Apparatus and methods for manufacturing hot-rolled metal strip

Abstract

An apparatus (1) and method for manufacturing hot-rolled metal strip (2), wherein the apparatus (1) comprises: a finishing mill (10) having at least one mill stand (11) having work rolls forming a roll gap for hot-rolling metal strip (2); and a rapid cooling mechanism (20) directly arranged downstream of the roll gap of the last mill stand (11) of the finishing mill (10), and configured to rapidly cool the metal strip (2) by applying a coolant, preferably a water-based coolant, to the upper and lower sides of the metal strip (2) along a cooling section of the rapid cooling mechanism (20); wherein the rapid cooling mechanism (20) is configured to apply 100-300 μm of coolant to both the upper and lower sides of the metal strip (2). 3 / (m 2 Cooling dose between (×h).

Description

Technical Field

[0001] The present invention relates to an apparatus and method for manufacturing hot-rolled metal strip, comprising a finishing mill for hot-rolled metal strip and a cooling mechanism for cooling the metal strip following the finishing mill. Background Technology

[0002] The overall optimization objective for rolled metal strip in rolling mills, especially hot-rolled strip mills, is to improve the strength and toughness of the material and avoid stress. To this end, the cooling of the hot-rolled product after forming can be specifically influenced.

[0003] It is well known that a fine-grained structure (fine-grained strengthening) in a microstructure has a positive impact on the strength and toughness of a material. According to the Hall-Petch-Beziehung and Cottrell-Petch-Beziehung relations, a reduction in the size of ferrite grains in the microstructure leads to an increase in strength and toughness. In principle, a decrease in ferrite grain diameter increases the yield strength and tensile strength; see also WO2014 / 177664A1 for further details.

[0004] Traditional thermomechanical rolling and cooling processes make it difficult to achieve ferrite grain sizes smaller than 5 μm. Therefore, solutions for equipment, processes, and methods for the industrial-scale production of high-strength metallic materials remain a subject of research and development. Summary of the Invention

[0005] The object of the present invention is to provide an improved apparatus and an improved method for manufacturing hot-rolled metal strip, in particular to improve the mechanical properties of the metal strip.

[0006] This objective is achieved by an apparatus having the features of claim 1 and a method having the features of the parallel method claims. Advantageous improvements are derived from the dependent claims, the following summary of the invention, and the description of preferred embodiments.

[0007] The apparatus is used for hot-rolled metal strip, such as metal strip with a final rolling temperature of approximately 850°C. This apparatus is particularly suitable for hot rolling mills, including CSP equipment or plate mills. The material to be rolled is metal strip, preferably steel strip, which, as a broader concept, includes flat rolled products with different properties, such as plates.

[0008] The apparatus has a finishing mill unit with at least one mill stand, which conventionally has work rolls forming a roll gap for hot-rolling metal strip. The metal strip is conveyed in the conveying direction during rolling and exits the final mill stand in the same direction.

[0009] The apparatus also includes a rapid cooling mechanism located directly downstream of the roll gap of the last mill stand in the finishing mill unit. This mechanism is configured to rapidly cool the metal strip by applying a coolant to the upper and lower sides of the strip along the cooling section of the rapid cooling mechanism. The coolant is preferably water or a liquid water-based coolant. The rapid cooling mechanism can be arranged such that the cooling of the metal strip still occurs at least partially within the extension of the last mill stand along the conveying direction.

[0010] According to the present invention, the rapid cooling mechanism is configured to apply 100-300 μm of cooling force to both the upper and lower sides of the metal strip. 3 / (m 2 Cooling dose between (×h).

[0011] Applying such a cooling dose within a small space and immediately after finishing rolling reliably suppresses grain growth during the austenite-ferrite transformation and recrystallization in the metal strip microstructure. According to the Hall-Page and Cottrell-Page relationships, this results in improved strength and toughness of the metal strip.

