Method for producing an aluminum strip and casting-rolling system for producing an aluminum strip

Abstract

A method for producing an aluminum strip (2) in a coupled casting-rolling process, includes the following steps: a) melting an aluminum raw material comprising at least one aluminum alloy in at least one melting assembly (4); b) determining the alloy composition of the melt (3); c) casting the melt (3) to form a hot strip by means of at least one strip-casting machine (6); d) rolling the hot strip in a rolling system (14) comprising at least one rolling device for shaping the hot strip for thickness and/or width reduction; and e) regulating and/or controlling at least one shaping parameter of the rolling system (14) as a function of the alloy composition of the melt (3). The disclosure also relates to a casting-rolling system (1) for carrying out the method.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This application is a national stage application, filed under 35 U.S.C. § 371, of International Patent Application PCT/EP2022/066325, filed on Jun. 15, 2022, which claims the benefit of German Patent Application DE 10 2021 208 437.0, filed on Aug. 4, 2021.

TECHNICAL FIELD

The disclosure relates to a method for producing an aluminum strip in a coupled casting-rolling process.

BACKGROUND

WO 2019/01 02841 discloses a method for producing an aluminum product from a cast aluminum strip, with which a hot strip is initially generated by means of at least one strip-casting machine and is subsequently hot-rolled.

DE 69319217 T2 discloses a method for producing can body sheet, which comprises the continuous hot rolling of a feed material consisting of hot aluminum for the purpose of reducing its thickness and the winding up of the feed material that is hot-rolled and still hot along with holding the feed strip, which has been reduced in thickness in the hot state, at or near the initial temperature of the hot rolling, wherein the hot wound feed material is subsequently unwound again and, immediately thereafter, rapid quenching of the tempered feed material to a temperature suitable for cold rolling is provided. The method is carried out as a continuous “in-line” method.

SUMMARY

For many products otherwise produced from sheet steel, lightweight materials such as aluminum are now being used. Increasing aluminum consumption will make larger quantities of aluminum scrap available in the medium term. The processing of aluminum waste is more energy-efficient than the extraction of primary aluminum by means of electrolysis. However, the problem with using aluminum scrap is that it consists of a mixture of different aluminum alloys that contain a wide variety of undesirable alloy components. Such alloy components are eliminated in conventional casting methods, such as ingot casting, due to the low solidification speed of the melt, and impair the grain structure of the solidified material. For this reason, a high proportion of primary aluminum is still used in the production of certain end products such as beverage cans, components for use in the electrical industry and car bodies.

The disclosure is based on the object of providing a method of the type mentioned at the beginning, with which a high proportion of aluminum scrap can be processed as an aluminum raw material/starting material for producing an aluminum strip in an industrially usable quality. The disclosure is also based on the object of providing an aluminum material that has been obtained using a high proportion of aluminum scrap. Finally, the disclosure is based on the object of providing a casting-rolling system that is particularly suitable for the method in accordance with the disclosure.

According to one aspect, a method for producing aluminum strip in a coupled casting-rolling process is provided, which is preferably operated as a continuous casting-rolling process comprising the following method steps:

• • a) melting an aluminum raw material comprising at least one aluminum alloy in at least one melting assembly,
  • b) determining the alloy composition of the melt
  • c) casting the melt to form a cast strip by means of at least one strip-casting machine,
  • d) rolling the hot strip in a rolling system comprising at least one rolling device for shaping the hot strip for thickness and/or width reduction, and
  • e) regulating and/or controlling at least one shaping parameter of the rolling system as a function of the alloy composition of the melt.

Within the context of the present disclosure, “coupled” means that the casting process and the rolling process are connected with one another in terms of process technology and material flow. Depending on the design of the melting assembly, the melting of the aluminum raw material, casting and rolling can also be effected continuously, wherein the throughput speed of the material is always determined by the strip speed during casting.

The alloy composition of the melt can be determined continuously or in batches.

The results of the analysis of the alloy composition can be fed online, preferably in real time, to a regulating and/or control device of a casting-rolling system. A suitable method for analyzing the alloy composition of the melt is, for example, a spectral analysis, an X-ray measurement or a similar known measurement method.

The aluminum raw material used is preferably a mixture of electrolytically generated pure aluminum/primary aluminum and aluminum scrap. The aluminum raw material can comprise impurities in the form of iron, copper, silicon, chromium, magnesium, manganese, nickel, zinc and tin, for example.

