EP4214010B1 - Method and spraying apparatus for thermal surface treatment of a metal product - Google Patents

Description

The invention relates to a method for the thermal surface treatment of a metallic product according to the preamble of claim 1, and a spray device provided for this purpose according to the preamble of claims 21, 22 and 27.

According to the prior art, it is known to subject metallic products, for example continuously cast products, to a heat treatment in the form of a thermal surface treatment. For this purpose, a metallic product can be passed through a spray chamber device, the metallic product being continuously cooled within this spray chamber device by applying water to a surface of the product. This achieves surface quenching of the outer layer of the metallic product. Such a technology is out, for example EP 0 650 790 B1 known.

For example, it is suitable for processing hot-rolled steel in the form of an intermediate steel product DE 196 81 466 T1 known to subject the steel after a rolling step to accelerated cooling at a rate of 12 ° C to 20 ° C / second in order to achieve an exit temperature in the range of approximately 470 ° C to approximately 570 ° C. A steel product treated in this way has increased strength and toughness with a preferred structure including a significant proportion of fine-grained bainite. Further processes and devices for thermal surface treatment of a metallic product are also from the documents WO 00/03042 A1 , EP 3 184 202 A1 and WO 2012/069234 A1 known.

In the prior art mentioned above, the heat treatment for a metallic product takes place essentially uniformly over its length or with the same cooling rates. In this respect, there is a disadvantage in that a possible different Energy content that may be present over the length of a metallic product to be cooled is not sufficiently taken into account in the course of the production or manufacture of the metallic product.

Accordingly, the invention is based on the object of optimizing the production of a metallic product with regard to its thermal surface treatment in order to be able to influence a resulting material or microstructure of the metallic product.

This object is achieved by a method with the features of claim 1 and by a spray device with the features of one of claims 21, 22 and 27. Advantageous developments of the invention are defined in the dependent claims.

The invention provides a method for the thermal surface treatment of a metallic product, in particular in the form of a casting strand or a slab formed therefrom, in which the metallic product is moved in a transport direction through a treatment section of a spray device equipped with cooling nozzles and cooling fluid is passed through the cooling nozzles of the spray device is applied to the surfaces of the metallic product. The metallic product has - viewed in the transport direction of the metallic product - a front section and a trailing rear section. When performing this process, the rear portion of the metallic product is cooled more than the front portion of the metallic product. The result of this is that the heat removal by means of the cooling fluid applied to the surfaces of the metallic product in the material of the metallic product at a predetermined depth thereof over a length range that extends between the front section and the rear section of the metallic product, a substantially uniform ferrite content is established.

In an advantageous development of the method according to the invention, the cooling nozzles are arranged at least in a first group and in a second group. It is provided here that the second group of cooling nozzles - viewed in the transport direction of the metallic product - is arranged downstream of the first group of cooling nozzles.

In an advantageous development of the method according to the invention, the cooling nozzles are connected to at least one frequency-controlled pump for supplying cooling fluid, with which the cooling fluid is conveyed to the cooling nozzles with a predetermined amount and a predetermined pressure. It can be provided here that separate frequency-controlled pumps are provided for the first group of cooling nozzles and for the second group of cooling nozzles. Alternatively, it can also be provided that the first and second groups of cooling nozzles are fed with cooling fluid by only one central frequency-controlled pump, with at least one control valve being provided in a line between the frequency-controlled pump and the cooling nozzles of the first and second groups, respectively in which a targeted amount of water and/or a predetermined pressure can be set for the cooling nozzles of the first or second group in relation to the cooling fluid.

The present invention also provides a spray device for the thermal surface treatment of a metallic product, in particular in the form of a casting strand or a slab formed therefrom, comprising a treatment section with an inlet area and an outlet area, the metallic product being sprayed along the treatment section from the inlet area in the direction of the outlet area can be moved in a transport direction, and a plurality of cooling nozzles, from each of which a cooling fluid can be applied to the surfaces of the metallic product. The cooling nozzles are arranged at least in a first group and in a second group, with the second group of cooling nozzles - seen in the transport direction of the metallic product - downstream of the first group Cooling nozzles are arranged. The cooling nozzles of the first group and the cooling nozzles of the second group are each connected to separate frequency-controlled pumps. With these respective frequency-controlled pumps, a predetermined quantity and/or a predetermined pressure for the cooling nozzles of the first group or for the cooling nozzles of the second group can be set, preferably regulated, with respect to the cooling fluid.

An alternative embodiment of the invention, which has an independent meaning, provides a spray device for the thermal surface treatment of a metallic product, in particular in the form of a casting strand or a slab formed therefrom, comprising a treatment section with an inlet area and an outlet area, the metallic product being sprayed along the treatment section which can be moved in the direction of the outlet area in a transport direction, and a plurality of cooling nozzles, from each of which a cooling fluid can be applied to the surfaces of the metallic product. The cooling nozzles are arranged at least in a first group and in a second group, with the second group of cooling nozzles - viewed in the transport direction of the metallic product - being arranged downstream of the first group of cooling nozzles. Here, the cooling nozzles of the first group and the cooling nozzles of the second group are connected to at least one frequency-controlled pump, with at least one control valve being provided in a line between the frequency-controlled pump and the cooling nozzles of the first and second groups, with which the cooling fluid is connected a quantity of water and/or a pressure for the cooling nozzles of the first or second group is adjustable, preferably controllable.

