ES2268574T3 - PROCEDURE TO CONTROL THE WEAR OF AN ELECTRODE. - Google Patents

Abstract

A method for monitoring wear of an electrode in an electric arc furnace comprising the steps of: taking a digital picture of the still incandescent tip of the electrode; applying a numerical edge detection filter to the digital picture so as to obtain a filtered image wherein abrupt changes in light intensity are represented as contour lines; and analysing the contour lines to determine the shape of the electrode tip and the presence of cracks. <IMAGE>

Description

Procedure to control the wear of a electrode.

The present invention relates to a procedure to control online and automatically wear of electrodes, in particular graphite electrodes in an oven of electric arc (EAF "electric arc furnace").

Background of the invention

The consumption of electrodes is an important factor to take into account in the optimization of the electrode quality and therefore in the optimization of the process costs of Steel manufacturing in an EAF. Know the wear of the electrodes allows to improve the quality of the electrode and reduce the electrode breakage In fact, in addition to being expensive, breaks of electrode slow down production. The recovery of a tip of Broken electrode of molten steel bath can interrupt the production for up to 5 minutes if deposited in the part higher. But a broken electrode could easily cause Delays of up to 45 minutes if you stay inside the bathroom. The electrodes are less likely to break later in the cycle of fusion, but usually it takes longer to remove them from the oven in a subsequent heat processing phase.

WO-A-00/74442 describes a procedure for the determination of electrode length and bath level in an electric arc furnace. According to this procedure, the electrode length is determined by moving the electrode down, at the end of each heating, towards the upper level of the steel bath and stopping the movement of the electrode when a specified stop criterion is reached. Therefore, the distance between the tip of the electrode and the level of the laundry is approximately constant for each measurement. In this state a first measurement of the position (height) of the electrode is carried out. The electrode is then lifted out of the oven vessel until its tip reaches the level of an optimal beam path located at a predetermined height with respect to the bottom of the laundry or the container. In this position a second measurement is carried out. Based on the two measurements, the actual length of the electrode can be determined, and therefore the consumption of the length per molten waste content of a basket. However, this method does not allow measurement of the electrode configuration, in particular the tip thereof, or the lateral wear of the electrode, produced, for example, by the oxidation of the graphite material of the electrode during the manufacturing process of
steel.

A report entitled "Überwachung der Elektrodenqualität und Verminderung des Elektrodenverbrauches von Lichtbogenöfen" by Gronau et al , published in "Technische Forschung Stahl" by the European Commission in 1988 (EUR12019DE) discloses a procedure to control the quality of electrodes and the reduction of electrode consumption for an EAF at the time of removal of the electrode from the oven after casting. However, the equipment used allows only measurement campaigns limited in time. In fact, it does not allow electrode control in a continuous and automatic way.

In addition, for comprehensive wear control of the electrode, important information such as the shape is required of the cone of the tip and lateral wear, the formation of cracks and the spread of cracks, bonding problems, cracking of the tip and "detachments", and the loss of material from Graphite due to particles and loose drops.

WO 02/28084 describes a technique digital electrode observation system previous.

Consequently, there is a need for provide a procedure and apparatus capable of supplying such information in order to evaluate the wear of the electrode of A continuous and automatic way.

Object of the invention

Therefore, an objective of the present invention is to provide an improved procedure to measure the wear of electrodes in an electric arc furnace system.

This objective is achieved by providing a procedure to control the wear of an electrode in a electric arc furnace comprising the following stages:

take a digital photograph of the tip of the electrode still incandescent;

apply a detection filter algorithm of the numerical edges to digital photography to get a picture filtered in which sudden changes in light intensity are identify as contour lines; Y

analyze the contour lines to determine the configuration of the electrode tip and the presence of cracks

Preferably, after the fusion of each basket of waste, the procedure involves indicating to a digital camera the passage of the electrode in front of the camera so that the camera I can take a picture of the electrode. The picture is sent to a personal computer, which is preferably equipped with a suitable software for automatic extraction of all the relevant information. The information is extracted through a specialized software All information can be stored, by example raw photographs and extracted features, to constitute a photo archive and to use it for subsequent analyzes.

