Apparatus and method for multi-mode production of steel strips

Abstract

A device for continuous or batch production of hot-rolled steel strips with a thickness of 0.6 mm comprises a continuous casting machine (1), an inlet roller bed (2), a first shearing machine (3), a roughing mill (4), a second shearing machine (5), an induction furnace (6), a finishing mill (7), a third shearing machine (8), and a multi-coiling machine (9) at the end, and the continuous casting machine (1), the first shearing machine (3), the roughing mill (4), the second shearing machine (5), the induction furnace (6), the finishing mill (7) and the third shearing machine (8) are arranged behind the continuous casting machine (1). Production can be carried out using both a thin slab from a casting machine (1) and an outsourcing slab having a thickness of 200-300 mm introduced through an off-line slab charging unit comprising: a reversible roughing mill (10) receiving the slab charged into a heating furnace (11) through a connecting roller bed (13); and a translating tunnel furnace (12) comprising at least two parallel segments (12a, 12b), where a first segment (12a) is movable between a position aligned with the reversible roughing mill (10) and an off-line rest position, and a second segment (12b) is movable between a position aligned with the reversible roughing mill (10) and a position aligned with the entry table (2).

Description

Technical Field

[0001] This invention relates to an apparatus and method for the continuous, batch, or combined production of hot-rolled steel strips of various specifications with high productivity, high equipment cost-effectiveness, and high product quality. In particular, the invention allows for the combination of rolling thin slabs (typically 90-140 mm thick) obtained by continuous casting with rolling thicker slabs (typically 200-300 mm thick) sourced from the market. Background Technology

[0002] As is well known, in the steel industry, given the rising costs of raw materials and energy, as well as the increasing competitiveness required by the global market and increasingly stringent environmental regulations, there is an urgent need for a method that can manufacture high-quality hot-rolled steel strip with lower investment and production costs, while providing greater production flexibility. This means that the final product manufacturing industry can also improve its competitiveness with lower energy consumption, thereby minimizing its negative impact on the environment.

[0003] The prior art is essentially the same as that described by the inventor in his previous patents, particularly EP 1558408 and EP 3606681, which can be consulted for further details. EP 1558408 employs a so-called "cast-rolling" technique that combines continuous casting of thin slabs with liquid core reduction (LCR) with an initial roughing stage using a roughing mill (HRM = high reduction rate mill). The roughing stage produces an intermediate product, which is heated in an induction furnace and subsequently derusted before further processing in a second finishing stage. This type of rolling is called continuous or "endless" rolling because, once started, it is not necessary to repeatedly feed the slab into the roughing and finishing mills as in batch mode, where the slabs are separated.

[0004] To improve productivity and production flexibility, EP 3606681 introduces the possibility of batch or combined production, i.e., interrupting billet casting between the casting unit (casting machine) and the rolling mill. The charging difficulties that may arise from such interruption are offset by the following advantages: If the casting rate of the casting machine (the so-called "mass flow" = slab thickness x casting speed) is lower than the rolling rate of the rolling mill, for example due to the reduced casting speed required by the steel type, batch mode allows for reduced energy consumption, especially in induction furnaces, thanks to the higher rolling speed and the resulting reduction in heat loss. When manufacturing two adjacent coils with significantly different thicknesses, the opening setting of the mill stand needs to be adjusted when no material passes between them. The combined mode allows the first coil to be produced mainly in a headless mode, but the last part of the strip is produced in a batch mode. By cutting the slab, it can be accelerated and rolled faster, thus creating the necessary time interval for the mill to set up the production of the second coil of different thicknesses when the mill is idle.

[0005] Furthermore, to improve the profitability of the equipment, the possibility of rolling purchased slabs has been introduced. When the casting machine located on the same line as the rolling mill is unavailable, purchased slabs can be loaded into the production cycle. For this purpose, an intermediate furnace with roller conveyors or movable beams is installed after continuous casting exits, allowing it to select between three operating modes: headless, combined, and batch. The production cycle can also be started by introducing room-temperature slabs into the furnace via a charging station, and the slabs can be removed when the rolling mill is unavailable; these slabs can then be recycled for production.

