Apparatus and method for producing a hot-rolled metal strip

Abstract

Apparatus (1) and method for producing a hot-rolled metal strip (2), wherein the apparatus (1) comprises: a finishing mill (10) with at least one rolling stand (11) having work rolls forming a roll gap for hot-rolling the metal strip (2); and a rapid cooling device (20) arranged immediately behind the roll gap of the last rolling stand (11) of the finishing mill (10) and configured to rapidly cool the metal strip (2) by applying a coolant, preferably water-based, to the top and bottom surfaces of the metal strip (2) along a cooling section of the rapid cooling device (20); wherein the rapid cooling device (20) is configured to apply a quantity of coolant between 100 and 300 m³ to both the top and bottom surfaces of the metal strip (2). 3 / (m 2 *h) to apply.

Description

Technical field

[0001] The invention relates to a device and a method for producing a hot-rolled metal strip, comprising a finishing mill for hot-rolling the metal strip and a cooling device for cooling the metal strip after the finishing mill. Background of the invention

[0002] A general optimization goal for rolling a metal strip in a rolling mill, especially in a hot strip mill, is to improve the material's strength and toughness properties and to prevent stresses. To this end, the cooling of the hot-rolled products after forming can be specifically controlled.

[0003] It is known that a fine grain structure (fine-grain hardening) has a positive effect on the strength and toughness properties of the material. According to the Hall-Petch and Cottrell-Petch relationships, a decrease in ferrite grain size in the material's microstructure leads to an increase in strength and toughness. Generally, a decrease in ferrite grain diameter results in an increase in yield strength and tensile strength; see also WO 2014 / 177664 A1.

[0004] It is difficult to achieve a ferrite grain size below 5 µm using conventional thermomechanical rolling and cooling processes. Therefore, concepts in plant, process, and plant engineering for the industrial-scale production of high-strength metallic materials remain the subject of ongoing research and development. Description of the invention

[0005] One object of the invention is to provide an improved device and an improved method for producing a hot-rolled metal strip, in particular to improve the mechanical properties of the metal strip.

[0006] The problem is solved by a device having the features of claim 1 and a method having the features of the dependent method claim. Advantageous embodiments follow from the dependent claims, the following description of the invention, and the description of preferred embodiments.

[0007] The device is used for hot rolling a metal strip, for example, with a final rolling temperature of approximately 850 °C. The device is particularly suitable for use in hot rolling mills, including CSP plants or heavy plate mills. The material to be rolled is a metal strip, preferably a steel strip, which, as a general term, includes flat rolled products such as sheets of varying properties.

[0008] The device comprises a finishing mill with at least one rolling stand, which includes work rolls forming a roll gap in the usual manner, for hot rolling the metal strip. The metal strip is transported in one conveying direction during rolling and exits the last rolling stand in the conveying direction.

[0009] The device further comprises a rapid cooling unit, which is arranged and configured immediately behind the roll gap of the last rolling stand of the finishing mill to rapidly cool the metal strip by applying a coolant to the top and bottom surfaces of the metal strip along a cooling section of the rapid cooling unit. The coolant is preferably water or a water-based liquid coolant. The rapid cooling unit can be arranged such that the cooling of the metal strip takes place at least partially within the reach of the last rolling stand in the conveying direction.

[0010] The rapid cooling device is configured according to the invention to apply a quantity of coolant between 100 and 300 m³ to both the top and the bottom of the metal strip. 3 / (m 2 *h) to apply.

[0011] Such a small quantity of coolant, applied immediately after finish rolling, reliably prevents grain growth during the austenite-ferrite transformation and recrystallization in the microstructure of the metal strip. According to the Hall-Petch and Cottrell-Petch relationships, this results in an increase in the strength and toughness of the metal strip.