Preferably, the specialized software Performs a photographic analysis of the photograph in pixels. He Photographic analysis allows electrode tracking. In particular, allows to study and know the influence of dimensional tolerances, the geometry of the joints, the moment of applied torque, mechanical and electrical properties as well as the condition of electrode use. Therefore this information allows to optimize the quality of the electrode and get that the use of an EAF be cheaper.

Brief description of the drawings

The above and other objectives, characteristics and advantages of the invention as well as the forms of presently preferred embodiment thereof, more will be put clearly manifest from a reading of the following description, in relation to the attached drawings in which:

Figure 1 is a schematic view of the apparatus according to the present invention;

Figure 2 is a schematic view of a placement of the chamber of the apparatus according to the present invention For use in a double electric arc furnace coating;

Figure 3 shows the rotation stage and deletion of annotations in the analysis procedure photographic according to the present invention;

Figure 4 shows the stage of artificial color of the image, for an electrode tip without deviation of the electric arc, in an analysis procedure photographic according to the present invention;

Figure 5 shows the stage of artificial coloring of the image for an electrode tip with deviation of the electric arc, in an analysis procedure photographic according to the present invention;

Figure 6 shows the detection stage of the electrode edges in an analysis procedure photographic according to the present invention;

Figure 7 shows the detection stage of the threshold in a photographic analysis procedure according to the present invention;

Figure 8 shows the filter matrix nonlinear for the stage of elimination of points or "grains" of light in a photographic analysis procedure according to the present invention;

Figure 9 shows the stage of removal of points or "grains" of light after applying the filter of Figure 8 in a photographic analysis procedure according to the present invention;

Figure 10 shows the detection stage of the electrode tip area in a procedure of photographic analysis according to the present invention;

Figure 11 shows the result of the detection stage of the electrode tip area of the Figure 10, when viewed according to the present invention;

Figure 12 shows an example of pixels of image used for the detection stage of the tip of the electrode and numerical approximation to the form in a procedure of photographic analysis according to the present invention;

Figure 13 shows the result of the electrode tip detection stage of figure 12, when displayed according to the present invention;

Figure 14 shows the result of the linear approximation of the flanks of the electrode cone, when it is displayed according to the present invention;

Figure 15 shows the definition of the oxidized zone of the electrode, when determined according to the present invention; Y

Figure 16 is a flow chart of blocks showing an embodiment of an analysis procedure photographic according to the present invention.

Detailed description of the invention

First of all with reference to figure 2, the Present installation of electric arc furnace comprises two electric arc furnace (EAF) containers 13, 14 and an electrode 12 graphite shared between the two EAFs 13, 14.

       \ newpage
    

After the merger of a waste basket, the electrode 12 passes from one EAF 13 to the other EAF 14. A digital camera 1 to take a picture of electrode 12 while passing from one EAF to the other. Figure 2 shows the step of an electrode 12 from a first EAF 13 to a second EAF 14. How to knows well in the art, the passage of electrode 12 from the first EAF 13 to the second EAF 14, or vice versa, is controlled by a programmable process controller 11 (PLC) (shown in the figure one). PLC 11 is connected to digital camera 1 to be able to shoot chamber 1 when electrode 12 is in a particular position between the two EAFs 13, 14. Since the PLC 11 controls the position of electrode 12 and knows the location of the camera 1, the PLC 11 can control the camera to take a photograph exactly at the moment when electrode 12 passes ahead of the camera.

Preferably the camera 1 is connected to a stable beam or wall (not shown) of foundry construction of steel in which one or more electric arc furnaces are arranged (EAF). Camera 1 can be realized as a digital camera of type CCD or CMOS sensor provided with or without a signal processor digital (not shown).

