Reversible rough rolling mill and related processes for aluminum or aluminum alloy products

Abstract

A reversing roughing mill for rough rolling an aluminium or aluminium alloy product fed along a feed plane, the roughing mill comprising: a reversing horizontal roughing stand 1; a first cooling device 10 arranged upstream of the reversing roughing stand 1 and configured to cool the product entering the reversing roughing stand 1 from above with a cooling liquid; and a second cooling device 15 arranged downstream of the reversing roughing stand 1 and configured to cool the product entering the reversing roughing stand 1 from above with the cooling liquid.

Description

[Technical Field]

[0001] The present invention relates to a reversing rough rolling mill and related processes for aluminum or aluminum alloy products. The solution of the present invention can be applied to both cast and cut-to-size slabs and ingots (coil-to-coil or semi-endless mode). [Background technology]

[0002] Hot rolling mills for aluminum or aluminum alloy products can be configured in a variety of ways depending on the final productivity required.

[0003] Typically, the slab to be rolled is heated to a temperature of 300 to 600°C in a heating furnace located upstream of the roughing stand.

[0004] In addition to varying widths, slab dimensions typically range from 450 to 750 mm thick and from 4 to over 10 meters long, depending on the configuration of the slab melting and casting section upstream of the furnace.

[0005] Hot rolling mills for aluminum products can have production capacities ranging from less than 100,000 tons / year to over 1 million tons / year, depending on the required capacity, and can be configured in a variety of ways, the most common of which are as follows: - A single reversing stand with upstream and downstream take-up reels is used as both a roughing mill and a finishing mill. - A configuration consisting of a single reversing roughing stand and a single reversing finishing stand with take-up reels upstream and downstream of the stands. - Configuration consisting of a single reversing roughing stand and a tandem finishing mill with multiple stands in a unidirectional line, with an exit winder.

[0006] These configurations are of increasing capacity, depending on the required size and quality combination, with the first configuration having the smallest capacity of less than 100,000 tonnes / year, and the last configuration having a capacity of over 1 million tonnes / year.

[0007] In a reversing roughing stand, the slab undergoes several rolling passes to reduce its thickness from the initial thickness to a transfer thickness suitable for the finishing mill, which customarily varies from about 25 mm to about 40 mm depending on the material quality and final product requirements.

[0008] In more productive rolling facilities, control of rolling time in both the roughing mill and the finishing mill is a key factor in achieving the expected production rate.

[0009] Furthermore, to maximize capacity, it is necessary to roll slabs in different sections of the facility. For example, while the finishing mill is rolling the product to obtain aluminum coils, at least two slabs may be rolling simultaneously in the roughing mill, with an intermediate thickness slab undergoing the head and tail cutting step, while another slab is being rolled in the roughing stand. To maximize facility capacity, the concept of rolling multiple pieces in a multi-stage roughing mill is applied to reduce the downtime when the roughing stand is not rolling product.

[0010] Because it is hot rolling, it is also essential to control the metallurgy of the product and manage the temperature of the product at every step so that it does not go out of specification in the rolling stand as it cools.

[0011] Unfortunately, one of the limitations on the hourly capacity of the roughing mill is the maximum product temperature in the roughing stand. Indeed, if the energy transferred by plastic deformation pushes the product above a threshold temperature of approximately 480-500°C, which is very close to the melting point of the product material, aluminum will adhere to the rolling rollers and material transport rollers, causing quality problems.

[0012] Thus, roughing stands limit the speed of the rolling passes and increase the residence time of the material in air, thereby increasing heat exchange and thereby avoiding exceeding the critical threshold, but this has a negative impact on productivity.

[0013] CN108326051 discloses a reversible roughing mill corresponding to the preamble of claim 1.

[0014] Therefore, a need is felt to provide a reversing roughing mill and related process that can overcome the aforementioned drawbacks. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Chinese Patent Application Publication No. 108326051 Summary of the Invention [Problem to be solved by the invention]

[0016] It is an object of the present invention to create a reversing roughing mill that provides efficient cooling of the product in at least one roughing stand, optimizing the productivity of the roughing mill.

[0017] Another object of the present invention is to create a reversing roughing mill that efficiently controls the product temperature in at least one roughing stand, maximizing productivity and thereby avoiding quality problems due to aluminum adhesion to the rolling rollers and material transport rollers.