[0012] The rapid cooling mechanism may have spray beams with multiple nozzles on both the upper and lower sides relative to the metal strip for spraying coolant onto the metal strip. The number of nozzles on the upper side of the metal strip is preferably 50 to 120 nozzles / m. 2 The preferred number of nozzles on the lower side is 80 to 150 nozzles / m. 2 The upper nozzle is preferably positioned at a distance of up to 800 mm above the metal strip, and the lower nozzle is preferably positioned at a distance of up to 170 mm below the metal strip. The nozzle diameter is preferably in the range of 3 to 8 mm. With the given parameters, a sufficient amount of coolant for rapid cooling can be applied to the metal strip within a short cooling section.

[0013] For the same reason, the pre-pressure of the coolant is preferably in the range of 2 to 5 bar. To this end, the rapid cooling mechanism has a coolant supply section and one or more coolant delivery sections in fluid communication with the injection beam for supplying coolant to the nozzles at the pressure, which can be achieved, for example, by means of an elevated container or riser of a corresponding height, or by means of a booster pump.

[0014] In addition to applying a sufficient amount of coolant to the metal strip, it is important that the coolant does not flow uncontrollably towards or in the opposite direction of the final mill stand of the finishing mill. For example, strip measuring devices can be installed immediately upstream and / or downstream of the rapid cooling mechanism, where coolant outflow should be avoided to prevent distortion of the measurement results.

[0015] To prevent uncontrolled leakage of coolant from the cooling section of the rapid cooling mechanism, it is preferable to provide one or more end-side spray beams in the upstream and downstream regions, such that the spray direction of coolant from the corresponding nozzles is obliquely directed towards the metal strip and towards the interior of the rapid cooling mechanism. For this purpose, the end-side spray beams and / or their nozzles may be obliquely arranged relative to the conveying direction of the metal strip.

[0016] Similarly, to prevent uncontrolled leakage of coolant from the cooling section of the rapid cooling mechanism, squeeze rollers and / or air blowing sections can be installed at the inlet and / or outlet of the rapid cooling mechanism. This measure is particularly meaningful on the upper side of the metal strip, as the coolant can accumulate there instead of dripping downwards.

[0017] Preferably, the rapid cooling mechanism is configured to set a cooling rate that meets the following condition: 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 mechanism is at least 4m and / or at most 10m, especially about 9m, thereby enabling rapid cooling within a relatively short cooling section.

[0019] The rapid cooling achieved in this way should not generate stress in the metal strip that could lead to edge waviness and / or unevenness. To prevent this, the cooling dosage on the upper and lower sides of the metal strip can be set in a specific ratio. When more coolant is applied to the lower side of the metal strip than to the upper side, good flatness is obtained. The ratio of the upper to lower cooling dosage can preferably be adjusted separately on the upper and lower sides of the metal strip by a flow regulating unit to specifically prevent stress in the strip. Here, the ratio of the upper to lower cooling dosage is preferably adjusted to at least within the range of 3:1 to 1:3. A ratio of 1:2 is optimal.

[0020] Preferably, the rapid cooling mechanism is configured to apply a cooling force of at least 800 m per meter of width to the upper and lower sides of the metal strip. 3 The total cooling dose per hour, preferably at least 1500m³, is preferred. 3 / h, preferably at least 2400m 3 / h.

[0021] Preferably, the apparatus has a second cooling mechanism downstream of the rapid cooling mechanism, which is configured to condition the metal strip to a desired final temperature, preferably a suitable winding temperature. This second cooling mechanism is preferably designed for laminar flow cooling.

[0022] The above objective is also achieved by a method for manufacturing hot-rolled metal strip, wherein the method comprises: hot-rolling the metal strip on a finishing mill having at least one mill stand with work rolls forming a roll gap; and immediately after hot rolling, cooling the metal strip by applying a coolant, preferably a water-based coolant, to the upper and lower sides of the metal strip along a cooling section of a rapid cooling mechanism, wherein the rapid cooling mechanism is directly arranged downstream of the roll gap of the last mill stand of the finishing mill; wherein the rapid cooling mechanism applies 100–300 μm of coolant to both the upper and lower sides of the metal strip. 3 / (m 2 Cooling dose between (×h).

[0023] The features, technical effects, advantages, and embodiments described regarding the apparatus are similarly applicable to the method.

