“PLANT FOR TREATING FLAT METAL PRODUCTS, SUCH AS SLABS OR SUCHLIKE, AND CORRESPONDING TREATMENT METHOD

FIELD OF THE INVENTION The present invention concerns a plant and the corresponding method for the surface treatment of flat metal products, particularly thin slabs with thicknesses even less than 200mm, coming from a continuous casting machine. The plant and the method according to the present invention are applied for the detection of surface defects of the slabs, even at high temperatures (for example above 850°C), and for the correction of such defects.

BACKGROUND OF THE INVENTION

It is known, in the steel sector of rolling flat metal products, to produce high quality steel strip free from surface defects.

In particular, this type of strip finds advantageous industrial application in the so-called “exposed steels”, that is, those products intended for the creation of “exposed” surfaces, used in the automotive industry, for example, but also in the production of household appliances or in other sectors where it is important to have surfaces free of defects in order to be acceptable from a commercial point of view.

However, such strip can also be used in similar products intended for different uses, such as for example those used as structural steels in the automotive industry with complex chemical compositions, such as peritectic steels for example.

A known solution for producing quality strip starting from thin slabs from continuous casting is to proceed with a surface deseaming, or scarfing, of the slabs themselves in the areas that have surface defects. This known solution provides to use oxygen torches disposed between the continuous casting machine and the subsequent rolling section, by means of which a few millimeters of product surface are removed in order to eliminate the defects detected.

It is clear that not all slabs have surface defects, therefore there is a need for quality control and selection prior to scarfing and sending to rolling. In this regard, both solutions with visual control by operators as well as electronic viewing systems based on cameras or thermal cameras are known, the resolution of the latter has however proven insufficient to recognize different types of defects on high-temperature slabs coming from continuous casting. Therefore, these known defect detection systems are not always reliable, particularly with slab temperatures above 800/850°C. This reduced reliability leads to a consequent reduction in the surface quality of the products at the end of rolling.

In addition, since the scarfing step is potentially longer than the times for casting a new slab, this operation is difficult to perform in line, therefore it is necessary to extract the slabs to be scarfed from the main line in order to take them onto a parallel circuit by means of mobile sections, or shuttles, possibly disposing them in accumulation areas, from which they are then progressively removed and subjected to scarfing. Another disadvantage of scarfing is the high environmental impact it causes.

In fact, the oxygen nozzles that are used produce CO2 from combustion; in addition, the material that is eliminated oxidizes, becoming difficult to recover and the treatment fumes have to be appropriately captured and filtered with a dedicated line, before being released into the atmosphere. Plants for the treatment of surface defects of metal products are known in the state of the art, such as that described in patent application WO-A-2004/041457 for example, in which alternative treatment systems to scarfing are provided. However, even this type of known plants remains linked to a preventive identification of the defects carried out with control by the operators, or with viewing based on cameras, whereby they fall into the aforementioned disadvantages linked to the high temperature of the slabs, with a consequent reduction in the quality of the products at the end of rolling.

Other known solutions for the detection and elimination of defects in flat metal products are described in documents US 2021 114 072 Al, US 4 601 762 A and US 6 184 924 Bl .

There is therefore the need to perfect a plant for treating flat metal products, such as slabs or suchlike, that can overcome at least one of the disadvantages of the state of the art.

To do this, it is necessary to solve the technical problem of reducing to a minimum, even trying to eliminate, the surface defects of the cast slabs and minimizing the costs, times and environmental impact for the surface treatment of the defective slabs, before the usual rolling steps.

In particular, one purpose of the present invention is to accurately identify the surface defects of thin slabs from continuous casting, even at high temperatures, and intervene in a targeted and effective manner to carry out the desired surface treatment of the slabs themselves, increasing the quality of the final product.

Another purpose of the present invention is to carry out an effective surface treatment of the slabs identified in an alternative manner to traditional scarfing, in order to limit the environmental impact and the generation of fumes, but also to promote the recovery of scrap that can thus be reused.

Yet another purpose is to prevent slowdowns in the production flow and the need for auxiliary equipment for moving the slabs. The Applicant has devised, tested and embodied the present invention to overcome the shortcomings of the state of the art and to obtain these and other purposes and advantages.

SUMMARY OF THE INVENTION

The present invention is set forth and characterized in the independent claims. The dependent claims describe other characteristics of the present invention or variants to the main inventive idea.