In an advantageous development of the spray device according to the invention, a control device is provided with which the frequency-controlled pump, or the frequency-controlled pumps, and / or the control valve is or are in signal connection. This makes it possible for the operation of these pumps and/or the control valve to be dependent on at least one process parameter metallic product can be controlled, preferably regulated. These process parameters of the metallic product may include the temperature upstream and/or downstream of the spray device, the temperature at the top and/or bottom, and/or a ferrite content that was measured downstream of the spray device.

The invention is based on the essential finding that the metallic product, which can be a continuous or endless casting strand or an isolated slab formed from it, is cooled unevenly with respect to its longitudinal extent. Specifically, in the method according to the invention, this occurs in such a way that the rear section of the metallic product - viewed in the transport direction of the metallic product - is cooled more strongly than its front section, with the result that in between the front and rear sections of the Metallic product extending length range of the metallic product a targeted microstructure is achieved, namely an essentially uniform ferrite proportion. Precisely for this purpose, in the spray device according to the invention, the cooling nozzles are arranged at least in a first group and in a second group, whereby these groups of cooling nozzles - seen in the transport direction of the metallic product - can each be fed with different amounts of cooling fluid. This is achieved either by a suitable control of the separate frequency-controlled pumps to which the cooling nozzles of the respective first and second groups are connected, or by a suitable control of the at least one control valve, which is in a line between the frequency-controlled pump and the cooling nozzles of the first or second group is provided.

In the course of the above-mentioned thermal surface treatment, which is characteristic of the present invention, a further aim is that the energy content of the metallic product with regard to a further Processing following thermal surface treatment is as large as possible. In other words, the metallic product is only cooled to the extent required for the desired constant structural transformation, thereby maintaining the uniform ferrite content in the material of the metallic product at a predetermined depth thereof, for example 5-10 mm, over one to achieve a length range extending between the front section and the rear section of the metallic product.

In an advantageous development of the method according to the invention, a plurality of cooling nozzles are arranged in the treatment section of the spray device above the metallic product and/or below the metallic product along the transport direction of the metallic product. A cooling fluid is sprayed under pressure from these cooling nozzles onto the surfaces of the metallic product. This cooling fluid is expediently used in the form of water or based on water.

In order to realize the above-mentioned characteristic cooling of the metallic product, which is stronger or more intensive at its rear section than at its front section, it is provided according to the present invention that the amount and / or the pressure for the cooling fluid for the cooling nozzles of the first Group are set larger than for the cooling nozzles in the second group. Such a supply of the cooling nozzles of the first group of cooling nozzles with a larger amount of cooling fluid and/or a greater pressure than in comparison to the second group of cooling nozzles is expediently set for the cooling nozzles both on the top and on the bottom of the metallic product.

In an advantageous development of the invention it can be provided that the temperature of the metallic product is measured. This can be done - viewed in the transport direction of the metallic product - upstream and/or downstream of the spray device. Furthermore, the can Temperature of the metallic product can be measured at its top and/or bottom. In any case, the temperature measurement for the metallic product is carried out for the purpose of adjusting or regulating the amount of cooling fluid that is applied from the cooling nozzles of the spray device onto the surfaces of the metallic product depending on this measured temperature of the metallic product.

In the same way, depending on a measured temperature of the metallic product, the transport speed of a metallic product in the form of a separated slab, or the change in this transport speed for the slab within the treatment section of the spray device, can also be adjusted or regulated. In this regard, it should be understood that by means of the transport speed at which an isolated slab is guided past the cooling nozzles provided therein in the treatment section of the spray device, or by specifically changing them, it can be achieved that the front section of the slab is guided past these cooling nozzles faster than the rear section of the slab, with the result that - as explained - the rear section of the slab is then cooled more strongly.

Another possibility for a targeted influence on the cooling of the metallic product is that - viewed in the transport direction of the metallic product - the surface quality of the metallic product is measured downstream of the spraying device in relation to the proportion of ferrite. This makes it possible for the amount of cooling fluid that is applied from the cooling nozzles of the spray device to the surfaces of the metallic product and/or its pressure and/or the transport speed of the slab or the change in this transport speed along the treatment section of the spray device in Depending on the measured proportion of ferrite can be set or regulated.

In the event that, according to an advantageous development of the invention, the cooling nozzles are arranged along the treatment section of the spray device on both sides of the metallic product, i.e. above and below it, it is expedient that the amount of water and / or the pressure for the cooling nozzles is below metallic product are chosen to be larger than for the cooling nozzles, which are arranged above the metallic product. This can be achieved by supplying the cooling nozzles, which are arranged on the bottom of the metallic product, with cooling fluid from their own frequency-controlled pump, which means that the cooling nozzles, which are arranged on the top of the metallic product, are supplied by a separate one Frequency-controlled pump can be fed with cooling fluid. In other words, the different supply of the cooling nozzles on the underside of the metallic product compared to the cooling nozzles on the top of the metallic product is achieved in that the cooling nozzles, which are arranged below and above the metallic product, are each supplied to different frequency-controlled pumps connected with cooling fluid.

In an advantageous development of the invention, it can be provided that the thickness of the metallic product for which the characteristic thermal surface treatment is implemented is at least 250 mm and/or that a width of the metallic product is at least 3000 mm.

In an advantageous development of the invention, it can also be provided that the cooling fluid is intermittently applied from the cooling nozzles to the surfaces of the metallic product. This leads to the advantage that a controlled local heat removal can be achieved by means of intensive water cooling, for example at a specific point on the metallic product in relation to its longitudinal extent.

