Abstract: Direct-current smelting furnace with control of deflection of the electric arc, which comprises an upper electrode (13) with relative return-flow lines and a plurality of bottom electrodes (11) positioned on the hearth of the furnace (12) and arranged in two or more assemblies, each assembly having its own controlled supply line connected to its own transformer (16), there being included downstream of each transformer (16) its own thyristor rectifier assembly (17) associated with its own means to control voltage (26), current (24) and firing angle (23), at least the lines supplying the bottom conductors (32) being at least partly screened in the vicinity of the melting furnace (12)

Abstract: A method and a device for improving the efficiency of slag-bath reactions, for example in connection with sulfur removal from steel melts, involves stirring the melt with at least one inductive stirrer in such a way that the stirring force includes both a horizontal and a vertical component.

Abstract: A hollow arc furnace electrode comprises a central channel formed in its upper part as a tube and in its lower part as a passage extending through a graphite tip of the electrode. A metallic electrode portion is arranged around the central tube above the tip, which electrode portion is provided with channels for liquid coolant flow.

Abstract: A control system for a DC arc furnace having a hearth adapted to contain a scrap or metal charge, an arcing electrode, a thyristor converter having a connection with the electrode and charge to form a circuit, current comparing comparator for comparing current in the circuit with a set-point current of fixed value and controlling the thyristor in response to the comparison so as to cause the current in the circuit to substantially equal the set-point current value, electrode positioning apparatus for moving the electrode up and down relative to a charge in the hearth, and a voltage comparison comparator for comparing the voltage in the circuit with a set-point voltage of fixed value and controlling the electrode positioning apparatus in response to the voltage comparison so as to keep the voltage in the circuit substantially equal to the set-point voltage.

Abstract: A DC arc furnace having a vertical arcing electrode adapted to be connected with a negative current lead and a hearth adapted to contain a melt below the electrode and having a hearth electrode, the hearth electrode extending laterally from the axis of the arcing electrode symmetrically with respect to the axis and having a plurality of electrical connections extending to the outside of the hearth and spaced laterally from the arcing electrode's axis symmetrically with respect to the axis, the connections being adapted for connection with a positive current lead and application of DC to the electrodes powering an arc between the arcing electrode and melt; wherein the improvement comprises a positive current lead below the bottom of the hearth and having an upper end positioned on the arcing electrode's axis below the hearth's bottom and extending from the positive current lead's upper end vertically downwardly on the axis to a low position where the magnetic field of the positive current lead cannot appreciab

Abstract: The invention relates to a method for temperature control in a channel of an inductor unit of a channel-type induction furnace for iron or steel. The method is characterized in that the current intensity or the power is measured, and the measuring signal (I, P) is compared with a desired value (I.sub.b, P.sub.b) in a control means for controlling the power of the inductor, the power to the inductor being switched off or reduced at a value I>I.sub.b or P>P.sub.b, where I.sub.b or P.sub.b corresponds to a temperature at or near the Curie point of the iron/steel.In those cases where the inductor is supplied from a thyristor unit, the control can also be carried out so that a constant impedance, corresponding to the conditions at the Curie point, is maintained in the inductor circuit.

Abstract: Apparatus for positioning an arc furnace electrode which includes a verticle tubular electrode mast which is both horizontally and vertically movable. Inside the mast is a hydraulic cylinder which has a double-acting piston. When the mast is in its uppermost position it may be locked whereby hydraulic fluid is removed from above the piston. Fluid is then introduced below the piston to raise it and the piston rod to a level above the furnace platform such that the mast can be moved horizontally over the platform.

Abstract: Apparatus for batching a metal melt such as steel from a pressure tapping furnace in which a level measuring device is provided for measuring the melt level in the tapping spout and using that level to calculate a signal for terminating the batching which is dependent on the integral of melt flow, and the rate of change of melt flow so as to take in to account the double draining which occurs after the termination of batching is initiated.