the access of gases from the furnace through the aperture to the atmosphere, and on the other hand to prevent air from flowing from the atmosphere into the furnace. The sealing device comprises a gas distribution chamber provided with an inlet channel for feeding essentially passive gas, such as nitrogen or air, into the gas distribution chamber. The sealing device also includes a slit nozzle encasing the electrode, through which nozzle a gas jet is arranged to be discharged from the gas distribution chamber towards the electrode in a direction that is at an angle with respect to the horizontal plane and has a slightly upwards inclined orientation, and that is, with respect to the furnace interior, pointed outwardly, so that the sealing is carried out owing to the effect of the created stagnation pressure.

Abstract: Disclosed herein is an electrode joint having a first carbon body having at least one end portion that includes a male tang with a convex tip and a second carbon body having a female socket with a concave base.

Abstract: A pin for use in connecting graphite electrodes into a joint, where the pin has at least one male tang having a tang factor, defined as the ratio of male tang length to diameter of the electrode into which hit is to be threaded, of at least about 1.0.

Abstract: A pin for use in connecting graphite electrodes into a joint, where the pin has at least one male tang having a tang factor, defined as the ratio of male tang length to diameter of the electrode into which hit is to be threaded, of at least about 0.60.

Abstract: A lifting apparatus for transporting a carbon based electrode having a threaded male end. The apparatus includes a casing having a top end and a bottom end. The casing defines an electrode aperture from the bottom end shaped to accept the threaded male end of the carbon based electrode to secure the lifting apparatus to the electrode. An attachment aperture is positioned in the top end while an attachment element is positioned in the attachment aperture and operatively engaging the top end of the casing. The attachment element is positioned to accept engagement from a crane or other powered lifting device, while the lifting apparatus is preferably manually attachable to the electrode.

Abstract: A device for adding graphite electrodes onto an electrode column is provided. This device, also known as an electrode robot, includes an engagement mechanism capable of being easily adapted to a plurality of thread pitches so that the device can add different electrodes having threaded connectors of different thread pitches.

Abstract: An electrode joint is presented, the joint including two joined graphite electrodes having blocked threads and having a locking ring interposed between the electrodes, the locking ring composed of a material having a coefficient of friction such that the tendency of the electrode joint to unscrew is retarded.

Abstract: Carbon electrodes have at least one socket with an internal thread to be mated with a threaded pin having at least one external thread. Also such a threaded pin is provided for connecting to such carbon electrodes. The internal thread or external thread of the carbon electrodes and/or the pins are provided with non-load bearing abutment thread windings.

Abstract: A lifting apparatus for transporting a carbon based electrode having a threaded male end. The apparatus comprises a casing having a top end and a bottom end. The casing defines an electrode aperture from the bottom end shaped to accept the threaded male end of the carbon based electrode to secure the lifting apparatus to the electrode. An attachment aperture is positioned in the top end while an attachment element is positioned in the attachment aperture and operatively engaging the top end of the casing. The attachment element is positioned to accept engagement from a crane or other powered lifting device, while the lifting apparatus is preferably manually attachable to the electrode.

Abstract: A joint for connecting two carbon members, with at least one carbon member having an asymmetrical coefficient of thermal expansion. The carbon member having the asymmetrical coefficient of thermal expansion also has either a male tang or a female socket with an elliptical cross section selectively oriented to the asymmetrical coefficient of thermal expansion.

Abstract: A male-female electrode joint is presented, the joint including two joined graphite electrodes having blocked threads and having a seal interposed between the electrodes, the seal composed of a material having an oxidation rate equal to or less than that of the electrodes.

Abstract: An electrode joint is presented, the joint including two joined graphite electrodes and having a joint strengthening ring interposed between the electrodes, the joint strengthening ring composed of a compressible.

Abstract: A graphite electrode joint, where the male tang has a tang factor, defined as the ratio of male tang length to electrode diameter, of at least about 0.60.

Abstract: An electrode joint having first and second complementary elements capable of being joined together to form the joint, wherein one of the threaded elements has at least one slot at least partially along its length; and wherein one of the threaded elements includes a source of a flowable adhesive in fluid communication with the slot.

Abstract: An end-face seal for graphite electrode joints, including a seal formed of a plurality of individual elements interlocked to form a unitary whole, and formed of a material having an oxidation rate equal to or less than that of the electrodes.

Abstract: A pin for use in connecting graphite electrodes into a joint, where the pin has at least one male tang having a tang factor, defined as the ratio of male tang length to diameter of the electrode into which hit is to be threaded, of at least about 0.60.