According to a further alternative embodiment of the invention, which has an independent meaning, is a spray device for the thermal surface treatment of a metallic product in the form of a separated slab, comprising a treatment section with an inlet area and an outlet area, the metallic product being moved along the treatment section on a roller table of the inlet area can be moved towards the outlet area in a transport direction, and a plurality of cooling nozzles, from each of which a cooling fluid can be applied to the surfaces of the metallic product. At least one roller element of the roller table is equipped with a motor drive. Preferably, the roller element equipped with the motor drive can be arranged adjacent to the treatment section.

In the last-mentioned embodiment of the spraying device according to the invention, by controlling the motor drive with which at least one roller element of the roller table is equipped, it can be achieved that an isolated slab with its front section - viewed in the transport direction - is attached to the cooling nozzles arranged in the treatment section is passed faster than the rear section of the isolated slab. As a result, this leads to the rear section of the isolated slab being cooled more strongly than its front section, with the result that, as already explained elsewhere above, there is a predetermined depth in the material of the slab Length range that extends between the front section and the rear section of the slab sets a substantially uniform ferrite proportion.

In an advantageous development of the last-mentioned embodiment of the spray device according to the invention, a control device is provided with which the motor drive of the roller element is in signal connection, namely such that the speed or the peripheral speed of the roller element depends on at least one process parameter of the metallic Product or the isolated slab can be controlled and preferably regulated.

In an advantageous development of the invention, the at least one process parameter of the metallic product, depending on which the amount and/or the pressure for the cooling fluid can be adjusted or regulated, can be selected from the group consisting of temperature, ferrite content in the material of the metallic Product and/or geometry of the metallic product, in particular in relation to its cross section perpendicular to the transport direction.

The present invention creates a technology for targeted thermal surface treatment that enables automated adjustment of the temperature for a metallic product and its resulting metal structure. For example, the targeted delivery of a larger amount of cooling fluid through the cooling nozzles of the first group than through the cooling nozzles of the second group causes the rear section of the metallic product to undergo locally controlled, more intensive cooling than the front section of the metallic product.

The present invention makes it possible to influence the surface quality and structure of a steel casting strand produced on a vertical, vertical bend (i.e. system with a vertical area), a horizontal or curved continuous casting system (without a vertical area), in particular a casting strand of any product format.

Fig. 1

eine schematisch vereinfachte Seitenansicht einer Stranggießanlage, die eine erfindungsgemäße Sprüheinrichtung zur thermischen Oberflächenbehandlung eines metallischen Produkts umfasst, und mit der ein erfindungsgemäßes Verfahren durchführbar ist,

Fig. 2

eine vergrößerte Darstellung der Sprüheinrichtung von Fig. 1 gemäß einer ersten Ausführungsform,

Fig. 3

eine vergrößerte Darstellung der Sprüheinrichtung von Fig. 1 gemäß einer zweiten Ausführungsform,

Fig. 4

eine vereinfachte Seitenansicht eines Rollgangs, der Teil der Stranggießanlage von Fig. 1 ist,

Fig. 5

eine vereinfachte Seitenansicht eines Rollgangs, der Teil der Stranggießanlage von Fig. 1 ist, gemäß einer weiteren Ausführungsform,

Fig. 6

eine Perspektivansicht eines Schnellwechselrahmens, der Teil der Sprüheinrichtung von Fig. 2 ist, und

Fig. 7

eine Perspektivansicht einer Mehrzahl von Schnellwechselrahmen wie in Fig. 6 gezeigt, die zu einer Sprüheinrichtung gemäß Fig. 2 zusammengefasst sind, und

Fig. 8

ein Flussdiagramm zur Veranschaulichung eines erfindungsgemäßen Verfahrens und dessen Durchführung.

Exemplary embodiments of the invention are described in detail below using a schematically simplified drawing. Show it:

Fig. 1

a schematically simplified side view of a continuous casting system, which has a spray device according to the invention for thermal surface treatment a metallic product, and with which a method according to the invention can be carried out,

Fig. 2

an enlarged view of the spray device from Fig. 1 according to a first embodiment,

Fig. 3

an enlarged view of the spray device from Fig. 1 according to a second embodiment,

Fig. 4

a simplified side view of a roller table, which is part of the continuous caster of Fig. 1 is,

Fig. 5

a simplified side view of a roller table, which is part of the continuous caster of Fig. 1 is, according to a further embodiment,

Fig. 6

a perspective view of a quick-change frame, which is part of the spray device Fig. 2 is and

Fig. 7

a perspective view of a plurality of quick-change frames as in Fig. 6 shown, which corresponds to a spray device Fig. 2 are summarized, and

Fig. 8

a flowchart to illustrate a method according to the invention and its implementation.

Below are with reference to the Fig. 1-8 preferred embodiments of a spray device 10 and a corresponding method for thermal surface treatment of a metallic product according to the present invention are shown and explained in order to achieve a targeted structural transformation or a desired structure, namely a substantially uniform ferrite content, for the metallic product. The same features in the drawing are each provided with the same reference numbers. At this point it should be noted that the drawing is simply simplified and, in particular, shown without a scale.

Fig. 1 basically shows a simplified side view of a continuous casting system 100, which is equipped with the spray device 10.

