EP4676665A1 - Reversible roughing mill for an aluminum or aluminum alloy product and related process - Google Patents

Reversible roughing mill for an aluminum or aluminum alloy product and related process

Info

Publication number
EP4676665A1
EP4676665A1 EP24715680.5A EP24715680A EP4676665A1 EP 4676665 A1 EP4676665 A1 EP 4676665A1 EP 24715680 A EP24715680 A EP 24715680A EP 4676665 A1 EP4676665 A1 EP 4676665A1
Authority
EP
European Patent Office
Prior art keywords
product
roughing
cooling device
cooling
reversible
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP24715680.5A
Other languages
German (de)
French (fr)
Inventor
Luciano Vignolo
Matteo GREGORATTI
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Danieli and C Officine Meccaniche SpA
Original Assignee
Danieli and C Officine Meccaniche SpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Danieli and C Officine Meccaniche SpA filed Critical Danieli and C Officine Meccaniche SpA
Publication of EP4676665A1 publication Critical patent/EP4676665A1/en
Pending legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/46—Roll speed or drive motor control
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B37/00—Control devices or methods specially adapted for metal-rolling mills or the work produced thereby
    • B21B37/74—Temperature control, e.g. by cooling or heating the rolls or the product
    • B21B37/76—Cooling control on the run-out table
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/22—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length
    • B21B1/30—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process
    • B21B1/32—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process in reversing single stand mills, e.g. with intermediate storage reels for accumulating work
    • B21B1/34—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling plates, strips, bands or sheets of indefinite length in a non-continuous process in reversing single stand mills, e.g. with intermediate storage reels for accumulating work by hot-rolling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B3/00—Rolling materials of special alloys so far as the composition of the alloy requires or permits special rolling methods or sequences ; Rolling of aluminium, copper, zinc or other non-ferrous metals
    • B21B2003/001—Aluminium or its alloys
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2261/00—Product parameters
    • B21B2261/20—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2275/00—Mill drive parameters
    • B21B2275/02—Speed
    • B21B2275/04—Roll speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B2275/00—Mill drive parameters
    • B21B2275/02—Speed
    • B21B2275/06—Product speed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B38/00—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product
    • B21B38/006—Methods or devices for measuring, detecting or monitoring specially adapted for metal-rolling mills, e.g. position detection, inspection of the product for measuring temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0218—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes for strips, sheets, or plates
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B45/00—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills
    • B21B45/02—Devices for surface or other treatment of work, specially combined with or arranged in, or specially adapted for use in connection with, metal-rolling mills for lubricating, cooling, or cleaning
    • B21B45/0203—Cooling
    • B21B45/0209—Cooling devices, e.g. using gaseous coolants
    • B21B45/0215—Cooling devices, e.g. using gaseous coolants using liquid coolants, e.g. for sections, for tubes
    • B21B45/0233—Spray nozzles, Nozzle headers; Spray systems

