JPH11183044A - Method to control power charged to electrode in electric furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the treating time of a whole and to prevent the occurrence of partial loss to a furnace wall by a method wherein through measurement of the furnace wall of each electrode part, respective powers charged to respective electrodes are previously individually set to average the furnace temperatures. SOLUTION: A three-phase AC arc furnace 11 is provided with a furnace body 12 and a furnace cover 13 with which the furnace body 12 is covered. The furnace body 12 and the furnace cover 13 is built from furnace shells 12a and 13a and fire resisting materials 12b and 13b, with which the furnace shells are lined. Three electrodes 21-23 are inserted through the furnace cover 13 in a furnace. Charged powers to the electrodes 21-23 are previously individually set at a control device 61 such that the furnace wall temperatures of electrode parts 21-23 or the treating state of a metallic material in a furnace is averaged. This constitution prevents the occurrence of a cold spot in the arc furnace 11, whereby the treating time of a whole is shortened and a partial wear of a furnace wall is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for controlling power supplied to electrodes in an electric furnace. Various electric furnaces are used for melting and refining metal materials. For example, an AC arc furnace or LF having two or more electrodes at the top of the furnace or a DC arc furnace having two or more electrodes at the bottom of the furnace is used for melting metal scrap. . The present invention relates to a method for individually controlling electric power supplied to each electrode at the start of operation in an electric furnace having a plurality of electrodes at an upper portion or a lower portion of the furnace.

[0002]

2. Description of the Related Art Conventionally, as a method for controlling power supplied to electrodes in an electric furnace, based on empirical rules in relation to operating conditions,
The input power is controlled over time or according to the cumulative input power from the start of the process. For example, when melting a metal scrap in a three-phase AC arc furnace or LF provided with three electrodes at the top of the furnace, the metal scrap is transferred to the three electrodes based on empirical rules in relation to the structure of the furnace and the properties of the metal scrap. Are controlled collectively over time or in accordance with the cumulative input power amount from the start of processing.
However, in the conventional method, so-called cold spots and hot spots are generated in the furnace during actual operation in which various conditions are intricately intertwined. There is a problem that the spot causes a particular increase in wear of a specific part of the furnace wall.

[0003]

The problem to be solved by the present invention is that, in the conventional method, the whole process actually takes a long time, and the wear of a specific part of the furnace wall increases.

[0004]

SUMMARY OF THE INVENTION The present invention, which solves the above-mentioned problems, is a method for controlling power supplied to electrodes in an electric furnace having a plurality of electrodes at the top or bottom of the furnace. The present invention relates to a method for controlling power input to electrodes in an electric furnace, wherein power input to each electrode is individually set in advance so that a temperature is measured and a furnace wall temperature around each electrode is averaged. . Further, the present invention is a method for controlling power supplied to an electrode in an electric furnace having a plurality of electrodes at an upper portion or a lower portion of the furnace. The present invention relates to a method for controlling power supplied to electrodes in an electric furnace, wherein power supplied to electrodes is individually set.

The present invention is directed to an electric furnace having a plurality of electrodes at the top or bottom of the furnace. Such an electric furnace includes a furnace body and a furnace cover attached to the furnace body, and an AC or DC arc having two or more electrodes inserted into the furnace through the furnace cover. Furnace, LF, DC arc furnace in which one or more electrodes are similarly inserted through the furnace lid and inserted into the furnace, and two or more electrodes are arranged at the bottom of the furnace body. There is an electric smelting furnace.