In accordance with the above purposes and to resolve the technical problem disclosed above in a new and original way, also achieving considerable advantages compared to the state of the prior art, a plant according to the present invention for treating flat metal products comprises at least optical scanning means which are configured to scan at least one surface of the metal products.

The optical scanning means are advantageously able to be positioned in operational continuity with and along a common axis of feed between a continuous casting line and a rolling line. Optical scanning, unlike normal human or electronic inspection viewing, cannot be influenced by high temperatures (even above 850°C) because it physically detects the surface of the metal product, being able to identify its surface defects through actual structural variation and not through visual identification. Therefore, the visual deformation, normally caused by heat in the contour of the metal product, is not of interest for the purposes of detecting actual surface defects.

This advantageous solution according to the present invention allows to identify substantially all the surface defects that can occur on the surfaces of the metal products, to the advantage of the precision of treatment and the quality of the final product.

Moreover, the integration of the plant for treating flat metal products between the casting line and the rolling line significantly increases the overall productivity of the production line by reducing inefficiencies and machine downtime, and guaranteeing a continuous flow of material toward the rolling line.

Advantageously, the optical scanning means are equipped with laser technology, for example using a 3D laser scanner, to perform an optical triangulation on the upper and lower surface of the metal products.

Thanks to this technique, surface defects such as depressions, cobbling or other surface deformation elements are detected and compared with defect models present in appropriate databases in order to identify and classify the defects, so as to be able to remove them in the subsequent steps.

In accordance with one aspect of the present invention, the plant also comprises at least one control and command unit configured to perform an electronic comparison between the scan performed by the optical scanning means and a plurality of feedback images, containing for example known errors or defects which derive from qualitative parameters or market demand, that is, know-how.

In this way, each defect detected is compared with a reference image and classified by type as a function of certain identification parameters and potential treatment interventions, programmed or programmable.

Furthermore, having a scan of the surface of the metal product available, and because this scan is processed within the command and control unit, it is possible to precisely identify the position and extent of the defect, optimizing the subsequent treatment steps, to the advantage of the necessary times and costs. In accordance with another aspect of the present invention, the control and command unit communicates at least with movement means; the latter being comprised in the plant and suitable to selectively move the metal products as a function of the results of the feedback. In particular, the movement means are configured to move the metal products into a position misaligned with respect to the axis of feed.

It is clear that by doing so both the time and also the costs of intervention to treat the defective metal products are reduced.

In accordance with one aspect of the present invention, in which the metal products are produced by means of a continuous casting line, the command and control unit is advantageously connected to the continuous casting line so that, as a function of the results of the comparison, it is possible to selectively modify the operating parameters of the casting line itself and prevent the formation of the detected defects upstream.

In this way, by correlating the detected data with the production data operating during the formation of the defective metal product, it is possible to preventively correct the potential situations that, statistically, led to the generation of the defect observed. With this advantageous solution according to the present invention, in addition to having greater precision and reliability in detecting defects, even at high temperatures, it is possible to intervene on the casting parameters in a targeted manner, so as to reduce the number of defects that can occur. Clearly, this aspect of the present invention allows the production of metal products to be optimized and the quality of the product thus made to be further increased.

In accordance with one aspect of the present invention, the plant comprises at least one station for conditioning the surface, in particular, but not only, through grinding, of the products which have been identified as defective and are moved by the movement means. Advantageously, the command and control unit can also be connected to the grinding station in order to optimize the operating parameters thereof as a function of the results of the electronic comparison, such as for example the extent, type or position of the defects specifically detected.

This advantageous solution allows to perform a localized grinding process, so as to limit both the environmental impact and also the generation of fumes to a minimum, but also encourage the recovery of scrap which can thus be reused.

The surface conditioning station is advantageously disposed in a position misaligned with respect to the axis of feed and it cooperates with the movement means.

In accordance with one aspect of the present invention, the movement means comprise at least a first slider suitable to pick up the metal product identified from the continuous casting line and selectively move it toward the grinding station. The first slider is normally disposed downstream of the optical scanning means in the direction of feed, and it can be selectively moved transversally to the direction of feed in order to transfer the metal product toward the surface conditioning station.

The slider is a mobile section, or shuttle, of the maintenance and/or heating tunnel furnace located downstream of the continuous casting machine.

This movement, according to some variants of the inventive idea, can be directed toward the grinding station in order to carry out a “hot” surface treatment, or toward a cooling member, such as a lateral transfer device for example, which allows to cool the metal product in order to carry out a “cold” surface treatment.