Definitions

  • the present invention relates to a reversible roughing mill for aluminum or aluminum alloy products and to the related process.
  • the solution of the invention can be applied to both slabs and ingots, cast and cut to size (coil-to-coil or semiendless modes).
  • Hot rolling mills for products in aluminum or alloys thereof can have different plant arrangements in relation to the final productivity required.
  • the slab to be rolled is heated to a temperature from 300 to 600°C in a heating furnace located upstream of the roughing stand.
  • the dimensions of the slab typically have a thickness from 450 to 750 mm and a length from 4 to more than 10 meters depending on the configuration of the slab melting and casting department located upstream of the heating furnace.
  • Hot rolling mills for aluminum products can have a production from less than 100,000 t/year up to more than 1 ,000,000 t/year, depending on the capacity required, and can have different plant arrangements among which we most commonly have:
  • These configurations have a gradually increasing capacity, going from less than 100,000 t/year, as the minimum capacity for the first configuration, up to more than 1 ,000,000 t/year for the last configuration depending on the dimensional and qualitative mix required.
  • the slab undergoes a reduction in thickness in several rolling passes, going from the initial thickness to a transfer thickness suitable for the finishing mill, which conventionally varies from about 25 to about 40 mm depending on the quality of the material and the requirements of the final product.
  • maximizing the capacity also involves rolling the slabs in the different sections of the plant; for example, it is possible that, while the finishing mill is rolling the product to obtain the aluminum coil, at least two slabs are being rolled at the same time in the roughing mill, a slab with an intermediate thickness is in the head and tail cutting step, while the other slab is being rolled in the roughing stand.
  • the concept of rolling multiple pieces in the multi-rolling roughing mill is applied, so as to reduce the downtime during which the roughing stand does not roll the product.
  • the maximum product temperature is the maximum product temperature.
  • the threshold is very close to the melting temperature of the product material, qualitative issues will appear due to the aluminum sticking against the rolling rollers and the material conveying rollers. Consequently, the roughing stand limits the speed of the rolling pass to increase the residence time of the material in the air, thus increasing the heat exchange, and therefore to avoid exceeding the critical threshold, although this has a negative impact on productivity.
  • Document CN108326051 A discloses a reversible roughing mill corresponding to the preamble of claim 1 .
  • the present invention achieves such and other objects, which will become apparent in light of the present description, by means of a reversible roughing mill for roughing an aluminum or aluminum alloy product, arriving at said roughing mill upon being fed along a first direction according to a feeding plane, said reversible roughing mill comprising
  • a first cooling device arranged upstream of said reversible roughing stand considering said first direction, and configured to cool down, above and below, by means of a cooling liquid, the product entering the reversible roughing stand for an odd roughing pass;
  • a second cooling device arranged downstream of said reversible roughing stand considering said first direction, and configured to cool down, above and below, by means of said cooling liquid, the product before further entering the reversible roughing stand for an even roughing pass; characterized in that there are provided:
  • a first adjustment system for adjusting the flow rate of the cooling liquid in said first cooling device and in said second cooling device on the basis of temperature data detected by said at least one temperature sensor and at least one further temperature sensor, respectively.
  • a roughing process is provided, which can be carried out by means of the aforesaid reversible roughing mill, comprising the following steps: a) performing a first odd roughing pass for the product in said first direction by means of the reversible roughing stand; b) performing a first even roughing pass for the product in a second direction, opposite to the first direction, by means of the reversible roughing stand; c) repeating step a), and possibly step b), until a predetermined reduction in the thickness of the product is obtained; wherein, before step a) and/or before step b), there is provided a step of cooling the product entering the reversible roughing stand, above and below, by means of a cooling liquid, fed respectively by the first cooling device or by the second cooling device; and wherein, by means of the first adjustment system, an adjustment of the flow rate of the cooling liquid in said first cooling device and in said second cooling device is provided on the basis of temperature data detected respectively by the at least one
  • the solution of the invention provides a product cooling system, located both downstream and upstream of the at least one roughing stand, and which can use, as a cooling liquid, the same emulsion used to lubricate and cool the rolling rollers of the roughing stand, or demineralized water.
  • the cooling devices comprise a plurality of cooling liquid manifolds with controlled emission of the liquid jets to ensure a considerable operating flexibility.
  • Figure 1 shows a diagram of an embodiment of a reversible roughing mill according to the invention
  • Figure 2 diagrammatically shows a cross section along the plane A-A of the roughing mill in Figure 1 ;
  • Figure 3 diagrammatically shows some details of part of a cooling device of the roughing mill of the invention
  • FIGS 4a and 4b diagrammatically show side views of two components of said cooling device
  • Figure 5 diagrammatically shows a perspective view of said two components
  • FIGS 6 and 7 diagrammatically show partial sectional views of said two components.
  • the aluminum or aluminum alloy product arrives at the mill being fed in a first direction (arrow B) along a feeding plane.
  • the reversible roughing mill comprises:
  • At least one reversible horizontal roughing stand 1 preferably, but not necessarily, a single reversible stand;
  • a first cooling device 10 arranged upstream of the reversible roughing stand 1 considering said first direction, and configured to cool down, above and below, by means of jets of a suitable cooling liquid, the product entering the reversible roughing stand 1 for an odd roughing pass;
  • a second cooling device 15 arranged downstream of the reversible roughing stand 1 considering said first direction, and configured to cool down, above and below, by means of jets of said cooling liquid, the product before further entering the reversible roughing stand 1 for an even roughing pass, in a second direction opposite to the first direction.
  • Inlet and outlet rollers are provided at said reversible roughing stand 1 .
  • the reversible roughing mill is provided with:
  • At least one temperature sensor arranged both at the inlet and at the outlet of the first cooling device 10, to detect the temperature of the product surface
  • At least one further temperature sensor arranged both at the inlet and at the outlet of the second cooling device 15, to detect the temperature of the product surface
  • a first adjustment system for adjusting the flow rate of the cooling liquid in the first cooling device 10 and in the second cooling device 15 on the basis of the temperature data detected by said at least one temperature sensor and at least one further temperature sensor, respectively.
  • said at least one temperature sensor can comprise:
  • a first temperature sensor 44 preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the inlet of the first cooling device 10 to detect the temperature of the product surface;
  • a second temperature sensor 43 preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the outlet of the first cooling device 10 to detect the temperature of the product surface;
  • a third temperature sensor 45 preferably a contact sensor, such as, for example, a thermocouple, arranged in proximity of the second temperature sensor 43, advantageously in proximity of or immediately after said second sensor, for the calibration of the latter, in particular to calibrate the emissivity thereof.
  • a contact sensor such as, for example, a thermocouple
  • an additional temperature sensor is arranged, for example a contact sensor such as a thermocouple, again in proximity of the first temperature sensor 44 for the calibration of the latter when the slab advances in the second direction, opposite to the first direction B.
  • Said at least one further temperature sensor can comprise:
  • a fourth temperature sensor 46 preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the inlet of the second cooling device 15 to detect the temperature of the product surface;
  • a fifth temperature sensor 48 preferably a contact sensor, such as, for example, a thermocouple, arranged in proximity of the fourth temperature sensor 46, advantageously in proximity of or immediately after said fourth sensor, for the calibration of the latter, in particular to calibrate the emissivity thereof;
  • a sixth temperature sensor 47 preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the outlet of the second cooling device 15 to detect the temperature of the product surface.
  • an infrared sensor such as, for example, a pyrometer or a thermal camera
  • an additional temperature sensor is arranged, for example a contact sensor such as a thermocouple, also in proximity of the sixth temperature sensor 47 for the calibration of the latter when the slab advances in the first direction B.
  • the measurement of the cooling liquid by the temperature sensors, associated with the flow rate of the cooling liquid, allows the energy removed from the cooling system and consequently the efficiency of the heat exchange between liquid and product to be evaluated.
  • the sensors measuring the three-dimensional shape of the product allow the evaluation of the presence of distorting effects, due to an unequally distributed cooling of the product, and the implementation of corrective actions by modifying the total flow rate of the liquid and the distribution thereof between the central portion and lateral portions, i.e., at the edges, of the product.
  • both the first cooling device 10 and the second cooling device 15 comprise respective upper manifolds 54 and respective lower manifolds 55 of the cooling liquid, preferably arranged parallel to each other and transversely to the feeding direction of the product.
  • Both the upper manifolds 54 as well as the lower manifolds 55 have a respective face 16 facing the product feeding plane, preferably parallel to said feeding plane, which is provided with a plurality of holes 11 to produce jets 26 of cooling liquid towards said feeding plane.
  • each manifold has the shape of a right parallelepiped, preferably a rectangular parallelepiped.
  • Figure 5 shows an upper manifold 54 and a lower manifold 55, facing each other with the face 16 thereof.
  • the lower face 16 of the upper manifold 54 is shown on the left, while the upper face 16 of the lower manifold 55 is shown on the right.
  • the number and size of the holes 11 are suitably chosen so as to ensure a flow rate of liquid within the range of 200 to 900 l/min/m 2 (liters per minute per square meter of product surface per face of the product).
  • a respective nozzle 56 is provided at each hole 11 , which allows a laminar flow of the jet of cooling liquid to be obtained.
  • the nozzles 56 are easily replaceable wear elements which reduce maintenance times and costs with respect to the situation in which a wear effect occurs, due to the passage of the liquid, in the holes 11 .
  • the lower manifolds 55 of the first cooling device 10 and of the second cooling device 15 can be arranged alternating with guide rollers 60 of horizontal roller tables of the product.