In a known manner, the continuous casting system 100 includes Fig. 1 a mold that has a lower opening and thereby a vertical outlet downwards. The mold is filled with liquid metal up to a level or liquid metal, for example steel or a steel alloy. A metallic product 1 emerges through the lower opening of the mold in the form of a casting strand 2, which then runs through a supporting strand guide and is thereby transferred to the horizontal.

The continuous casting system 100 comprises a roller table 8 with a plurality of roller elements 9, on which the casting strand 2 is moved further in the transport direction T after it has been transferred to the horizontal.

For the continuous casting plant 100 according to Fig. 1 It can be a thick slab plant with which a casting strand 2 with a thickness of preferably 250 mm, or possibly even larger casting thicknesses, can be produced.

The spray device 10 according to the invention is arranged in a part of the continuous casting system 100 in which the casting strand 2 has already been transferred to the horizontal. This spray device 10 is used for the thermal surface treatment of the casting strand 2 and for this purpose is equipped with a plurality of cooling nozzles 16 which are provided in a treatment section 12 of the spray device 10.

The spray device 10 comprises a housing G. In a front region of this - seen in the transport direction T of the casting strand 2 - an inlet region 14 is formed for the casting strand 2, with in a - seen in the transport direction T of the casting strand 2 - rear region of the housing G an outlet area 15 is formed.

Adjacent to the inlet area 14 and the outlet area 15, temperature measuring devices 13 are provided within the housing G, with which the Temperature of the casting strand 2 can be determined both when entering the housing G and when leaving the housing G. These temperature measuring devices 13 can each be arranged above and below the casting strand 2 or the roller table 8, on which the casting strand 2 is also moved in the transport direction T within the treatment section 12 of the spray device 10.

Irrespective of whether the casting strand 2 enters the treatment section 12 of the spray device 10 as an endless product, i.e. before being separated into a slab, or already as a separated slab, it can generally be stated that the metallic product 1, if it is within the treatment section 12 the spray device 10, has a front section 4 - seen in the transport direction T of the casting strand 2 - with which the metallic product 1 enters the treatment section 12. In the same way, the metallic product has a rear section 5 - seen in the transport direction T of the casting strand 2 - which lags behind the front section 4 or - again seen in the transport direction T of the casting strand 2 - is located upstream of the front section 4 .

The individual cooling nozzles 16 are combined into at least two groups within the treatment section 12 of the spray device 10, namely in a first group 16.1 and in a second group 16.2. Here, the second group 16.2 of the cooling nozzles 16 - seen in the transport direction T of the casting strand 2 - is arranged downstream of the first group 16.1 of the cooling nozzles 16.

Both the first group 16.1 and the second group 16.2 each contain cooling nozzles 16, which are arranged both on the top 6 of the casting strand 2 and on its underside 7. The top 6 and the bottom 7 of the casting strand are, for example, in the Fig. 2 and Fig. 3 referred to as such.

The continuous casting system 100 comprises a separating device in the form of scissors S, which - seen in the transport direction T of the casting strand 2 - is arranged upstream of the spray device 10. In the same way, a cleaning device 22, for example in the form of a descaler, is also arranged upstream of the spray device 10.

The following are with reference to the Fig. 2 and Fig. 3 various embodiments for the spray device 10 according to the invention are shown and explained. As far as these two embodiments are already mentioned above in connection with the Fig. 1 have the characteristics explained and agree in this respect, these characteristics will not be explained again.

A first embodiment for the spray device 10 according to the invention is shown in FIG Fig. 2 shown. In this embodiment, separate frequency-controlled pumps 18 are provided, with which the cooling nozzles 16 on the one hand of the first group 16.1 and on the other hand of the second group 16.2 are supplied with cooling fluid separately. For this purpose, the cooling nozzles 16 of the first group 16.1 and the second group 16.2 are each connected via a line 17 to the frequency-controlled pump 18 assigned to them.

The two frequency-controlled pumps 18 are connected to a control device 20 for signaling purposes. Both of these pumps 18 are connected by unspecified lines to a tank or the like in which cooling fluid is contained. Operation of these pumps 20 can thus be suitably controlled or regulated by the control device 20 in order to thereby supply the cooling nozzles 16 of both the first group 16.1 and the second group 16.2 with cooling fluid.

In the lines 17 between the frequency-controlled pumps 18 and the first group 16.1 or the second group 16.2 of cooling nozzles 16, control valves 19 are provided, which are also connected to the control device in terms of signaling 20 are connected and can thereby be actuated. A suitable operating position of these control valves 19 can be used to control whether cooling fluid is applied to the surfaces of the casting strand 2 or not.

Fig. 3 shows a second embodiment for the spray device 10 according to the invention. In contrast to the first embodiment according to Fig. 2 In the second embodiment, the cooling nozzles 16 of both the first group 16.1 and the second group 16.2 are now connected to a common frequency-controlled pump 18 for the purpose of supplying cooling fluid. By means of a control valve 19, which is provided in a line 17 between the frequency-controlled pump 18 and the two groups 16.1 and 16.2 of the cooling nozzles 16, it is possible to adjust the amount and at what pressure the cooling fluid is supplied to the cooling nozzles 16 of the first group 16.1 and is fed to the second group 16.2.

In the same way as in the first embodiment of Fig. 2 can also be used in the second embodiment Fig. 3 the frequency-controlled pump 18 and the control valve 17 are each controlled or regulated by the control device 20.