[0018] A further object of the present invention is to make the associated rough rolling process highly efficient. [Means for solving the problem]

[0019] The present invention achieves these and other objects which will become apparent in view of the description herein by a reversing roughing mill for rough rolling an aluminium or aluminium alloy product which is fed along a first direction according to a feed face and arrives at the reversing roughing mill, the reversing roughing mill comprising: - at least one reversible horizontal roughing stand; - a first cooling device arranged upstream of the reversing roughing stand with respect to the first direction and configured to cool from above and below by a cooling liquid the products entering the reversing roughing stand for an odd number of roughing passes; - a second cooling device arranged downstream of the reversing rolling stand with respect to the first direction and configured to cool the product from above and below with a cooling liquid before it further enters the reversing rolling stand for an even number of roughing passes, - at least one temperature sensor arranged at both the inlet and the outlet of the first cooling device; - at least one further temperature sensor arranged at both the inlet and the outlet of the second cooling device; - a first regulating system for regulating the flow rates of the coolant in the first cooling device and in the second cooling device based on temperature data detected by the at least one temperature sensor and the at least one further temperature sensor, respectively.

[0020] According to a further aspect of the present invention, there is provided a rough rolling process executable by the reversible rough rolling mill as described above, the process comprising the following steps: a) performing a first odd number of rough rolling passes on the product in a first direction with a reversing rough rolling stand; b) performing a first even number of rough rolling passes on the product in a second direction opposite to the first direction with a reversible rough rolling stand; c) repeating step a) and optionally step b) until the thickness of the product is reduced by a predetermined amount; Before step a) and / or before step b), a step is provided in which the product entering the reversible roughing stand is cooled from above and below by a cooling liquid supplied by a first cooling device or a second cooling device, respectively; The first adjusting system also adjusts the flow rates of the coolant in the first cooling device and the second cooling device based on temperature data detected by the at least one temperature sensor and the at least one further temperature sensor, respectively.

[0021] Advantageously, the solution of the invention provides a product cooling system that is arranged both downstream and upstream of at least one roughing stand and that is able to use as coolant the same emulsion as that used to lubricate and cool the rolling rollers of the roughing stands, or demineralized water.

[0022] By operating the cooling system between roughing passes, it is possible to increase the rolling speed and therefore the productivity of the facility.

[0023] By reducing the temperature at the surface of the material, the outer strength of the product is improved, which allows the material deformation to propagate to deeper levels during the next rolling pass, thereby reducing overall defects and therefore the length of product that is scrapped.

[0024] In a preferred variant, the cooling device comprises multiple coolant manifolds with controlled liquid jet discharge rates to ensure high operational flexibility.

[0025] Further advantages of the inventive solution over the prior art include: - High manufacturing flexibility and - A high ability to control the metallurgical and therefore mechanical properties of the product, which remain constant throughout the entire length of the rolled product; - The high ability of the prior art to control the distortion effects on flatness caused by temperature differences across the product.

[0026] Further features and advantages of the present invention will become more apparent upon consideration of the detailed description of the preferred, but non-limiting, embodiments.

[0027] The dependent claims describe particular embodiments of the invention.

[0028] The description of the invention refers to the accompanying drawings which show non-limiting examples. [Brief explanation of the drawings]

[0029] [Figure 1] 1 is a diagram of an embodiment of a reversible roughing mill according to the present invention; FIG. [Figure 2] FIG. 2 is a cross-sectional view schematically showing the roughing mill of FIG. 1 along plane AA. [Figure 3] FIG. 2 is a detailed schematic view of a portion of the cooling device of the roughing mill of the present invention. [Figure 4] 1 a) and b) are schematic side views of two parts of the cooling device. [Figure 5] FIG. 1 is a perspective view showing these two parts in a simplified manner. [Figure 6] FIG. 1 is a partial cross-sectional view showing the two components in a simplified manner. [Figure 7] FIG. 1 is a partial cross-sectional view showing the two components. DETAILED DESCRIPTION OF THE INVENTION

[0030] The same reference numbers in the figures identify the same elements or parts.

[0031] Some examples of reversing hot rough rolling mills for aluminum or aluminum alloy products, which are the object of the present invention, will now be described with reference to the drawings.

[0032] Referring to Figure 1, an aluminium or aluminium alloy product, for example a slab, arrives at the mill being fed in a first direction (arrow B) along a feed face.