As Figure 1 shows, camera 1 is connected, for control and remote data transmission purposes, to an electronic data transmission box 3 through a connection 2. Connection 2 can be made of an optical fiber or any other electrical means. In case of using a fiber optical, to connect long distances and avoid interference electromagnetic data transmission, a Electric to optical converter A near chamber 1 and installed a second similar converter B inside the box 3 of transmission. The electric to optical converter B is connected to or equipped with an electric transmission box 3 that also contains or It is connected to electrical communication modules such as 8 and 10 current loop modules that provide a direct electrical communication to both PLC 11 and computer 7 personnel (PC) through connections 6, 15.

The personal computer 7 (PC) is used for both The electrode image treatment as for storage  of images and display by the oven operator.

The current loop modules 8 and 10 of the electric transmission box 3 are connected through a connection 9, preferably a cable connection, for provide direct communication between PC 7 and PLC eleven.

Preferably all modules and Previous converters can transmit signals according to the standard RS232 interface, although the implementation of others is expected communication standards, such as signal transmission analog, Ethernet, TCP / IP, or FireWire IEEE-1394 falls within the scope of the present invention.

The picture taken by camera 1 is transfers with a suitable software to PC 7 for the extraction of the relevant information The software is a specialized program, which will be explained in detail later in this memory.

The photographs are stored on PC 7 and They constitute a digital photo archive. The comparison between the current photograph with one or more previous electrodes specific helps to establish electrode consumption.

In a particularly advantageous manner, according to one aspect of the invention, the information extracted from the photograph  includes electrode wear control information, such as electrode tip length, total wear, loss of tip, the shape of the tip cone and lateral wear, the crack formation and crack propagation, oxidation of the sides, joint problems, total cracks, "detachment" of the electrode tip, loss of graphite material due to particles and drops, and profiles of non-homogeneous temperature related to the deviations of the Electric arc.

An extraction procedure will be announced of preferred photographs with reference to the following description. It is indicated that the extraction procedure can be performed both in real time, that is "online" or at a later stage, specifically "offline."

In the present non-limiting example, each Photography may be characterized by the following data:

format coding: JPG,

colors: monochrome with 256 shades of gray,

coding: of 8 bits per pixel,

resolution of a photo or frame: 632 x 480 pixels,

factor of conversion: 5.0456 mm / pixel,

surface Physics of the photograph: 3.18 x 2.68 meters,

size of JPG file: from 11 to 18 kB, with a compression factor of twenty%.

Digital filtration is defined as the product of convolution between two matrices, the first being defined matrix for photography as and presenting a dimension (number of pixels) same as the one of the analyzed photograph, and containing the second matrix the weighting coefficients of the filter used. A Preferred numerical filtration algorithm can use the following formula:

       \ vskip1.000000 \ baselineskip
    

one

       \ vskip1.000000 \ baselineskip
    

where M is a constant (usually the sum of the assigned weights of the filter matrix), R is the filtered photograph, S is the photograph before filtration, K represents the weights of the filter, and \ Beta is a compensation constant.

An original photograph, as described previously, it contains 632 x 480 pixels, each being encoded 8-bit pixel, which allows 256 (2 8) gray tones, in the that the value of 0 corresponds to black, or not exposure, and the value of 255 corresponds to white, or maximum exposure.

It should be noted that the photographs supplied by a CCD (digital) camera, with processor Integrated digital signals, usually contain two types of information, specifically the photographs captured by the CCD camera used during photographic analysis and annotations added by the digital signal processor of the chamber after electrode tip detection.

1. Rotation and deletion of annotations

Annotations are deleted before analysis photographic. In the flowchart of Figure 16, the stage of Annotation rotation and deletion is indicated by the number of reference 101.

In the rotation stage, photograph 90 is rotated degrees in the counterclockwise direction without distortion of its physical dimensions. This stage is indicated in the figure 3.