  • a first roller table 6, arranged at the entrance of the mill, and a second roller table 13, arranged at the exit of the mill, can be provided, which allow the product, given the reversibility of the mill, to move away from or towards the reversible roughing stand 1 .
  • an upper delivery line 19 feeds the upper manifolds 54, while a lower delivery line 20 feeds the lower manifolds 55.
  • an upper delivery line 21 feeds the upper manifolds 54, while a lower delivery line 22 feeds the lower manifolds 55.
  • each upper manifold 54 and each lower manifold 55 are divided internally into at least three chambers 51 , 52, 53, for example only three chambers.
  • a central chamber 51 is adapted to adjust the flow rate of the cooling liquid, and therefore of the jets 26, at a central portion of the surface of the product being fed to control the temperature thereof; while the two side chambers 52, 53 are adapted to adjust the flow rate of the cooling liquid, and therefore of the jets 26, at respective lateral portions of the surface of the product being fed to control the temperature thereof.
  • the first adjustment system for adjusting the flow rate of the cooling liquid in the first cooling device 10 and in the second cooling device 15 comprises a plurality of proportional valves for adjusting the flow rate of the cooling liquid which is then directed towards the feeding plane of the product, maintaining a substantially uniform temperature between the head, center and tail of said product.
  • the first adjustment system comprises respective proportional valves 30, 31 and 35, 36 to adjust the flow rate of the cooling liquid in each chamber 51 , 52, 53.
  • a proportional valve 30 adjusts the flow rate of the cooling liquid in the central chamber 51 of each upper manifold 54; and at least one proportional valve 31 adjusts the flow rate of the cooling liquid in the side chambers 52, 53 of each upper manifold 54.
  • a single proportional valve 31 or two proportional valves 31 can be provided. In the latter case, each proportional valve 31 adjusts the flow rate in a respective side chamber 52, 53.
  • a proportional valve 35 adjusts the flow rate of the cooling liquid in the central chamber 51 of each lower manifold 55; and at least one proportional valve 36 adjusts the flow rate of the cooling liquid in the side chambers 52, 53 of each lower manifold 55.
  • a single proportional valve 36 or two proportional valves 36 can be provided. In the latter case, each proportional valve 36 adjusts the flow rate in a respective side chamber.
  • the first adjustment system Upstream of the proportional valves 30, 31 and of the respective ducts 27, 28, the first adjustment system further comprises an automatic on/off valve 29 along the upper delivery line 19 which feeds the ducts 27, 28 and the upper manifolds 54 of the first cooling device 10.
  • the first adjustment system further comprises an automatic on/off valve 32 along the lower delivery line 20 which feeds the ducts 33, 34 and the lower manifolds 55 of the first cooling device 10.
  • each pipe 40 is engaged with a lower end thereof into a respective hole 11 of the face 16 facing the product feeding plane.
  • each nozzle 56 if provided, is mounted on the lower end of the respective pipe 40, preferably externally to the manifold 54.
  • the presence of the pipes 40 allows to minimize both the blocking time of the jets 26 of the cooling liquid at the end of the passage of the product through the cooling device, as well as the turning on time of said jets 26.
  • the automatic on/off valve 29 is closed to almost instantaneously obtain the interruption of the exit of the liquid jets from the upper manifolds 54 as soon as the level of the liquid is lower than the weir level.
  • the automatic on/off valve 29 is opened to almost instantaneously obtain the production of the jets directed towards the product, as only a minimum volume is to be filled inside the upper manifold to produce the jets.
  • a filtering plate 37 is provided, arranged above the upper ends of the pipes 40, to filter any coarse particles that would clog the laminar jet spray nozzles 56.
  • reference numeral 38 indicates the level of the cooling liquid inside the upper manifold 54 when the cooling device is in the off condition; while reference numeral 39 indicates a level of the cooling liquid when the cooling device is in the on condition, or simply a working level.
  • the flow rate of cooling liquid entering the upper manifolds 54 and the lower manifolds 55 increases, the pressure inside the manifolds increases and, therefore, the pressure of the jets exiting from the holes 11 or from the nozzles 56 increases.
  • the flow rate of cooling liquid entering each chamber can be adjusted by means of the aforesaid proportional valves.
  • FIG 7 instead, partially shows a lower manifold 55, for which the flow rate of the entering cooling liquid is 20-30% greater than the flow rate entering an upper manifold 54, to take into account the difference in impact on the surface and the shorter time the liquid remains on the same surface.
  • This different flow rate distribution by means of the respective proportional valves, allows the efficiency of the cooling system to be increased.
  • the mill of the invention can be provided with at least one first actuator 49 and at least one second actuator 50 ( Figure 1 ) to vertically move the single upper manifold, or the set of upper manifolds 54, of the first cooling device 10 and of the second cooling device 15, respectively, so as to keep the distance of the upper manifolds 54, and therefore the distance of the holes 11 or nozzles 56 facing the product feeding plane, from the upper surface of the product being rolled, constant, as the thickness varies due to the effect of the rolling.
  • This distance is preferably maintained at a value within a range of 300 to 1200 mm.
  • only one first actuator 49 and one second actuator 50 are provided.
  • the first cooling device 10 is installed between the lateral inlet guides 9, while the second cooling device 15 is installed between the lateral outlet guides 14.
  • collection channels 25 are provided in the space between the lateral edges of the upper manifolds 54, preferably parallel to the feeding direction, and the underlying lateral inlet guides 9 (or outlet guides 14), to protect the lateral edges of the product 24 being fed from the jets 26 of the cooling liquid, thus avoiding any overcooling of the lateral edges of the product.
  • At least one vertical rolling stand 2 ( Figure 1 ) can be provided, arranged between the first cooling device 10 and said at least one reversible roughing stand 1 , to roll the edges of the product.
  • Inlet and outlet rollers are provided at said vertical rolling stand 2.
  • a second adjustment system can be provided to adjust the rolling speed in said reversible roughing stand 1 on the basis of the temperature data detected by the temperature sensor or sensors at the exit of the product from the respective cooling device.
  • first blower 12 or air blade device arranged at the inlet of the mill
  • second blower 17 or air blade device arranged at the outlet of the mill, to dry the upper surface of the product and contain the cooling liquid inside the mill structure, thus allowing the entire collection thereof in the collection tank 18;
  • a tank (not shown) for storing the dirty cooling liquid, and possibly other liquid used in the mill, which is conveyed into said tank by means of at least one discharge pipe 23 of the collection tank 18;
  • a cleaning device 5 for example with demineralized water jets, arranged upstream of the at least one reversible roughing stand 1 or, where the at least one vertical rolling stand 2 is provided, upstream of said vertical rolling stand 2, to perform a descaler function;
  • At least one first bar 3 arranged upstream of the at least one reversible roughing stand 1 or the at least one vertical rolling stand 2, and at least one second bar 4, arranged downstream of the at least one reversible roughing stand 1 , to eliminate the cooling liquid or other liquid from the upper surface of the product entering the reversible roughing stand 1 .
  • the rolling plant comprising the reversible roughing mill of the present invention can include:
  • a hot roughing process of an aluminum or aluminum alloy product arriving at the reversible roughing mill according to the present invention, being fed along a first direction according to a feeding plane, is described below.
  • the process comprises the following steps: a) performing a first odd roughing pass for the product in said first direction by means of the reversible roughing stand 1 ; b) performing a first even roughing pass for the product in a second direction, opposite to the first direction, by means of the reversible roughing stand 1 ; c) repeating step a), and possibly step b), until a predetermined reduction in the thickness of the product is obtained; wherein, before step a) and/or before step b), there is provided a step of cooling the product entering the reversible roughing stand 1 , above and below, by means of a cooling liquid, fed respectively by the first cooling device 10 or by the second cooling device 15.
  • an adjustment of the flow rate of the cooling liquid in said first cooling device 10 and in said second cooling device 15 is provided on the basis of temperature data detected respectively by the at least one temperature sensor 44, 43, 45 and the at least one further temperature sensor 46, 48, 47.
  • the upper and lower cooling of the product is provided
  • the controlled cooling of the process of the invention allows the product to be roughened at the maximum possible rolling speed, thus preventing the product from exceeding a critical temperature threshold.
  • the achievable increase in productivity is within the range from 10% to 20%.
  • a variant of the process which involves this controlled cooling, by means of at least one cooling device, comprises the following steps:
  • the cooling liquid can be an appropriate emulsion, demineralized water or another suitable cooling liquid.
  • the inlet temperature of the cooling liquid can vary from 20 to 60°C.
  • an adjustment of the rolling speed of the reversible roughing stand 1 is provided, on the basis of the temperature data detected at the exit of the product from the respective cooling device.
  • the cooling of the product by means of the cooling liquid, and possibly the rolling speed in the subsequent respective roughing pass are adjusted so as to keep the product during the roughing pass always below a temperature within a range from 440 to 460°C, thus avoiding quality problems due to the sticking of the aluminum onto the rolling rollers and onto the product conveying rollers.
  • the flow rate of the cooling liquid in the cooling devices is adjusted to obtain cooling gradients from -30 to -200°C/s depending on the thickness of the product to be cooled down and on the speed at which the product passes through the cooling device.
  • the adjustment of the flow rate of the cooling liquid entering, above and below, the first cooling device 10 and the second cooling device 15 is performed by means of proportional valves 30, 31 , 35, 36, arranged along a respective delivery line 19, 20, 21 , 22, and at least one on/off valve 29, 32 arranged upstream of said proportional valves.
  • each upper manifold 54 and each lower manifold 55 are internally divided into at least three chambers 51 , 52, 53
  • the adjustment of the flow rate of the cooling liquid fed into each chamber 51 , 52, 53 is performed by means of respective proportional valves 30, 31 , 35, 36.
  • the adjustment of the flow rate of the 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 directed to a central portion of the surface of the product being fed is performed by means of a respective proportional valve 30, 35; while the adjustment of the flow rate of the cooling liquid in the side chambers 52, 53 of each upper manifold 54 and lower manifold 55, and therefore of the jets 26 directed to respective lateral portions of the surface of the product being fed, is carried out by means of at least one respective proportional valve 31 .
  • This adjustment allows temperature differences on the surfaces of the product, transversely to the feeding direction, to be minimized.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Metal Rolling (AREA)
  • Control Of Metal Rolling (AREA)