[0024] Therefore, for the reasons mentioned above, the rapid cooling mechanism preferably has a spray beam with a plurality of nozzles for spraying coolant onto the metal strip on the upper and lower sides, respectively, a coolant supply section, and one or more coolant delivery sections in fluid communication with the spray beam for supplying coolant to the nozzles, wherein the coolant supply section preferably adjusts the pre-pressure of the coolant in the coolant delivery section to a pressure of 2 to 5 bar.

[0025] Preferably, for the reasons stated above, the rapid cooling mechanism has one or more end-side spray beams in its upstream and / or downstream regions, the nozzles of which apply coolant to the metal strip at an angle inclined toward the interior of the rapid cooling mechanism.

[0026] Preferably, for the reasons mentioned above, a cooling rate is set in the rapid cooling mechanism that satisfies the following condition: cooling rate × strip thickness > 500 K / s × mm.

[0027] Preferably, for the reasons mentioned above, the amount of coolant applied to the underside of the metal strip in the rapid cooling mechanism is at least twice that applied to the upper side of the metal strip.

[0028] Preferably, for the reasons mentioned above, a bandwidth of at least 800m per meter is applied to the upper and lower sides of the metal strip in the rapid cooling mechanism. 3 The total cooling dose per hour, preferably at least 1500m³, is preferred. 3 / h, preferably at least 2400m 3 / h.

[0029] Other advantages and features of the invention will become apparent from the following description of preferred embodiments. The described features may be implemented individually or in combination with one or more of the features described above, provided that these features do not contradict each other. The preferred embodiments will be described below with reference to the accompanying drawings. Attached Figure Description

[0030] Other preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Wherein:

[0031] Figure 1 An apparatus for manufacturing metal strip is schematically shown, comprising a finishing mill and a rapid cooling mechanism; and

[0032] Figure 2 A rapid cooling mechanism according to an embodiment is schematically shown. Detailed Implementation

[0033] Preferred embodiments will now be described with reference to the accompanying drawings. In these drawings, identical, similar, or functionally equivalent elements are given the same reference numerals, and to avoid redundancy, some repeated descriptions of these elements have been omitted.

[0034] Figure 1 An apparatus 1 for manufacturing metal strip 2 is schematically shown. Apparatus 1 is particularly suitable for hot rolling mills, including CSP equipment or plate mills. The material to be rolled is metal strip 2, preferably steel strip, which, as a broader concept, includes flat rolled products with different properties, such as plates.

[0035] The apparatus 1 has a finishing mill 10, the last mill stand 11 of which is located in... Figure 1 As shown in the figure, the metal strip 2 is hot-rolled on the finishing mill 10 and leaves the final mill stand 11 in the conveying direction F.

[0036] Downstream of the last mill stand 11 of the finishing mill 10, particularly downstream of the roll gap of the last mill stand 11, a rapid cooling mechanism 20 is arranged. This rapid cooling mechanism is configured to rapidly cool the metal strip 2 immediately after hot rolling. The rapid cooling on the rapid cooling mechanism 20 takes place in a relatively short cooling section of length L1, for example less than 10 m, preferably about 9 m, which is measured from the roll gap of the last mill stand 11 of the finishing mill 10.

[0037] Downstream of the rapid cooling mechanism 20 is another cooling mechanism 30, configured to condition the metal strip 2 to a desired final temperature, such as a suitable winding temperature. This other cooling mechanism 30 may be designed for laminar flow cooling, in which a coolant, particularly cooling water, is applied to the rolled material at a relatively low line pressure (e.g., between 0.05 and 0.1 bar). The cooling mechanism 30 has multiple spray beams 31 that apply the coolant to the metal strip 2 from above or both above and below, preferably in a uniform, curtain-like laminar flow pattern.

[0038] The other cooling mechanism 30 may be divided into multiple sections or segments, for example, ten sections according to this embodiment. The distance L2 between the other cooling mechanism 30 and the roll gap of the last mill stand 11 of the finishing mill 10 (measured starting from the beginning of the cooling mechanism 30) is preferably less than 20m, and in particular about 14m.