In both embodiments of the spray device 10 according to Fig. 2 and Fig. 3 It can be provided that at least one roller element 9 of the roller table 8 is equipped with a motor drive M. Accordingly, this driven roller element is shown in the illustrations Fig. 2 and Fig. 3 each labeled "9(M)". This driven roller element 9 (M) is also in signal connection with the control device 20, as shown, for example, in the Fig. 3 is symbolized by the dotted line and can be controlled accordingly by means of the control device 20.

The invention now works as follows:

During operation of the continuous casting system 100, a metallic product 1 is first produced in the form of a casting strand 2, which, after leaving the mold, first passes through the supporting strand guide and, after being transferred to the horizontal on the roller table 8, is moved further in the transport direction T. It can be provided here that the surfaces of the casting strand 2 are cleaned by means of the cleaning device 22, for example by applying water under high pressure.

As it moves on the roller table 8, the metallic product 1 also passes through the treatment section 12 of the spray device 10. A thermal surface treatment for the metallic product 1 is carried out in that cooling fluid 16 is directed onto the surfaces through the cooling nozzles of the first group 16.1 and the second group 16.2 of the metallic product 1 is applied.

The metallic product 1 can be a casting strand 2 that has not yet been separated and accordingly represents an endless profile. This is in the representation of Fig. 4 illustrated, in which such an endless casting strand 2 is moved on the roller table 8 in the transport direction T.

The thermal surface treatment of the casting strand 2 within the treatment section 12 of the spray device 10 can be carried out in such a way that cooling fluid is applied to the surfaces of the casting strand 2 from the cooling nozzles 16 of the first group 16.1 with a larger amount and/or a greater pressure than in the comparison from the Cooling nozzles 16 of the second group 16.2. This then has the consequence that the trailing rear section 5 of the casting strand 2 within the treatment section 12 of the spray device 10 is cooled more strongly than its front section 4. With this cooling strategy the result is achieved that in the material of the casting strand 2 at a predetermined depth of this, over a length range that extends between the front section 4 and the rear section 5, a substantially uniform ferrite proportion is established.

In the course of the present invention, thermal surface treatment is also possible for an isolated slab 3, which has previously been formed from the casting strand 2, within the treatment section 12 of the spray device 10. Here, the casting strand 2 is separated by means of the scissors S before it reaches the spray device 10 on the roller table 8, so that a correspondingly separated slab 3 then enters the treatment section 12 of the spray device 10 or its housing G.

Moving the separated slab 3 within the treatment section 12 of the spraying device 10 in the transport direction T can be achieved by the driven roller element 9 (M). This is, for example, in the representation of Fig. 5 illustrated.

Even in the event that a metallic product 1 in the form of an already separated slab 3 is subjected to a thermal surface treatment in the spray device 10, the cooling strategy already explained above can be pursued, according to which a rear section 5 of the slab 3 is cooled more strongly than the front one Section 4 hereof. This can be achieved by, as already explained, cooling fluid being applied to the surfaces of the slab 3 from the cooling nozzles 16 of the first group 16.1 with a larger quantity and/or greater pressure than from the cooling nozzles 16 of the second group 16.2. Additionally or alternatively, this cooling strategy can be achieved by moving the isolated slab 3 into the treatment section 12 of the spray device 10 or into its housing G in such a way that the front section 4 of the slab 3 passes the cooling nozzles 16 faster than the trailing one rear section 5 of the slab 5. This can be achieved with a suitable control of the driven roller element 9 (M) by the control device 20.

In the 6 and 7 Further features for the spray device 10 according to the invention are shown and explained, which can be implemented in all of the embodiments already mentioned above.

Fig. 6 shows a simplified perspective view of a quick-change frame 24 in which a group of cooling nozzles 16 are arranged. A line 17 for cooling fluid leads laterally into such a quick-change frame 24 and is connected to spray pipes to which the individual cooling nozzles 16 are attached. As already explained above, the line 17 is connected to a frequency-controlled pump 18 in order to thereby supply the cooling nozzles 16 with cooling fluid.

The perspective representation of Fig. 6 clarifies that the quick-change frame 24 is designed in cross section in the form of a rectangular profile that encloses a central opening. In this regard, it should be understood that the roller table 8, which is in the for simplification Fig. 6 is not shown, extends through this central opening. Thus, the top 6 and the bottom 7 of the metallic product 1 can be supplied with cooling fluid when this cooling fluid is discharged through the cooling nozzles 16 in the direction of the metallic product 1.

The quick-change frame 24 is equipped with a height adjustment device H. This height adjustment device H acts on the spray pipes, which are arranged above the roller table 8. Accordingly, by activating this height adjustment device H, it is possible to change the distance between the cooling nozzles 16, which are arranged above the metallic product 1, relative to the top side 6 of the metallic product 1.

With regard to a quick-change frame 24 according to Fig. 6 It should be pointed out separately at this point that this applies to the cooling nozzles 16 of the first group 16.1 as well as to the cooling nozzles 16 of the second group 16.2 can be used. This means that in the embodiments according to Fig. 2 and Fig. 3 A total of two quick-change frames 24 are used, namely on the one hand for the cooling nozzles 16 of the first group 16.1 and on the other hand for the cooling nozzles 16 of the second group 16.2.

Fig. 7 shows a perspective view of the spray device 10 according to a further embodiment, in which - seen in the transport direction T of the metallic product - a total of three groups of cooling nozzles 16 are arranged. In addition to the groups 16.1 and 16.2 already mentioned, a third group 16.3 of cooling nozzles 16 is now also provided, which - viewed in the transport direction T of the metallic product - is arranged downstream of the second group 16.2.