[0033] In all embodiments of the present invention, the reversing roughing mill comprises: - at least one reversing horizontal roughing mill stand 1, preferably, but not necessarily, a single reversing stand; - a first cooling device 10 arranged upstream of the reversing roughing stand 1 with respect to the first direction and adapted to cool from above and below by jets of a suitable cooling liquid the products entering the reversing roughing stand 1 for an odd number of roughing passes; - a second cooling device 15 arranged downstream of the reversible roughing stand 1 with respect to the first direction and configured to cool the product from above and below by jets of cooling liquid before it further enters the reversible roughing stand 1 for an even number of roughing passes in a second direction opposite to the first direction.

[0034] The reversible roughing mill stand 1 is provided with an entrance roller and an exit roller.

[0035] Advantageously, the reversing roughing mill comprises: - at least one temperature sensor arranged at both the inlet and the outlet of the first cooling device 10 to detect the temperature of the product surface; - at least one further temperature sensor arranged at both the inlet and the outlet of the second cooling device 15, for detecting the temperature of the product surface; a first regulating system for regulating the flow rates of the coolant in the first cooling device 10 and in the second cooling device 15 based on temperature data detected by the at least one temperature sensor and at least one further temperature sensor, respectively.

[0036] In a variant (FIG. 1), considering the first direction (arrow B), the at least one temperature sensor is a first temperature sensor 44, preferably an infrared sensor such as a pyrometer or a thermal camera, arranged at the inlet of the first cooling device 10 and adapted to detect the temperature of the surface of the product; a second temperature sensor 43, preferably an infrared sensor such as a pyrometer or a thermal camera, arranged at the outlet of the first cooling device 10 and adapted to detect the temperature of the surface of the product; a third temperature sensor 45, preferably a contact sensor such as a thermocouple, arranged in the vicinity of the second temperature sensor 43, advantageously in the vicinity of or immediately after the second temperature sensor, for calibrating the second temperature sensor, in particular for calibrating its emissivity;

[0037] Preferably, an additional temperature sensor, for example a contact type sensor such as a thermocouple, is again positioned near the first temperature sensor 44 to calibrate the first temperature sensor 44 as the slab travels in a second direction opposite to the first direction B.

[0038] Alternatively, the at least one further temperature sensor comprises: a fourth temperature sensor 46, preferably an infrared sensor such as a pyrometer or a thermal camera, arranged at the inlet of the second cooling device 15 and adapted to detect the temperature of the surface of the product; a fifth temperature sensor 48, preferably a contact sensor such as a thermocouple, arranged in the vicinity of the fourth temperature sensor 46, advantageously in the vicinity of or immediately after the fourth sensor, for calibrating the fourth sensor, in particular its emissivity; a sixth temperature sensor 47, preferably an infrared sensor such as a pyrometer or a thermal camera, arranged at the outlet of the second cooling device 15 and adapted to detect the temperature of the surface of the product;

[0039] Preferably, an additional temperature sensor, for example a contact type sensor such as a thermocouple, is positioned also in the vicinity of the sixth temperature sensor 47 to calibrate the sixth temperature sensor 47 as the slab advances in the first direction B.

[0040] Other sensors that may be provided in the mill of the invention, interacting with the above-mentioned regulation system, include: - a temperature sensor for detecting the temperature of the cooling liquid entering the mill and exiting the mill after having been used to cool the product; - 3D shape sensors for detecting the shape and warpage of products.

[0041] Measurement of the coolant temperature by a temperature sensor, related to the flow rate of the coolant, allows assessment of the energy removed from the cooling system and therefore the efficiency of the heat exchange between the liquid and the product.

[0042] Sensors measuring the product's three-dimensional shape can assess whether the product is suffering from distortion due to unevenly distributed cooling, and corrective measures can be implemented by modifying the total liquid flow rate and the liquid distribution between the center and sides, or edges, of the product.

[0043] Preferably, both the first cooling device 10 and the second cooling device 15 comprise upper and lower cooling liquid manifolds 54 and 55, respectively, which are preferably arranged parallel to each other and transverse to the product feed direction.

[0044] Both the upper manifold 54 and the lower manifold 55 each have a surface 16 facing the product supply surface, preferably parallel to the supply surface, and surface 16 is provided with a plurality of holes 11 for generating jets 26 of cooling liquid toward the supply surface.

