Sandia Corporation

Brian K Damkroger

David K Melgaard

Frank J Zanner

Eugene A Aronson

Gregory J Shelmidine

Michael C Maguire

Mark E Miszkiel

A method of and apparatus for controlling an electroslag remelting furnace by driving the electrode at a nominal speed based upon melting rate and geometry while making minor proportional adjustments based on a measured metric of the electrode immersion depth. Electrode drive speed is increased if a measured metric of electrode immersion depth differs from a set point by a predetermined amount, indicating that the tip is too close to the surface of a slag pool. Impedance spikes are monitored to adjust the set point for the metric of electrode immersion depth based upon one or more properties of the impedance spikes.

Control of electrode depth in electroslag remelting

An apparatus and method for controlling an electroslag remelting furnace, imposing a periodic fluctuation on electrode drive speed and thereby generating a predictable voltage swing signal. The fluctuation is preferably done by imposition of a sine, square, or sawtooth wave on the drive dc offset signal.

Directly induced swing for closed loop control of electroslag remelting

Method and apparatus for controlling electrode immersion depth in an electroslag remelting furnace. The phase difference of the alternating current circuit established in the furnace is calculated in real time and employed to more accurately control immersion depth than possible with voltage-swing systems.

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Albuquerque, NM, United States of America

Brian K Damkroger