[0012] The rapid cooling device can have spray bars on its upper and lower surfaces, relative to the metal strip, each with a plurality of nozzles for spraying the coolant onto the metal strip. The number of nozzles on the upper surface of the metal strip is preferably 50 to 120 nozzles / m. 2 and preferably 80 to 150 nozzles / m² on the underside 2The upper nozzles are preferably positioned a maximum of 800 mm above the metal strip, and the lower nozzles are preferably positioned a maximum of 170 mm below the metal strip. The nozzle diameter is preferably in the range of 3 to 8 mm. Using these parameters, a sufficient quantity of coolant for rapid cooling can be applied to the metal strip within a short cooling section.

[0013] For the same reason, the coolant pressure is preferably in the range of 2 to 5 bar. The rapid cooling system therefore has a coolant supply and one or more coolant supply lines that are in fluid connection with the spray bars, in order to supply the nozzles with the coolant at the aforementioned pressure, which can be achieved, for example, by means of a sufficiently tall tank or standpipe, or by means of booster pumps.

[0014] In addition to ensuring the metal strip is supplied with a sufficient quantity of coolant, it is important to prevent the coolant from escaping uncontrollably towards the last rolling stand of the finishing mill or in the opposite direction. For example, strip temperature measuring devices can be installed directly before and / or after the rapid cooling unit, but coolant leakage should be prevented to avoid distorting the measurement results.

[0015] To prevent uncontrolled leakage of coolant from the cooling section of the rapid cooling device, one or more end spray bars are preferably arranged in the front and rear sections such that the spray direction of the coolant from the corresponding nozzles is directed obliquely onto the metal belt, into the interior of the rapid cooling device. For this purpose, the end spray bars and / or their nozzles can be inclined relative to the conveying direction of the metal belt.

[0016] To prevent uncontrolled leakage of coolant from the cooling section of the rapid cooling unit, a squeezing roller and / or an air blower can be installed at the inlet and / or outlet of the rapid cooling unit. Such measures are particularly useful on the top of the metal belt, where coolant can collect without dripping downwards.

[0017] Preferably, the rapid cooling device is configured to set cooling rates such that: cooling rate * strip thickness > 500 K / s * mm, thereby achieving particularly rapid cooling of the metal strip.

[0018] Preferably the length L1 of the cooling section of the rapid cooling device is at least 4 m and / or a maximum of 10 m, in particular approximately 9 m, whereby rapid cooling takes place within a comparatively short cooling section.

[0019] The rapid cooling process achieved in this way is designed to prevent stresses in the metal strip that could lead to edge waviness and / or unevenness. To prevent this, the coolant flow rates on the top and bottom of the metal strip can be adjusted in a specific ratio. Good flatness is achieved when more coolant is applied to the underside of the metal strip than to the top. The coolant flow rate ratio between the top and bottom is preferably adjustable separately on the top and bottom of the metal strip by means of a flow control system, in order to specifically prevent stresses in the strip. The coolant flow rate ratio between the top and bottom is preferably adjustable in the range of at least 3:1 to 1:3. An optimal coolant flow rate ratio between the top and bottom is 1:2.

[0020] Preferably, the rapid cooling device is configured to apply a total coolant quantity of at least 800 m³ to the top and bottom of the metal strip. 3 / h per meter of bandwidth, preferably at least 1500 m 3 / h, preferably at least 2400 m 3 / h.

[0021] Preferably, the device includes a further cooling device downstream of the rapid cooling unit, which is configured to adjust the metal strip to the desired final temperature, preferably a suitable coil temperature. The further cooling device is preferably designed for laminar cooling.

[0022] The aforementioned problem is further solved by a method for producing a hot-rolled metal strip, the method comprising: hot rolling of a metal strip in a finishing mill with at least one rolling stand having work rolls forming a roll gap; and immediate cooling of the metal strip following hot rolling by applying a coolant, preferably water-based, to the top and bottom surfaces of the metal strip along a cooling section of the rapid cooling device, the rapid cooling device being arranged directly behind the roll gap of the last rolling stand of the finishing mill; the rapid cooling device applying a quantity of coolant between 100 and 300 m³ to both the top and bottom surfaces of the metal strip. 3 / (m 2 *h) applies.