[0045] In one example, each manifold has the shape of a right-angled parallelepiped, preferably a rectangular parallelepiped.

[0046] Figure 5 shows upper manifold 54 and lower manifold 55 facing each other at their faces 16. In Figure 4, the lower face 16 of upper manifold 54 is shown on the left, while the upper face 16 of lower manifold 55 is shown on the right.

[0047] Preferably, the number and size of the holes 11 are set to allow the liquid flow rate to be 200 to 900 l / min / m 2 (liters per minute per square metre of product surface per product surface).

[0048] Optionally, each hole 11 is provided with a nozzle 56 to obtain a laminar flow of the jet of cooling liquid.

[0049] Advantageously, the nozzle 56 is an easily replaceable wear element, reducing maintenance time and costs for situations where the passage of liquid within the bore 11 causes wear effects.

[0050] Preferably, the lower manifolds 55 of the first and second cooling devices 10, 15 can be arranged alternately with the guide rollers 60 of the horizontal roller table of the product.

[0051] In particular, a first roller table 6 can be provided at the entrance of the mill and a second roller table 13 can be provided at the exit of the mill, allowing the product to be moved away from or towards the reversible roughing stand 1, taking into account the reversibility of the mill.

[0052] In the first cooling device 10 , an upper delivery line 19 feeds an upper manifold 54 and a lower delivery line 20 feeds a lower manifold 55 .

[0053] Similarly, in the second chiller 15 , the upper delivery line 21 feeds the upper manifold 54 and the lower delivery line 22 feeds the lower manifold 55 .

[0054] Each cooling device 10, 15 is provided with an upper manifold and a lower manifold each having a surface 16 facing the product supply surface, preferably parallel to the supply surface, and the manifolds are provided with a plurality of holes 11 divided into groups of holes, each group of holes being provided in the space between the guide roller 60 and the next roller on the horizontal roller table of the product, although this is not excluded as a possibility.

[0055] 4 and 5, each upper manifold 54 and each lower manifold 55 is internally divided into at least three chambers 51, 52, 53, for example only three chambers. The central chamber 51 is configured to adjust the flow rate of the cooling liquid, and thus the flow rate of the jets 26, at a central portion of the surface of the product being dispensed to control the temperature of the product, while the two lateral chambers 52, 53 are configured to adjust the flow rate of the cooling liquid, and thus the flow rate of the jets 26, at respective lateral portions of the surface of the product being dispensed to control the temperature of the product.

[0056] Preferably, the first regulating system for regulating the flow rate of the cooling liquid in the first cooling device 10 and the second cooling device 15 comprises a plurality of proportional valves for regulating the flow rate of the cooling liquid directed towards the product feed surface so that a substantially uniform temperature is maintained between the head, middle and rear of the product.

[0057] As shown schematically in FIG. 3, for each upper manifold 54 and each lower manifold 55 of the first cooling device 10, the first regulating system comprises proportional valves 30, 31 and 35, 36, respectively, for regulating the flow rate of the cooling liquid in each chamber 51, 52, 53.

[0058] In particular, a proportional valve 30 regulates the flow rate of coolant in the central chamber 51 of each upper manifold 54, and at least one proportional valve 31 regulates the flow rate of coolant in the side chambers 52, 53 of each upper manifold 54. A single proportional valve 31 or two proportional valves 31 may be provided, in which case each proportional valve 31 regulates the flow rate in a respective side chamber 52, 53.

[0059] Similarly, a proportional valve 35 regulates the flow rate of coolant in the central chamber 51 of each lower manifold 55, and at least one proportional valve 36 regulates the flow rate of coolant in the side chambers 52, 53 of each lower manifold 55. A single proportional valve 36 or two proportional valves 36 may be provided, in which case each proportional valve 36 regulates the flow rate in a respective side chamber.

[0060] Upstream of the proportional valves 30, 31 and each duct 27, 28, the first regulating system further comprises an automatic on / off valve 29 along the upper delivery line 19 feeding the ducts 27, 28 and the upper manifold 54 of the first cooling device 10.

[0061] Similarly, upstream of the proportional valves 35, 36 and each duct 33, 34, the first regulating system further comprises an automatic on / off valve 32 along the lower delivery line 20 that feeds the ducts 33, 34 and the lower manifold 55 of the first cooling device 10.