Abstract

A reversible roughing mill for roughing an aluminum or aluminum alloy product, being fed along a feeding plane, the roughing mill comprising: - a reversible horizontal roughing stand (1); - a first cooling device (10), arranged upstream of said reversible roughing stand (1) configured to cool down, above and below, the product entering the reversible roughing stand (1) by means of a cooling liquid; - a second cooling device (15), arranged downstream of said reversible roughing stand (1) configured to cool down, above and below, the product entering the reversible roughing stand (1) by means of said cooling liquid.

Description

REVERSIBLE ROUGHING MILL FOR AN ALUMINUM OR ALUMINUM ALLOY PRODUCT AND RELATED PROCESS
Field of the invention
The present invention relates to a reversible roughing mill for aluminum or aluminum alloy products and to the related process. The solution of the invention can be applied to both slabs and ingots, cast and cut to size (coil-to-coil or semiendless modes).
Background art
Hot rolling mills for products in aluminum or alloys thereof can have different plant arrangements in relation to the final productivity required.
Usually, the slab to be rolled is heated to a temperature from 300 to 600°C in a heating furnace located upstream of the roughing stand.
The dimensions of the slab, in addition to varying in width, typically have a thickness from 450 to 750 mm and a length from 4 to more than 10 meters depending on the configuration of the slab melting and casting department located upstream of the heating furnace.
Hot rolling mills for aluminum products can have a production from less than 100,000 t/year up to more than 1 ,000,000 t/year, depending on the capacity required, and can have different plant arrangements among which we most commonly have:
- single reversible stand with upstream and downstream winding reels, said stand being used both as a roughing machine and as a finishing machine;
- single reversible roughing stand and single reversible finishing stand with winding reels upstream and downstream of these stands;
- single reversible roughing stand and tandem finishing machine with multiple stands in a one-way line with an outlet winder.
These configurations have a gradually increasing capacity, going from less than 100,000 t/year, as the minimum capacity for the first configuration, up to more than 1 ,000,000 t/year for the last configuration depending on the dimensional and qualitative mix required.
In the reversible roughing stand, the slab undergoes a reduction in thickness in several rolling passes, going from the initial thickness to a transfer thickness suitable for the finishing mill, which conventionally varies from about 25 to about 40 mm depending on the quality of the material and the requirements of the final product.
In higher productivity rolling plants, the management of the rolling times, both for the roughing mill and for the finishing mill, is an essential factor for ensuring the achievement of the expected production rate.
Furthermore, maximizing the capacity also involves rolling the slabs in the different sections of the plant; for example, it is possible that, while the finishing mill is rolling the product to obtain the aluminum coil, at least two slabs are being rolled at the same time in the roughing mill, a slab with an intermediate thickness is in the head and tail cutting step, while the other slab is being rolled in the roughing stand. To maximize the capacity of the plant, the concept of rolling multiple pieces in the multi-rolling roughing mill is applied, so as to reduce the downtime during which the roughing stand does not roll the product.
Since it is hot rolling, managing the temperature of the product is also essential during all steps, so as to control the metallurgy of the product and prevent the product from going out of specification for rolling stands as it cools down.
Disadvantageously, in the roughing stand, one of the constraints on the hourly capacity of the roughing mill is the maximum product temperature. In fact, if the product exceeds the threshold of about 480-500°C due to the energy transferred by the plastic deformation, since this temperature threshold is very close to the melting temperature of the product material, qualitative issues will appear due to the aluminum sticking against the rolling rollers and the material conveying rollers. Consequently, the roughing stand limits the speed of the rolling pass to increase the residence time of the material in the air, thus increasing the heat exchange, and therefore to avoid exceeding the critical threshold, although this has a negative impact on productivity.
Document CN108326051 A discloses a reversible roughing mill corresponding to the preamble of claim 1 .
The need is therefore felt to achieve a reversible roughing mill and a related process capable of overcoming the aforesaid drawbacks. Summary of the invention
It is an object of the present invention to make a reversible roughing mill which provides an efficient cooling of the product at the at least one roughing stand to optimize the productivity of the roughing mill.
It is another object of the present invention to make a reversible roughing mill which provides efficient control of the product temperature at the at least one roughing stand to maximize productivity, thus avoiding qualitative issues due to the aluminum sticking to the rolling rollers and to the material conveying rollers.
It is a further object of the present invention to make a relative roughing process which is extremely efficient.
The present invention achieves such and other objects, which will become apparent in light of the present description, by means of a reversible roughing mill for roughing an aluminum or aluminum alloy product, arriving at said roughing mill upon being fed along a first direction according to a feeding plane, said reversible roughing mill comprising
- at least one reversible horizontal roughing stand;
- a first cooling device, arranged upstream of said reversible roughing stand considering said first direction, and configured to cool down, above and below, by means of a cooling liquid, the product entering the reversible roughing stand for an odd roughing pass;
- a second cooling device, arranged downstream of said reversible roughing stand considering said first direction, and configured to cool down, above and below, by means of said cooling liquid, the product before further entering the reversible roughing stand for an even roughing pass; characterized in that there are provided:
- at least one temperature sensor arranged both at the inlet and at the outlet of the first cooling device;
- at least one further temperature sensor arranged both at the inlet and at the outlet of the second cooling device;
- a first adjustment system for adjusting the flow rate of the cooling liquid in said first cooling device and in said second cooling device on the basis of temperature data detected by said at least one temperature sensor and at least one further temperature sensor, respectively.
According to a further aspect of the invention, a roughing process is provided, which can be carried out by means of the aforesaid reversible roughing mill, comprising the following steps: a) performing a first odd roughing pass for the product in said first direction by means of the reversible roughing stand; b) performing a first even roughing pass for the product in a second direction, opposite to the first direction, by means of the reversible roughing stand; c) repeating step a), and possibly step b), until a predetermined reduction in the thickness of the product is obtained; wherein, before step a) and/or before step b), there is provided a step of cooling the product entering the reversible roughing stand, above and below, by means of a cooling liquid, fed respectively by the first cooling device or by the second cooling device; and wherein, by means of the first adjustment system, an adjustment of the flow rate of the cooling liquid in said first cooling device and in said second cooling device is provided on the basis of temperature data detected respectively by the at least one temperature sensor and by the at least one further temperature sensor. Advantageously, the solution of the invention provides a product cooling system, located both downstream and upstream of the at least one roughing stand, and which can use, as a cooling liquid, the same emulsion used to lubricate and cool the rolling rollers of the roughing stand, or demineralized water.
With the cooling system active between roughing passes, it is possible to increase the rolling speed and consequently the productivity of the plant.
Reducing the temperature on the surface of the material will increase the strength of the outer part of the product. This will transfer the deformation of the material to a deeper level during the next rolling pass, thus reducing the head and tail defect and therefore allowing the length of discarded product to be reduced.
