Device and method for determining the loss on ignition of at least part of an iron and steel product

Abstract

Disclosed is a method and device for determining the loss on ignition of at least part of an iron and steel product during passage through a furnace upstream of a descaler. The device includes electromagnetic sensors, with at least one arranged to scan the product's lower surface near the furnace outlet, the sensor oriented so the scanning plane of the electromagnetic radiation from the sensor is perpendicular to a direction of movement; a set of at least two electromagnetic sensors upstream of the descaler, oriented so their scanning planes are substantially on a single plane perpendicular to the direction of movement of the at least part of the product; and at least two electromagnetic sensors downstream of the descaler, oriented so their scanning planes are substantially on a single plane perpendicular to the product's movement direction. The sensors determine the height of the product upstream and downstream of the descaler.

Claims

1. A device for determining the scale loss of at least one part of a steel product (5) during passage of the steel product through a reheating furnace (4) located upstream of a descaler (8), said device comprising: a set of electromagnetic sensors (20, 30, 31, 40, 41) that includes a first electromagnetic sensor (20) of said set of electromagnetic sensors arranged to scan, along a first scanning plane, a lower face (50) of the steel product (5) in vicinity of an outlet of the furnace (4), said first electromagnetic sensor oriented so that said first scanning plane (P20) of an electromagnetic radiation of said first electromagnetic sensor is perpendicular to a run direction of the steel product, second and third electromagnetic sensors (30, 31) of said set of electromagnetic sensors, placed upstream of the descaler (8) and oriented so that scanning planes (P30, P31) of electromagnetic radiation of said second and third electromagnetic sensors are substantially on a same plane (P32) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a first roller table (3), and fourth and fifth electromagnetic sensors (40, 41) of said set of electromagnetic sensors, placed downstream of the descaler (8) and oriented so that scanning planes (P40, P41) of electromagnetic radiation of said fourth and fifth electromagnetic sensors are substantially on a same plane (P42) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a second roller table (6), each of said second, third, fourth and fifth sensors (30, 31, 40, 41) being arranged so as to determine heights of the steel product upstream and downstream of the descaler.

2. The device as claimed in claim 1, wherein the second and fourth sensors (30, 40) of the set of electromagnetic sensors are arranged to scan an upper face (51) of the steel product (5) and the third and fifth sensors of the set of electromagnetic sensors (31, 41) are arranged to scan a side face (52, 53) of the steel product (5).

3. The device as claimed in claim 1, wherein scanning planes (P30, P40) of the second and fourth sensors (30, 40) are inclined at an angle () with respect to a longitudinal axis of the rollers of the first and second roller tables (3, 6).

4. A process for determining scale loss of at least one part of a steel product during passage thereof through a reheating furnace (4), comprising: using a device comprised of a set of electromagnetic sensors, the set of electromagnetic sensors including a first electromagnetic sensor (20) of said set of electromagnetic sensors arranged to scan, along a first scanning plane, a lower face (50) of the steel product (5) in vicinity of an outlet of the furnace (4), said first electromagnetic sensor oriented so that said first scanning plane (P20) of an electromagnetic radiation of said first electromagnetic sensor is perpendicular to a run direction of the steel product, second and third electromagnetic sensors (30, 31) of said set of electromagnetic sensors, placed upstream of the descaler (8) and oriented so that scanning planes (P30, P31) of electromagnetic radiation of said second and third electromagnetic sensors are substantially on a same plane (P32) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a first roller table (3), and fourth and fifth electromagnetic sensors (40, 41) of said set of electromagnetic sensors, placed downstream of the descaler (8) and oriented so that scanning planes (P40, P41) of electromagnetic radiation of said fourth and fifth electromagnetic sensors are substantially on a same plane (P42) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a second roller table (6), each of said second, third, fourth and fifth sensors (30, 31, 40, 41) being arranged so as to determine heights of the steel product upstream and downstream of the descaler; and determining oxide scale fallen from surfaces of the steel product scanned by the first, third, and fifth sensors by analyzing respective reliefs of the surfaces scanned by the first, third, and fifth sensors (20, 31, 41).

5. The process as claimed in claim 4, further comprising: determining oxide scale present on the surfaces scanned by the first, third, and fifth sensors (20, 31, 41) by analyzing of the respective reliefs of the surfaces obtained by the first, third, and fifth sensors (20, 31, 41).