[0062] This allows the distribution of the cooling liquid on the surface of the product to be adjusted or controlled to obtain the desired temperature profile, and the flow rate of the cooling liquid can be measured by suitable flow transducers 42 located along the upper delivery line 29 upstream of the automatic on / off valve 29 and along the lower delivery line 20 upstream of the automatic on / off valve 32.

[0063] The same arrangement as shown diagrammatically in FIG. 3 is provided for the upper delivery line 21 and the lower delivery line 22 for the second cooling device 15 .

[0064] In one variant of the invention, as shown in Figure 6, a plurality of pipes 40 are provided inside the upper manifold 54, preferably vertical and of equal height, with their upper ends being free and defining a weir level for the cooling liquid. The lower end of each pipe 40 is engaged in a respective hole 11 in the surface 16 facing the product supply surface. In this case, if a nozzle 56 is provided, each nozzle 56 is attached to the lower end of the respective pipe 40, preferably outside the manifold 54.

[0065] The presence of the pipe 40 minimizes both the time that the jets 26 of cooling liquid are shut off at the end of the product's passage through the cooling device, as well as the time that the jets 26 are on.

[0066] When the regulating system controls the shutoff of the coolant jet, the automatic on / off valve 29 closes, almost instantly shutting off the exit of the liquid jet from the upper manifold 54 as soon as the liquid level falls below the weir level.

[0067] When the regulating system controls the operation of the coolant jet, the automatic on / off valve 29 opens, almost instantly creating a jet that flows towards the product, since only a minimum amount is filled in the upper manifold to create the jet.

[0068] Preferably, a filter plate 37 is provided above the upper end of the pipe 40 to filter out coarse particles that may clog the laminar jet spray nozzle 56.

[0069] In FIG. 6, reference numeral 38 indicates the level of coolant in the upper manifold 54 when the cooling system is in the off state, while reference numeral 39 indicates the level of coolant when the cooling system is in the on state, i.e. simply the operating level.

[0070] Increasing the flow rate of coolant entering the upper manifold 54 and the lower manifold 55 increases the pressure inside the manifolds and therefore also the pressure of the jets issuing from the holes 11 or nozzles 56. In variants in which the manifold is divided internally into at least three chambers, the flow rate of coolant entering each chamber can be regulated by the proportional valves mentioned above.

[0071] Alternatively, Figure 7 partially illustrates the lower manifold 55, where the flow rate of the incoming coolant is 20-30% higher than the flow rate entering the upper manifold 54, to account for the difference in impact on the surface and the shorter time the liquid remains on the surface. This different flow distribution is achieved by respective proportional valves, which can improve the efficiency of the cooling system.

[0072] Preferably, the mill of the present invention is provided with at least one first actuator 49 and at least one second actuator 50 (FIG. 1) for vertically moving the single upper manifold or set of upper manifolds 54 of the first cooling device 10 and the second cooling device 15, respectively, so that the distance of the upper manifolds 54, and therefore the distance between the holes 11 or nozzles 56 facing the product feed surface and the top surface of the product being rolled, can be kept constant even if the thickness changes due to the effects of rolling. This distance is preferably maintained at a value within the range of 300 to 1200 mm.

[0073] In one embodiment, only one first actuator 49 and one second actuator 50 are provided.

[0074] In all embodiments of the mill of the present invention: - a side entry centering guide 9 for guiding and centering the product entering the mill laterally; - Lateral exit centering guides 14 may be provided for guiding and centering the product laterally as it leaves the mill.

[0075] Preferably, the first cooling device 10 is located between the side inlet guides 9, while the second cooling device 15 is located between the side outlet guides 14.

[0076] Optionally, as shown diagrammatically in FIG. 2, collection channels 25 are provided in the space between the lateral edges of the upper manifold 54 and the lateral inlet guides 9 (or outlet guides 14) located below it, preferably parallel to the feed direction, to protect the lateral edges of the products 24 supplied by the jets 26 of cooling liquid, thereby avoiding overcooling of the lateral edges of the products.

[0077] These collection channels 25 direct the intercepted coolant to a collection tank 18 located at the bottom of the mill (FIG. 1).

[0078] In all embodiments of the roughing mill of the invention, at least one vertical rolling stand 2 (FIG. 1) may be provided for rolling the edges of the product, which is arranged between the first cooling device 10 and the at least one reversible roughing stand 1. The vertical rolling stand 2 is provided with entrance and exit rollers.

