Abstract: The present application describes and claims an integrated remelting manager for the VAR and ESR remelting processes comprising the following three integrated components: a pre-process manager, a real-time process manager and a post-process manager. The present application also describes and claims a method of using the integrated remelting manager.

Abstract: An apparatus for and method of controlling a remelting furnace comprising adjusting current supplied to an electrode based upon a predetermined pool power reference value and adjusting the electrode drive speed based upon the predetermined pool power reference value.

Abstract: A vacuum arc remelt furnace system that automatically monitors for electrode to crucible arcing in a VAR furnace. The vacuum arc remelt furnace system includes a crucible, an electrode provided within the crucible, and a spectrometer operatively coupled to the gap between the electrode and the crucible. The spectrometer detects the presence of one or more copper-specific light wavelengths in light that is present in the gap, and preferably generates an alarm and/or shuts the furnace down depending upon what is detected. Also, a method of operating a vacuum arc remelt furnace to automatically monitor for electrode top crucible arcing. The method includes collecting light that is present in the gap between the crucible and said electrode, and determining whether one or more copper-specific light wavelengths are present in the light. An alarm is generated and/or the furnace is shut down depending upon what is detected.

Abstract: The present invention relates to a method for weighing an electrode submerged in the charge of an electric smelting furnace. The electrode is moved in vertical direction at least once, whereafter the electrode is lifted and the weight of the electrode is registered shortly after the electrode has been lifted.

Abstract: A consumable electrode is suspended by a stub. The stub includes upper and lower hangers between which is vertically mounted a loadcell for weighing the electrode attached to the lower hanger. An electrical conductor is joined between the upper and lower hangers for carrying electrical current therebetween to power the electrode without damaging the loadcell.

Abstract: An arrangement and method for determining the height position of a vertically movable electrode (2) in an arc furnace (1). The arrangement includes an elongated, flexible element (9), preferably a heavy chain, whose one end is attached to a first attachment point on the movable electrode (2). The other end of the chain is attached to a fixed second attachment point. The total weight of those flexible element parts that are carried by the movable and the fixed attachment points respectively will vary in response to vertical movement of the electrode. The arrangement also includes load cell for sensing the part of the total weight supported by the fixed attachment point, for determining the height position of the electrode (2).

Abstract: An apparatus and method of controlling a remelting process by providing measured process variable values to a process controller; estimating process variable values using a process model of a remelting process; and outputting estimated process variable values from the process controller. Feedback and feedforward control devices receive the estimated process variable values and adjust inputs to the remelting process. Electrode weight, electrode mass, electrode gap, process current, process voltage, electrode position, electrode temperature, electrode thermal boundary layer thickness, electrode velocity, electrode acceleration, slag temperature, melting efficiency, cooling water temperature, cooling water flow rate, crucible temperature profile, slag skin temperature, and/or drip short events are employed, as are parameters representing physical constraints of electroslag remelting or vacuum arc remelting, as applicable.

Abstract: A method and apparatus for controlling vacuum arc remelting (VAR) furnaces by estimation of electrode gap based on a plurality of secondary estimates derived from furnace outputs. The estimation is preferably performed by Kalman filter. Adaptive gain techniques may be employed, as well as detection of process anomalies such as glows.

Abstract: The electrode gap of a VAR is monitored by determining the skewness of a distribution of gap voltage measurements. A decrease in skewness indicates an increase in gap and may be used to control the gap.

Abstract: An apparatus and method for controlling electrode gap in a vacuum arc remelting furnace, particularly at low melting currents. Spectrographic analysis is performed of the metal vapor plasma, from which estimates of electrode gap are derived.

Abstract: A system for controlling electrode gap in an electro-slag remelt furnace has a constant regulated voltage and an eletrode which is fed into the slag pool at a constant rate. The impedance of the circuit through the slag pool is directly proportional to the gap distance. Because of the constant voltage, the system current changes are inversely proportional to changes in gap. This negative feedback causes the gap to remain stable.

Abstract: A remelting furnace has a crucible (2) and a raisable pot (3) placed thereon. An electrode rod (6) leads into the pot (3) through a stuffing box (8) borne by a lower platform (9). The lower platform (9) is carried by rods (12, 13) which are fastened each at its upper end to a weighing platform (14). The connection of the lower platform (9) to the particular rod (12, 13) is performed in each case through a releasable clutch (10,11 ). Consequently, a lifter (17) can lift the pot (3) such that it shifts upwardly with the bottom platform (9) relative to the rods (12, 13).

Abstract: The invention provides a direct current electric arc furnace which is composed of a feeding system of direct current to the furnace, a movable electrode at the roof of the furnace, and a bottom electrode attached to the bottom of the furnace at the position deviated from the center of the bottom of the furnace, the deviated distance from the center being determined by a magnetic field, generated by a current in the steel bath of the furnace, from under an arc generated by the movable electrode to the bottom electrode, which can cancel a second magnetic field generated by the current of the feeding system.