Preferably, the melt is continuously fed to the at least one strip-casting machine via a casting channel, wherein the melt can thereby be filtered in order to remove any impurities. The continuous feeding of the melt into the strip-casting machine has the advantage that the level of the melt upstream of the casting nozzle is largely constant and thus relatively constant casting conditions can be set. As a result, the melting process can be directly coupled with the casting-rolling process.

Preferably, at least one shaping parameter is selected from a group of parameters comprising a thickness reduction of the hot strip, a width reduction of the hot strip, the strip temperature of the hot strip, the rolling speed, the strip tension of the hot strip, the rolling force, the roll bending, an axial adjustment of at least one roll, the roll gap geometry, the rolling torque, the cooling of the rolls and the lubrication of the rolls.

This is advantageous in connection with the method in the respect that the material hardness of the cast strip and thus the shaping resistance during rolling changes depending on the content of impurities and the properties of the hot strip change accordingly after rolling. It is provided to adjust the force and work requirements and other shaping parameters during rolling accordingly. Such adjustments can also comprise influencing the strip geometry along with the rheological roll gap conditions and influencing the material properties of the aluminum strip/the hot strip, for example through cooling and lubrication devices.

With a preferred variant of the method, it is provided that the regulation comprises a pre-control of the rolling system for a given and/or selected strip length section of the hot strip as a function of the alloy composition determined according to method step b).

Particularly preferably, the pre-control comprises the specification of at least one target value for thickness and/or profile regulation of at least one rolling device. Mathematical correlations between changes in the alloy composition and the shaping resistances occurring during rolling have been determined from experimental investigations with comparative analyses.

Thus, deviations in the alloy composition contained in the melt are not treated during casting with regard to the properties of the finished material, but only later during shaping by rolling.

Alternatively or additionally, casting parameters such as the casting thickness, the casting speed and the cast strip temperature can be adjusted using regulation technology. The material hardness H, as well as similarly the shaping resistance as a function of the alloy composition, can be represented with an exponent to a constant as the basic factor of the material hardness.

$H=K*\left(e1*e1\%\right)*\left(e2*e2\%\right)*\left(\mathrm{en}*\mathrm{en}\%\right)$

• • with K=standard alloy-specific strength within the alloy group (AAXXXX)
  • e1 to en=influence exponent of an alloying element
  • e1% to en %=percentage of the alloying element

Exponents of the alloy composition

• • Group AL-Mg—Mn
  • Constant 57.484
  • SI −0.03252
  • FE 0
  • Cu 0.03422
  • Mn 0.2238
  • Mg 0.59534
  • Cr 0
  • Zn 0
  • Ti 0
  • Certainty 0.9687
  • Without influence FE

The constant is the basic factor within the alloy group. The exponents serve as the exponent of the content in the alloy of the respective element. The material hardness H due to the alloy change can be calculated by means of inserting the contents. This makes it possible to pre-calculate the change in rolling force and thus to pre-control, for example, the adjustment position of the working rolls of a rolling device, in order to produce the (originally) intended rolled product.

The same algorithm can be used to pre-control the roll gap profile. Thereby, the roll gap profile is changed due to the expected change in rolling force by means of pre-control of the working roll bending device or roll displacement.

Through alloy fluctuations, the shaping resistance of the hot strip changes. When the hot strip enters the roll gap of a rolling device, the rolling force changes and thus also the reduction in thickness of the hot strip. A thickness error can be calculated by measuring the rolling force and knowing the reaction forces/stiffness of the rolling device. Such thickness error is attributed to an adjustment position of the working rolls with an adjusted reinforcement, with which the target thickness of the hot strip is set. On the basis of experimental investigations with comparative analyses, approximate calculations can be used to show relationships between changing circumferential resistances on the basis of analysis fluctuations. By means of a pre-control, a correction of the thickness regulation can be effected as soon as hot strip with a different alloy composition enters the rolling device. In this manner, a pre-control can provide an additional target value for the adjustment of at least one rolling device, such that a thickness regulation is no longer necessary or only necessary to a small extent.