[0079] In a preferred variant of the invention, a second regulating system can be provided for adjusting the rolling speed in the reversible roughing stand 1 based on temperature data detected by one or more temperature sensors provided at the product outlet from each cooling device.

[0080] In all embodiments of the roughing mill of the invention, taking into account the first direction B, the following components (FIG. 1) are considered: - a first blower 12 or air blade device located at the inlet of the mill, which dries the top surface of the product and confines the cooling liquid within the mill structure, thereby allowing the entire cooling liquid to be collected in a collection tank 18, and a second blower 17 or air blade device located at the outlet of the mill; a tank (not shown) for storing the dirty coolant used in the mill, and possibly other liquids, which are delivered to the tank by at least one outlet 23 of the collecting tank 18; - a washing device 5, for example with a demineralized water jet, which performs a descaling function and is arranged upstream of at least one reversing roughing stand 1 or, if at least one vertical rolling stand 2 is provided, upstream of the vertical rolling stand 2; - at least one first bar 3 arranged upstream of at least one reversing roughing stand 1 or at least one vertical rolling stand 2, and at least one second bar 4 arranged downstream of at least one reversing roughing stand 1, for removing coolant or other liquid from the top surface of the product entering the reversing roughing stand 1; One or more of the following may be provided.

[0081] The rolling equipment equipped with the reversible roughing mill of the present invention includes: - a preheating furnace upstream of the reversing roughing mill; a finishing mill downstream of the reversing roughing mill.

[0082] The process of hot rough rolling of an aluminium or aluminium alloy product arriving at a reversing rough rolling mill according to the invention, fed along a first direction according to a feed face, is described below.

[0083] In all its embodiments, the process comprises the following steps: a) performing a first odd number of rough rolling passes on the product in a first direction by a reversible rough rolling stand 1; b) performing a first even number of rough rolling passes on the product by the reversible rough rolling stand 1 in a second direction opposite to the first direction; c) repeating step a) and optionally step b) until the thickness of the product is reduced by a predetermined amount; Before step a) and / or before step b), a step is provided in which the product entering the reversible roughing stand 1 is cooled from above and below by a cooling liquid supplied by the first cooling device 10 or the second cooling device 15, respectively.

[0084] Advantageously, the first regulating system regulates the flow rate of the coolant in the first cooling device 10 and the second cooling device 15 based on temperature data detected by at least one temperature sensor 44, 43, 45 and at least one further temperature sensor 46, 48, 47, respectively.

[0085] In a preferred variant, the upper and lower cooling of the product is carried out by: before the odd number of rough rolling passes by means of a cooling liquid supplied by a first cooling device 10; - both before the even number of rough rolling passes by means of a coolant supplied by a second cooler 15.

[0086] The controlled cooling in the process of the present invention allows the product to be rough rolled at the highest possible rolling speed, thereby preventing the product from exceeding the critical temperature threshold. Achievable productivity improvements are in the range of 10% to 20%.

[0087] More specifically, a variant of the process involving controlled cooling by at least one cooling device comprises the following steps: - measuring the temperature of the product entering the cooling device; - defining rolling parameters for the reversing roughing mill stand and setting a maximum rolling speed that conforms to the stand's design limits and takes into account the size, material, and chemical and physical properties of the product; - calculating the temperature of the product leaving the reversing roughing stand by means of a thermal model of the rolling compartment of the stand taking into account the rolling parameters; - if the calculated temperature of the product leaving the reversing roughing mill stand is lower than a predetermined critical temperature, performing rolling according to the aforementioned rolling parameters; - measuring the temperature of the product exiting the reversing roughing stand.

[0088] If the calculated discharge product temperature is equal to or greater than the predetermined critical temperature, the following steps are performed before rolling: - calculating the flow rate of the coolant supplied to the cooler by means of a thermal model of the cooler contained in the first regulating system and optionally selecting the number of upper and lower manifolds to be activated in order to obtain an optimal temperature of the product leaving the cooler and thus the temperature of the product entering the reversible roughing stand, which after rolling can reach a temperature higher than 420°C but below a predetermined critical temperature; - cooling the product by operating a cooling device and supplying the cooling device with the flow rate of cooling liquid, and optionally by operating a selected number of upper and lower manifolds; - measuring the temperature of the product exiting the cooling device; - if the measured temperature of the product leaving the cooling device is equal to the optimum temperature, rolling in accordance with the aforementioned rolling parameters; - measuring the temperature of the product leaving the reversing roughing stand.