[0023] The features, technical effects, advantages and embodiments described in relation to the device apply analogously to the method.

[0024] For the reasons mentioned above, the rapid cooling device preferably comprises, on the top and bottom sides relative to the metal strip, spray bars with a plurality of nozzles each for spraying the coolant onto the metal strip, a coolant supply and one or more coolant supply lines which are in fluid communication with the spray bars for supplying the nozzles with the coolant, wherein the coolant supply preferably sets the inlet pressure of the coolant in the coolant supply lines to a pressure of 2 to 5 bar.

[0025] Preferably, for the reasons mentioned above, the rapid cooling device has one or more end spray bars in the front and / or rear area of ​​the rapid cooling device, the nozzles of which apply the coolant to the metal strip at an angle directed obliquely into the interior of the rapid cooling device.

[0026] Preferably, for the reasons mentioned above, a cooling rate is set in the rapid cooling device for which the following applies: Cooling rate * strip thickness > 500 K / s * mm.

[0027] For the reasons mentioned above, preferably the underside of the metal strip in the rapid cooling device is exposed to at least twice as much coolant as the top side of the metal strip.

[0028] Preferably, for the reasons mentioned above, a total coolant quantity of at least 800 m³ is applied to the top and bottom of the metal strip in the rapid cooling device. 3 / h applied per meter of bandwidth, preferably at least 1500 m 3 / h, preferably at least 2400 m 3 / h.

[0029] Further advantages and features of the present invention will become apparent from the following description of preferred embodiments. The features described therein can be implemented individually or in combination with one or more of the features set out above, provided that the features do not contradict each other. The following description of preferred embodiments is given with reference to the accompanying drawings. Brief description of the characters

[0030] Preferred further embodiments of the invention are explained in more detail by the following description of the figures. These show: Fig. 1. Schematic representation of a device for the production of a metal strip, comprising a finishing line and a rapid cooling device; and Fig.2 Schematically, the rapid cooling device according to an exemplary embodiment. Detailed description of preferred embodiments

[0031] Preferred embodiments are described below with reference to the figures. Identical, similar, or equivalent elements in the figures are designated with identical reference numerals, and repeated descriptions of these elements are sometimes omitted to avoid redundancy.

[0032] The Fig. Figure 1 schematically shows a device 1 for producing a metal strip 2. The device 1 is used particularly in hot rolling mills, including CSP plants or heavy plate rolling mills. The material to be rolled is a metal strip 2, preferably a steel strip, which as a general term includes flat rolled products such as sheets of varying properties.

[0033] The device 1 has a finishing mill 10, the last rolling stand 11 of which is located in the Fig. Figure 1 shows the metal strip 2 being hot-rolled in the finishing mill 10 and exiting the last rolling stand 11 in a conveying direction F.

[0034] Immediately behind the last rolling stand 11 of the finishing mill 10, and in particular behind the roll gap of the last rolling stand 11, a rapid cooling device 20 is arranged, which is designed to rapidly cool the metal strip 2 immediately after hot rolling. The rapid cooling in the rapid cooling device 20 takes place within a comparatively short cooling section with a length L1 of, for example, less than 10 m, preferably approximately 9 m, measured from the roll gap of the last rolling stand 11 of the finishing mill 10.

[0035] Downstream of the rapid cooling device 20, a further cooling device 30 is arranged, which is configured to adjust the metal strip 2 to the desired final temperature, for example, to a suitable coiling temperature. The further cooling device 30 can be designed for laminar cooling, in which the coolant, in particular cooling water, is applied to the rolled material at a comparatively low line pressure (for example, between 0.05 and 0.1 bar). The cooling device 30 has a plurality of spray bars 31 that apply the coolant to the metal strip 2 from above or from both above and below, preferably in a uniform, curtain-like laminar flow.

[0036] The further cooling device 30 can be divided into several segments or sections, for example ten segments according to the present embodiment. The distance L2 of the further cooling device 30 from the roll gap of the last rolling stand 11 of the finishing mill 10, measured at the beginning of the cooling device 30, is preferably less than 20 m, in particular approximately 14 m.