With a particularly advantageous embodiment of the method, it is provided that the melt has a recyclate proportion, preferably in the form of aluminum scrap, of at least 60 percent by weight, preferably of at least 70 percent by weight, further preferably of at least 85 percent by weight and particularly preferably of at least 95 percent by weight.

By returning mixed aluminum scrap from the life cycle to renewed production, aluminum strips can be produced in a manner that conserves resources in terms of energy and the environment. The method enables the production of particularly high-quality alloys.

The aluminum alloy can be selected from a group comprising the aluminum alloys AA2XXX, AA5XXX, AA6XXX and AA7XXX. Such alloy groups have multiple alloy components and are used for applications in the electrical and automotive industries, among other things.

Preferably, the casting of the melt into a cast strip is effected with a thickness of 10 mm to 30 mm. For example, casting can be carried out at a casting speed of 4 m/min to 16 m/min.

Rolling is preferably carried out at a temperature of 150° C. to 600° C., preferably 300°−500° C., with a thickness reduction of 20 to 75° per rolling mill stand percent in relation to the initial thickness of the hot strip.

It is particularly preferred that the casting of the melt into cast strip is carried out using at least one casting machine with a moving mold. The moving mold of the strip-casting machine can be designed as a revolving trip (so-called “belt caster”) or as revolving blocks (so-called “block caster”). Within the context of the disclosure, a strip-casting machine is thus understood to be a casting machine that produces strip-shaped casting material. The advantage here is that casting takes place at an increased cooling rate and thus at an increased solidification speed compared to conventional slab casting machines, as a result of which impurities are partially kept in solution during casting. The fact that the melt solidifies without relative movement to the mold results in a very intensive heat transfer and the melt can solidify relatively rapidly, which is particularly advantageous because this keeps impurities in the melt partially in solution.

With a preferred variant of the method, a parallel operation of a plurality of melting assemblies is provided for the provision of different desired alloy compositions.

One or more multi-chamber melting furnaces can be provided as the melting assemblies. As a function of the desired alloy composition, the melting assemblies can be fed from a corresponding stock of different aluminum scrap with different compositions.

It is also possible to mix melts with different alloy compositions in order to be able to adjust the chemical composition of the liquid aluminum within narrow limits prior to casting in accordance with the requirements of the end product.

Expediently, the temperature of the cast strip is set prior to rolling. For this purpose, a temperature influencing device in the form of a temperature increase or cooling of the cast strip prior to rolling can be provided.

With the method, the hot strip can be quenched downstream of the at least one rolling device/downstream of at least one rolling device, for example to a temperature of 150° C. to 250° C. Such quenching is particularly advantageous in order to avoid the formation of coarse grains in the structure.

Furthermore, an abrasive surface conditioning is preferably provided for the upper side and/or the lower side of the cast hot strip, in order to be able to remove impurities from each side of the strip surface.

The disclosure further relates to an aluminum product preferably obtained by the method of the type described above. The aluminum product is characterized by a high recyclate proportion of at least 70 percent by weight, preferably at least 85 percent by weight and particularly preferably at least 95 percent by weight.

A further aspect of the disclosure relates to a casting-rolling system for producing aluminum strip, in particular for carrying out the method described above, comprising at least one melting assembly, at least one strip-casting machine and at least one rolling device, means for determining the alloy composition of an aluminum melt and at least one regulating and/or control device for regulating and/or controlling at least one shaping parameter of the at least one rolling device as a function of the alloy composition of the melt.

The strip-casting machine can be designed as a casting machine with a moving mold.

At least one multi-chamber melting furnace can be provided as a melting assembly.

Expediently, the casting-rolling system comprises a plurality of rolling mill stands, each of which preferably has at least two working rolls and two support rolls along with at least two hydraulic adjusting cylinders for setting a roll gap.

The working rolls can be designed as so-called CVC (continuous variable crown) rolls with a crowned contour.

Expediently, the casting-rolling system comprises at least one trimming shear, which is arranged downstream of a rolling device and upstream of a coiler. This is used to set the width of the finished rolled strip in a defined manner and to remove tight strip edges or edge cracks

Preferably, the casting-rolling device comprises means for conditioning the surface of the cast hot strip, for example in the form of brushing devices, means for applying high pressure to the hot strip with liquid media or the like. Preferably, such means are arranged upstream of the rolling devices in the direction of transport of the hot strip.