6. A process for determining scale loss of at least one part of a steel product (5) during passage thereof through a reheating furnace (4), comprising: using a device comprised of a set of electromagnetic sensors, the set of electromagnetic sensors including a first electromagnetic sensor (20) of said set of electromagnetic sensors arranged to scan, along a first scanning plane, a lower face (50) of the steel product (5) in vicinity of an outlet of the furnace (4), said first electromagnetic sensor oriented so that said first scanning plane (P20) of an electromagnetic radiation of said first electromagnetic sensor is perpendicular to a run direction of the steel product, second and third electromagnetic sensors (30, 31) of said set of electromagnetic sensors, placed upstream of the descaler (8) and oriented so that scanning planes (P30, P31) of electromagnetic radiation of said second and third electromagnetic sensors are substantially on a same plane (P32) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a first roller table (3), and fourth and fifth electromagnetic sensors (40, 41) of said set of electromagnetic sensors, placed downstream of the descaler (8) and oriented so that scanning planes (P40, P41) of electromagnetic radiation of said fourth and fifth electromagnetic sensors are substantially on a same plane (P42) perpendicular to the run direction of the steel product passing through a generatrix of a roller of a second roller table (6), each of said second, third, fourth and fifth sensors (30, 31, 40, 41) being arranged so as to determine heights of the steel product upstream and downstream of the descaler; and determining an amount of oxide scale fallen into the descaler (8) from a height difference of the heights of the steel product (5) upstream and downstream of the descaler as provided by the second, third, fourth, and fifth sensors (30, 31, 40, 41).

7. The process as claimed in claim 6, wherein, heights of the steel product (5) are determined by determining a height between the lower face of the steel product and the generatrix of the roller of the first roller table (3) determined by the third and fifth sensors (31, 41), subtracted from a height of the steel product (5) determined by the second and fourth sensors (30, 40).

8. A process for controlling a furnace (4) for reheating semi-finished steel products (5), comprising: determining, for at least one part of a steel product (5), an amount of oxide scale formed on the steel products by a reheating of said steel product, said determination comprising the steps of the method recited in claim 4; and correcting operating parameters of the furnace as a function of the determined amount of oxide scale so as to modify the amount of oxide scale formed by the reheating.

9. The process as claimed in claim 8, wherein the correcting comprises injecting steam into the furnace.

10. The process as claimed in claim 8, wherein the correcting comprises increasing an amount of at least one of combustion air and oxidant injected into the furnace.

11. The process as claimed in claim 8, wherein the correcting comprises using atmospheres having controlled oxygen contents in various zones of the furnace.

12. The process as claimed in claim 8, wherein the correcting comprises using two or more types of fuels for supplying the burners of the furnace and producing different atmospheres.

13. The process as claimed in claim 8, wherein an operating parameter of the furnace comprises a use of product heating curves.

14. The device as claimed in claim 2, wherein scanning planes (P30, P40) of the second and fourth sensors (30, 40) are inclined at an angle () with respect to a longitudinal axis of the rollers of the first and second roller tables (3, 6).

Description

DESCRIPTION OF THE FIGURES

(1) Other distinctive features and advantages of the invention will become apparent on reading the detailed description of uses and embodiments that are in no way limiting, with respect to the appended figures in which:

(2) FIG. 1 presents a schematic view of a plant for reheating a steel product;

(3) FIG. 2 presents a schematic view of a plant for descaling and rolling the product reheated by the reheating plant;

(4) FIG. 3 illustrates an example of a temperature curve of the product during the heating time thereof in the reheating plant;

(5) FIG. 4 schematically illustrates the implantation of an electromagnetic sensor that will scan the surface of a product according to the invention;

(6) FIG. 5 schematically illustrates the implantation of an electromagnetic sensor that will scan the lower surface of a product according to the invention;

(7) FIG. 6 schematically illustrates the implantation of sensors that will measure the height of a product according to the invention;

(8) FIG. 7 schematically illustrates the implantation of a sensor according to the invention that will measure the distance between the edge of a product and the roller on which it rests;

(9) FIG. 8 schematically illustrates the implantation of a sensor according to the invention that will estimate the height of a product.

DESCRIPTION OF THE INVENTION

(10) Since these embodiments are in no way limiting, variants of the invention could in particular be carried out that comprise only a selection of features described subsequently, as described or generalized, isolated from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention with respect to the state of the art.