For the third group 16.3 of cooling nozzles 16, it goes without saying that a quick-change frame 24 is also required for this purpose Fig. 6 can be used to arrange the cooling nozzles 16 above and below the metallic product 1.

In the embodiment of Fig. 7 , in which, as just explained, a total of three groups of cooling nozzles 16 are provided, it goes without saying that cooling fluid is discharged from the cooling nozzles 16 of the third group 16.3 with a smaller amount and/or a smaller pressure than from the cooling nozzles 16 of the second group 16.2 . In other words, the amount of cooling fluid discharged from the cooling nozzles 16 and/or its pressure for the three groups 16.1, 16.2 and 16.3, in this order, are continuously reduced along the transport direction T.

With regard to the third group 16.3 of cooling nozzles 16, it can be provided that this is assigned to the front section 4 of the metallic product 1. Correspondingly, the cooling nozzles 16 of the second group 16.2 are then located approximately in an area between the front section 4 and the rear section 5 of the metallic product 1.

The quick-change frames 24 are positioned along the roller table 8 in such a way that they are integrated into the housing G of the spray device 10 and thereby a closed housing chamber K is formed at least in the area of the treatment section 12 of the spray device 10. In the upper area of this housing chamber K a cover is provided, which is shown in the illustration Fig. 7 marked with the designation “D”.

With regard to the above-mentioned closed housing chamber K, it is understood that the inlet area 14 and the outlet area 15 of the housing chamber K are each equipped with a lock function in order to prevent the metallic product 1 from entering into the housing chamber K or the metallic product 1 from running out out of the housing chamber K to ensure.

With regard to the individual groups of cooling nozzles 16, it should be pointed out separately at this point that - seen in the transport direction T - a distance between these groups can be adjusted in relation to one another. This applies equally to both the embodiment of Fig. 2 and Fig. 3 , in each of which a first group 16.1 and a second group 16.2 of cooling nozzles 16 are provided, as well as for the embodiment of Fig. 7 , in which a total of three groups 16.1, 16.2 and 16.3 are provided for the cooling nozzles 16. Such an adjustment of a distance between the groups of cooling nozzles 16 can be implemented in a simple manner if, as explained, a quick-change frame 24 is used for each of these groups Fig. 6 is used.

In all of the above-mentioned embodiments of the spray device 10 according to the invention, the housing G can be equipped with a water vapor suction direction (not shown). It is therefore possible that water vapor, which can form within the closed housing chamber K when a metallic product 1 is inside the treatment section 12 of the Spray device 10 is subjected to a thermal surface treatment, is suctioned off suitably by means of this water vapor suction direction.

Further features for carrying out a method according to the invention for thermal surface treatment are in the flow chart of Fig. 8 called. With regard to the spray device 10, it should be emphasized that a defined heat removal for the metallic product 1 can be achieved using an adjustable amount of water. In the case of treating an isolated slab 3, this can also be achieved by means of an adjustable transport speed with which the slab 3 is moved into the treatment section 12 of the spray device 10 and thereby moved past the cooling nozzles 16.

Furthermore, the flowchart from Fig. 8 that it is possible by means of individual process parameters, which can include the geometry, the measured temperature of the metallic product 1 within the spray device 10 in its inlet area 14 and/or outlet area 15 and/or the surface quality of the metallic product 1 measured downstream of the spray device 10 is to implement automated process control that influences the operation of the continuous casting plant 100.

Reference symbol list

1

metallic product

2

casting strand

3

Bram

4

front section (of metallic product 1)

5

lagging rear section (of metallic product 1)

6

Top (of metallic product 1)

7

Bottom (of metallic product 1)

8th

Roller table

9

Role element

10

Spray device

12

Treatment section

13

Temperature measuring device

14

Inlet area

15

Run-out area

16

Cooling nozzles

16.1

first group of cooling nozzles 16

16.2

second group of cooling nozzles 16

16.3

third group of cooling nozzles 16

17

Line

18

frequency-controlled pump

19

control valve

20

Control device

22

Cleaning device (e.g. descaler)

24

Quick change frame

100

Continuous casting plant

D

Lid

G

Housing

H

Height adjustment device

K

Housing chamber

M

motor drive (for a roller element)

R

Spray pipes

S

Scissors

T

Transport direction

v

Transport speed (of slab 3)

Claims (32)