[0037] Downstream of the further cooling device 30, a reeling device 40 is installed for winding up the finished metal strip 2.

[0038] On the treatment section for the metal strip 2, one or more temperature measuring devices 50, 60 can be installed, for example between the rapid cooling device 20 and the further cooling device 30 as well as downstream of the further cooling device 30, in order to measure the temperature(s) at the corresponding locations for monitoring the process.

[0039] To achieve immediate cooling of the metal strip 2 following hot rolling in the finishing mill 10, the rapid cooling unit incorporates 20 different features which, individually but especially in combination, enable the microstructure to be "frozen" after the final forming operation in the finishing mill 10, thus preventing grain growth and recrystallization. The subsequent austenite-ferrite transformation results in an extremely small ferrite grain size, preferably less than 5 µm. According to the Hall-Petch and Cottrell-Petch relationships, this leads to an increase in the strength and toughness of the metal strip 2.

[0040] The applied deformation in the rolling stands before rapid cooling is preferably between 10 and 50%.

[0041] The cooling process in the rapid cooling unit 20 is designed to ensure that, if possible, only an austenite-ferrite transformation occurs. If the final rolling temperature is approximately 850 °C, the rapid cooling unit 20 is preferably configured so that the temperature after rapid cooling is approximately 700 °C. In a subsequent cooling stage in the further cooling unit 30, which connects to the rapid cooling unit 20, the desired final temperature or coil temperature can be set.

[0042] Materials whose mechanical properties are particularly improved by this immediate cooling preferably have a ferritic microstructure.

[0043] The chemical analysis of such materials preferably lies in the following areas: Table 1: Exemplary chemical analysis of a ferritic microstructure for the metal strip 2. element Minimum content (wt%) Maximum content (wt%) C 0,002 0,15 Si 0,006 0,5 Mn 0,1 2,2 Cr 0,01 0,4 Mon 0,01 0,2 Ni 0,01 0,3 Cu 0,01 0,25 N 0,0 0,01 Al 0,01 0,3 Note 0 0,1 V 0 0,1 Ti 0 0,1 P, S 0 0,05

[0044] To achieve immediate cooling in the rapid cooling unit 20 with the aforementioned results, the rapid cooling unit 20 is configured to apply a sufficiently large quantity of coolant compactly to the metal strip 2. The application rate is between 100 and 300 m² on both the top and bottom surfaces. 3 / (m 2 *h).

[0045] The rapid cooling unit 20, see also Fig. 2, has spray bars 21 on the upper and lower sides (relative to the metal strip 2), each with a plurality of nozzles 22, which are supplied with a coolant via a coolant supply 23 and one or more coolant supply lines 24. The coolant is preferably water or a liquid water-based coolant.

[0046] The coolant pressure in the coolant supply lines 24 is preferably in the range of 2 to 5 bar, which can be achieved, for example, by means of a correspondingly tall reservoir or standpipe, or by means of one or more booster pumps in the coolant supply system 23. The number of nozzles 22 on the top surface is preferably 50 to 120 nozzles / m². 2 and preferably 80 to 150 nozzles / m² on the underside 2 The height of the upper spray bars 21 or nozzles 22 is preferably a maximum of 800 mm above the belt edge. The lower nozzles 22 are preferably arranged a maximum of 170 mm below the belt edge. The diameter of the nozzles 22 is preferably in the range of 3 to 8 mm.

[0047] In addition to supplying the metal strip 2 with a sufficient quantity of coolant, it is important that the coolant does not escape uncontrollably towards the last rolling stand 11 of the finishing mill 10 or in the other direction, i.e., towards the further cooling unit 30. For example, strip measuring devices can be installed directly before and / or after the rapid cooling unit 20, whereby coolant leakage should be avoided to prevent distorting the measurement result.