Subsequently, as indicated on the side of on the right of figure 3, the annotations of the rotated photographs Therefore, the present procedure provides a stage to convert the annotation areas into a Dark gray tone uniform. For example, the scale value grays of converted annotation areas may be between the values of 0 to 10. The stage of converting (provide a "fit") in the annotation zone allows advantageously optimizing a later stage of detection of the edges, which will be described later in the present specification.

The annotation areas converted to gray already will not be considered during photo processing later.

2. Artificial coloration

In addition, according to the method of the present invention, an artificially colored electrode photograph is obtained (indicated as step 108 in the flow chart of Figure 16). In this last stage, the intensity of the electrode light, as shown by the camera photograph, is associated with an electrode surface temperature. The artificial coloring stage allows a better visualization of the temperature gradient present on the electrode surface when the camera captures the photograph. In addition, this stage of mapping the intensity of the light emitted by the electrode surface allows advantageously to quickly estimate an asymmetry in the temperature resulting from a deviation of the arc during the process of melting the charge (indicated as step 109 in the flow chart of figure 16). According to a presently preferred embodiment of the present invention, the 256 shades of gray become 8 colors in the artificial coloring stage, according to table 1. However, the person skilled in the art will quickly understand that the number of shades of gray and the number of artificial colors is not limited to the above figures, and that such figures can be conveniently selected according to factors known to the person skilled in the art such as speed of treatment, accuracy of temperature gradient required,
etc.

TABLE 1

Gray tone level Color 0-31 Black 32-63 Brown 64-95 Green 96-127 Green olive 128-159 blue Marine 160-191 Purple 192-223 blue turquoise 224-255 Gray

Figure 4 shows the coloring stage artificial, without arc deviation while figure 5 shows the artificial coloring stage, with arc deviation. In the present request, since the figures are shown exclusively in shades of gray, the color cannot be seen.

As is evident from Figure 4, when not there is arc deviation, the hottest area of the electrode is placed in the center of the electrode.

In Figure 5 it can be clearly seen that the electrode is brighter (hotter) on its left side, more specifically on side 13 of the EAF. The deviation of the zone warmest shown calculated at approximately 20% of left edge of the figure. The vertical line provided in the electrode photography surface makes viewing easier of the arc deviation. Note that in figure 4 the line vertical runs approximately in the center of the electrode (around the axis thereof) while in figure 5 the line vertical is shifted to the left side.

It should be borne in mind that in the context of the previous artificial coloring stage and after the stage of rotation and deletion of annotations could be provided a stage of calculation of the intensity of the average light. This last average light intensity calculation stage provides particular advantages when the value of light intensity mean provided therein is used in a detection stage of threshold that will be described later in the present specification.

3. Edge detection

Furthermore, according to the present invention, it can provide an electrode edge detection stage (indicated as step 102 in the flow chart of Figure 16). The detection stage of the electrode edges is carried out preferably on a copy of the photograph or photographs provided, after the rotation and elimination stage of annotations

The detection stage of the edges of the electrode is carried out based on a detection filter of digital borders comprising two digital filters of the type described above herein.

Preferably, each of the filters digital is comprised of a 3 x 3 matrix. The first (N-S) of the digital filters detects the edges in an orientation from north to south and the second (E-O) of the digital filters detects the edges in an orientation of East to west. The mean square values (RMS) of the filtration by the two filters provide a detection of the edges of the electrode in the orientations mentioned above.

The coefficients of the two matrices (filter N-S and E-O) are selected preferably as indicated below:

2

The row transitions of the intensities of light (edges) obtained by the edge detection stage of the electrode are shown in Figure 6. The results of the stage Edge detection are important for treatment subsequent photographic analysis.

       \ newpage
    

4. Threshold detection

According to the present invention a threshold detection stage, illustrated in Figure 7 (and indicates as step 103 in the flow chart of figure 16). He threshold for light intensity is preferably defined as the average light intensity multiplied by 2. As explained, the average light intensity can be provided after the stage of rotation and deletion of annotations. The threshold detected is applies to the photograph obtained at the end of the detection stage of The electrode edges.