The casting-rolling system can also comprise means for cooling the rolled strip downstream of the rolling mill/downstream of a final rolling device.

The casting-rolling system preferably comprises at least two rolling devices/rolling mill stands arranged directly one behind the other.

The distance between the rolling devices and the at least one strip-casting machine can amount to between 5 m and 20 m. Through the compact arrangement, separation processes in the rolled material are prevented.

The casting-rolling system preferably comprises a scrap return system of process scrap to a storage level of the melting units.

The invention is explained below with reference to an exemplary embodiment shown in the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of a casting-rolling process and

FIG. 2 shows a schematic representation of a control scheme of the method in accordance with the disclosure.

DETAILED DESCRIPTION

FIG. 1 shows a casting-rolling system 1 for producing an aluminum strip 2. The casting-rolling system 1 comprises a plurality of melting assemblies 4 for producing a melt 3 of aluminum. The melting assemblies 4, which are only shown schematically, can be designed as multi-chamber melting furnaces, for example. The melting assemblies 4 are fed with an aluminum raw material from a storage level 5, on which aluminum scrap is stored in various scrap stores A, B, C, D, among others. The aluminum scrap consists, for example, of can scrap obtained from a waste management company and partially of process scrap that is generated in the method described below.

The casting-rolling system 1 further comprises a strip-casting machine 6, which is designed, for example, as a so-called belt caster or block caster for producing cast strip 7, along with two rolling mill stands 15, which are connected downstream in the direction of transport and with which the aluminum strip 2 is reduced in thickness. The rolling mill stands 15 are arranged at a short distance of between 5 m and 20 m downstream of the strip-casting machine 6 in the direction of transport. Immediately connected downstream of the strip-casting machine 6 is a surface cleaning device 11 of the cast aluminum strip 2 and a capping shear 12 for cutting off the cast strip head and/or cast strip foot that is produced during the casting of the aluminum strip 2 and cannot be further processed. The pieces of cast strip 7 cut off by the capping shear 12 are collected in a scrap bunker 13A and fed to a system for process scrap 25, which returns unmixed process scrap to the storage level 5 and can thus be reintroduced into the production cycle. Optionally, a temperature influencing device 16, which is designed as a heating and/or cooling device, can be provided upstream of the rolling mill stands 15.

The rolling mill stands 15 each comprise two driven working rolls and two support rolls and a hydraulic adjustment system for the working rolls, via which the roll rise can be set. The rolling mill stands 15 also each comprise a working roll bending system and means for axial adjustment of the working rolls.

The aluminum melt 3 generated by the melting assemblies 4 is fed to the strip-casting machine 6 via a casting channel 8 with a regulated mass flow. To regulate the mass flow of the melt 3, a flow regulator 9 is provided in the casting channel 8, downstream of which a filter 10 is connected to filter impurities from the melt 3. Thus, the melt can be fed to the casting machine continuously, such that a quasi-continuous casting-melting-rolling process is possible. A strip cooling device 18 is arranged downstream of the two rolling mill stands 15 forming the rolling system 14 and is followed by a trimming shear 19. This is followed by a flying shear 21. Finally, two coilers 23 are provided for winding up the rolled aluminum strip. Further scrap bunkers 13B and 13C are arranged downstream of the trimming shear 19 and downstream of the flying shear 21 respectively, from which the process scrap can be fed via the system for process scrap 25. The material cuttings collected in the scrap bunkers 13A, 13B and 13C can be fed to the respective scrap stores A, B, C, D of the storage level 5 as unmixed scrap. Scrap logistics can be provided for the system for process scrap 25, which can be operated automatically, semi-automatically or manually.

The aluminum scrap pre-sorted in the scrap stores A, B, C, D is initially subjected to a two-stage melting process in the melting assemblies 4. The scrap is first heated until any paint and other organic compounds are evaporated. The steam can be reused as an energy source, for example. The aluminum is then melted down. By means of an analysis device 40, the chemical composition of the melt is analyzed, for example to determine the proportion of metal impurities in the form of iron, copper, silicon, chromium, magnesium, manganese, nickel, zinc and tin. As a function of the analysis, the alloy composition is recharged to achieve certain desired properties. For this purpose, corresponding proportions of process scrap and/or pure aluminum are fed from the storage level 5/from the scrap stores A, B, C, D. The temperature of the melt is also set by the proportion of scrap added.