[0048] To prevent uncontrolled escape of coolant from the cooling section of the rapid cooling device 20, one or more end-side spray bars 21' are arranged in the front and / or rear area such that the spray direction of the coolant from the corresponding nozzles 22' is directed obliquely into the interior of the rapid cooling device 20, cf. Fig.2. For this purpose, the end spray bars 21' and / or their nozzles 22' can be inclined relative to the conveying direction F.

[0049] Further measures can be taken to prevent uncontrolled coolant leakage from the rapid cooling unit 20. Preferably, a coolant spray system with a pre-pressure of approximately 8 to 15 bar is installed, featuring flat jet nozzles arranged in a row, preferably perpendicular to the conveying direction F. Furthermore, at least one squeezing roller 25 can be provided at the outlet of the rapid cooling unit 20. An air blow-off system 26 can be installed immediately upstream of any measuring devices to completely clean the strip surface of coolant and vapor. Typical air velocities at the nozzle outlet of the air blow-off system are preferably between 200 and 750 m / s.

[0050] The coolant supply 23 and / or coolant supply lines 24 can have a bypass circuit used to switch the coolant on and off very quickly. This makes it possible to set defined head and foot lengths very precisely.

[0051] Preferably, the rapid cooling device 20 is configured to set cooling rates such that: cooling rate * strip thickness > 500 K / s * mm. The length L1 of the immediate cooling in the rapid cooling device 20 is preferably at least 4 m.

[0052] The rapid cooling process must not cause any stresses in the metal strip 2 that could lead to edge waves and / or unevenness. To achieve this, the coolant volumes on the top and bottom surfaces of the metal strip 2 should be adjusted to a specific ratio. Good flatness is achieved when twice the amount of coolant is applied to the underside of the metal strip.

[0053] The total amount of coolant on the top and bottom of the metal strip 2 should be at least 800 m³. 3 / h per meter of bandwidth, preferably at least 1500 m 3 / h, preferably at least 2400 m 3 / h.

[0054] The coolant flow ratio from the top to the bottom is preferably adjustable separately on the top and bottom of the metal strip 2 by means of a flow control, in order to specifically prevent tension in the strip. The coolant flow ratio from top to bottom is preferably adjustable in the range of at least 3:1 to 1:3. An optimal coolant flow ratio from top to bottom is 1:2.

[0055] For different applications, the cooling in the rapid cooling unit 20 should be flexible in order to allow for lower cooling rates in addition to the highest cooling rates for other metal strips 2. For this purpose, the spray bars 21 are preferably equipped, either collectively or individually, with flow meters and flow controls, for example in the form of control valves and / or pumps. This allows the coolant quantity to be reduced to at least 30% of the maximum flow rate, preferably 20%, and particularly preferably 10%.

[0056] Temperature measuring devices 50 and 60, in the form of pyrometers, can only measure surface temperatures. During rapid cooling within the rapid cooling unit 20, such measurements are not possible. Therefore, one or more measurements in the production line 10 and / or after rapid cooling, for example using temperature measuring devices 50 and 60, are advisable.

[0057] Since a temperature measurement immediately after the last rolling stand 11 of the finishing mill 10 is not possible or only possible with difficulty due to the immediately subsequent rapid cooling unit 20, a temperature measurement is preferably carried out directly before the last rolling stand 11 and / or in one of the preceding rolling stands. Temperature measurement at the entrance to the roll gap of the last rolling stand 11 is difficult due to the ambient conditions (roll cooling, intermediate stand cooling, etc.). For this reason, in addition to a pyrometer, a compressed air nozzle with a pressure of approximately 3 to 8 bar is preferably installed at a height of 200–600 mm relative to the metal strip 2 for a temperature measurement before the rapid cooling unit 20, in order to enable interference-free measurement.Nevertheless, the pyrometer should continue to measure at a wavelength that is insensitive to stray coolant, especially water, in order to exclude any influence of residual coolant if possible.