In a preferred variant, the cooling devices comprise a plurality of cooling liquid manifolds with controlled emission of the liquid jets to ensure a considerable operating flexibility.
Further advantages of the solution of the present invention over the prior art are listed below:
- high production flexibility;
- high ability to control the metallurgy and therefore the mechanical features of the product, which are kept constant along the entire length of the rolled product;
- high ability to control any distorting effects on flatness due, in the prior art, to different temperatures transversally across the product.
Further features and advantages of the invention will be more apparent in light of the detailed description of the preferred, but not exclusive embodiments.
The dependent claims describe particular embodiments of the invention.
Brief description of the Figures
The description of the invention refers to the accompanying drawings, which show non-limiting examples, in which:
Figure 1 shows a diagram of an embodiment of a reversible roughing mill according to the invention;
Figure 2 diagrammatically shows a cross section along the plane A-A of the roughing mill in Figure 1 ;
Figure 3 diagrammatically shows some details of part of a cooling device of the roughing mill of the invention;
Figures 4a and 4b diagrammatically show side views of two components of said cooling device;
Figure 5 diagrammatically shows a perspective view of said two components;
Figures 6 and 7 diagrammatically show partial sectional views of said two components.
The same reference numerals in the Figures identify the same elements or components.
Description of illustrative embodiments of the invention
Some examples of a reversible hot roughing mill for an aluminum or aluminum alloy product, which forms the object of the present invention, are described with reference to the Figures.
With reference to Figure 1 , the aluminum or aluminum alloy product, for example a slab, arrives at the mill being fed in a first direction (arrow B) along a feeding plane. In all embodiments of the invention, the reversible roughing mill comprises:
- at least one reversible horizontal roughing stand 1 , preferably, but not necessarily, a single reversible stand;
- a first cooling device 10, arranged upstream of the reversible roughing stand 1 considering said first direction, and configured to cool down, above and below, by means of jets of a suitable cooling liquid, the product entering the reversible roughing stand 1 for an odd roughing pass;
- a second cooling device 15, arranged downstream of the reversible roughing stand 1 considering said first direction, and configured to cool down, above and below, by means of jets of said cooling liquid, the product before further entering the reversible roughing stand 1 for an even roughing pass, in a second direction opposite to the first direction.
Inlet and outlet rollers are provided at said reversible roughing stand 1 . Advantageously, the reversible roughing mill is provided with:
- at least one temperature sensor arranged both at the inlet and at the outlet of the first cooling device 10, to detect the temperature of the product surface;
- at least one further temperature sensor arranged both at the inlet and at the outlet of the second cooling device 15, to detect the temperature of the product surface;
- and a first adjustment system for adjusting the flow rate of the cooling liquid in the first cooling device 10 and in the second cooling device 15 on the basis of the temperature data detected by said at least one temperature sensor and at least one further temperature sensor, respectively.
In a variant (Figure 1), considering the first direction (arrow B), said at least one temperature sensor can comprise:
- a first temperature sensor 44, preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the inlet of the first cooling device 10 to detect the temperature of the product surface;
- a second temperature sensor 43, preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the outlet of the first cooling device 10 to detect the temperature of the product surface;
- and a third temperature sensor 45, preferably a contact sensor, such as, for example, a thermocouple, arranged in proximity of the second temperature sensor 43, advantageously in proximity of or immediately after said second sensor, for the calibration of the latter, in particular to calibrate the emissivity thereof.
Preferably, an additional temperature sensor is arranged, for example a contact sensor such as a thermocouple, again in proximity of the first temperature sensor 44 for the calibration of the latter when the slab advances in the second direction, opposite to the first direction B.
Said at least one further temperature sensor, instead, can comprise:
- a fourth temperature sensor 46, preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the inlet of the second cooling device 15 to detect the temperature of the product surface;
- a fifth temperature sensor 48, preferably a contact sensor, such as, for example, a thermocouple, arranged in proximity of the fourth temperature sensor 46, advantageously in proximity of or immediately after said fourth sensor, for the calibration of the latter, in particular to calibrate the emissivity thereof;
- and a sixth temperature sensor 47, preferably an infrared sensor, such as, for example, a pyrometer or a thermal camera, arranged at the outlet of the second cooling device 15 to detect the temperature of the product surface.
Preferably, an additional temperature sensor is arranged, for example a contact sensor such as a thermocouple, also in proximity of the sixth temperature sensor 47 for the calibration of the latter when the slab advances in the first direction B.
Other sensors which can be provided in the mill of the invention, interacting with the aforesaid adjustment system, are:
- temperature sensors for detecting the temperature of the cooling liquid entering the mill and exiting the mill, after the use thereof when cooling the product;
- three-dimensional shape sensors for detecting the shape of the product and the camber thereof.
The measurement of the cooling liquid by the temperature sensors, associated with the flow rate of the cooling liquid, allows the energy removed from the cooling system and consequently the efficiency of the heat exchange between liquid and product to be evaluated.
The sensors measuring the three-dimensional shape of the product allow the evaluation of the presence of distorting effects, due to an unequally distributed cooling of the product, and the implementation of corrective actions by modifying the total flow rate of the liquid and the distribution thereof between the central portion and lateral portions, i.e., at the edges, of the product.
Preferably, both the first cooling device 10 and the second cooling device 15 comprise respective upper manifolds 54 and respective lower manifolds 55 of the cooling liquid, preferably arranged parallel to each other and transversely to the feeding direction of the product.
Both the upper manifolds 54 as well as the lower manifolds 55 have a respective face 16 facing the product feeding plane, preferably parallel to said feeding plane, which is provided with a plurality of holes 11 to produce jets 26 of cooling liquid towards said feeding plane.
As an example, each manifold has the shape of a right parallelepiped, preferably a rectangular parallelepiped.
Figure 5 shows an upper manifold 54 and a lower manifold 55, facing each other with the face 16 thereof. In Figure 4, the lower face 16 of the upper manifold 54 is shown on the left, while the upper face 16 of the lower manifold 55 is shown on the right.
Preferably, the number and size of the holes 11 are suitably chosen so as to ensure a flow rate of liquid within the range of 200 to 900 l/min/m2 (liters per minute per square meter of product surface per face of the product).
Optionally, a respective nozzle 56 is provided at each hole 11 , which allows a laminar flow of the jet of cooling liquid to be obtained.
Advantageously, the nozzles 56 are easily replaceable wear elements which reduce maintenance times and costs with respect to the situation in which a wear effect occurs, due to the passage of the liquid, in the holes 11 .
Preferably, the lower manifolds 55 of the first cooling device 10 and of the second cooling device 15 can be arranged alternating with guide rollers 60 of horizontal roller tables of the product.
In particular, a first roller table 6, arranged at the entrance of the mill, and a second roller table 13, arranged at the exit of the mill, can be provided, which allow the product, given the reversibility of the mill, to move away from or towards the reversible roughing stand 1 .
In the first cooling device 10, an upper delivery line 19 feeds the upper manifolds 54, while a lower delivery line 20 feeds the lower manifolds 55.
Similarly, in the second cooling device 15, an upper delivery line 21 feeds the upper manifolds 54, while a lower delivery line 22 feeds the lower manifolds 55.