[0039] Downstream of another cooling mechanism 30 is a winding device 40 for winding up the finished metal strip 2.

[0040] One or more temperature measuring instruments 50, 60 can be installed along the processing path of the metal strip 2, for example, between the rapid cooling mechanism 20 and another cooling mechanism 30 and downstream of the other cooling mechanism 30, to measure one or more temperatures at the corresponding locations to monitor the process.

[0041] To achieve immediate cooling of the metal strip 2 after hot rolling on the finishing mill 10, the rapid cooling mechanism 20 incorporates multiple properties that, individually and especially in combination, enable the final microstructure on the finishing mill 10 to be "frozen," preventing grain growth and recrystallization. During the subsequent austenite-ferrite transformation, extremely small ferrite grains, preferably less than 5 μm, are obtained. Based on the Hall-Page and Cottrell-Page relationships, this improves the strength and toughness of the metal strip 2.

[0042] Before rapid cooling, the amount of deformation applied in the rolling mill stand is preferably between 10% and 50%.

[0043] Cooling on the rapid cooling mechanism 20 is carried out in a manner that causes only austenite-ferrite transformation as much as possible. When the final rolling temperature is about 850°C, the rapid cooling mechanism 20 is preferably configured such that the temperature after rapid cooling is about 700°C. In the subsequent cooling process on another cooling mechanism 30 connected to the rapid cooling mechanism 20, a desired final temperature or coiling temperature can be set.

[0044] The mechanical properties of such materials are particularly improved by this immediate cooling, and they preferably have a ferritic microstructure. The chemical analysis of such materials is preferably within the following range:

[0045]

[0046] Table 1: Exemplary chemical analysis of the ferrite microstructure used in metal strip 2.

[0047] To achieve the aforementioned immediate cooling effect in the rapid cooling mechanism 20, the rapid cooling mechanism 20 is configured to apply a sufficiently high cooling dose tightly to the metal strip 2. The application amount on both the upper and lower sides is 100–300 μm. 3 / (m 2 Between ×h).

[0048] See also Figure 2 The rapid cooling mechanism 20 has spray beams 21 with multiple nozzles 22 on its upper and lower sides relative to the metal strip 2. These nozzles are supplied with coolant through a coolant supply section 23 and one or more coolant delivery sections 24. The coolant is preferably water or a liquid water-based coolant.

[0049] The pre-pressure of the coolant in the coolant delivery section 24 is preferably in the range of 2 to 5 bar, which can be achieved, for example, by means of an elevated container tank or riser of a corresponding height, or by means of one or more booster pumps in the coolant supply section 23. The number of nozzles 22 on the upper side is preferably 50 to 120 nozzles / m. 2 The number of nozzles 22 on the lower side is preferably 80 to 150 nozzles / m. 2 The height of the upper spray beam 21 or nozzle 22 is preferably at a maximum of 800 mm above the strip edge. The lower nozzle 22 is preferably arranged at a maximum of 170 mm below the strip edge. The diameter of the nozzle 22 is preferably in the range of 3 to 8 mm.

[0050] In addition to applying a sufficient amount of coolant to the metal strip 2, it is important that the coolant does not flow uncontrollably toward the final mill stand 11 of the finishing mill unit 10 or in the other direction, i.e., toward another cooling mechanism 30. For example, strip measuring devices can be installed directly upstream and / or downstream of the rapid cooling mechanism 20, where coolant outflow should be avoided to prevent distortion of the measurement results.

[0051] To prevent uncontrolled outflow of coolant from the cooling section of the rapid cooling mechanism 20, one or more end-side spray beams 21' are provided in the upstream and / or downstream regions, such that the spray direction of coolant from the corresponding nozzles 22' is obliquely directed towards the interior of the rapid cooling mechanism 20 (see [link]). Figure 2 Therefore, the jet beam 21' and / or its nozzle 22' on the end side can be tilted relative to the conveying direction F.