The set melt is fed to the strip-casting machine 6 via the casting channel 8 with a regulated mass flow. The melt passes through the filter 10, which filters out any impurities in the melt. A casting nozzle, not more specifically designated, guides the melt into the solidification region. The mold of the strip-casting machine 6 is designed as a moving mold. The melt solidifies without relative movement to the mold. As a result, a highly intensive heat transfer arises and the melt can solidify relatively rapidly. The melt is molded with a thickness of 10 mm to 30 mm, particularly preferably with a thickness of 15 to 25 mm as a cast strip 7, wherein the casting speed is 4 m/min to 16 m/min. The rapid solidification of the melt prevents segregation and suppresses the precipitation of impurities in the form of iron, copper, silicon, chromium, nickel, zinc and tin, for example. The alloy components remain largely in solution. As a result, the casting process is more tolerant to impurities. The rigid, moving mold of the strip-casting machine 6 prevents the solidifying strand from detaching. The heat transfer remains uniformly high.

The solidified cast strip 7 is fed directly to the rolling system 14 and reduced in thickness to aluminum strip 2. Due to the fact that there is only a relatively small distance between the rolling system 14 and the strip-casting machine 6, as already explained above, separation processes in the rolled material are prevented.

The stitch reduction per rolling mill stand 15 is preferably between 25% and 70% per rolling mill stand. As a result, the cast structure of the cast strip 7 is transformed into a rolled structure of the aluminum strip 2 and a rolled texture in the material is generated. As also mentioned above, hydraulically acting actuators are arranged on each rolling mill stand 15, with which the roll rise and/or a roll bending system and/or an axial adjustment of the working rolls can be effected.

A regulation of the rolling system is provided as a function of the alloy composition of the melt 3, which is determined via the analysis device 40 and is fed to a regulating and/or control device designated by 50. This controls the actuators of the rolling mill stands 15 accordingly, wherein a pre-control of the rolling system 14 for a given or selected strip length section of the cast strip 7 is provided. The pre-control comprises the specification of at least one target value for thickness and/or profile regulation of at least one of the rolling mill stands 15. By means of the pre-control, the at least one thickness and/or profile regulation is corrected as soon as the molded cast strip 7 with a certain known alloy composition enters the rolling system 14.

The setting of the thickness, stitch reduction and width of the aluminum strip 2 result from various parameters that define the shaping resistance. Such parameters comprise the alloy composition, the strip temperature, the strip tension, the roll lubrication, the strip lubrication, the roll diameter, the roll geometry (bending, camber, crown), the rolling force and the rolling torque.

It is provided to regulate at least some of these parameters, wherein the calculation can be effected within the control device 50 and the control device uses a process model 55 or alternatively the calculation is effected within the process model 55 and the results of the calculation in the control device are converted into setting parameters of the casting-rolling system 1. In particular, it is provided that the results of the analysis device 40 for regulating and/or controlling act at least on the rolling system 14, preferably independently of the casting process and the strip-casting machine 6.

The control scheme is roughly schematically illustrated in FIG. 2. Method step a) designates the melting of the aluminum raw material, method step b) the analysis of the alloy composition of the melt, method step c) the casting of the melt by means of the strip-casting machine 6 and method step d) the rolling of the hot strip. In FIG. 2, identical parts of the casting-rolling system 1 are marked with the same reference signs.

The reference sign 60 designates a production planning and control module that is connected to the process model 55, in order to incorporate production specifications such as bandwidths, target thicknesses, target structures, etc. into the calculation. The production planning and control module 60 is used, for example, to influence the composition of the melt 3 via the target specification X, for example by feeding aluminum scrap from the various scrap stores A, B, C, D. The subsequent analysis device 40 determines the proportion of impurities in the melt 3, which is fed to the control device 50 as an input variable.