[0058] Preferably, the temperature distribution of the metal strip 2 in the rapid cooling system is known in order to be able to adjust the required coolant quantities in the rapid cooling device 20 as accurately as possible.

[0059] For this purpose, a cooling model is preferably used that calculates the temperature distribution of the metal strip 2 in the rolling stands of the finishing mill 10 and the rapid cooling unit, preferably using Fourier's heat equation, and preferably over the entire strip thickness, thus enabling precise adjustment of the target values. Any deviation between measurement and calculation can be corrected at a temperature measuring point. This allows the temperature in the roll gap as well as in the cooling section of the rapid cooling unit 20 to be optimally adjusted.

[0060] Furthermore, the cooling model can take into account the target coil temperature, which must be precisely maintained depending on the application. In the additional cooling unit 30, located downstream of the rapid cooling unit, the cooling model switches the necessary coolant quantities to regulate the coil temperature.

[0061] The coolant application via the spray bars 21, 21' of the rapid cooling device 20 is preferably variable across the width in order to compensate for incoming temperature profiles and to achieve uniform temperatures and thus properties across the width of the metal strip 2 on the outlet side.

[0062] The final rolling temperature, i.e., the temperature of the metal strip 2 upon entering the rapid cooling unit 20, can be controlled by changing the speed in the finishing mill 10. The coil temperature can be controlled by changing the coolant quantity, particularly in the subsequent cooling unit 30.

[0063] The immediate, strong cooling of the metal strip 2 after the last forming pass in the finishing line 10, as described herein, results in the production of a very fine microstructure and thus an improvement in the mechanical properties of the metal strip 2.

[0064] Where applicable, all individual features shown in the exemplary embodiments can be combined and / or exchanged without leaving the scope of the invention. Reference symbol list 1 Device for producing a metal strip 2 metal bands 10 Finishing Road 11 Last rolling mill 20 Rapid cooling unit 21 spray bars 21' End spray bars 22 nozzle 22' Nozzle of an end spray bar 23 Coolant supply 24 Coolant supply line 25 Squeeze roller 26 Air blow-off 30 Additional cooling equipment 31 spray bars 40 reel device 50 temperature gauges 60 temperature gauges F Conveyor direction L1 Length of the cooling section of the rapid cooling unit L2 Distance between the roll gap of the last rolling stand and the further cooling device QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2014 / 177664 A1

[0003]