[0006] WO 93 / 23182 describes a similar scheme, providing a casting machine for thin slabs with a thickness of 90-140 mm, followed by a shearing machine for cutting the slabs onto a conveyor roller table, from which they can be loaded into a roller-type or moving-beam intermediate furnace, or transferred to a storage area. At the furnace exit, the slabs are fed into a reversible rolling mill, which consists of a mill stand and coilers and heaters arranged before and after it. The slabs collected in the storage area can then be fed into the furnace for delivery to the rolling mill, and slabs from outside the equipment can also be loaded through the storage area; therefore, the furnace must be able to heat slabs loaded from room temperature to the rolling temperature.

[0007] Given the current highly uncertain costs of electricity and raw materials (especially scrap steel and direct reduced iron or hot briquetted iron), there is a need to consider new equipment and methodological solutions for endless or batch production models. Furthermore, a hybrid solution is also needed to allow the use of commercially available thick slabs in strip production as an alternative to thin slabs cast on-site using a casting machine. In other words, having an alternative to continuous casting on the same line as the rolling mill is useful, so that the rolling mill can remain operational even if the casting machine experiences technical problems, or if the energy and raw material costs for obtaining the molten steel for casting make it more cost-effective to purchase slabs from elsewhere.

[0008] However, purchased slabs must have a minimum standard weight to obtain a sufficient weight of strip coil. If the purchased slabs are already as thin as when they come out of the continuous casting machine, they become too inconvenient to transport. For example, if I use a thin slab (typically 100 mm thick and 30 m long) from the casting machine as the starting material to obtain the required strip coil, transporting a purchased slab of similar length would be very complicated and expensive, while a 200 mm thick slab is half the length and therefore much easier to transport. On the other hand, a rolling mill on the same line as the casting machine, as described in EP 3606681, cannot reach the required strip thickness starting from a 200 mm thick slab because this would require more mill stands.

[0009] Even in the equipment described in WO 93 / 23182, where additional passes can be added to the reversible mill, similar problems arise due to the excessive initial slab thickness. In fact, the flat slab needs to pass through the reversible mill multiple times before it can be coiled into the heated coiler, as at least three passes are required even starting with a slab of approximately 100 mm thickness, as in the example given in WO 93 / 23182. Furthermore, achieving the 0.6 mm strip thickness envisioned in EP 3606681 also requires a large number of passes, as nine passes are needed from 100 mm to approximately 2.5 mm in the aforementioned example. Therefore, the processing time becomes unacceptably long, as it takes approximately 10 minutes to go from 100 mm to 2.5 mm (thinning factor 40) in the cited example, making the time incompatible with sufficient productivity for achieving a thinning factor of approximately 330 (from 200 mm to 0.6 mm).

[0010] WO 2013 / 046348 describes an apparatus according to the preamble of claim 1, wherein the translation furnace can be moved toward the soaking furnace of the rolling line, thus not aligned with the roller table at the casting machine exit, or toward the plate processing line if it is not necessary to roll the slab roughed by the reversible roughing mill into strip. In both cases, when the translation furnace is not aligned with the reversible roughing mill, it is impossible to continue roughing another slab charged into the outer furnace.

[0011] EP 2667983 describes a slab conveying system between two rolling mills using two shuttles. The rough-rolled slab is transferred from one shuttle to the other at an intermediate position, thus eliminating the need for a shuttle to travel the entire distance between the two rolling mills. In this configuration, it is also impossible to continue rough-rolling another slab if the first shuttle is not aligned with the reversible roughing mill of the first rolling mill.

[0012] Therefore, the technical challenge lies in providing a more convenient and faster way to use purchased slabs to achieve seamless integration with cast billets and shorter cycle times. Summary of the Invention

[0013] Therefore, the object of the present invention is to provide a solution for producing hot-rolled strip steel with a thickness of up to 0.6 mm, which offers superior productivity and flexibility compared to the aforementioned prior art. This object is achieved by using an offline slab charging unit, which mainly comprises a reversible roughing mill arranged between a heating furnace (through which slabs are charged, typically a sufficiently long movable beam furnace capable of accommodating multiple slabs) and a translational tunnel furnace. The translational tunnel furnace comprises at least two parallel sections, one of which is movable between a position aligned with the reversible roughing mill and a position aligned with the casting rolling line, and the other of which is movable between a position aligned with the reversible roughing mill and an offline rest position.