(11) FIG. 1 presents the principle of a steel product rolling plant. A furnace charging machine 1, for example of finger type, grasps a steel product 2 transported by a roller table 3. The roller table 3 transports the product 2 in front of a furnace 4 for reheating semi-finished steel products. The grasped product 2 is placed by the furnace charging machine 1 in the furnace 4 on transfer frames (not represented).

(12) During its passage through the furnace, the product 2 to be loaded into the furnace is gradually reheated according to a predetermined heating curve, for example in order to be brought from the ambient temperature outside of the furnace 4 typically to a furnace discharge temperature, on leaving the furnace, of between 1100 C. and 1300 C.

(13) A reheated product 5 is removed from the furnace by a finger machine 7 and placed on another roller table 6 which discharges it to a rolling mill (not represented).

(14) FIG. 2 shows the roller table 6 for discharging the reheated product 5 after it has left the furnace 4. This product is moved by the roller table 6 to a deoxide scaler 8. In FIG. 2, the product within the deoxide scaler 8 is numbered 5. The product 5 is exposed, in the deoxide scaler 8, to high-pressure water jets 9, 10. The high-pressure water jets 9, 10 are respectively oriented on an upper and lower part of the product 5. These water jets 9, 10 are arranged in order to detach the oxide scale formed at the surface of the product 5 and to discharge the detached oxide scale along a circuit 11 to settling tanks (not represented) for the recovery thereof.

(15) After descaling by the deoxide scaler 8, the product is transported to the inlet of a rolling mill. In the rolling mill, the product is referenced 5. The product 5 passes through various rolling sections 12a, 12b. The rolling sections 12a, 12b are arranged in order to obtain a desired wire, section or sheet from the product 5.

(16) In the state-of-the-art plants, the oxide scale recovered in the circuit 11 is weighed in order to define overall the mass recovered and the loss on ignition, that is to say the relative amount of oxide scale produced during the product reheating operation.

(17) According to the invention, a device for continuously measuring the oxide scale produced by the reheating is positioned at the outlet of the furnace 4, optionally after the deoxide scaler. This measurement device is arranged in order to compare the amount of oxide scale to limits set according to the heating method and to the nature of the steel reheated in the furnace.

(18) This comparison makes it possible to deduce a heating efficiency of the furnace and to develop a corrective strategy of the heating suitable for bringing the oxide scale produced back to within the desired quantity and quality limits.

(19) FIGS. 4 to 8 present devices for continuously measuring the oxide scale by measuring its thickness by means of optical distance measurement sensors.

(20) Measurement is carried out by optical analysis on the width of the product and also on the length of the product during the movement thereof in front of the sensor. For each point of the zone scanned by a sensor, that is to say of the surface of the product seen by the sensor, a distance measurement is carried out with an accuracy of the order of a micrometer which enables the measurement of the actual height, that is to say of the thickness of the product.

(21) It is thus easy to calculate the volume of the product, therefore its weight before and after reheating with, by comparison, the amount of oxide scale discharged.

(22) The measurement made also makes it possible to evaluate the thickness of oxide scale formed and, thus, to compensate for the mass of oxide scale that is detached from the product and that has fallen into the furnace and into the deoxide scaler. It is also possible, by calculation, to compensate for the expansion of the products. These calculations may be carried out with simple physical algorithms.

(23) Seen schematically represented in FIG. 4 is an electromagnetic sensor 20, the electromagnetic radiation of which scans the surface of the lower face of a product 5 while moving over a plane P20 according to an angle of view. In this figure, the product 5 is represented in transverse cross section.

(24) The distance of the sensor with respect to the product and the angle of view of the sensor make it possible to cover the entire width of the product. When the distance of the product and/or the angle of view of the sensor do not make it possible to cover the entire width of the product, several sensors are advantageously used to cover the entire width of the product.

(25) However, in order to limit the cost of the plant, it is possible to only install a single sensor and to use the data collected by this sensor in order to transpose this data onto the surface of the product not covered by the sensor.

(26) It is thus considered, by approximation, that the amount and the features of the oxide scale are the same on the surface covered by the sensor and the surface not covered by the sensor.

(27) A portion of the amount of oxide scale fallen into the furnace 4 is thus determined by at least one sensor 20 placed underneath the product 5, which scans the lower face thereof.

(28) Said sensor is placed at the outlet of the furnace and as close as possible thereto.

