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 method is provided for output control of a pulse width modulated power inverter used with a substantially resistive, single phase, ac load such as an electro-slag remelting furnace. In one application of the method, during each of the inverter's half cycle outputs, active switching devices are alternatively pulsed on and off during the half cycle so that only half of the switching transients in the half cycle are handled by one of the active switching devices.

Abstract: In a method for determining a dividedness and/or position of a batch material (7) existing essentially in the solid phase in an arc furnace (1) having a furnace vessel (2), acoustic signals (Ne, Ng, Nd) are generated by an arc discharge (6) between an electrode (3a, 3b, 3c) and the batch material (7). The acoustic signals (Ne, Ng, Nd) reflected and/or transmitted through by the batch material (7) are measured by acoustic sensors (5a, 5b, 5c, 5e, 5g, 5h, 5s, 5t), wherein at least one acoustic sensor (5a, 5b, 5c, 5e, 5g, 5h, 5s, 5t) is provided per segment (Sn) of the furnace vessel (2) subdivided into a plurality of segments (Sn), and wherein the dividedness and/or position of the batch material (7) in the arc furnace (1) is determined by evaluating the measured acoustic signals (Ne, Ng, Nd).

Abstract: An apparatus and method for controlling an electroslag remelting furnace comprising adjusting electrode drive speed by an amount proportional to a difference between a metric of electrode immersion and a set point, monitoring impedance or voltage, and calculating the metric of electrode immersion depth based upon a predetermined characterization of electrode immersion depth as a function of impedance or voltage.

Abstract: A power source for an arc furnace having an intermediate circuit transformer including a magnetic decoupled booster transformer and an AC main-driven converter. Such a power source comprises a current controller and a zero voltage switch. The current controller and the zero voltage switch are integrated in the intermediate circuit transformer. The zero voltage switch short-circuits the main reactance of the booster transformer whenever the current controller faces a current cut off and is blocked.

Abstract: The present invention relates to a method for determination of the electrode tip position for consumable electrodes in electric smelting furnaces, which electrodes being submerged in the furnace charge. The voltage between two geometrically displaced points on the outside of the steel wall of the furnace pot is measured during operation of the furnace, points being situated as close as possible to the electrode for which the electrode tip position is to be determined, and as far away as possible from the other electrodes in the furnace. The electrode current for the electrode for which the electrode tip position is to be determined, is recorded at the same time as the voltage between the two points are measured, whereafter the difference between measured voltage between the two points and measured electrode current is calculated, and where the absolute value of difference increases when the electrode tip position increases and decreases when the absolute value of difference decreases.

Abstract: A method of controlling the course over time of a target temperature of a molten metal in a ladle, for example, in which the required heating power is produced by at least one plasma torch. Determination is made of the variation with time of a target temperature, the mass of an outwardly flowing melt, and a specific heat value of the melt present in the ladle. From the foregoing values there is ascertained the course of a corresponding setting signal for obtaining the heating power necessary to obtain the desired temperature course. Simultaneously and continuously the actual temperature of the melt is measured. When the actual temperature of the melt deviates from its target temperature in excess of a predetermined tolerance, the setting signal for the heating power is changed by decreasing such setting when an actual temperature exceeds the target temperature, and increasing such setting when an actual temperature is less than the target temperature.

Abstract: According to this process and this device:a signal representing the derivative of the intensity of the current in the arc is sensed,the sensed signal is amplified,the amplified signal is directed simultaneously into two band pass filters (6, 7) respectively having a high frequency broad band (6) and having a narrow band centered on a low fundamental frequency (7),the signals emanating from the filters (6, 7) are transmitted to effective value extractors (8, 9),by means of a divider module (11) an energy signal is formulated, which is proportional to the ratio of the effective value of the signal emanating from the broad band filter (6) and the effective value of the signal emanating from the narrow band filter (7),and the proportional energy signal obtained is displayed on a scale (12), where it is expressed as a percentage, this percentage being indicative of the behaviour of the arc, signifying the formulation phase.

Abstract: A clear optical path is provided in a furnace in which high intensity top surface heating is carried out. The path extends through a viewport to the interior of the furnace chamber. The path extends to a clear metal mirror surface and from the mirror surfaced to other portions of the furnace chamber which are not viewable directly through the viewport.

Abstract: A method of monitoring the degree of exposure of an electric arc within a furnace having a molten charge, e.g. an arc furnace or ladle furnace, in which characteristic frequency spectra of the waveforms from the supply associated with (a) arc-exposure and (b) arc-submersion are predetermined and in which signals (e.g. indicative of the arc current) emitted during operation are measured and processed and a comparison effected with a set level established from these characteristic signals whereby to provide an indication of the degree of arc exposure.The predetermined characteristic frequency spectra selected may be the harmonic content of the arc current.

Abstract: The height position of three-phase electrodes R, S, T immersed in a resistive medium is controlled first in dependence of the values for the equivalent star network load impedances Z.sub.RO, Z.sub.SO, Z.sub.TO of the electrodes, these impedances being calculated on the basis of measured values representative of valid delta network load impedances Z.sub.RS, Z.sub.ST and Z.sub.TR of the electrodes. The height positions of the electrodes are then equalized by selective adjustment of the electrical conductivity of the resistive medium at respective electrodes, preferably by using the so-called derivative method.

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: The method consists of maintaining constant the magnitude of the interelectrode gap. For this purpose a melting current is measured and averaged for a constant predetermined time interval, whereafter a derivative of an averaged value of the melting current is determined, an amplitude of oscillations of the melting current relative to the averaged values of the melting current is detected, and a derivative of the rectified amplitude of oscillations of this current is determined. Then the obtained data are compared, and from the results of this comparison the melting current is controlled in such manner that said values are reduced to zero.The apparatus for controlling the process of casting thin walled ingots using the electroslag melting method comprises a melting current pick-up having an output connected to the inputs of a comparison unit and of a determination unit for determining an averaged value of the melting current.