US 4,395,771 A · Method and apparatus for controlling process of casting thin walled ingots using electroslag melting process

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. The output of the determination unit is connected via a detecting unit for detecting an amplitude of oscillations of the melting current and via a first derivative unit for determining a derivative of this detected amplitude to a third input of a logic unit. The output of the detecting unit is connected to a second input of the unit whose first input is connected via a second derivative unit 13 for determining a derivative of the averaged value of the melting current to the output of the determination unit. The output of the logic unit is connected via the comparison unit to the input of the control unit.

Claims3

Dependent claims

A method of controlling a process of casting thin walled ingots using the electroslag melting method by maintaining a magnitude of an interelectrode gap constant, comprising the steps of, during the process of maintaining the magnitude of the interelectrode gap constant, measuring and averaging the melting current for a constant predetermined time interval;

determining a derivative of the averaged value of the melting current;
detecting an amplitude of oscillation of the melting current relative to the averaged values of the current;
determining a derivative of the detected amplitude of oscillations of the melting current;
comparing obtained values of the derivative of the averaged melting current, of the detected amplitude of oscillations of the melting current, and of the derivative of the detected amplitude of oscillations of the melting current;
and, regulating the melting current from the results of said comparison so that said values are reduced to zero.

2 more elements

An apparatus for controlling a process of casting thin walled ingots using the electroslag melting method, comprising:

a drive displacing a consumable electrode and maintaining the magnitude of the interelectrode gap constant;
a control unit connected to said drive, forming a control action signal, and having an input;
a melting current pick-up having outputs;
a comparison unit having a first input connected to one of said outputs of said pick-up, a second input, and an output connected to said input of said control unit;
a determination unit determining an averaged value of the melting current for a predetermined time interval, and having an input connected to one of said outputs of said pick-up and an output;
a detecting unit detecting an amplitude of oscillations of the melting current relative to averaged values of the melting current, and having an input connected to said output of said determination unit and an output;
a first derivative unit determining a derivative of the detected amplitude of oscillations of the melting current, and having an input connected to said output of said detecting unit and an output;
a second derivative unit determining a derivative of the averaged value of the melting current, and having an input connected to said output of said determination unit and an output;
and, a logic unit having inputs respectively connected to said outputs of said detecting unit, said first derivative unit and said second derivative unit, and an output connected to said second input of said comparison unit.

6 more elements

Dependencies are inferred from the claim text.

Method and apparatus for controlling process of casting thin walled ingots using electroslag melting process

Life of this patent

Method and apparatus for controlling process of casting thin walled ingots using electroslag melting process

Life of this patent

Abstract

Claims3