5. Elimination of light grains

After the threshold detection stage, provides, according to the present invention, a step to eliminate the "grains" or points of light (indicated as step 104 in the flow chart of Figure 16), as illustrated in the Figures 8 and 9. It is understood that the "grains" on the inner side of the electrode, which are noticed both in the right hand section of figure 7 as on the left hand side of figure 9, are a consequence of a significant temperature gradient over small surfaces, while "grains" are believed outside the electrode are caused by illuminated water drops by the tip of the electrode and by graphite particles incandescent that fall from it.

The stage of elimination of the "grains" of light is preferably carried out by means of a digital filter nonlinear, which is recalculated for each new intensity of light that, for example, for a pixel that has the intensity of light original c will be a function of the maximum and minimum light intensity of two adjacent pixels, as shown in Figure 9. In the preferred method of the present invention the following formula:

(2) I_ {c} \ = \ min (max (a, b, c,), max (b, c, d), max (c, d, e), ..., max (c, h, i))

in which from a to i are the light intensities of the pixels shown in the figure 8.

Preferably, the stage of elimination of grains are repeated up to 15 times to get the result shown on the right side of figure 9.

6. Tip detection

According to the invention, the photograph, preferably the photograph obtained after the removal of the light grains, is scanned (swept), for example from the bottom to the top and from left to right, to detect the area of the tip of the electrode, as shown in Figure 10. The external contours of the electrode tip are determined by an algorithm, which calculates the variables Punta_i_Min, Punta_i_Max, Punta_j_Min and Punta_j_Max .

The scanning or scanning of the photograph starts from the lower left side of Figure 10, and when the first 3 successive white pixels are detected on the same horizontal line, the algorithm, which is known to those skilled in the art, detects Punta_j_Max which represents the lowest point of the electrode tip area. Punta_j_Min , which is the highest point in the area of the electrode tip, is set, for example, approximately 50 pixels above.

The values of Punta_i_Min, Punta_i_Max that represent the respective left and right contours of the electrode tip area, are determined by scanning approximately 50 lines from left to right and up, after the detection of the Punta_j_Max value. Again, 3 successive white pixels of the same vertical line are indicative of the detection of Punta_i_Min and Punta_i_Max .

The results of the detection of the electrode tip area including the variables Punta_i_Min, Punta_i_Max, Punta_j_Min and Punta_j_Max are shown in Figure 11.

Figure 12 shows by way of example the stage of extraction of the pixels of the electrode at the height of the tip of the electrode to obtain the representation of the tip of the electrode shown in figure 13 (and indicated as step 105 in the flow chart of figure 16). Note that the pixels that represent the tip of the electrode are preferably removed after the stage of elimination of "grains" or points of light.

In Figure 12, in which, by way of example, shows an area of the photograph of 5 lines and 24 columns, the White squares represent the white pixels of the photograph. As the area of the photograph is swept, from left to right and from the bottom to the top, the four squares (pixels) on line 5 are marked (crossed), when meet the condition of at least 3 successive pixels on a line. The same goes for line 4. However, they will not be marked. (cross) the pixels in a column already marked (specifically the pixels M4, N4, 04, and P4. In line 3 the condition of 3 successive pixels on a line, and therefore no one will be marked pixel On line 2, all pixels will be marked as they meets the condition of 3 successive pixels on a line and the pixels do not belong to a column already marked. On line 1 I don't know meets the condition of 3 successive pixels in a line, and therefore no pixel will be marked.

       \ newpage
    

In this way the 50 lines of the photograph of the electrode tip area and the pixels that they are conserved as before they are subjected to an approximation numerical grade 2 (parabolic) (indicated as step 106 in the flow chart of figure 16) according to the equation:

(3) and \ = \ k_ {0} \ + \ k_ {1} x \ + \ k_2 x2

The coefficients k_ {0}, k_ {1} and k_ {2} like this as the γ coefficient that represents the quality of the approximation, are calculated based on the coordinates of the conserved pixels (crossed). The results of the approach parabolic of the electrode tip are shown in the section right of figure 13.