[0052] Other measures can be taken to prevent uncontrolled leakage of coolant from the rapid cooling mechanism 20. Preferably, a coolant injection section with flat jet nozzles and a pre-pressure of approximately 8–15 bar is installed, these nozzles being arranged in rows preferably orthogonal to the conveying direction F. Furthermore, at least one squeeze roller 25 can be provided at the outlet of the rapid cooling mechanism 20. An air blowing section 26 can be installed directly upstream of any measuring device to completely remove coolant and vapor from the strip surface. The typical air velocity at the nozzle outlet of the air blowing section is preferably between 200 and 750 m / s.

[0053] The coolant supply section 23 and / or the coolant delivery section 24 may have a bypass line that allows for very rapid switching on and off of the coolant. This allows for very precise setting of the defined head and tail lengths.

[0054] Preferably, the rapid cooling mechanism 20 is configured to achieve a cooling rate that satisfies the following condition: cooling rate × strip thickness > 500 K / s × mm. The length L1 of direct cooling in the rapid cooling mechanism 20 is preferably at least 4 m.

[0055] This rapid cooling process should not generate stresses in the metal strip 2 that could lead to edge waviness and / or unevenness. Therefore, the amount of coolant applied to the upper and lower sides of the metal strip 2 should be set in a specific ratio. Good flatness can be achieved when twice the amount of coolant is applied to the lower side of the metal strip compared to the upper side.

[0056] The total cooling charge on the upper and lower sides of metal strip 2 should be at least 800m per meter of strip width. 3 / h, preferably at least 1500m 3 / h, preferably at least 2400m 3 / h.

[0057] The cooling dose ratio between the upper and lower sides can preferably be adjusted separately on the upper and lower sides of the metal strip 2 by the flow regulating unit, so as to specifically prevent stress in the strip. Here, the cooling dose ratio between the upper and lower sides can preferably be adjusted in the range of at least 3:1 to 1:3. A cooling dose ratio of 1:2 between the upper and lower sides is optimal.

[0058] For different applications, the cooling on the rapid cooling mechanism 20 should be flexible so that, in addition to the maximum cooling rate, a lower cooling rate can be set for other metal strips 2. To this end, the spray beam 21 is preferably equipped, integrally and / or separately, with a flow meter and flow control unit, for example, in the form of a regulating valve and / or pump. This allows the cooling dose to be reduced to at least 30%, preferably 20%, and particularly preferably 10% of the maximum flow rate.

[0059] Temperature measuring instruments 50 and 60, in the form of pyrometers, can only measure surface temperature. Measurements cannot be performed in this way during rapid cooling within the rapid cooling mechanism 20. Therefore, it is meaningful to perform one or more measurements, for example, via temperature measuring instruments 50 and 60, within the finishing mill 10 and / or downstream of rapid cooling.

[0060] Because of the immediate rapid cooling mechanism 20, it is difficult or impossible to directly measure the temperature downstream of the last mill stand 11 of the finishing mill unit 10. Therefore, temperature measurement is preferably performed directly upstream of the last mill stand 11 and / or in one of the preceding mill stands. Due to environmental conditions (roll cooling, inter-stand cooling, etc.), it is difficult to measure the temperature at the roll gap entrance of the last mill stand 11. Therefore, in order to perform temperature measurement upstream of the rapid cooling mechanism 20, in addition to a pyrometer, it is preferable to install a compressed air nozzle with a pressure of about 3 to 8 bar, at a height of 200 to 600 mm relative to the metal strip 2, so as to enable interference-free measurement. Nevertheless, the pyrometer should still be used to measure at a wavelength that is insensitive to drifting coolant, especially water, to eliminate the influence of residual coolant as much as possible.

[0061] Preferably, the temperature distribution of the metal strip 2 in the rapid cooling section is known so that the required cooling dose in the rapid cooling mechanism 20 can be set as accurately as possible.

[0062] Therefore, a cooling model is preferably applied, which preferably uses the Fourier thermodynamic equation to calculate the temperature distribution of the metal strip 2 in the mill stand and rapid cooling section of the finishing mill 10, and preferably performs the calculation over the entire strip thickness, thereby enabling precise setting of the target value. Any deviation between the measurement and calculation can be corrected at the temperature measurement point. Thus, the temperature in the roll gap and in the cooling section of the rapid cooling mechanism 20 can be optimally regulated.