According to some variants, regardless of whether a hot or cold surface treatment is performed, a storage warehouse for the metal products can be provided upstream of the grinding station, so as to both decouple grinding times from production times and also allow the supply of metal products coming from other casting lines or, more generally, from other production lines.

Likewise, according to other advantageous variants of the present invention, another storage warehouse can be provided downstream of the grinding station to the advantage of possible supplies to different production or finishing lines.

In accordance with another aspect of the present invention, the movement means comprise at least one heating member disposed at exit from the grinding station, or from the possible other storage warehouse, so as to bring the treated metal products to a determinate temperature and send them to subsequent processing lines, such as a rolling line for example.

Advantageously, for this purpose the movement means can comprise at least a second slider suitable to take the metal product from the heating member toward a subsequent rolling line.

In accordance with another aspect of the present invention, the heating member comprises a heating furnace with a length at least twice the length of the slab, the heating furnace consisting of at least 2 induction modules, each one preferably of 6 MW, mostly disposed in a central zone thereof, so as to be able to make the slab pass upstream and then downstream of the induction modules for a complete heating also of the head and tail edges. The heating member is designed to perform an efficient heating and bring the treated slab to a temperature of approximately 600-650°C.

In accordance with another aspect of the present invention, the heating member comprises an accumulation furnace disposed at exit from the heating furnace, configured to store between 10 and 20 slabs disposed one on top of the other waiting to be sent to the rolling line, according to the operating times of the latter. The heating member is designed to keep the slabs at a temperature of approximately 1000-1050°C. In accordance with another aspect of the present invention, downstream of the accumulation furnace there is provided a heating and homogenization buffer furnace which allows to contain at least three slabs in line before they are sent in sequence to the rolling line. The heating buffer furnace is designed to perform an increase of the temperature of the slabs up to approximately 1150°C. The present invention also concerns a method for treating flat metal products.

The method is performed after a continuous casting process and before a rolling process of the metal products, which advance along a common axis of feed between a continuous casting line and a rolling line. The method comprises at least one optical scanning step, in which at least one surface of the metal products is scanned by means of optical scanning means, at least one processing step, in which an electronic comparison is performed, by means of at least one control and command unit, between the scan performed in the scanning step and a plurality of feedback images, at least one movement step, in which the metal products are selectively moved, by means of movement means communicating electronically with the control and command unit, as a function of the results of the feedback, and at least one surface conditioning step, for example a grinding step, in which at least the metal products, moved in the movement step by the movement means, are surface treated by means of a surface conditioning station.

Therefore, the method of the present invention is advantageously integrated into a traditional continuous casting and subsequent rolling process, to the full advantage of production continuity and overall efficiency.

In accordance with another aspect of the present invention, the optical scanning step is performed with laser technology in order to carry out an optical triangulation on the surface of the metal products. In accordance with another aspect of the present invention, upstream of the optical scanning step there is provided at least one step of producing the metal products by means of a continuous casting line. As a function of the results of the electronic comparison performed in the processing step, the operating parameters of the continuous casting line are selectively modified in order to adjust a subsequent step of producing the metal products.

DESCRIPTION OF THE DRAWINGS

These and other aspects, characteristics and advantages of the present invention will become apparent from the following description an embodiment, given as a non-restrictive example with reference to the attached drawings wherein:

- fig. 1 is a schematic view of a plant for treating flat metal products, according to the present invention, associated with a continuous casting line and a rolling line;

- fig. 2 is a schematic three-dimensional view of a detail of the plant of fig. 1 ; - fig. 3 is a partial plan view of a first embodiment of the plant of fig. 1 ;

- fig. 4 is a partial plan view of a second embodiment of the plant of fig. 1 ;

- fig. 5 is a block diagram of a method for treating flat metal products, according to the present invention.

We must clarify that in the present description the phraseology and terminology used, as well as the figures in the attached drawings also as described, have the sole function of better illustrating and explaining the present invention, their function being to provide a non-limiting example of the invention itself, since the scope of protection is defined by the claims.

To facilitate comprehension, the same reference numbers have been used, where possible, to identify identical common elements in the drawings. It is understood that elements and characteristics of one embodiment can be conveniently combined or incorporated into other embodiments without further clarifications.