7. Edge detection

In addition to the detection and representation of the electrode tip, the present invention also advantageously provides the detection feature of the electrode cone flanks (indicated as step 110 in the flow chart of Figure 16). As a starting point for this last feature of electrode flank detection, the "grainless" photograph shown in the right hand section of Figure 9 may be provided. The scanning area for flank detection comprises an area that begins from Punta_j_Min to the top of the picture and from Punta_i_Min-10 (pixels) to Punta_i_Max + 10 (pixels), see also figure 10. This area is swept from the top to the bottom and from left to right.

The first and last white pixel of each swept line for the respective linear approximations of the left and right flanks (indicated as stage 111 in the flow chart of figure 16), according to the following equation:

(4) y = kx + d

Consequently, the angular coefficients of straight lines allow to estimate the lateral wear of the electrode. In other words, the more worn the electrode, more marked will be the slope of the straight line. The Figure 14 shows the result of the linear approximation of the electrode flanks.

8. Determination of the tip size of the electrode

Based on the stages to determine the tip of the electrodes and the flanks thereof, the present invention also provides a stage to determine the tip size of the electrode (indicated as step 107 in the flow chart of figure 16). In particular, the size of the electrode tip It is defined mathematically by the following three equations:

(5) Tip: y \ = \ k_ {0} \ + \ k_ {1} x \ + \ k_2 x2

(6) Flank left: y \ = \ k_ {Left} x \ + \ d_ {Left}

(7) Flank right: y \ = \ k_ {Dch} x \ + \ d_ {Dch}

By solving equations (5) and (6) you can meet the coordinates of the two points of intersection between the parabola and the straight line that represents the left flank.

3

representing (x_ {1}, y_ {1}) the first intersection point and representing (x_ {2}, y_ {2}) the second point of intersection.

Similarly, the coordinates of the two intersection points between the parabola and the straight line that They represent the right flank can be calculated as follows:

4

40

representing (x_ {3}, y_ {3}) the first intersection point and representing (x_ {4}, y_ {4}) the second point of intersection.

Only two of the four solutions of the previous equations represent the intersections of the lines straight with the parabola at the level of the electrode tip. The two others are discarded. The small circles in figure 14 they represent the intersection points preserved. Distance between the two circles of figure 14 is defined as the size of the tip of the electrode, which is also referred to as L_ {tip} and is shown in Figure 15.

9. Determination of wear length

Advantageously, the present invention also provides the calculation of the length of the oxidized part of the electrode (also indicated as step 107 in the diagram of flow of figure 16). As is known in the art, the conical electrode configuration undergoes changes during its life Useful. The calculation of the length of the non-cylindrical section of the electrode, which represents the oxide length, is performed according to the following formula:

41

in which Punta_j_Min, Punta_j_Max , L_ {tip}, k_ {left}, and k_ {dch} are as defined above, and D_ {Nom} represents the nominal (known) diameter of the cylindrical section of electrode 12.

10. Determination of the presence of cracks

Another feature of the present invention it is foreseen with the forecast of the length of the cracks that appear on the surface of the electrode (indicated as step 112 in the flow chart of figure 16). Consequently, the latter length of the cracking detection stage is based on the edge detection stage, in a separate area 10 pixels of the flanks detected and extending from the tip of the electrode. A scan of this area provides accurate detection of the total cracking length of the electrode.

The detection stage of the length of the electrode cracking can be advantageously performed adjusting a threshold, so that all pixels that are counted have a light intensity greater than, for example 96. The count number is divided by 2 (since the cracks are detected at the 2 edges of the electrode) and multiplies (at the present specific non-limiting intended embodiment) by 5.04 mm, see photo data in JPG, for length Total cracks.