1. Method for thermal surface treatment of a metallic product (1), particularly in the form of a cast strip (2) or a slab (3) formed therefrom, in which the metallic product (1) is moved in a transport direction (T) through a treatment section (12), which is equipped with cooling nozzles (16), of a spray device (10) and in that case cooling fluid is applied by the cooling nozzles (16) of the spray device (10) to the surfaces of the metallic product (1), wherein the metallic product (1) as seen in the transport direction (T) of the metallic product (1) has a front section (4) and a trailing rear section (5),
   characterised in that
   the rear section (5) of the metallic product (1) is more strongly cooled than the front section (4) of the metallic product (1) in such a way that by virtue of the heat extraction by means of the cooling fluid applied to the surfaces of the metallic product (1) a substantially more uniform ferrite proportion arises in the material of the metallic product (1) to a predetermined depth thereof over a length region extending between the front section (4) and the rear section (5) of the metallic product (1).
2. Method according to claim 1, characterised in that a plurality of cooling nozzles (16) is arranged in the treatment section (12) of the spray device (10) above the metallic product (1) and/or below the metallic product (1) along the transport direction (T) of the metallic product (1), wherein cooling fluid particularly in the form of or on the basis of water is sprayed under pressure from each of the cooling nozzles (16) onto the surface of the metallic product (1).
3. Method according to claim 2, characterised in that the cooling nozzles (16) are arranged at least in a first group (16.1) and a second group (16.2), wherein the second group (16.2) of the cooling nozzles (16) as seen in the transport direction (T) of the metallic product (1) are arranged downstream of the first group (16.1) of the cooling nozzles (16).
4. Method according to claim 2 or 3, characterised in that the cooling nozzles (16) are for supply of a cooling fluid connected with at least one frequency-regulated pump (18) by which the cooling fluid is conveyed to the cooling nozzles (16) in a predetermined quantity and at a predetermined pressure.
5. Method according to claim 4, characterised in that respective separate frequency-regulated pumps (18) are provided for the first group (16.1) and the second group (16.2) of the cooling nozzles (16).
6. Method according to any one of claims 3 to 5, characterised in that at least one setting valve (19) by which with respect to the cooling fluid a water quantity and/or a pressure for the cooling nozzles (16) of the first or second group (16.1, 16.2) is settable is provided in a duct (17) between the frequency-regulated pump (18) and the cooling nozzles (16) of the first or second group (16.1, 16.2).
7. Method according to claim 5 or 6, characterised in that the water quantity and/or the pressure for the cooling fluid is or are selected to be greater for the cooling nozzles (16) of the first group (16.1) than for the cooling nozzles (16) of the second group (16.2) so that the rear section (5) of the metallic product (1) is thereby more strongly cooled than its front section (4).
8. Method according to any one of the preceding claims, characterised in that the metallic product (1) as seen in its transport direction (T) is cut upstream of the spray device (10) and thus is separated to form a slab (3).
9. Method according to claim 8, characterised in that the transport speed (v) of the slab (3) is changed in the treatment section (12) of the spray device (10) in such a way that the front section (4) of the slab (3) is moved more quickly past the cooling nozzles (16) than the rear section (5) of the slab (3).
10. Method according to any one of the preceding claims, characterised in that the metallic product (1) as seen in its transport direction (1) is cleaned, preferably descaled, upstream of the spray device (10).
11. Method according to any one of the preceding claims, characterised in that the temperature of the metallic product (1) as seen in its transport direction is measured upstream of the spray device (10).
12. Method according to any one of the preceding claims, characterised in that the temperature of the metallic product (1) as seen in its transport direction is measured downstream of the spray device (10).
13. Method according to claim 11 or 12, characterised in that the temperature of the metallic product (1) is measured at its upper side (6).
14. Method according to any one of claims 11 to 13, characterised in that the temperature of the metallic product (1) is measured at its lower side (7).
15. Method according to any one of claims 11 to 14, characterised in that the quantity of cooling fluid delivered from the cooling nozzles (16) of the spray device (10) to the surfaces of the metallic product (1) is set or regulated in dependence on the measured temperature of the metallic product (1).
16. Method according to any one of claims 11 to 15 insofar as dependent on claim 9, characterised in that the transport speed (v) of the slab (3) or the change in this transport speed (v) is set or regulated within the treatment section (12) of the spray device (10) in dependence on the measured temperature of the metallic product (1).
17. Method according to any one of the preceding claims, characterised in that the surface quality of the metallic product (1) is measured with respect to the proportion of ferrite component downstream of the spray device (10) as seen in the transport direction (T) of the metallic product (1), wherein the quantity of cooling fluid delivered from the cooling nozzles (16) of the spray device (10) to the surfaces of the metallic product (1) and/or the pressure thereof and/or the transport speed of the slab (3) or the change in this transport speed (v) is or are set or regulated along the treatment section (12) of the spray device (10) in dependence on the measured proportion of ferrite.
18. Method according to any one of claims 2 to 17, characterised in that the cooling nozzles (16) are arranged along the treatment section (12) of the spray device (10) not only above the metallic product (1), but also below the metallic product (1), wherein the water quantity and/or the pressure for the cooling nozzles (16) below the metallic product (1) is or are selected to be greater than for the cooling nozzles (16) above the metallic product (1), preferably in that the cooling nozzles (16) arranged below the metallic product (1) and the cooling nozzles (16) arranged above the metallic product (1) are connected with pumps (18) with respectively different frequency regulation.
19. Method according to any one of the preceding claims, characterised in that the thickness of the metallic product (1) is at least 250 mm and/or a width of the metallic product (1) is at least 3000 mm.
20. Method according to any one of the preceding claims, characterised in that the cooling fluid is delivered from the cooling nozzles (16) to the surfaces of the metallic product (1) intermittently.
21. Spray device (10) for thermal surface treatment of a metallic product (1), particularly in the form of a cast strip (2) or a slab (3) formed therefrom, for performing the method according to any one of claims 1 to 20, comprising

    a treatment section (12) with an inlet region (14) and an outlet region (15), wherein the metallic product (1) is movable in a transport direction (T) along the treatment section (12) from the inlet region (14) in the direction of the outlet region (15) and

    a plurality of cooling nozzles (16), from each of which a cooling fluid can be delivered to the surfaces of the metallic product (1),