Abstract: An electrode column and a method of determining the length of the electrode in it in an active furnace. The column is a Söderberg column including a mantel in which the electrode is movable in an axial direction by lower and upper slipping clamps which are movable relatively to each other by slipping cylinders. The method includes the steps of moving, with the slip clamps, the electrode in a downslip relatively to the mantel with the slipping cylinders and gravity and measuring the force required to move the electrode with only the upper slipping clamp against predetermined reaction forces acting against movement of the electrode and computing these parameters to determine the mass and so the length of the electrode relatively to the theoretical mass of the undamaged electrode at the time of movement.

Abstract: A graphite electrode joint, where the male tang has a tang factor, defined as the ratio of male tang length to electrode diameter, of at least about 0.60.

Abstract: A method of manufacturing titanium electrodes in a vacuum arc remelting furnace as well as a reusable header for use in the remelting process is disclosed. An electrode may be attached to the reusable header and remelted in the furnace a number of times until a final ingot of the desired metallurgical quality is produced. The header and electrode are provided with a complimentarily shaped interlocking recess and projection to secure them together. The electrode may alternatively be integrally formed with a starter stub that includes a recess or projection that interlocks with a complimentarily shaped projection or recess on the header. At least a section of the header is made of the same metal as the electrode to be melted to reduce contamination of the ingot being formed in the furnace. Alternatively the starter stub is made from the same metal as the electrode.

Abstract: A threaded connection is secured against loosening/unscrewing for columns of carbon and/or graphite electrodes. The electrodes are connected in columns with threaded connection elements, i.e., carbon connecting pins. At least one part has a wedge ramp on the root of the thread winding. When the components of the threaded connection are screwed together, the crests of the thread windings of one part abut with the wedge ramps of the other threaded connection component. A contact line is created, possibly multiple sections of a contact line. When the parts are screwed together, all forces are transferred from one part to the other only via the contact line. In a special case, the contour of the thread winding along whose root the wedge ramp is running is reduced e.g. to a connecting line between two wedge ramps located one above the other in the cross-section.

Abstract: A method of measuring the instantaneous parameters of a consumable electrode by: (a) providing a laser measuring device and positioning the laser measuring device in the vicinity of the electrode to be measured; (b) activating the laser measuring device to obtain data relating to the instantaneous parameters of the consumable electrode; and (c) transferring the data obtained from the laser measuring device to a computer data processing and storage device to determine the instantaneous parameters of the electrode.

Abstract: Electrode columns made from carbon and graphite are screwed together from individual elements, for example, the electrodes and nipples. The elements have directionally structured contact surfaces. Such a structure of the contact surfaces gives rise to the elements of a column demonstrating increased resistance to loosening after intensive machine screwing or screwing applied by hand, which, therefore, is often inadequate, whereby a higher level of operational reliability is achieved, in particular, in the case of electrode columns that are screwed together by hand.

Abstract: A electrode and method for periodic elongation of the electrode of an electric arc furnace, includes screwing to the electrode column, a new electrode and a nipple with a longitudinal hole and a metal rod therein. The rod melts at working temperatures of the furnace and fills cavities in the joint between the electrodes and nipple, as well as partially filling an additional cavity in the body of the electrode. A gas mixture from the additional cavity is free of liquid metal being drawn to the working area of the furnace through the holes in the body of the electrode. The electrode is made with additional cavities, placed along the central axis in the bottom of the threaded sockets, the cavities having different diameters and depths and one of them being connected to the external surface of the electrode by holes.

Abstract: An electrode connection includes coated contact surfaces in differently constructed electrode strings formed of carbon and graphite being provided with sliding layers. With the aid of these sliding layers, the elements of a string can be screwed more firmly against one another, with the result that a higher release torque and higher operating reliability are achieved.

Abstract: A carbon or graphite electrode comprising a first end having a planar surface and a second end having a second planar surface. The first planar surface has a male dovetailed tenon projecting therefrom. The second planar surface has a female dovetailed groove dimensioned for snugly receiving and engaging the male dovetail tenon. The male dovetail tenon has the same shape and dimension of the female dovetail groove so that the two, when joined, form a snug dovetail joint. Also disclosed is a joint for a carbon or graphite electrode in an electrode column.