DESCRIPTION OF AN EMBODIMENT OF THE PRESENT INVENTION

With reference to fig. 1, a plant 10 according to the present invention is applied for the surface treatment of flat metal products, in this case thin slabs 50 (fig. 2), that is, with thicknesses less than 200 mm, intended in particular for forming steel strip to be used, preferably but not exclusively, for “exposed” uses in the automotive, household appliance, or similar industrial sectors.

In this case, the plant 10 is interposed between a continuous casting line 110, by means of which the thin slabs 50 are made, and a rolling line 120, in which the treated slabs 50 are rolled until the desired rolled metal strip is obtained. The continuous casting line 110 and the rolling line 120 can be of a substantially traditional type and, therefore, will not be described in detail and are only shown schematically in the drawings.

The continuous casting line 110 can for example comprise a continuous casting machine, feeding means for making the cast metal product advance and a maintenance and/or heating tunnel furnace 14, located downstream of the continuous casting machine.

The plant 10 according to the present invention generally comprises optical scanning means, in this case a scanning station 11 , movement means, in this case a movement unit 12, and a surface conditioning station, which in this specific example case is a grinding station 13. The plant 10 is also provided with a command and control unit, hereafter processing unit 15, configured to command, control and coordinate the functionality of the stations 11 and 13 and of the movement unit 12.

The scanning station 11 is favorably disposed between the continuous casting line 110 and the rolling line 120. More in detail, the continuous casting line 110, the scanning station 11 and the rolling line 120 are advantageously disposed along a common axis of feed X of the slabs 50.

The scanning station 11 is favorably disposed upstream of the tunnel furnace 14 of the continuous casting line 110.

The grinding station 13 is, on the contrary, preferably disposed offline, that is, off the axis of feed X. In this way, the feed of the de feet- free slabs 50 can continue without interruptions or slowdowns in the process, while the slabs 50 to be treated continue along a preferential path distinct from that of the slabs 50 that go directly to the rolling line 120.

With particular reference to fig. 2, the scanning station 11 comprises a structure made, in this case, as a portal 16, disposed substantially astride the hypothetical axis of transit of the slabs 50, and a plurality of sliding rollers 17 on which the slabs 50 transit in a guided manner. In any case, the structure could be flag-like, a robotic arm, articulated or other.

The axis of transit can advantageously coincide with the axis of feed X of the slabs 50. Therefore, each slab 50 at exit from a casting machine of the continuous casting line 110 can transit, in continuity, through the scanning station 11 and subsequently undergo a selective conditioning in the surface conditioning station, in this case the grinding station 13. The portal structure 16 is conformed to support a plurality of laser scanners 19, shown only schematically in the drawing, disposed and configured so as to perform a three-dimensional triangulation of the external surfaces of the slabs 50. The scanners 19 generally form optical scanning means. Advantageously, the scanners 19 are disposed to scan substantially all of the surfaces of the slabs 50 passing through the portal structure 16, so as to be able to inspect all of the surfaces of each of the slabs 50.

This laser scanning performed with the scanners 19 cannot, by definition, be influenced by the high temperature of the slab 50, which exits from the casting line 110 at over 850°C.

Each scanner 19, in fact, inspects the surface of the slab 50 by scanning it and detecting any depressions, cobbling or other surface elements, without having to identify their image.

The data thus detected are sent to the processing unit 15, which performs a comparison with its internal database, which contains thousands of images corresponding to predefined errors/defects, or ones that can be implemented.

This operation allows, mainly, both to accurately locate the defect on the surface of the slab 50, possibly identifying its coordinates X, Y, Z, and also to classify the type of defect. In this way, by being able to understand in which zone of the slab 50 the defect is located, it is possible to program the grinding station 13 in such a way as to perform the specific treatment only in the identified zone, thus saving time and material removed.

Moreover, the classification of the type of defect is useful to determine its origin. In this way, by recording the casting parameters of each slab 50, when a particular type of defect is detected on a specific slab 50 it is possible to trace back to the parameters with which it was produced, thus searching for the causes that led to the defect and making the appropriate corrections to the casting line 110 so that this situation does not occur in the future. According to an advantageous solution of the present invention, the processing unit 15 is programmed with a self-learning algorithm which, on the basis of the correlations between the parameters and the continuation of the casting, estimates and predicts the quality of the resulting slabs 50. In this advantageous solution according to the present invention, the scanning of the product therefore allows further verification with respect to the prediction, so as to further optimize the administration of the process parameters and the consequent predictions. In the embodiment shown in fig. 3, the plant 10 according to the present invention is suitable to cold surface treat the defective slabs 50, that is, at a temperature comprised between about 100°C and ambient temperature, which can conventionally be around 20°C.