LIST OF REFERENCE SIGNS

• • 1 Casting-rolling system
  • 2 Aluminum strip
  • 3 Melt
  • 4 Melting assemblies
  • 5 Storage level
  • 6 Strip-casting machine
  • 7 Cast strip
  • 8 Casting channel
  • 9 Flow regulator
  • 10 Filter
  • 11 Surface cleaning device
  • 12 Capping shear
  • 13A, 13B, 13C Scrap bunker
  • 14 Rolling system
  • 15 Rolling mill stands
  • 16 Temperature influencing device
  • 17 Not assigned
  • 18 Strip cooling devices
  • 19 Trimming shear
  • 20 Not assigned
  • 21 Flying shear
  • 23 Coiler
  • 24 Collar bearing
  • 25 Scrap return system
  • 40 Analysis device
  • 50 Control device
  • 55 Process model
  • 60 Production planning and control module
  • A, B, C, D Scrap stores

Claims

1.-24. (canceled)

25. A method for producing a cast aluminum strip in a coupled casting-rolling process, comprising:

melting an aluminum raw material comprising an aluminum alloy in a melting assembly;

determining an alloy composition of the melt;

casting the melt to form a hot strip by a strip-casting machine;

rolling the hot strip in a rolling system comprising a rolling device and thereby shaping the hot strip by reducing a thickness and/or a width thereof; and

regulating and/or controlling a shaping parameter of the rolling system as a function of the alloy composition of the melt.

26. The method according to claim 25,

wherein the coupled casting-rolling process is a continuous process.

27. The method according to claim 25,

wherein the shaping parameter is selected from the group of parameters consisting of thickness reduction of the hot strip, width reduction of the hot strip, strip temperature of the hot strip, rolling speed, strip tension of the hot strip, rolling force, roll bending, axial adjustment of at least one roll, roll gap geometry, rolling torque, cooling of the rolls, and lubrication of the rolls.

28. The method according to claim 25,

wherein the regulating and/or controlling comprises a pre-control of the rolling system for a given and/or selected strip length section of the cast aluminum strip as a function of the alloy composition.

29. The method according to claim 28,

wherein the pre-control comprises specifying a target value for thickness and/or profile regulation of the rolling device.

30. The method according to claim 25,

wherein the melt has a recyclate content in the form of aluminum scrap of at least 95 percent by weight.

31. The method according to claim 25,

wherein the aluminum alloy is selected from the group consisting of aluminum alloys AA2XXX, AA5XXX, AA6XXX, and AA7XXX.

32. The method according to claim 25,

wherein casting the melt produces the hot strip with a thickness of 10 mm to 30 mm.

33. The method according to claim 25,

wherein casting the melt is effected at a casting speed of 4 m/min to 16 m/min.

34. The method according to claim 25, further comprising

abrasive surface conditioning an upper side and/or a lower side of the cast aluminum strip.

35. The method according to claim 25,

wherein the rolling is carried out at a temperature between 300° C. and 500° C. and with a thickness reduction of 20% to 75% per rolling mill stand in relation to an initial thickness of the hot strip.

36. The method according to claim 25,

wherein the casting of the melt is carried out using at least one casting machine with a moving mold.

37. The method according to claim 25, further comprising

operating a plurality of melting units with different alloy compositions in parallel.

38. The method according to claim 25, further comprising

mixing melts with different alloy compositions.

39. The method according to claim 25, further comprising

setting a temperature of the hot strip prior to rolling.

40. The method according to claim 25, further comprising

quenching the cast aluminum strip downstream of the at least one rolling device.

41. An intermediate aluminum product obtained by the method in accordance with claim 25, comprising at least 95% by weight of recyclate.

42. A casting-rolling system for producing a cast aluminum strip, comprising:

a melting assembly;

a strip-casting machine; and

a rolling device;

means for determining an alloy composition of an aluminum melt; and

a regulating and control device, configured for regulating and/or controlling a shaping parameter of the rolling device as a function of the alloy composition of the melt.

43. The casting-rolling system according to claim 42,

wherein the strip-casting machine is a casting machine with a moving mold.

44. The casting-rolling system according to claim 42,

wherein the melting assembly is a multi-chamber melting furnace.

45. The casting-rolling system according to claim 42, further comprising

a plurality of rolling mill stands, each having two working rolls and at least two support rolls along with at least two hydraulic adjusting cylinders for setting a roll gap.

46. The casting-rolling system according to claim 42, further comprising

means for abrasive surface conditioning of the cast aluminum strip, arranged upstream of the rolling device.

47. The casting-rolling system according to claim 42, further comprising

a trimming shear, which is arranged downstream of a rolling device and upstream of a coiler.

48. The casting-rolling system according to claim 42, further comprising

a scrap return system of process scrap into a storage level of the melting assembly.