[0089] If the measured temperature of the product leaving the cooling unit is different from the optimum temperature, the following steps should be taken before rolling: - calculating the heat exchange coefficient between the coolant and the product and calibrating a thermal model of the cooling device, the thermal model calculating a new flow rate of the coolant to obtain an optimal temperature of the product leaving the cooling device; - cooling the product by activating the cooling device and supplying the cooling device with this new flow rate of cooling liquid; - performing rolling in accordance with said rolling parameters; - measuring the temperature of the product leaving the reversing roughing stand.

[0090] The coolant may include a suitable emulsion, demineralized water, or other suitable coolant.

[0091] The inlet temperature of the coolant can vary from 20 to 60°C.

[0092] Preferably, a second regulating system regulates the rolling speed of the reversing roughing mill stand 1 based on temperature data detected at the product outlet from each cooling device.

[0093] Preferably, the cooling of the product with the coolant, and optionally the rolling speed in each subsequent rough rolling pass, is adjusted so that the product during the rough rolling pass is always kept below a temperature in the range of 440-460°C, thereby avoiding quality problems due to aluminum adhering to the rolling rollers and product transport rollers.

[0094] For example, the flow rate of the cooling liquid in the cooling device is adjusted to obtain a cooling gradient of -30 to -200°C / sec, depending on the thickness of the product being cooled and the speed at which the product passes through the cooling device.

[0095] In a variation of this process, the flow rates of the coolant entering from above and below the first and second cooling devices 10, 15 are regulated by proportional valves 30, 31, 35, 36 located along the respective delivery lines 19, 20, 21, 22 and at least one on / off valve 29, 32 located upstream of the proportional valves.

[0096] By adjusting the flow rate of the cooling liquid entering the cooling devices 10, 15 and thus the flow rate of the jets 26 directed at the top and bottom of the product being fed, a uniform temperature can be maintained between the head, middle and rear of the product being rolled.

[0097] In a variant of the mill in which each upper manifold 54 and each lower manifold 55 is divided internally into at least three chambers 51, 52, 53, the flow rate of the coolant supplied to each chamber 51, 52, 53 is regulated by proportional valves 30, 31, 35, 36, respectively.

[0098] In particular, the flow rate of cooling liquid in the central chamber 51 of each upper manifold 54 and lower manifold 55, and therefore the flow rate of the jets 26 delivered to the central portion of the surface of the product being delivered, is regulated by proportional valves 30 and 35, respectively, while the flow rate of cooling liquid in the side chambers 52 and 53 of each upper manifold 54 and lower manifold 55, and therefore the flow rate of the jets 26 delivered to the respective lateral portions of the surface of the product being delivered, is regulated by at least one proportional valve 31, respectively.

[0099] This adjustment minimizes temperature differences across the surface of the product transverse to the feed direction.

Claims

1. 1. A reversing roughing mill for rough rolling an aluminum or aluminum alloy product fed along a first direction according to a feed face and arriving at the reversing roughing mill, comprising: at least one reversing horizontal roughing stand (1), a first cooling device (10) arranged upstream of the reversing roughing stand (1) with respect to the first direction and adapted to cool the products entering the reversing roughing stand (1) from above and below with a cooling liquid for odd-numbered roughing passes; a second cooling device (15) arranged downstream of the reversing roughing stand (1) with respect to the first direction and adapted to cool the product from above and below with the cooling liquid before it further enters the reversing roughing stand (1) for an even number of roughing passes, at least one temperature sensor (44, 43, 45) placed both at the inlet and at the outlet of said first cooling device (10); at least one further temperature sensor (46, 48, 47) arranged both at the inlet and at the outlet of said second cooling device (15); a first regulating system for adjusting the flow rates of the cooling liquid in the first cooling device (10) and in the second cooling device (15) based on temperature data detected by the at least one temperature sensor (44, 43, 45) and the at least one further temperature sensor (46, 48, 47), respectively.

2. 2. The roughing mill according to claim 1, further comprising a second adjusting system configured to adjust the rolling speed in the reversible roughing rolling stand (1) based on the temperature data detected by the one or more temperature sensors at the outlet of the product from each cooling device (10, 15).