Claims

[1] Device (1) for producing a hot-rolled metal strip (2), comprising: a finishing train (10) with at least one rolling stand (11) having work rolls forming a roll gap for hot rolling the metal strip (2); and a rapid cooling device (20) arranged immediately behind the roll gap of the last rolling stand (11) of the finishing train (10) and configured to rapidly cool the metal strip (2) by applying a coolant, preferably water-based, to the top and bottom of the metal strip (2) along a cooling section of the rapid cooling device (20); wherein the rapid cooling device (20) is designed to apply a quantity of coolant between 100 and 300 m to both the top and the bottom of the metal strip (2) 3 / (m 2 *h) to be applied. [2] Device (1) according to claim 1, characterized bythat the rapid cooling device (20) has, on the top and bottom sides, relative to the metal strip (2), spray bars (21, 21') each having a plurality of nozzles (22, 22') for spraying the coolant onto the metal strip (2), wherein the number of nozzles (22, 22') on the top side is preferably 50 to 120 nozzles / m 2 and on the underside preferably 80 to 150 nozzles / m 2 wherein the upper nozzles (22, 22') are preferably arranged at most 800 mm above the metal strip (2) and the lower nozzles (22, 22') are preferably arranged at most 170 mm below the metal strip (2), wherein the diameter of the nozzles (22, 22') is preferably in the range from 3 to 8 mm. [3] Device (1) according to claim 2, characterized byin that the rapid cooling device (20) has a coolant supply (23) and one or more coolant feed lines (24) which are in fluid communication with the spray bars (21) for supplying the nozzles (22, 22') with the coolant, wherein the coolant supply (23) is designed to set the pre-pressure of the coolant in the coolant feed lines (24) preferably to a pressure of 2 to 5 bar. [4] Device (1) according to claim 2 or 3, characterized by that the rapid cooling device (20) has one or more end-side spray bars (21') in the front and / or rear region of the rapid cooling device (20), which are arranged such that their nozzles (22') apply the coolant to the metal strip (2) at an angle which is directed obliquely into the interior of the rapid cooling device (20). [5] Device (1) according to one of the preceding claims, characterized bythat a squeeze roller (25) and / or an air blower (26) is installed and arranged at the inlet and / or outlet of the rapid cooling device (20) to prevent coolant from escaping from the cooling section of the rapid cooling device (20). [6] Device (1) according to one of the preceding claims, characterized by that the rapid cooling device (20) is designed to set cooling rates for which the following applies: cooling rate * strip thickness > 500 K / s * mm. [7] Device (1) according to one of the preceding claims, characterized by that the length (L1) of the cooling section of the rapid cooling device (20) is preferably at least 4 m and / or a maximum of 10 m, preferably approximately 9 m. [8] Device (1) according to one of the preceding claims, characterized by that the rapid cooling device (20) is arranged to apply at least twice more coolant to the underside of the metal strip (2) than to the top side of the metal strip (2). [9] Device (1) according to one of the preceding claims, characterized by that the rapid cooling device (20) is designed to apply a total coolant quantity of at least 800 m 3 / h per meter of strip width, preferably at least 1500 m 3 / h, particularly preferably at least 2400 m 3 / h. [10] Device (1) according to one of the preceding claims, characterized by that the device (1) has, downstream of the rapid cooling device (20), a further cooling device (30) which is designed to adjust the metal strip (2) to the desired final temperature, preferably a suitable coiling temperature, wherein the further cooling device (30) is preferably designed for laminar cooling. [11] A method for producing a hot-rolled metal strip (2), comprising: Hot rolling of a metal strip (2) in a finishing train (10) with at least one rolling stand (11) having work rolls forming a roll gap; and immediate cooling of the metal strip (2) following hot rolling in the finishing train (10) by applying a coolant, preferably water-based, to the top and bottom of the metal strip (2) along a cooling section of the rapid cooling device (20), wherein the rapid cooling device (20) is arranged immediately behind the roll gap of the last rolling stand (11) of the finishing train (10); wherein the rapid cooling device (20) applies a quantity of coolant between 100 and 300 m to both the top and the bottom of the metal strip (2) 3 / (m 2 *h) applies. [12] Method according to claim 11, characterized bythat the rapid cooling device (20) has, on the top and bottom sides, as seen relative to the metal strip (2), spray bars (21, 21') each having a plurality of nozzles (22, 22') for spraying the coolant onto the metal strip (2), a coolant supply (23) and one or more coolant feed lines (24) which are in fluid communication with the spray bars (21) for supplying the nozzles (22, 22') with the coolant, wherein the coolant supply (23) sets the pre-pressure of the coolant in the coolant feed lines (24) preferably to a pressure of 2 to 5 bar. [13] Method according to claim 12, characterized by that the rapid cooling device (20) has one or more end-side spray bars (21') in the front and / or rear region of the rapid cooling device (20), the nozzles (22') of which apply the coolant to the metal strip (2) at an angle which is directed obliquely into the interior of the rapid cooling device (20). [14] Method according to one of claims 11 to 13, characterized by that a cooling rate is set in the rapid cooling device (20) for which the following applies: cooling rate * strip thickness > 500 K / s * mm. [15] Method according to one of claims 11 to 14, characterized by that in the rapid cooling device (20) the underside of the metal strip (2) is exposed to at least twice as much coolant as the top side of the metal strip (2). [16] Method according to one of claims 11 to 15, characterized by that in the rapid cooling device (20) a total coolant quantity on the top and bottom of the metal strip (2) of at least 800 m 3 / h per meter of strip width, preferably at least 1500 m 3 / h, particularly preferably at least 2400 m 3 / h.

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