[0014] The fundamental advantage of this configuration is that it allows for offline roughing of slabs while they are being transferred from the translation tunnel furnace to the rolling line, thereby significantly reducing cycle time and increasing equipment productivity.

[0015] The second embodiment also includes a joining unit located upstream of the mill for connecting slabs to create an “artificial” headless pattern, with the added advantage of avoiding slab loading problems even though the slabs are loaded into the equipment separately.

[0016] In the third embodiment, a shearing machine and a heat-insulating roller conveyor are arranged between the continuous casting machine outlet and the translational tunnel furnace, resulting in higher productivity because purchased slabs and online cast slabs can be alternated when loading the rolling mill (preferably via the aforementioned joining unit). Attached Figure Description

[0017] Other advantages and features of the apparatus and methods of the present invention will become apparent to those skilled in the art from the following detailed and non-limiting description of some embodiments of the invention with reference to the accompanying drawings, wherein: Figure 1A This is a schematic diagram of the equipment in the simplest embodiment, in which the translational tunnel furnace is positioned offline relative to the rolling mill; Figure 1B yes Figure 1A A schematic diagram of the equipment, showing the translational tunnel furnace aligned and positioned with the rolling mill; Figure 2A This is a schematic diagram of the device in the second embodiment, which is similar to the previous one but also includes a joining unit, wherein the translational tunnel furnace is positioned offline relative to the rolling mill; Figure 2B yes Figure 2A A schematic diagram of the equipment, showing the translational tunnel furnace aligned and positioned with the rolling mill; Figure 3A This is a schematic diagram of the equipment in the most complete embodiment, wherein the translational tunnel furnace is equipped with three sections and is positioned such that one of the side sections is aligned with the rolling mill; Figure 3B yes Figure 3A The schematic diagram of the equipment shown shows that the center section of the translational tunnel furnace is aligned with the rolling mill. Detailed Implementation

[0018] Please note that in the above schematic drawings, for ease of understanding, both the casting rolling line and the offline slab charging unit are shown in side view, and the offline slab charging unit is drawn above the casting rolling line. However, in reality, the offline slab charging unit is located on the same horizontal plane as the casting rolling line and is located next to it. In other words, the translational tunnel furnace does not move vertically, but horizontally, that is, perpendicular to the plane of the drawing.

[0019] Furthermore, although the mill is shown in the diagram as a roughing mill and a finishing mill with an induction furnace between them, the following description also applies to mills that are not segmented and have no induction furnaces between stands (as in EP 3606681). Similarly, the number of stands comprising a roughing mill, a finishing mill, or a non-segmented mill can vary freely according to production requirements.

[0020] Reference Figure 1A-1B As can be seen, the equipment according to the invention conventionally includes a continuous casting machine 1, followed by a preferably insulated inlet roller conveyor 2, a first shear 3, a roughing mill 4 (e.g., a three-stand mill), a second shear 5, an induction furnace 6, a finishing mill 7 (e.g., a five-cage mill), a third shear 8 (preferably a flying shear), and finally a multi-coiler 9 (e.g., a three-coiler mill). Since these are conventional components, those skilled in the art do not need further details about their structure and operation, and the presence of other components (e.g., control units, cooling systems, outlet roller conveyors, sensors, etc.) is taken for granted.

[0021] The offline slab charging unit mainly comprises a reversible roughing mill 10, located between a heating furnace 11 (through which purchased slabs are charged and heated) and a translational tunnel furnace 12. As described above, the first innovative aspect of the invention is that the furnace 12 comprises at least two parallel sections 12a, 12b, with a spacing P equal to the distance D between the reversible roughing mill 10 and the casting rolling line. More specifically, each section 12a, 12b includes a motorized and insulated roller conveyor, and heating elements such as gas-fired heating nozzles or electric heating resistors.