According to the present invention, in an electric furnace having a plurality of electrodes on the upper or lower part of the furnace as described above, the temperature of the furnace wall around each electrode, the processing state of the metal material in the furnace, or the wear state of the furnace wall is measured. Alternatively, in order to prevent the occurrence of cold spots and hot spots in the furnace by observing, the temperature of the furnace wall around each electrode, the processing status of metal materials in the furnace, or the wear status of the furnace wall should be averaged. The power to be applied to each electrode is set individually. In the conventional method in which the amount of power supplied to a plurality of electrodes is controlled collectively, impedance varies depending on, for example, the length of a power supply path to each electrode, and as a result, a difference occurs in the power supplied to each electrode. This is one of the causes of the generation of so-called cold spots and hot spots in the furnace, which makes it impossible to uniformly melt metal scrap. Since such inconvenience occurs as a characteristic of the furnace itself, the positions of the cold spots and hot spots are more specific to the furnace. In order to eliminate such inconvenience, in the present invention, the power supplied to each electrode in advance at the start of operation so that the furnace wall temperature around each electrode, the processing state of the metal material in the furnace, or the wear state of the furnace wall is averaged. Is set individually to prevent the occurrence of cold spots and hot spots. For example, when the power supply path to each electrode has a length, the power supplied to the electrode having a longer power supply path is higher than the power supplied to the electrode having a shorter electrode.

According to the present invention, the so-called cold spot or hot spot can be prevented from being generated in the furnace by individually controlling the electric power supplied to the plurality of electrodes at the start of the operation. The time can be reduced, and partial wear of the furnace wall can be prevented.

[0008]

FIG. 1 is an overall view schematically showing an embodiment of a supplied power control method according to the present invention. FIG. 1 shows a case of a three-phase AC arc furnace. Three-phase AC arc furnace 1
1 includes a furnace main body 12 and a furnace lid 13 attached to the furnace main body 12, and the furnace main body 12 and the furnace lid 13 are provided with furnace shells 12a and 1a.
3a and refractory materials 12b, 13b lined with the three electrodes 2a and 3b.
1 to 23 are inserted. Each of the electrodes 21 to 23 is connected to an electrode device 51 for individually controlling the ascent and descent of the electrodes and individually supplying power thereto.
Is connected to a control device 61 for instructing the lifting and lowering of each of the electrodes 21 to 23 and the power supplied thereto.

FIG. 1 shows a state immediately before metal scrap A is loaded into the furnace body 12 and an AC voltage is applied between the electrodes 21 to 23 to start melting the metal scrap A. In the present invention, at this time, each of the electrodes 21 to 2
In order to prevent so-called cold spots and hot spots from occurring in the furnace with the same relative position of 3, the furnace wall temperature around each electrode, the processing status of metal materials in the furnace or the wear status of the furnace wall are averaged. In advance, the input power to each of the electrodes 21 to 23 is individually set in the control device 61 in advance. For example, assuming that the input power to the electrode 21 is 100, the input power to the electrode 23 having a longer power supply path than the electrode 21 is 95%.
In addition, the input power to the electrode 22 having a shorter power supply path than the electrode 21 is set to 105.

[0010] In FIG. 1, three electrodes are provided at the upper part of the furnace.
Although the phase-change arc furnace was described, the object of the present invention is 3
The present invention is not limited to an alternating current arc furnace,
The present invention can be similarly applied to a DC arc furnace having one or two or more electrodes at the top of the furnace and two or more electrodes at the bottom (bottom) of the furnace, and can be applied to LF.

[0011]

As is clear from the above, the present invention described above has the effects that the entire processing time can be shortened in the processing by the electric furnace, and the partial wear of the furnace wall can be reduced.

[Brief description of the drawings]

FIG. 1 is an overall view schematically showing an embodiment of a supplied power control method according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 ... Arc furnace, 12 ... Furnace main body, 13 ... Furnace lid, 21-23 ... Electrode, 51 ... Electrode apparatus, 61
···Control device

Claims (2)

[Claims] 1. A method for controlling power supplied to electrodes in an electric furnace having a plurality of electrodes at an upper part or a lower part of a furnace, wherein a furnace wall temperature around each electrode is measured, and a furnace wall temperature around each electrode is averaged. A method for controlling the power input to the electrodes in an electric furnace, wherein the power input to each electrode is individually set in advance so as to achieve the desired power. 2. A method for controlling power supplied to an electrode in an electric furnace having a plurality of electrodes in an upper part or a lower part of a furnace. A method for controlling power supplied to an electrode in an electric furnace, wherein the power supplied to the electrode is individually set.