In this embodiment, the movement unit 12 comprises a first slider 20 which constitutes the mobile section, or shuttle, of the maintenance and/or heating tunnel furnace 14 located downstream of the continuous casting machine. The first slider 20 picks up the defective slab 50 from the scanning station 11 and transports it to the entrance of a lateral transfer device 21, unloading it thereon. A first auxiliary slider 20’, normally offline, takes the place of the first slider 20 so as not to leave an empty space and give continuity to the tunnel furnace 14 and thus allow the transit of the slabs that do not have to be treated toward the rolling line 120. The first auxiliary slider 20’ again gives way to the first slider 20 when the latter has to pick up another slab to be treated.

The sizes and functions of the transfer device 21 are such that the slab 50 is cooled, passing from about 870-950°C to a temperature of about 20-50°C, for example by means of a controlled cooling.

Furthermore, in this case, a first storage warehouse 22 for storing the slabs 50 can be provided immediately at the exit of the transfer device 21. This warehouse also allows previously stored slabs 50, or ones coming from external sources with respect to the casting line 110, to be taken for processing.

By means of the first slider 20, forming part of the movement unit 12, the slabs 50 stored in the warehouse 22 are directed, in sequence, toward the grinding station 13.

The latter preferably comprises a rotating disk grinder 25, of a substantially known type and shown only schematically in the drawings, which, compared to the scarfing operation, has the advantage of not burning the steel leading it to oxidize. This means that there is no generation of fumes and CO2 emissions and that the scrap can be recovered and reused as scrap in the smelting processes. Furthermore, since the slab 50 is at almost ambient temperature, the grinder 25 has no problem working its surface with specific operation in the zones indicated by the processing unit 15, as a function of the data provided by the scanning station 11. Advantageously, a second grinder 25b can be provided, in this case detached from the grinder 25 and suitable to intervene with specificity on a second surface of the slab 50.

It is not excluded that, by means of a tilter, or other member not shown, the same grinder 25 can perform the working on all the defective surfaces of the slab 50, or equally that the two grinders 25 and 25b can be mounted opposite each other so as to intervene simultaneously on different surfaces of the same slab 50, or two or more grinding stations 13 are used to perform different grinding interventions or on several slabs 50 in parallel.

A second storage warehouse 26 can be provided downstream of the grinding station 13, in which the treated slabs 50 can be selectively stored both so that they can be sent to the rolling line 120 in a second instant, and also to introduce slabs 50 even coming from external sources, possibly purchased or processed in other areas, to the rolling line 120.

The movement unit 12 also comprises a heating furnace 27 which is disposed downstream of the second warehouse 26 and the grinding station 13, and is conformed so as to be able to receive the treated slab 50 and move it alternately therein, so as to heat it along its entire length to a temperature close to that suitable for rolling.

Advantageously, the Applicant has experimented that the heating furnace 27 has to have a length at least twice, preferably at least 3 times, the length of the slab 50 in order to carry out an effective heating and bring the treated slab 50 to a temperature of about 600-650°C. Preferably, the heating furnace 27 can have 2-3 induction modules 27’, or simply inductors, each preferably of 6 MW, disposed in series mostly in a central zone thereof, so as to be able to make the slab 50 pass upstream and then downstream of the same inductors, for a complete heating also of the head and tail edges.

The heating cycle can have a variable duration as a function of the thickness of the slab 50 and the difference between the temperature at entry and the desired temperature at exit. Therefore, in the case of a cold cycle, the heating cycle can have a duration of about 1 hour.

In a preferred embodiment, taking advantage of the reduced thickness of the slabs 50, the heating furnace 27 uses transverse flow induction modules 27’ or, according to a variant, longitudinal flow modules, or a combination of the two.

Moreover, the heating furnace 27 can also provide an active power supply by means of electric heating elements, preferably made of a metal alloy known as Resithom alloy (FeCrAl).