[0022] from Figure 1A Starting at the indicated position, multiple purchased slabs S (typically 200 to 300 mm thick) are loaded into furnace 11, preferably a movable beam furnace, to raise and homogenize their temperature to a value between 1150°C and 1300°C. Once the slabs S are sufficiently heated, they are then transferred via connecting rollers 13 to a reversible roughing mill 10, where their thickness is reduced through multiple passes (always an odd number of passes) until a so-called “intermediate slab” with a thickness typically between 60 and 140 mm is obtained.

[0023] Note that when the slab S passes through the reversible roughing mill 10, it is contained in the translational tunnel furnace 12, specifically in... Figure 1A Within the second section 12b, it is supported by the roller conveyor 13 when it returns to the furnace 11. Therefore, both the roller conveyor 13 and the furnace 12 must be long enough to accommodate the intermediate slab produced after rough rolling, approximately 30-35 meters. It is best to limit the length of the furnace 12, and thus limit the distance between the casting machine 1 and the rough rolling mill 4, which should be as short as possible in endless rolling (when thin slabs are directly cast) to limit the cooling of the slab before rolling.

[0024] In the final roughing pass, the intermediate billet is positioned within the second section 12b, and then furnace 12 moves toward the rolling line, as... Figure 1B As shown, section 12b is aligned with roller table 2, while the first section 12a is aligned with roughing mill 10 to receive the next slab S' while it is being processed in reversible roughing mill 10. The roller table of section 12b (preferably controlled by a frequency converter) is accelerated so that the intermediate slab is loaded onto the heat-insulating roller table 2 and enters roughing mill 4.

[0025] Once the intermediate billet leaves section 12b, furnace 12 can return to... Figure 1A The position is shown, and the transfer is performed when the next purchased slab S' is on the roller table 13. If the slab S' has been sufficiently thinned, it only needs to pass through the reversible roughing mill 10 once more to serve as the intermediate billet loading section 12b, then the furnace 12 can immediately return to the position shown. Figure 1B The location shown. Otherwise, in Figure 1A The position shown is used to perform additional passes to achieve the required thickness of the intermediate billet, while other slabs are heated in furnace 11.

[0026] Note that the thickness of the intermediate billet is typically less than that of the thin slab cast by casting machine 1 to avoid problems when it enters roughing mill 4. These problems do not exist when the line operates in headless mode and uses continuous slabs from casting machine 1. For example, if casting machine 1 is set to produce 100 mm thick slabs, reversible roughing mill 10 can produce 80 mm thick intermediate billets (the thinning limit of purchased slabs is determined by the length of furnace 12 and roller table 13).

[0027] Therefore, the mill loading process implemented in the first embodiment of this equipment can be summarized as follows: a) Multiple purchased slabs are loaded into a heating furnace 11, which is designed to increase and homogenize the temperature of the slabs, preferably to a value between 1150°C and 1300°C; b) The heated slab is transferred from the furnace 11 to the reversible roughing mill 10 via the connecting roller conveyor 13, where it is thinned to obtain an intermediate slab with a preferred thickness between 60 and 140 mm. c) Load the intermediate billet into the second section 12b of the translational tunnel furnace 12, and move the second section 12b to a position aligned with the inlet roller table 2, while moving the first section 12a to a position aligned with the reversible roughing mill 10. d) The intermediate billet is transferred from the second section 12b to the inlet roller table 2, and the next slab heated by the furnace 11 is transferred to the reversible roughing mill 10, where the slab is at least partially or almost completely thinned; e) Move the first segment 12a to its rest position and the second segment 12b to the position aligned with the reversible roughing mill 10, at which point the next slab is located on the connecting roller table 13; f) Complete the thickness reduction of the next slab until an intermediate slab is obtained; g) Repeat steps c) - f) in a loop.

[0028] The second innovative aspect of the invention, such as Figure 2A-2B As shown, a joining unit is added between the roller conveyor 2 and the first shearing machine 3. As described above, the presence of this unit allows the tail of each slab to be connected to the head of the next slab to reproduce the effect of continuous casting, thus enabling endless rolling even when using purchased slabs separately loaded into furnace 11. Although the joining unit itself is known in the prior art, its application in such equipment is novel and inventive, and its structure and operation are described below for completeness.