Abstract: The invention provides a direct current electric arc furnace which is composed of a feeding system of direct current to the furnace, a movable electrode at the roof of the furnace, and a bottom electrode attached to the bottom of the furnace at the position deviated from the center of the bottom of the furnace, the deviated distance from the center being determined by a magnetic field, generated by a current in the steel bath of the furnace, from under an arc generated by the movable electrode to the bottom electrode, which can cancel a second magnetic field generated by the current of the feeding system.

Abstract: A process for casting an ingot of pre-alloyed metal from a consumable electrode. It includes the steps of: providing a consumable electrode corresponding to the desired metallurgical composition of the to-be-cast ingot; providing a second electrode; striking an arc between the consumable electrode and the second electrode to melt the consumable electrode and thereby form a molten pool; maintaining the arc between the consumable electrode and the molten pool; rotating or oscillating the consumable electrode about its axis during melting; providing a controlled atmosphere for the melting of the consumable electrode; delivering molten metal into a fluid cooled mold; and withdrawing the ingot from the mold.

Abstract: An apparatus and method for inductively melting a quantity of metal, without having to contain the metal in a crucible, is described. The solid metal to be melted is placed within a first induction coil excited by an alternating current and adapted to provide a greater electromagnetic force towards the lower portion of the quantity of metal. The solid metal rests on a support, having an opening therethrough, which also comprises means for keeping the support at a low temperature relative to the metal as it melts. When energy in the form of the alternating current is provided to the coil, the metal melts from the top downward, but the concentration of electro-magnetic force towards the bottom of the metal causes the liquid metal to retain a cylindrical shape. A non-varying electromagentic field is applied to the quantity of metal to minimize violent stirring of the molten portion of the quantity of metal caused by the time-varying field.

Abstract: Apparatus for the detection and evaluation of process parameters arising during the remelting of an electrode (31) to a metallic block (32) in a vacuum arc furnace detects deviations of at least one process parameter from a predetermined course and uses them to locate faults in the electrode and/or in the metal block (32).

Abstract: In a melting furnace with weight-related control of the consumable electrode, the electrode mounting is disposed in a separate pressure chamber which has an inverted bottle-shaped configuration. The downwardly extending neck-like portion is passed sealingly through an opening in the cover plate of the melting chamber. The pressure chamber is suspended from a crossbeam which can be driven vertically by means of spindles. On the upper end of the pressure chamber there is provided a bellows whose upper edge is joined to the upper, tubular portion of the electrode holding rod, while a solid rod holding a current-carrying tube extends coaxially through the tubular portion and is hung from a frame which suspends the electrode holding rod and which is supported on the crossbeam by a sensor.

Abstract: A compensation device for the influence of the weight of a power feed line on a weight measurement device determining the weight of an electrode and/or the melting rate in an electro-slag remelting process, in a vacuum arc furnace or the like. When an x-y device is adjusted, a weight jump occurs due to the forces of the power cable or the forces of the bellows, which has a disturbing effect on the rate definition. This weight jump can be prevented by means of mechanical devices, or can be made so small that it no longer constitutes a disturbance. However, the expenditure for this is disproportionately high. The invention is more cost efficient, since hardware or software means suffice. The weight function G=f(t) is extrapolated and compared with the actually measured weight G'=f(t). The magnitude of the difference between the two is stored and later added as a correction value.

Abstract: During vacuum consumable arc remelting the electrode gap between a consumable electrode and a pool of molten metal is difficult to control. The present invention monitors drop shorts by detecting a decrease in the voltage between the consumable electrode and molten pool. The drop shorts and their associated voltage reductions occur as repetitive pulses which are closely correlated to the electrode gap. Thus, the method and apparatus of the present invention controls electrode gap based upon drop shorts detected from the monitored anode-cathode voltage. The number of drop shorts are accumulated, and each time the number of drop shorts reach a predetermined number, the average period between drop shorts is calculated from this predetermined number and the time in which this number is accumulated. This average drop short period is used in a drop short period electrode gap model which determines the actual electrode gap from the drop short.

Abstract: An improved consumable electrode remelting furnace and a method of monitoring decreases in the weight of a consumable electrode during remelting are provided. An electrode support structure is movably supported above a mold for moving the electrode into and out of substantially coaxial relationship with the mold. The base of a load cell is supported above the mold by the electrode support structure so that the load cell is electrically remote from the electric melting current conducting paths in the furnace. Apparatus are provided for: (1) suspending the weight of the electrode and substantially only that weight from the top of the load cell; and (2) vertically displacing the mold and the electrode relative to each other toward and away from a position of the electrode in the mold where the electrode can be remelted.

Abstract: A method and apparatus for vacuum arc furnaces monitors the arc by spectrum analysis of the arc's light obtained with a radiation receiver. Upon the occurrence of spectrum lines indicating vaporization of the crucible material, the melting process is stopped or adjusted to extinguish the arc burning on the crucible which vaporized the crucible material for the spectrum analysis.