A block flow diagram showing a advantageous embodiment of an analysis procedure Photographic according to the present invention is shown in Figure 16. However, the person skilled in the art will easily understand that the order of some of the stages can be omitted and / or changed shown in the flow chart of Figure 16. Such steps they can be advantageously performed on a personal computer such as the PC 7.

As can be seen in a step 100, the original photograph, preferably in JPG format as explained above, it is introduced from camera 1 to PC 7. In a subsequent stage 101, the original photograph is subjected to the rotation stage and deletion of electrode annotations. Subsequently, the flowchart is directed to step 108 of artificial coloring of the electrode and at step 102 of detecting  The electrode edges. The result of the detection stage 102 of the electrode edges is used by the subsequent step 103 of electrode threshold detection. In turn, the result of the step 103 of electrode threshold detection is provided to the step 104 of removing grains or points. Then, based on the grain-free data output of step 104, can be detected the tip of the electrode in step 105. Based on the latter data, the parabolic approach is performed in step 106. The resulting from the parabolic approach, step 106, is used together with step 108 of artificial coloring of the electrode for obtain the electrode arc deviation in step 109. The step 105 can also be directed to step 110 of detecting the flanks (left and right) of the electrode, which is followed by a step 111 of linear approximation of the electrode flanks left and right. The result of step 111 can be used also in a step 109. In addition, based on steps 106 and 111 electrode tip size and length can be calculated of oxidation in step 107. Finally, the length is calculated Total electrode cracks in step 112 based on stages 105, 106 and 111.

The invention, as described and shown in This report is open to change and modification through the addition of additional detection steps based on the previous detection stages without departing from its scope.

For example, the "detachment" of the electrode tip analyzing the shape of its cross sectional and its cracks. Alternatively, tip detachment could be detected of the electrode analyzing at the same time the length of the tip and the slope of its flanks. Finally i could analyze the surface temperature of the electrode to provide the oven operator with the necessary data to achieve optimal performance

When the technical characteristics mentioned in any claim they are followed by reference numbers, These reference numbers have been included for the sole purpose of increasing the intelligibility of the claims and, in consequently, such reference numbers have no effect limiting the scope of each element identified as example using these reference numbers.

Claims (9)

1. Procedure to control wear of an electrode in an electric arc furnace, comprising the following stages: take a digital photograph of the still incandescent tip of said electrode; characterized in that it presents the following stages: apply an algorithm to said digital photography of numerical edge detection filter to get a filtered image in which abrupt changes in the intensity of the light are represented as contour lines; Y analyze those contour lines to determine electrode tip configuration and presence  of cracks. 2. Method according to claim 1, in which a threshold filter is applied to said filtered image before analyzing these contour lines. 3. Method according to claim 1 or 2, which comprises the stage of eliminating the grains of light by means of a numerical filter before analyzing these lines of contour. 4. Procedure according to any of the claims 1 to 3, wherein the step of analyzing said contour lines to determine the configuration of the tip of the electrode comprises: detect the lower contour line of the electrode tip and make an approximation to a curve parabolic; detect the contour line that corresponds to each of the flanks of the electrode tip and perform a approach to a straight line. 5. Procedure according to any of the claims 1 to 4, further comprising the step of detecting asymmetries in the light intensity of the electrode tip to warn deviations of the electric arc. 6. Procedure according to any of the claims 1 to 5, further comprising the steps following: a) place a chamber in the arc furnace electric; b) provide a connection between the camera and an electrode process controller; c) operate the camera together with electrode displacement, so that the camera can capture a photograph of the electrode after the fusion of each basket of electric arc furnace debris; Y d) provide the photograph captured through of an additional connection to storage media and Photo processing 7. Method according to claim 6, which also includes the stage of indicating to the camera the passage of electrode in front of the camera by means of the controller processes 8. Procedure according to any of the claims 6 and 7, further comprising the step of storing the photograph captured in the storage and treatment media of photographs. 9. Procedure according to any of the claims 1 to 8, further comprising the step of comparing the photographs captured from the electrode with the photograph of a unused electrode