[0063] Furthermore, the cooling model can be designed to precisely adhere to the target winding temperature required for the application. The cooling model is connected to the necessary cooling dose in another cooling mechanism 30 located downstream of the rapid cooling section to set the winding temperature.

[0064] The coolant applied by the jet beams 21, 21' of the rapid cooling mechanism 20 is preferably variable in width in order to compensate for the temperature distribution that occurs and to obtain a uniform temperature on the outlet side and thus uniform performance across the entire width of the metal strip 2.

[0065] The final rolling temperature, i.e., the temperature of the metal strip 2 when it enters the rapid cooling mechanism 20, can be adjusted by changing the speed in the finishing mill 10. The coiling temperature can be adjusted by changing the cooling dosage, especially by changing the cooling dosage in another cooling mechanism 30.

[0066] The immediate and intense cooling of the metal strip 2 described herein after the last forming pass in the finishing mill 10 results in a very fine microstructure, which in turn improves the mechanical properties of the metal strip 2.

[0067] Where applicable, all individual features shown in the embodiments may be combined and / or interchanged with each other without departing from the scope of the invention.

[0068] List of reference numerals

[0069] 1 Apparatus for manufacturing metal strip

[0070] 2 Metal strip

[0071] 10 Finishing Mill Unit

[0072] 11 The final rolling mill stand

[0073] 20 Rapid cooling mechanism

[0074] 21 Sprayed Beam

[0075] 21' End side spray beam

[0076] 22 nozzles

[0077] 22' end side spray beam nozzle

[0078] 23 Coolant Supply Department

[0079] 24 Coolant Delivery Section

[0080] 25 squeeze rollers

[0081] 26. Air blowing section

[0082] 30 Another cooling mechanism

[0083] 31 Sprayed Beam

[0084] 40 Winding device

[0085] 50 Temperature measuring instrument

[0086] 60 Temperature measuring instrument

[0087] F Conveying direction

[0088] The length of the cooling section of the L1 rapid cooling mechanism

[0089] The distance between the roll gap of the last stand of L2 and another cooling mechanism

Claims

1. An apparatus (1) for manufacturing hot-rolled metal strip (2), comprising: A finishing mill (10) having at least one mill stand (11) having work rolls forming a roll gap for hot-rolling metal strip (2); and A rapid cooling mechanism (20) is arranged directly downstream of the roll gap of the last mill stand (11) of the finishing mill (10), and is configured to rapidly cool the metal strip (2) by applying a coolant, preferably a water-based coolant, to the upper and lower sides of the metal strip (2) along the cooling section of the rapid cooling mechanism (20); wherein, The rapid cooling mechanism (20) is configured to apply 100-300 μm of cooling force to both the upper and lower sides of the metal strip (2). 3 / (m 2 Cooling dose between (×h).

2. The apparatus (1) according to claim 1, characterized in that, The rapid cooling mechanism (20) has spray beams (21, 21') on the upper and lower sides relative to the metal strip (2), respectively, with a plurality of nozzles (22, 22') for spraying the coolant onto the metal strip (2), wherein the number of nozzles (22, 22') on the upper side is preferably 50 to 120 nozzles / m. 2 The number of nozzles (22, 22') on the lower side is preferably 80 to 150 nozzles / m. 2 The upper nozzles (22, 22') are preferably arranged at a maximum distance of 800 mm above the metal strip (2), and the lower nozzles (22, 22') are preferably arranged at a maximum distance of 170 mm below the metal strip (2). The diameter of the nozzles (22, 22') is preferably in the range of 3 to 8 mm.

3. The apparatus (1) according to claim 2, characterized in that, The rapid cooling mechanism (20) has a coolant supply section (23) and one or more coolant delivery sections (24) in fluid communication with the spray beam (21) for supplying the coolant to the nozzles (22, 22'), wherein the coolant supply section (23) is configured to preferably adjust the pre-pressure of the coolant in the coolant delivery section (24) to a pressure of 2 to 5 bar.