The possibility is not excluded of providing, for each cooling device 10, 15, a single upper manifold and a single lower manifold, having the respective face 16 facing the product feeding plane, preferably parallel to said feeding plane, provided with a plurality of holes 11 which are divided into groups of holes, each group of holes being provided at a space between a guide roller 60 and the next one of the horizontal roller table of the product.
In a preferred variant, shown in Figures 4 and 5, each upper manifold 54 and each lower manifold 55 are divided internally into at least three chambers 51 , 52, 53, for example only three chambers. A central chamber 51 is adapted to adjust the flow rate of the cooling liquid, and therefore of the jets 26, at a central portion of the surface of the product being fed to control the temperature thereof; while the two side chambers 52, 53 are adapted to adjust the flow rate of the cooling liquid, and therefore of the jets 26, at respective lateral portions of the surface of the product being fed to control the temperature thereof.
Preferably, the first adjustment system for adjusting the flow rate of the cooling liquid in the first cooling device 10 and in the second cooling device 15 comprises a plurality of proportional valves for adjusting the flow rate of the cooling liquid which is then directed towards the feeding plane of the product, maintaining a substantially uniform temperature between the head, center and tail of said product.
As diagrammatically shown in Figure 3, for each upper manifold 54 and each lower manifold 55 of the first cooling device 10, the first adjustment system comprises respective proportional valves 30, 31 and 35, 36 to adjust the flow rate of the cooling liquid in each chamber 51 , 52, 53.
In particular, a proportional valve 30 adjusts the flow rate of the cooling liquid in the central chamber 51 of each upper manifold 54; and at least one proportional valve 31 adjusts the flow rate of the cooling liquid in the side chambers 52, 53 of each upper manifold 54. A single proportional valve 31 or two proportional valves 31 can be provided. In the latter case, each proportional valve 31 adjusts the flow rate in a respective side chamber 52, 53.
Similarly, a proportional valve 35 adjusts the flow rate of the cooling liquid in the central chamber 51 of each lower manifold 55; and at least one proportional valve 36 adjusts the flow rate of the cooling liquid in the side chambers 52, 53 of each lower manifold 55. A single proportional valve 36 or two proportional valves 36 can be provided. In the latter case, each proportional valve 36 adjusts the flow rate in a respective side chamber.
Upstream of the proportional valves 30, 31 and of the respective ducts 27, 28, the first adjustment system further comprises an automatic on/off valve 29 along the upper delivery line 19 which feeds the ducts 27, 28 and the upper manifolds 54 of the first cooling device 10.
Similarly, upstream of the proportional valves 35, 36 and the respective ducts 33, 34, the first adjustment system further comprises an automatic on/off valve 32 along the lower delivery line 20 which feeds the ducts 33, 34 and the lower manifolds 55 of the first cooling device 10.
Thereby, it is possible to modulate or control the distribution of the cooling liquid on the surface of the product so as to obtain the desired thermal profile, possibly measuring the flow rate of the cooling liquid with appropriate flow rate transducers 42, respectively arranged 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.
The same configuration, diagrammatically shown in Figure 3, is provided for the second cooling device 15 at the upper delivery line 21 and the lower delivery line 22.
In a variant of the invention, as shown in Figure 6, inside the upper manifolds 54 a plurality of pipes 40 is provided, preferably vertical and equal in height, the upper ends of said pipes are free and define a weir level of the cooling liquid. Each pipe 40 is engaged with a lower end thereof into a respective hole 11 of the face 16 facing the product feeding plane. In this case, each nozzle 56, if provided, is mounted on the lower end of the respective pipe 40, preferably externally to the manifold 54.
The presence of the pipes 40 allows to minimize both the blocking time of the jets 26 of the cooling liquid at the end of the passage of the product through the cooling device, as well as the turning on time of said jets 26.
When the adjustment system controls the interruption of the jets of the cooling liquid, the automatic on/off valve 29 is closed to almost instantaneously obtain the interruption of the exit of the liquid jets from the upper manifolds 54 as soon as the level of the liquid is lower than the weir level.
When the adjustment system controls the activation of the jets of the cooling liquid, the automatic on/off valve 29 is opened to almost instantaneously obtain the production of the jets directed towards the product, as only a minimum volume is to be filled inside the upper manifold to produce the jets.
Preferably, a filtering plate 37 is provided, arranged above the upper ends of the pipes 40, to filter any coarse particles that would clog the laminar jet spray nozzles 56.
In Figure 6, the reference numeral 38 indicates the level of the cooling liquid inside the upper manifold 54 when the cooling device is in the off condition; while reference numeral 39 indicates a level of the cooling liquid when the cooling device is in the on condition, or simply a working level.
As the flow rate of cooling liquid entering the upper manifolds 54 and the lower manifolds 55 increases, the pressure inside the manifolds increases and, therefore, the pressure of the jets exiting from the holes 11 or from the nozzles 56 increases. In the variant in which the manifolds are internally divided into at least three chambers, the flow rate of cooling liquid entering each chamber can be adjusted by means of the aforesaid proportional valves.
Figure 7, instead, partially shows a lower manifold 55, for which the flow rate of the entering cooling liquid is 20-30% greater than the flow rate entering an upper manifold 54, to take into account the difference in impact on the surface and the shorter time the liquid remains on the same surface. This different flow rate distribution, by means of the respective proportional valves, allows the efficiency of the cooling system to be increased.
Preferably, the mill of the invention can be provided with at least one first actuator 49 and at least one second actuator 50 (Figure 1 ) to vertically move the single upper manifold, or the set of upper manifolds 54, of the first cooling device 10 and of the second cooling device 15, respectively, so as to keep the distance of the upper manifolds 54, and therefore the distance of the holes 11 or nozzles 56 facing the product feeding plane, from the upper surface of the product being rolled, constant, as the thickness varies due to the effect of the rolling. This distance is preferably maintained at a value within a range of 300 to 1200 mm.
In one embodiment, only one first actuator 49 and one second actuator 50 are provided.
In all embodiments of the mill of the invention, there can be provided:
- lateral inlet centering guides 9 to laterally guide and center the product entering the mill;
- lateral outlet centering guides 14 to laterally guide and center the product exiting the mill.
Preferably, the first cooling device 10 is installed between the lateral inlet guides 9, while the second cooling device 15 is installed between the lateral outlet guides 14.
Optionally, as diagrammatically shown in Figure 2, collection channels 25 are provided in the space between the lateral edges of the upper manifolds 54, preferably parallel to the feeding direction, and the underlying lateral inlet guides 9 (or outlet guides 14), to protect the lateral edges of the product 24 being fed from the jets 26 of the cooling liquid, thus avoiding any overcooling of the lateral edges of the product.
These collection channels 25 divert the intercepted cooling liquid towards a collection tank 18, located in the lower part of the mill (Figure 1).
In all embodiments of the roughing mill of the invention, at least one vertical rolling stand 2 (Figure 1 ) can be provided, arranged between the first cooling device 10 and said at least one reversible roughing stand 1 , to roll the edges of the product. Inlet and outlet rollers are provided at said vertical rolling stand 2.
In a preferred variant of the invention, a second adjustment system can be provided to adjust the rolling speed in said reversible roughing stand 1 on the basis of the temperature data detected by the temperature sensor or sensors at the exit of the product from the respective cooling device.
In all embodiments of the roughing mill of the invention, one or more of the following components (Figure 1) can also be provided, considering the first direction B:
- a first blower 12 or air blade device, arranged at the inlet of the mill, and a second blower 17 or air blade device, arranged at the outlet of the mill, to dry the upper surface of the product and contain the cooling liquid inside the mill structure, thus allowing the entire collection thereof in the collection tank 18;
- a tank (not shown) for storing the dirty cooling liquid, and possibly other liquid used in the mill, which is conveyed into said tank by means of at least one discharge pipe 23 of the collection tank 18;
- a cleaning device 5, for example with demineralized water jets, arranged upstream of the at least one reversible roughing stand 1 or, where the at least one vertical rolling stand 2 is provided, upstream of said vertical rolling stand 2, to perform a descaler function;
- at least one first bar 3, arranged upstream of the at least one reversible roughing stand 1 or the at least one vertical rolling stand 2, and at least one second bar 4, arranged downstream of the at least one reversible roughing stand 1 , to eliminate the cooling liquid or other liquid from the upper surface of the product entering the reversible roughing stand 1 .
The rolling plant comprising the reversible roughing mill of the present invention can include:
- a preheating furnace, upstream of said reversible roughing mill;
- and a finishing mill, downstream of said reversible roughing mill.
A hot roughing process of an aluminum or aluminum alloy product arriving at the reversible roughing mill according to the present invention, being fed along a first direction according to a feeding plane, is described below.
In all the embodiments thereof, the process comprises the following steps: a) performing a first odd roughing pass for the product in said first direction by means of the reversible roughing stand 1 ; b) performing a first even roughing pass for the product in a second direction, opposite to the first direction, by means of the reversible roughing stand 1 ; c) repeating step a), and possibly step b), until a predetermined reduction in the thickness of the product is obtained; wherein, before step a) and/or before step b), there is provided a step of cooling the product entering the reversible roughing stand 1 , above and below, by means of a cooling liquid, fed respectively by the first cooling device 10 or by the second cooling device 15.
Advantageously, by means of the first adjustment system, an adjustment of the flow rate of the cooling liquid in said first cooling device 10 and in said second cooling device 15 is provided on the basis of temperature data detected respectively by the at least one temperature sensor 44, 43, 45 and the at least one further temperature sensor 46, 48, 47.
In a preferred variant, the upper and lower cooling of the product is provided
- both before an odd roughing pass, by means of the cooling liquid supplied by the first cooling device 10,
- and before an even roughing pass, by means of the cooling liquid supplied by the second cooling device 15.
The controlled cooling of the process of the invention allows the product to be roughened at the maximum possible rolling speed, thus preventing the product from exceeding a critical temperature threshold. The achievable increase in productivity is within the range from 10% to 20%.
In more detail, a variant of the process, which involves this controlled cooling, by means of at least one cooling device, comprises the following steps:
- measuring the temperature of the product entering the cooling device;
- defining the rolling parameters of the reversible roughing stand, providing a maximum rolling speed in compliance with the design limits of the stand and considering the size, material and chemical-physical features of the product;
- calculating the temperature of the product exiting the reversible roughing stand, by means of a thermal model of the rolling compartment of the stand which takes into account said rolling parameters;
- if said calculated temperature of the product exiting the reversible roughing stand is lower than a predetermined critical temperature, performing the rolling according to the aforesaid rolling parameters; - measuring the temperature of the product exiting the reversible roughing stand.
In the case where said calculated temperature of the exiting product is equal to or higher than the predetermined critical temperature, the following steps are required before performing the rolling:
- calculating a flow rate of the cooling liquid to be fed into the cooling device, and possibly selecting the number of upper and lower manifolds to be activated, by means of a thermal model of the cooling device included in the first adjustment system, to obtain an optimal temperature of the product exiting from said cooling device, and therefore a temperature of the product entering the reversible roughing stand, which allows a temperature higher than 420°C, but lower than said predetermined critical temperature, to be reached after the rolling;
- cooling the product by activating the cooling device by feeding it with said flow rate of the cooling liquid, possibly activating a selected number of upper and lower manifolds;
- measuring the temperature of the product exiting said cooling device;
- if the measured temperature of the product exiting the cooling device is equal to said optimal temperature, performing the rolling according to the aforesaid rolling parameters;
- and measuring the temperature of the product exiting the reversible roughing stand.
In case the measured temperature of the product exiting the cooling device is other than said optimal temperature, the following steps are required before performing the rolling:
- calculating a cooling liquid-product heat exchange coefficient to calibrate the thermal model of the cooling device which calculates a new flow rate of the cooling liquid to obtain said optimal temperature of the product exiting the cooling device;
- cooling the product by activating the cooling device by feeding it with said new flow rate of the cooling liquid;
- performing the rolling according to the aforesaid rolling parameters;
- and measuring the temperature of the product exiting the reversible roughing stand.
The cooling liquid can be an appropriate emulsion, demineralized water or another suitable cooling liquid.
The inlet temperature of the cooling liquid can vary from 20 to 60°C.
Preferably, by means of a second adjustment system, an adjustment of the rolling speed of the reversible roughing stand 1 is provided, on the basis of the temperature data detected at the exit of the product from the respective cooling device.
Preferably, the cooling of the product by means of the cooling liquid, and possibly the rolling speed in the subsequent respective roughing pass, are adjusted so as to keep the product during the roughing pass always below a temperature within a range from 440 to 460°C, thus avoiding quality problems due to the sticking of the aluminum onto the rolling rollers and onto the product conveying rollers.
For example, the flow rate of the cooling liquid in the cooling devices is adjusted to obtain cooling gradients from -30 to -200°C/s depending on the thickness of the product to be cooled down and on the speed at which the product passes through the cooling device.
In a variant of the process, the adjustment of the flow rate of the cooling liquid entering, above and below, the first cooling device 10 and the second cooling device 15 is performed by means of proportional valves 30, 31 , 35, 36, arranged along a respective delivery line 19, 20, 21 , 22, and at least one on/off valve 29, 32 arranged upstream of said proportional valves.
This adjustment of the flow rate of the cooling liquid entering the cooling devices 10, 15, and therefore of the flow rate of the jets 26 directed towards the upper and lower surfaces of the product being fed, allows to maintain a uniform temperature between head, center and tail of the product to be rolled.
In the variant of the mill in which each upper manifold 54 and each lower manifold 55 are internally divided into at least three chambers 51 , 52, 53, the adjustment of the flow rate of the cooling liquid fed into each chamber 51 , 52, 53 is performed by means of respective proportional valves 30, 31 , 35, 36.
In particular, the adjustment of the flow rate of the 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 directed to a central portion of the surface of the product being fed, is performed by means of a respective proportional valve 30, 35; while the adjustment of the flow rate of the cooling liquid in the side chambers 52, 53 of each upper manifold 54 and lower manifold 55, and therefore of the jets 26 directed to respective lateral portions of the surface of the product being fed, is carried out by means of at least one respective proportional valve 31 . This adjustment allows temperature differences on the surfaces of the product, transversely to the feeding direction, to be minimized.