(29) The sensor produces a map of the relief of the lower face of the product while this product is running. The analysis of the map of the relief of the surface of the product makes it possible to determine the amount of oxide scale fallen into the furnace. Specifically, the high points at the surface of the product correspond to the locations where the oxide scale is still present on the product. Conversely, the low points correspond to the locations at the surface of the product where the oxide scale has detached and has fallen into the furnace.

(30) The analysis of the data supplied by the sensor makes it possible to determine possible singular points, for example a point substantially higher than the average of the high points. At this point, it is likely that oxide scale has greatly detached from the product but has remained present thereon. The statistical analysis of the data supplied by the sensor makes it possible to take into account these singular points, for example in order to dismiss them during the processing of the data so as not to disturb the determination of the thickness of the oxide scale.

(31) Since the sensor 20 is placed underneath the product, it is necessary to prevent the oxide scale from falling thereon and hampering its operation. For this, a screen 15 that is inclined relative to the ground level is placed between the product 5 and the sensor 20.

(32) This screen must be substantially transparent for the beam so as not to degrade the accuracy of the measurement. It may for example be a glass-ceramic plate.

(33) The inclination of the screen is selected so that the oxide scale that falls onto the screen slides and does not remain thereon.

(34) Since the sensor is placed underneath the screen, it is inclined by the same angle as the screen so as to avoid any optical disturbance of the laser when passing through the screen.

(35) For a finer determination of the loss of oxide scale in the furnace, a sensor is placed on each side of the product leaving the furnace. Just like the sensor placed above the product, these sensors produce a map of the relief of the side faces of the product while this product is running in order to determine the amount of oxide scale formed on said side faces that has fallen into the furnace.

(36) In the case where a single sensor is placed on one of the faces of the product, the total amount of oxide scale lost by the two faces of the product is estimated by doubling that of the instrumented face of the product.

(37) Advantageously according to the invention, a sensor is also placed above the product leaving the furnace so as to produce a map of the upper face of the product. As this oxide scale predominantly remains present on the product leaving the furnace, this map of the upper face is not therefore used to determine the amount of oxide scale fallen into the furnace. This map makes it possible for example to detect a difference in oxidation on the upper face of the products which may be useful for optimizing the operating parameters of the furnace.

(38) Seen schematically represented in FIG. 5 is a product 5 traveling on a furnace outlet roller table 6 along a longitudinal side view.

(39) An electromagnetic sensor 20 is placed underneath the product. Its electromagnetic radiation scans the surface of the lower face of the product by moving over a plane P20.

(40) An inclined screen 15 is placed between the product and the sensor 20. This screen makes it possible to prevent oxide scale from being deposited on the sensor and hampering its operation.

(41) The sensor 20 is inclined by the same angle as the inclined screen 15 so that the scanning plane P20 of the sensor is perpendicular to the screen 15.

(42) The amount of oxide scale fallen into the deoxide scaler 8 is determined by two sets of sensors, the first set placed upstream of the deoxide scaler, the second set downstream of the deoxide scaler.

(43) Each set of sensors comprises at least a first sensor 30, 40 placed on the upper face of the product and at least a second sensor 31, 41 placed on one of the sides of the product.

(44) The sensors 30 and 31 are placed upstream of the deoxide scaler and the sensors 40 and 41 are placed downstream of the deoxide scaler.

(45) Only the set of sensors 30 and 31 will subsequently be described knowing that the layout of these sensors is identical to that of the sensors 40 and 41.

(46) The sensor 30 placed above the product is positioned in a vertical line with a roller 14 of the roller table on which the products move. It makes it possible to measure the distance between the upper face of the product 5 and the upper generatrix of the roller 14. For a product resting perfectly on the support roller 14, this distance corresponds to the height of the product.

(47) The sensor is placed so that its measuring range covers, at least in part, the upper face of the product and at least one part of the upper generatrix of said roller.

(48) The sensor is advantageously inclined by an angle alpha relative to the longitudinal axis of said roller, for example by an angle of 5. This inclination makes it possible to guarantee that the beam of the sensor covers, at at least one point 18, the upper generatrix of the roller. Specifically, if the sensor was positioned with its measuring range parallel to the axis of the roller, it would be necessary to have a perfect vertical alignment of the sensor relative to the roller in order for the sensor to see the upper generatrix of the roller and not a generatrix placed on a lower plane. This sensor also makes it possible to measure the relief of the upper face of the product covered by its measuring range.