In a particularly advantageous solution, shown in the drawings, an accumulation furnace 29 is provided disposed at exit from the heating furnace 27 and in which the treated and heated slab 50 is stored and maintained at temperature waiting to be sent to the rolling line 120, according to the operating timings thereof. The heating furnace 27 can store from 10 to 20 treated and heated slabs, disposed one on top of the other, and maintain them at a temperature of 1000-1050°C. In addition, a heating and homogenization buffer furnace 30 is advantageously provided downstream of the accumulation furnace 29, which allows to contain at least three slabs 50 in line and allows to perform an increase of the temperature of the slabs themselves up to about 1150°C, before the latter are sent in sequence to the rolling line 120. The heating and homogenization buffer furnace 30 heats the slab 50 by means of 3-4 induction modules 30’, preferably of 6 MW each, disposed in series in the exit terminal segment.

Downstream of the heating buffer furnace 30, the movement unit 12 comprises a second slider 31, substantially similar to the first slider 20 but with substantially the opposite function, namely, to pick up the treated slabs 50 heated to the rolling temperature in order to put them back into the production line feeding the rolling line 120. A second auxiliary slider 31 ’ can be provided which, similarly to the first auxiliary slider 20’, guarantees continuity to the tunnel furnace 1 for the time during which the second slider 31 remains offline. In the embodiment shown in fig. 4, the plant 10 according to the present invention is suitable to heat treat the defective slabs 50, that is, at a temperature below 800°C, so as not to damage the grinding wheels or not to shorten their useful life. In this embodiment, the first slider 20 of the movement unit 12 is suitable to pick up the defective slab 50 at exit from the scanning station 11 and transport it directly toward the grinding station 13. The operational functionality of the first slider 20 is, in this case, such as to allow a modest cooling of the removed slab 50, before feeding it to the grinding station 13.

The slab 50 is then surface treated as previously described, preferably at the upper part, at the lower part, possibly at the edges, and is then sent toward the heating furnace 27 to be brought to the temperature close to that suitable for rolling. In this embodiment, starting from a slab 50 with a higher temperature, the heating cycle can last about half an hour.

Although not specifically shown in fig. 4, storage warehouses 22 and 26 can also be provided in this embodiment, upstream and downstream of the grinding station 13.

Unlike the previously described solution of the cold cycle, in this case, the storage warehouses 22 and 26 can be suitably insulated or heated by means of active electrical heating elements, of a substantially known type.

At the end of the heating, the slab 50 can be sent to an accumulation furnace 29 and from there to a heating furnace 30 of the type already described, to ensure that the slab 50 reaches the temperature of about 1150°C, suitable for rolling. With reference to the block diagram shown in fig. 5, the operation of the plant 10 described heretofore, which corresponds to the method according to the present invention, comprises the following steps.

Initially, the thin slabs 50 are made by means of a normal continuous casting process. Once the casting steps are finished, each slab 50 is subjected to a laser scanning through which it is possible to detect any surface defects, regardless of the high temperatures of the slabs 50 at exit from the continuous casting.

As a function of the comparison between the scanning performed and the feedback images provided in the processing unit 15, the movement unit 12 is activated or not.

In fact, in case of negativity, the slabs 50 are sent to rolling in order to produce the desired coils of strip.

On the other hand, in case of positivity to a defect, the slabs 50 are moved toward the grinding station 13 for the correction of the defects. Simultaneously, a modification of the casting parameters is commanded in order to prevent, or at least limit, the occurrence of the same defect.

At this point, once the defect has been corrected, the slabs 50 are sent to rolling in order to produce the desired coils of strip.

According to an advantageous variant of the main inventive idea, at the end of the rolling, an additional automatic qualitative verification with optical systems can be provided, to verify the possible permanence of some defects.

In this case, it will also be possible to use systems different from those of laser scanning, for example based on cameras, since the rolled strip is substantially cold.

This verification allows to compare the error present on the finished product with the scanning of the initial slab 50, to determine if the defect originated in casting or not. In fact, when the defect is absent in the scans downstream of the casting, but appears in those downstream of the rolling, it can be deduced that some parameters of the rolling itself have to be modified in order to prevent the occurrence of unwanted defects.

It is clear that modifications and/or additions of parts or steps may be made to the plant 10 and to the method as described heretofore, without departing from the field and scope of the present invention, as defined by the claims. It is also clear that, although the present invention has been described with reference to some specific examples, a person of skill in the art will be able to achieve other equivalent forms of plant for treating flat metal products, such as slabs or suchlike, and corresponding treatment method, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.

In the following claims, the sole purpose of the references in brackets is to facilitate their reading and they must not be considered as restrictive factors with regard to the field of protection defined by the claims.