Abstract: A system is disclosed for assembling a composite, self-baking electrode for electric arc furnaces. The electrode includes an outer metal ferrule, a central column of prebaked carbon or graphite sections assembled by nipples. New sections are added to the column from carbon paste placed between the ferrule and the central column. The assembling system principally includes a support that is vertically mobile over a length greater than the length of each of the sections. The support suspends the central column. A device is provided for temporarily blocking the column and a clamping device applies a preset torque to a newly added section while the blocking device temporarily blocks the column from movement thereby screwing the newly added section to an adjacently positioned section of the column.

Abstract: An apparatus for joining a threaded free electrode section with a threaded fixed electrode section for use in electric arc furnaces. The apparatus comprises a driver and a coupler with a plurality of pawls to grip the free electrode section and turn it in one direction. After the driver and coupler pass through a range of motion causing the free electrode to turn in the same direction, they reverse direction, with the pawls releasing the free electrode so that the free electrode does not reverse direction, and the driver and coupler return to the original position in a ratchet-like action.

Abstract: In an arc furnace or melter furnace employing concentric graphite inner and outer electrodes, the accumulations of tolerances, distortion and mechanical forces can cause a loss of concentricity leading to reduced performance and eventually to electrode degradation. To avoid that condition, a plurality of insulating spherical or cylindrical spacers are disposed in the annular gap between the inner and outer electrodes. The spacers are held in position by arcuate recesses in the outer surface of the inner electrode or in the inner surface of the outer electrode. The electrodes may be constructed in segments that are assembled by threading one segment into another segment.

Abstract: The present invention relates to a method for production of carbon electrodes where a first unbaked carbonaceous electrode paste containing a binder which cures at a temperature below 500.degree. C. is supplied to an annulus between a curing chamber having an inner cross section corresponding to the cross section of the electrode which is to be produced and an inner mould material, curing of the first electrode paste by means of supplying heat to the curing chamber, removing of elongated sections of the cured first electrode paste from the curing chamber. The lengths of the cured first electrode paste are mounted on the top of the electrode column in an electric smelting furnace, a second electrode paste is optionally supplied to the central opening of the cured body of the first electrode paste, whereby the cured body of the first electrode paste and the second electrode paste are baked into a solid carbon electrode in the area of supplying electric operating current to the electrode.

Abstract: An electric arc furnace having a partially insulated electrode produces molten metal such as foundry iron from an iron source where little or no slag is produced. The furnace includes at least one insulated electrode assembly for immersing deep into the metal charge. The electrode assembly has an electrically conducting member coupled to an electrode. The electrode has a coupling member at the upper end for coupling with the electrically conducting member and a coupling member at the lower end for coupling with an adjacent electrode to form an electrode column. The coupling members can be an internally threaded recess in the ends thereof. An externally threaded coupling member can be threaded into the recesses of the electrodes for coupling two or more electrodes together.

Abstract: System for connection of pneumatic and/or hydraulic hoses (11) on composite electrodes (12) for arc furnaces, the electrodes (12) comprising, at least one hollow adapter (13) associated at their lower part with a replaceable graphite element (14), the electrode (12) cooperating with an electrode-holder arm (15) and being displaceable axially in relation to that electrode-holder arm (15), the hoses (11) being associated at one end with a first connection assembly (18a) associated with a support (17), the adapter (13) including a solidly attached second connection assembly (18b) mating functionally with the first connection assembly (18a), the first (18a) and second (18b) connection assemblies comprising mating connecting elements (19a, 19b) equipped with elements to interrupt the flow of the fluid which can be temporally actuated, the a support (17) associated with the first connection assembly (18a) having a first inactive position temporally solid with the electrode-holder arm (15) and a second working posit

Abstract: Cooling system for electrodes (11) in D.C. electric arc furnaces, the electrodes (11) comprising a part (11a) subjected to the hot environment of the furnace, this part being made of graphite in the case of a cathode and of copper in the case of an anode, the part (11a) being associated with a metallic part (11b) by means of a joint (13) which includes inside itself a hollow (14), comprising at least in correspondence with the metallic part (11b) a cooling circuit (20) with at least a delivery channel (15), a return channel (16) and a heat exchanger (18), the circuit (20) using liquid metal as a cooling fluid, there also being included means for the forced circulation of the cooling fluid consisting of a hydromagnetic pump (17).

Abstract: In order to prevent the rupturing of a graphite electrode comprising electrode sections joined with one another by a socket and a nipple, electrical insulating material is applied on the joined surfaces to decrease the current across the nipple.