(49) The sensor placed on the side of the product is positioned on the same vertical plane as the sensor placed above the product, that is to say level with the generatrix of the same support roller. When the sensor placed above the product does not cover the two sides of the support roller located on either side of the product, the sensor placed on the side of the product is located on the side of the roller of which the sensor located on the upper face of the product sees the generatrix.

(50) The sensor placed on the side of the product makes it possible to correct the height of the product measured by the sensor placed on the upper face when the product does not rest exactly on the support roller. Specifically, for a deformed product that would not rest on the generatrix of the roller, the height of the product determined by the upper sensor would correspond to the sum of the actual height of the product to be taken and that of the gap between the lower face of the product and the generatrix of the roller.

(51) The combination of these two sensors enables an accurate measurement of the height of the product. The comparison of the height of the product measured by the first set of sensors positioned upstream of the deoxide scaler and the height measured by the second set of sensors positioned downstream of the deoxide scaler makes it possible to determine the loss of height of the product in the deoxide scaler. This loss of height corresponds to most of the oxide scale fallen into the deoxide scaler.

(52) Sensors placed on the side of the product also make it possible to produce a map of the relief of the face of the product that they scan.

(53) The analysis of the map of the relief of the face of the product makes it possible to determine the amount of oxide scale fallen into the furnace, for the sensor placed upstream of the deoxide scaler, and the amount fallen into the deoxide scaler for the sensor placed downstream of the deoxide scaler. Specifically, the high points at the surface of the product correspond to the locations where the oxide scale is still present on the product. Conversely, the low points correspond to the locations at the surface of the product where the oxide scale has detached and has fallen into the furnace.

(54) When the side sensors are only placed on one of the faces of the product, the total amount of oxide scale lost by the two faces of the product is estimated by doubling that of the instrumented face of the product.

(55) Seen represented in transverse view in FIG. 6 is a product 5 traveling on a roller table.

(56) An electromagnetic sensor 30 is placed above the product and scans a portion of the upper face of the product and also a portion of the roller 14 of the roller table located in a vertical line with the sensor.

(57) The plane P30 over which the beam of the sensor moves is perpendicular to the product and substantially parallel to the axis of the roller 14 while being inclined by an angle alpha relative to this axis.

(58) The sensor 30 makes it possible to carry out a first estimation of the height of the product 5 by measuring the distance between the upper face and product and the high point of the generatrix of the roller 14.

(59) An electromagnetic sensor 31 is placed on the side of the product and scans the side face of the product and also a portion of the roller 14.

(60) The plane P31 over which the beam of the sensor 31 moves is perpendicular to the roller and passes through the axis of the roller. The upper generatrix of the roller 14 is thus on the plane P31.

(61) The sensor 31 makes it possible to analyze the relief of the side face of the product and measure a possible space between the edge of the product 5 and the generatrix of the roller 6.

(62) Seen represented in transverse view in FIG. 7 is an enlargement of FIG. 6 level with the sensor 31 showing a deformed product 5, the side edge of which does not rest on the roller 14. The sensor 31 thus makes it possible to measure the height 16 of the space between the edge of the product 5 and the generatrix of the roller 14. This height is subtracted from the height of the product determined by the sensor 30 in order to obtain the actual height of the product.

(63) Seen schematically represented in FIG. 8 in a top view is a product 5 traveling on a roller table, one roller 14 of which is represented.

(64) An electromagnetic sensor 30 is placed above the product and scans a portion of the upper face of the product and also a portion of the roller 14.

(65) The plane P30 over which the beam of the sensor moves is perpendicular to the product and substantially parallel to the axis of the roller 14 while being inclined by an angle alpha relative to this axis. This inclination of the sensor makes it possible to guarantee that the plane P30 passes through the upper generatrix of the roller 14 at a point 18. The sensor 30 thus makes it possible to carry out a first estimation of the height of the product 5 by measuring the distance between the upper face and product and this high point 18 of the generatrix of the roller.

(66) These various devices according to FIGS. 4 to 8 may be used at various steps of the manufacturing process, in particular for demonstrating a difference in the dimensions of the products or in the weight thereof which is representative of the production of oxide scale in terms of amount or behavior thereof.

(67) It is thus possible to demonstrate the amount that may be deposited in the furnace during the reheating or after the furnace during the uptake of the product by the furnace discharging machine or at each step of the process after the furnace, for example during the transfer of the product to the roller tables, in the deoxide scaler or in the various units of the rolling mill.