4. The apparatus (1) according to claim 2 or 3, characterized in that, The rapid cooling mechanism (20) has one or more end-side spray beams (21') in its upstream and / or downstream regions, respectively, which are configured such that their nozzles (22') apply the coolant to the metal strip (2) at an angle that is inclined toward the interior of the rapid cooling mechanism (20).

5. The apparatus (1) according to any one of the preceding claims, characterized in that, The squeeze roller (25) and / or the blowing section (26) are installed at the inlet and / or outlet of the rapid cooling mechanism (20) and are configured to prevent coolant from flowing out of the cooling section of the rapid cooling mechanism (20).

6. The apparatus (1) according to any one of the preceding claims, characterized in that, The rapid cooling mechanism (20) is configured to set a cooling rate that meets the following conditions: cooling rate × strip thickness > 500 K / s × mm.

7. The apparatus (1) according to any one of the preceding claims, characterized in that, The length (L1) of the cooling section of the rapid cooling mechanism (20) is preferably at least 4m and / or at most 10m, preferably about 9m.

8. The apparatus (1) according to any one of the preceding claims, characterized in that, The rapid cooling mechanism (20) is configured to apply at least twice the amount of coolant to the lower side of the metal strip (2) as to the upper side of the metal strip (2).

9. The apparatus (1) according to any one of the preceding claims, characterized in that, The rapid cooling mechanism (20) is configured to apply a cooling force of at least 800 m / s to the upper and lower sides of the metal strip (2). 3 The total cooling dose per hour is preferably at least 1500 m³ / h. 3 / h, preferably at least 2400m 3 / h.

10. The apparatus (1) according to any one of the preceding claims, characterized in that, The device (1) has another cooling mechanism (30) downstream of the rapid cooling mechanism (20), which is configured to adjust the metal strip (2) to a desired final temperature, preferably a suitable winding temperature, wherein the other cooling mechanism (30) is preferably designed for laminar flow cooling.

11. A method for manufacturing hot-rolled metal strip (2), comprising: Hot-rolled metal strip (2) on a finishing mill (10) having at least one mill stand (11) having work rolls forming a roll gap; as well as Immediately after hot rolling on the finishing mill (10), the metal strip (2) is cooled by applying a coolant, preferably a water-based coolant, to the upper and lower sides along the cooling section of a rapid cooling mechanism (20), wherein the rapid cooling mechanism (20) is directly arranged downstream of the roll gap of the last mill stand (11) of the finishing mill (10); wherein, The rapid cooling mechanism (20) applies 100-300 μm of cooling force to both the upper and lower sides of the metal strip (2). 3 / (m 2 Cooling dose between (×h).

12. The method according to claim 11, characterized in that, The rapid cooling mechanism (20) has, on its upper and lower sides relative to the metal strip (2), a spray beam (21, 21') with a plurality of nozzles (22, 22') for spraying the coolant onto the metal strip (2), a coolant supply section (23), and one or more coolant delivery sections (24) in fluid communication with the spray beam (21) for supplying the coolant to the nozzles (22, 22'), wherein the coolant supply section (23) preferably adjusts the pre-pressure of the coolant in the coolant delivery section (24) to a pressure of 2 to 5 bar.

13. The method according to claim 12, characterized in that, The rapid cooling mechanism (20) has one or more end-side spray beams (21') in its upstream and / or downstream regions, respectively, whose nozzles (22') apply the coolant to the metal strip (2) at an angle inclined toward the interior of the rapid cooling mechanism (20).

14. The method according to any one of claims 11 to 13, characterized in that, In the rapid cooling mechanism (20), a cooling rate is set that satisfies the following condition: cooling rate × strip thickness > 500 K / s × mm.

15. The method according to any one of claims 11 to 14, characterized in that, The amount of coolant applied to the underside of the metal strip (2) in the rapid cooling mechanism (20) is at least twice that applied to the upper side of the metal strip (2).

16. The method according to any one of claims 11 to 15, characterized in that, In the rapid cooling mechanism (20), a bandwidth of at least 800 m per meter is applied to the upper and lower sides of the metal strip (2). 3 The total cooling dose per hour is preferably at least 1500 m³ / h. 3 / h, preferably at least 2400m 3 / h.

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