Abstract: A new electrode is joined to a consumed electrode of the electric furnace according to a method comprising the steps of lifting and transporting the new electrode suspended from a joining apparatus by a crane, aligning both electrodes by throwing a laser beam from a projector disposed to the crane on a positioning marker disposed on a deck plate provided in the vicinity of the electric furnace, screwing a screw thread of the new electrode into a threaded hole of the consumed electrode by actuating an electric motor disposed in the joining apparatus, and tightening both electrodes at desired tightening torque by operating the motor in a stalled state with a small electric current of low frequency.

Abstract: A new electrode is joined to a consumed electrode of the electric furnace according to a method comprising the steps of lifting and transporting the new electrode suspended from a joining apparatus by a crane, aligning both electrodes by throwing a laser beam from a projector disposed to the crane on a positioning marker disposed on a deck plate provided in the vicinity of the electric furnace, screwing a screw thread of the new electrode into a threaded hole of the consumed electrode by actuating an electric motor disposed in the joining apparatus, and tightening both electrodes at desired tightening torque by operating the motor in a stalled state with a small electric current of low frequency.

Abstract: A device for mounting a self-baking composite electrode for an electric arc furnace, which includes a hollow metallic shell, a central column of graphite or pre-baked carbon comprising a plurality of elements fitted together by means of nipples. A carbonaceous paste is disposed between the shell and the column. The column is suspended from a support which is movable in a vertical direction with respect to the shell, along a length which is greater than the length of each of the elements. The invention is particularly relevant to furnaces for the production of silicon by carbothermic means.

Abstract: A method of producing a transition joint between components produced from two different grades of ferritic steel comprises the steps of successively re-melting in a vacuum arc furnace a first electrode of one of the required grades of ferritic steel and a second electrode of the required grade of ferritic steel and solidifying the melt as it is progressively formed to produce a single composite component.

Abstract: A graphite body which is capable of connecting a plurality of the graphite bodies one by one. The graphite body includes one connecting end surface having a T-shaped mound and the other connecting end surface having an inverted T-shaped groove so that the graphite bodies may be connected by means of the mound and groove. The mound and groove each have a width linearly varied in the longitudinal direction thereof.

Abstract: The present invention resides in improved graphite nipples which are suitable for connecting graphite electrodes. The graphite nipples are prepared by adding mesophase pitch-based carbon fibers into a typical nipple extrusion blend.

Abstract: This invention includes apparatus and method for providing a support mechanism for electrode assemblies including positioning spacer of electrically nonconductive material having an inside surface forming an internal cavity and a heat pipe for passing a heat transfer fluid through the cavity along the inside surface. The heat pipe transfers heat away from the positioning spacer to form a protective layer of frozen bath around the positioning spacer.

Abstract: An electrode adding apparatus which adds a new electrode to an electrode held by the electrode holder of an electric furnace by screwing the lower end of the new electrode in the upper end of the electrode held by the electrode holder, when the electrode held by the electrode holder is consumed. In adding the new electrode to the consumed electrode, the new electrode is gripped by a clamping device rotatably held by a casing, then the casing is transported by a crane to bring the new electrode directly above the consumed electrode, and following which the casing is lowered to position the new electrode in alignment with the consumed electrode. Then, the clamping device is driven for rotation to screw the lower end of the new electrode in the upper end of the consumed electrode. In adding the new electrode to the consumed electrode, the rotative reaction force of the casing is received by the electrode holder so that the casing is restrained from rotation.

Abstract: An electrode joint for connecting two electrode sections together including a threaded nipple screwed into a threaded socket within the end of one electrode section is provided with a reservoir containing a cementitious bonding material comprising pitch particles and a foaming agent selected from the group consisting of sulfur, nitrated decant oil, 2,4-dinitroanoline and mixtures thereof.

Abstract: The present invention relates to a machine for replacing the electrodes of electric arc furnaces.Machine characterized in that the sheath (3) is provided, between its gripping chucks, with a centering chuck (7), in that the upper chuck (4) is provided with an expansible support (8) limiting its opening, and with pinions (9) for driving the gripping spiral of the retractable jaws (10), and in that the device (6) for driving in rotation the sheath (3), is constituted by a screw (11)-nut (12) assembly for the translatory movement of the sheath (3), by motors (13) for final screwing of the electrode, and by a device (14) for driving in rotation and braking the sheath (3), the assembly of the control elements being actuated pneumatically.

Abstract: Carbon losses are reduced in that an operative carbon anode is glued beneath a carbon core in an inert anode top. The operative anode carbon is almost completely consumed. The anode top is then cleaned and a new operative carbon is glued to its underside.