(68) A person skilled in the art specifically knows how to place such sensors around the furnace. The sensor is protected in a water-cooled housing and aims through a viewing window swept with cold air that maintains it at temperature despite the radiation that it receives from the furnace or from the product.

(69) In particular, the advantage is understood of placing a device for measuring the product before the charging thereof into the furnace and also another after the discharging thereof from the furnace or after the deoxide scaler in order to obtain, from the difference between these measurements, an image of the amount of oxide scale produced and its behavior. It is also possible to carry out several measurements, for example before the furnace, on leaving the furnace and after the deoxide scaler in order to better evaluate the various steps of the life of the oxide scale.

(70) The device described by FIGS. 4 to 8 may be installed at the furnace inlet in order to define a volume model of the product at the furnace charging thereof, it may be installed at the outlet of the furnace or at the outlet of the deoxide scaler in order to produce a volume model of the product after reheating and descaling.

(71) The comparison of the models makes it possible to learn lessons regarding the result of the heating. This teaching may be used in particular to act on the settings of the furnace in order to thereby modify the heating curve and/or the control of the burners and/or the atmosphere in the chamber of the furnace and in particular the excess air and/or a possible injection of steam into certain zones of the furnace and/or to operate the furnace with reducing zones and oxidizing zones and/or to modify the setting parameters of the deoxide scaler such as water pressure, number of descaling ramps used, feed speed of the product.

(72) The capture of this information on the product, before and after reheating, is processed by a computer according to simple or elaborate physical model, for example in order to take into account the behavior of the oxide scale, an evaluation of the portion of the weight of oxide scale that is deposited in the furnace during the reheating, an evaluation of the oxide scale formed at the upper surface of the product and at the lower surface thereof. It is thus possible to take into account the dropping of a portion of the oxide scale formed on the lower face of the product during the transfer thereof on the frames of the furnace or on the discharge roller tables or else an evaluation of the residual portion of oxide scale at the surface of the product after the descaling.

(73) The invention thus proposes a computer program product comprising program code instructions for executing the steps of the process according to any one of the claims according to the invention when the program is executed on a computer.

(74) It is also possible to envisage the use of a computer program product, for example of fuzzy logic or self-adapting type, for continuously analyzing the formation of oxide scale on the product in order to validate the action performed on the operation of the furnace or to evaluate the changes in the oxide scale (in terms of quantity and quality) over time according to the process modifications performed.

(75) It is seen that by means of the continuous measurement of the amount of oxide scale formed at the surface of the product and of the operating system of the furnace by computer, it is possible to continuously adapt the operating parameters of the furnace according to a predefined strategy or predefined objectives, for example to reduce the amount of oxide scale provided, to stabilize the amount of oxide scale produced at a predefined value as a function of the nature of the product to be treated and its treatment process, to modify the amount of oxide scale produced in order to obtain a oxide scale quality suitable for the process, for example for its discharging characteristics in the deoxide scaler.

(76) This process for continuously controlling the furnace according to the measurement of the oxide scale produced makes it possible to optimize the complete rolling process and to optimize the energy consumption by reducing the amount of oxide scale produced.

(77) Of course, the invention is not limited to the examples that have just been described and many adjustments may be made to these examples without departing from the scope of the invention. Furthermore, the various features, forms, variants and embodiments of the invention may be combined with one another in various combinations as long as they are not mutually exclusive or incompatible.

NOMENCLATURE

(78) 1 furnace charging machine 2 steel product 3 furnace inlet roller table 4 reheating furnace 5 steel product 5 product in the descaler 5 product in a rolling mill 6 furnace outlet roller table 7 furnace discharging machine 8 descaler 9 upper high-pressure water jet 10 lower high-pressure water jet 11 discharge circuit 12a, 12b rolling sections 14 support roller 15 inclined screen 16 distance between the edge of the product and a support roller 18 intersection between a plane P30 and the upper generatrix of a roller 20 electromagnetic sensor scanning the lower face of a product 30 electromagnetic sensor scanning the upper face of a product upstream of the descaler 31 electromagnetic sensor scanning a side face of a product upstream of the descaler 40 electromagnetic sensor scanning the upper face of a product downstream of the descaler 41 electromagnetic sensor scanning a side face of a product downstream of the descaler P20 scanning plane of the laser of a sensor 20 P30 scanning plane of the laser of a sensor 30 P40 scanning plane of the laser of a sensor 40 P41 scanning plane of the laser of a sensor 41 P42 scanning plane of the laser of a sensor 42