3. the first conditioning system along at least one delivery line (19, 20, 21, 22) configured to supply the cooling liquid to the first cooling device (10) and the second cooling device (15); proportional valves (30, 31, 35, 36) for adjusting the flow rate of the cooling liquid entering from above and below the first cooling device (10) and the second cooling device (15); - at least one on / off valve (29, 32) arranged upstream of said proportional valve.

4. 4. A roughing mill according to claim 1, wherein the first cooling device (10) and the second cooling device (15) comprise one or more upper manifolds (54) and one or more lower manifolds (55) for the cooling liquid, which are arranged transversely to the product feed direction and have respective surfaces facing the product feed surface, each of said surfaces being provided with a plurality of holes (11) for generating a jet (26) of the cooling liquid towards said feed surface, preferably with a nozzle (56) in each hole (11).

5. 5. A roughing mill according to claim 4, wherein each upper manifold (54) and each lower manifold (55) is divided internally into at least three chambers (51, 52, 53), preferably comprising at least one central chamber (51) configured to adjust the flow rate of the cooling liquid delivered to a central portion of the surface of the product being supplied, and two side chambers (52, 53) configured to adjust the flow rate of the cooling liquid delivered to each lateral portion of the surface of the product.

6. 6. A roughing mill according to claim 5, further comprising a proportional valve (30, 31, 35, 36) for adjusting the flow rate of the cooling liquid supplied to each of the at least three chambers (51, 52, 53).

7. 7. The roughing mill according to claim 4, wherein a plurality of pipes (40) are provided inside the upper manifold (54), the upper ends of the pipes defining a weir height (38) of the cooling liquid, and the lower ends of the pipes (40) are inserted into respective holes of the plurality of holes (11).

8. 8. The roughing mill according to claim 4, wherein at least one first actuator (49) and at least one second actuator (50) are provided to vertically move the upper manifold or set of upper manifolds (54) of the first cooling device (10) and the second cooling device (15), respectively, to maintain a constant distance from the top surface of the product to be rolled to the upper manifolds (54).

9. - a side entry guide (9) for guiding the products entering the roughing mill; - a lateral exit guide (14) for guiding the product leaving the roughing mill; 9. A roughing mill according to any one of claims 1 to 8, wherein the first cooling system (10) is installed between the side inlet guides (9) and the second cooling system (15) is installed between the side outlet guides (14).

10. 10. A roughing mill according to claim 9, dependent on claim 4, wherein a channel (25) is provided in a space between a side edge of the upper manifold (54) and a side inlet guide (9) and an outlet guide (14) located thereunder, for protecting the side edge of the product from the jet (26) of the cooling liquid by directing the blocked cooling liquid toward a collection tank (18).

11. 11. A roughing mill according to claim 1, wherein at least one vertical rolling stand (2) is provided, arranged between the first cooling device (10) and the reversible roughing stand (1) for rolling the edges of the products.

12. 12. A hot rough rolling process for an aluminium or aluminium alloy product by a reversing rough rolling mill according to any one of claims 1 to 11, wherein the product is fed along a first direction according to a feed face, the process comprising the following steps: a) performing a first odd number of rough rolling passes on the product in the first direction by the reversing rough rolling stand (1); b) performing a first even number of rough rolling passes on the product by the reversible rough rolling stand (1) in a second direction opposite to the first direction; c) repeating step a) and optionally step b) until a predetermined reduction in thickness of the product is achieved, before step a) and / or before step b), a step is provided in which the product entering the reversible roughing rolling stand (1) is cooled from above and below by a cooling liquid supplied by the first cooling device (10) or the second cooling device (15), respectively; and wherein the first adjusting system adjusts the flow rates of the coolant in the first cooling device (10) and the second cooling device (15) based on temperature data detected by the at least one temperature sensor (44, 43, 45) and the at least one further temperature sensor (46, 48, 47), respectively.

13. 13. The process according to claim 12, wherein a second regulating system regulates the rolling speed in the reversing roughing stand (1) based on the temperature data.

14. 14. A process according to claim 12 or 13, wherein the cooling of the product and the rolling speed in each subsequent rough rolling pass are adjusted so that the product is always maintained below a temperature in the range of 440 to 460°C during the rough rolling passes.

15. 15. The process of claim 14, wherein the flow rate of the cooling liquid is adjusted to obtain a cooling gradient of -30 to -200°C / sec, depending on the thickness of the product being cooled and the speed at which the product passes through the cooling device.

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