Claims

1. A reversible roughing mill for roughing an aluminum or aluminum alloy product, arriving at said roughing mill being fed along a first direction according to a feeding plane, the roughing mill comprising:
- at least one reversible horizontal roughing stand (1);
- a first cooling device (10), arranged upstream of said reversible roughing stand (1 ) considering said first direction, and configured to cool down, above and below, by means of a cooling liquid, the product entering the reversible roughing stand (1 ) for an odd roughing pass;
- a second cooling device (15), arranged downstream of said reversible roughing stand (1 ) considering said first direction, and configured to cool down, above and below, by means of said cooling liquid, the product before further entering the reversible roughing stand (1 ) for an even roughing pass; characterized in that there are provided:
- at least one temperature sensor (44, 43, 45) arranged both at the inlet and at the outlet of the first cooling device (10);
- at least one further temperature sensor (46, 48, 47) arranged both at the inlet and at the outlet of the second cooling device (15);
- a first adjustment system for adjusting the flow rate of the cooling liquid in said first cooling device (10) and in said second cooling device (15) on the basis of temperature data detected by said at least one temperature sensor (44, 43, 45) and at least one further temperature sensor (46, 48, 47), respectively.
2. A roughing mill according to claim 1 , wherein a second adjustment system is provided, adapted to adjust the rolling speed in said reversible roughing stand (1 ) on the basis of the temperature data detected by the temperature sensor or temperature sensors at the exit of the product from the respective cooling device (10, 15).
3. A roughing mill according to claim 1 or 2, wherein said first adjustment system comprises, along at least one delivery line (19, 20, 21 , 22) adapted to feed the first cooling device (10) and the second cooling device (15) with the cooling liquid:
- proportional valves (30, 31 , 35, 36) for adjusting the flow rate of the cooling liquid entering, above and below, said first cooling device (10) and second cooling device (15);
- and at least one on/off valve (29, 32) arranged upstream of said proportional valves.
4. A roughing mill according to any one of the preceding claims, wherein the first cooling device (10) and the second cooling device (15) comprise a respective upper manifold (54), or respective upper manifolds (54), and a respective lower manifold (55), or respective lower manifolds (55), of the cooling liquid, arranged transversally to a product feeding direction and having a respective face facing the product feeding plane which is provided with a plurality of holes (11) to produce jets (26) of the cooling liquid towards said feeding plane; preferably wherein a respective nozzle (56) is provided at each hole (11 ).
5. A roughing mill according to claim 4, wherein each upper manifold (54) and each lower manifold (55) are internally divided into at least three chambers (51 , 52, 53); preferably wherein said at least three chambers comprise at least one central chamber (51 ), adapted to adjust the flow rate of the cooling liquid directed to a central portion of the surface of the product being fed, and two side chambers (52, 53) adapted to adjust the flow rate of the cooling liquid directed to respective lateral portions of the product surface.
6. A roughing mill according to claim 5, wherein proportional valves (30, 31 , 35, 36) are provided for adjusting the flow rate of the cooling liquid fed into each chamber of said at least three chambers (51 , 52, 53).
7. A roughing mill according to any one of claims 4 to 6, wherein, inside the upper manifolds (54), a plurality of pipes (40) is provided; the upper ends of said pipes define a weir height (38) of the cooling liquid, each pipe (40) being inserted with a lower end thereof in a respective hole of said plurality of holes (11 ).
8. A roughing mill according to any one of claims 4 to 7, wherein at least one first actuator (49) and at least one second actuator (50) are provided for vertically moving the upper manifold, or the set of upper manifolds (54), of the first cooling device (10) and of the second cooling device (15), respectively, so as to keep the distance of the upper manifold or manifolds (54) from the upper surface of the product being rolled constant.
9. A roughing mill according to any one of the preceding claims, wherein there are provided
- lateral inlet guides (9) to guide the product entering the roughing mill;
- lateral outlet guides (14) to guide the product exiting the roughing mill; and wherein the first cooling system (10) is installed between the lateral inlet guides (9), while the second cooling system (15) is installed between the lateral outlet guides (14).
10. A roughing mill according to claim 9, when dependent on claim 4, wherein channels (25) are provided in the space between lateral edges of the upper manifolds (54) and the underlying lateral inlet (9) and outlet (14) guides, to protect lateral edges of the product from the jets (26) of the cooling liquid, by diverting the intercepted cooling liquid towards a collection tank (18).
11. A roughing mill according to any one of the preceding claims, wherein at least one vertical rolling stand (2) is provided, arranged between the first cooling device (10) and said reversible roughing stand (1 ), to roll the edges of the product.
12. A hot roughing process for an aluminum or aluminum alloy product, by means of a reversible roughing mill according to any one of the preceding claims, said product being fed along a first direction according to a feeding plane, the process comprising the following steps: a) performing a first odd roughing pass for the product in said first direction by means of the reversible roughing stand (1 ); b) performing a first even roughing pass for the product in a second direction, opposite to the first direction, by means of the reversible roughing stand (1); c) repeating step a), and possibly step b), until a predetermined reduction in the thickness of the product is obtained; wherein, before step a) and/or before step b), there is provided a step of cooling the product entering the reversible roughing stand (1 ), above and below, by means of a cooling liquid, fed respectively by the first cooling device (10) or by the second cooling device (15); and wherein, by means of the first adjustment system, an adjustment of the flow rate of the cooling liquid in said first cooling device (10) and in said second cooling device (15) is provided on the basis of temperature data detected respectively by the at least one temperature sensor (44, 43, 45) and the at least one further temperature sensor (46, 48, 47).
13. A process according to claim 12, wherein, by means of a second adjustment system, an adjustment of the rolling speed in said reversible roughing stand (1 ) is provided, on the basis of said temperature data.
14. A process according to claim 12 or 13, wherein the cooling of the product and the rolling speed in the subsequent respective roughing pass are adjusted so as to keep the product during the roughing pass always below a temperature in a range from 440 to 460°C.
15. A process according to claim 14, wherein the flow rate of the cooling liquid is adjusted to obtain cooling gradients from -30 to -200°C/s depending on the thickness of the product to be cooled down and on the speed at which the product passes through the cooling device.
EP24715680.5A 2023-03-06 2024-03-05 Reversible roughing mill for an aluminum or aluminum alloy product and related process Pending EP4676665A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
IT102023000004038A IT202300004038A1 (en) 2023-03-06 2023-03-06 REVERSIBLE ROLLING MILL FOR ROUGHING AN ALUMINIUM OR ALUMINIUM ALLOY PRODUCT AND RELATED PROCESS
PCT/IB2024/052107 WO2024184803A1 (en) 2023-03-06 2024-03-05 Reversible roughing mill for an aluminum or aluminum alloy product and related process

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EP4676665A1 true EP4676665A1 (en) 2026-01-14

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JP (1) JP2026507716A (en)
CN (1) CN121038910A (en)
IT (1) IT202300004038A1 (en)
WO (1) WO2024184803A1 (en)

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Publication number Priority date Publication date Assignee Title
CN202824183U (en) * 2012-09-20 2013-03-27 浙江永杰铝业有限公司 Cooling device used for rolling aluminum alloy medium-thick plate at differential temperature
CN108326051B (en) * 2018-01-29 2019-08-27 东北大学 A kind of coupled preparation process method of aluminum alloy plate
EP3623068B1 (en) * 2018-09-12 2021-07-14 Primetals Technologies Germany GmbH Application devices for cooling lines with second connection
CN115702048A (en) * 2020-06-04 2023-02-14 新布里萨什肯联铝业 Cooling method and equipment for reversing hot rolling mill

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JP2026507716A (en) 2026-03-04
WO2024184803A1 (en) 2024-09-12
IT202300004038A1 (en) 2024-09-06

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