    characterised in that

    the cooling nozzles (16) are arranged at least in a first group (16.1) and a second group (16.2), wherein the second group (16.2) of the cooling nozzles (16) as seen in the transport direction (T) of the metallic product (1) is arranged downstream of the first group (16.1) of the cooking nozzles (16), and

    the cooling nozzles (16) of the first group (16.1) and the cooling nozzles (16) of the second group (16.2) are respectively connected with separate frequency-regulated pumps (18), wherein with respect to the cooling fluid a predetermined quantity and/or a predetermined pressure for the cooling nozzles (16) of the first group (16.1) or for the cooling nozzles (16) of the second group (16.2) is settable, preferably regulable, by the respective frequency-regulated pumps (18).
22. Spray device (10) for thermal surface treatment of a metallic product (1), particularly in the form of a cast strip (2) or a slab (3) formed therefrom, for performing the method according to any one of claims 1 to 20, comprising

    a treatment section (12) with an inlet region (14) and an outlet region (15), wherein the metallic product (1) is movable in a transport direction (T) along the treatment section (12) from the inlet region (14) in the direction of the outlet region (15) and

    a plurality of cooling nozzles (16), from each of which a cooling fluid can be delivered to the surfaces of the metallic product (1),

    characterised in that

    the cooling nozzles (16) are arranged at least in a first group (16.1) and a second group (16.2), wherein the second group (16.2) of the cooling nozzles (16) as seen in the transport direction (T) of the metallic product (1) is arranged downstream of the first group (16.1) of the cooking nozzles (16), and

    the cooling nozzles (16) of the first group (16.1) and the cooling nozzles (16) of the second group (16.2) are connected with at least one frequency-regulated pump (18) and at least one setting valve (19) by which with respect to the cooling fluid a water quantity and/or a pressure for the cooling nozzles (16) of the first or second group (16.1, 16.2) is or are settable, preferably regulable, is provided in a duct (17) between the frequency-regulated pump (18) and the cooling nozzles (16) of the first or second group (16.1, 16.2).
23. Spray device (10) according to claim 21 or claim 22, characterised by a control device (20) by which the frequency-regulated pump or pumps (18) and/or the setting valve (19) is or are in signal connection in such a way that the operation of this pump or these pumps (18) and/or the setting valve (19) is controllable, preferably regulable, in dependence on at least one process parameter of the metallic product (1).
24. Spray device (10) according to any one of claims 21 to 23, characterised in that the metallic product is movable in the transport direction (T) along the treatment section (12) on a roller path (8) from the inlet region (14) to in the direction of the outlet region (15), wherein at least one roller element (9) of the roller path (8) is equipped with a motorised drive (M), preferably in that the roller element (9) equipped with the motorised drive (M) is arranged adjacent to the treatment section (12).
25. Spray device (10) according to any one of claims 21 to 24, characterised in that the first group (16.1) of cooling nozzles (16) and the second group (16.2) of cooling nozzles (16) are respectively arranged in separate quick-change frames (24).
26. Spray device (10) according to any one of claims 21 to 25, characterised in that a spacing of the first group (16.1) of cooling nozzles (16) and the second group (16.2) of cooling nozzles (16) relative to one another in the transport direction (T) of the metallic product (1) is adjustable to be variable.
27. Spray device (10) for thermal surface treatment of a metallic product (1) in the form of a separated slab (3), for performance of the method according to any one of claims 1 to 20, comprising

    a treatment section (12) with an inlet region (14) and an outlet region (15), wherein the metallic product (1) is movable in a transport direction (T) along the treatment section (12) on a roller path (8) from the inlet region (14) in the direction of the outlet region (15) and

    a plurality of cooling nozzles (16), from each of which a cooling fluid can be delivered to the surfaces of the metallic product (1),

    characterised in that

    at least one roller element (9) of the roller path (8) is equipped with a motorised drive (M), preferably in that the roller element (9) equipped with the motorised drive (M) is arranged adjacent to the treatment section (12).
28. Spray device (10) according to claim 27, characterised in that a control device (20) is provided, with which the motorised drive (M) of the roller element (9) is in signal connection in such a way that the rotational speed or the circumferential speed of the roller element (9) is controllable, preferably regulable, in dependence on at least one process parameter of the metallic product (1).
29. Spray device (10) according to claim 23 or 27, characterised in that the at least one process parameter of the metallic product (1) is selected from the group consisting of temperature, ferrite proportion in the material of the metallic product (1) and/or geometry of the metallic product (1), particularly with respect to its cross-section perpendicularly to the transport direction (T).
30. Spray device (10) according to any one of claims 21 to 29, characterised by a housing (G) in which the treatment section (12) is provided, preferably in that the housing is equipped with a water-steam suction device, further preferably that the housing (G) is constructed in the form of a chamber (K) and is substantially closed, wherein the inlet region (14) and the outlet region (15) of the housing chamber (K) are each furnished with gate function so as to ensure running of the metallic product into the housing chamber (K) or running of the metallic product (1) out of the housing chamber (K).
31. Spray device (10) according to any one of claims 27 to 30, characterised in that the cooling nozzles (16) are arranged in at least one quick-change frame (24).
32. Spray device (10) according to any one of claims 21 to 31, characterised by a height adjusting device (H) by which cooling nozzles (16) arranged at an upper side (6) of the metallic product (1) are arranged to be adjustable in their height so that a spacing of these cooling nozzles (16) relative to the roller path (8) is thereby settable.

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