[0029] The unit includes a trimming shear 14 for trimming the tail of the previous intermediate billet bitten in by the roughing mill 4 and the head of the next intermediate billet from the roller table 2, followed by a welding station 15, including an induction welder or a welder based on other technologies such as flash butt welding or laser welding, and then a deburring station 16, whose task is to remove excess steel material formed around the joint during the welding stage.

[0030] As an example, the operation of the joining unit can be described as follows: From Figure 2B Starting at the position shown, the intermediate billet in section 12b of the tunnel furnace 12 is transferred to the roller conveyor 2 at a speed preferably 4 to 12 meters per minute. The trimming shear 14 cuts the tail of the previous intermediate billet and the head of the intermediate billet loaded onto the roller conveyor 2, which is divided into two sections controlled by two frequency converters to accelerate the intermediate billet so that its head reaches the tail of the previous intermediate billet.

[0031] When two intermediate billets are adjacent, the device locks their ends (head and tail) with a small gap, and then the two ends partially melt until the desired amount of molten steel is obtained, for example by passing a strong current, typically for no more than 5 seconds. Subsequently, the two molten intermediate billet ends are pressed together by a hydraulic mechanism until a complete joint is obtained. After the joint is formed, the locking device is released, and the joined intermediate billets advance to the roughing mill 4. However, because the applied pressure causes a small amount of molten steel to leak around the joint, this steel cools rapidly and forms protrusions that can interfere with rolling. Therefore, before entering the roughing mill 4, the intermediate billets are processed in a deburring station 16, which preferably uses a rotary cutter equipped with a special cutter head positioned on an adjustable hydraulic arm.

[0032] In a preferred embodiment, the welding station is located on a slide that moves synchronously with the rolling speed of the first roughing mill stand, and the aforementioned welding stages (locking, melting, extrusion) are performed during the advance stroke of the slide. When the joining process is complete, the slide returns to its initial position, ready for the next joining process, and an automatic cleaning cycle is performed during the return stroke to remove molten steel splashes.

[0033] Note that the deburring station 16 operates independently of the welding station 15, thus not extending the overall cycle time. Furthermore, when the joining unit is not in use, it is preferably removed from the line by a carriage operated by a hydraulic cylinder and replaced by a roller conveyor to allow for endless rolling of the slabs from continuous casting.

[0034] In this second embodiment, the mill loading process therefore includes an additional stage d'): transferring the intermediate billet from the roller table 2 to the joining unit, where it joins with the previous intermediate billet. This stage d') occurs after stage d) and is substantially simultaneous with stage e) and possibly also with stage f).

[0035] The third innovative aspect of this invention is... Figures 3A-3B In its most complete configuration, a fourth shear 17 is added between the casting machine 1 and the transverse furnace 12, followed by a second heat-insulating roller conveyor 18. Furthermore, the transverse furnace 12 is equipped with a third section 12c, which has the same spacing P as the second section 12b, so that when section 12b is aligned with the reversible roughing mill 10 (… Figure 3A The third section is aligned with the first roller conveyor 2. In this way, the equipment can operate in a "mixed" charging mode, using thin slabs from the casting machine 1 and intermediate billets from the transverse furnace 12 alternately, to achieve significantly higher productivity.

[0036] Essentially, the configuration of this third embodiment is batch casting and rolling technology and Figure 2A-2B The second embodiment is combined. In practice, the shearing machine 17 cuts the slab exiting the casting machine 1, which is then loaded onto the roller conveyor 18 and reaches the roller conveyor 2 via the third section 12c of the translation furnace 12. Simultaneously, the purchased slab is thinned in the reversible roughing mill 10 by passing back and forth between the second section 12b and the connecting roller conveyor 13. Figure 3A ).

[0037] When the intermediate billet is ready and positioned in section 12b, furnace 12 moves, section 12b is positioned to align with roller table 2, while section 12a is positioned to align with roughing mill 10 to receive the next billet, and section 12c is positioned in a waiting position on the other side of the casting rolling line, as shown below. Figure 3B As shown. Section 12b's roller conveyor forward feeds the intermediate billet onto roller conveyor 2, while roller conveyor 18 receives new slabs from casting machine 1. After the intermediate billet is unloaded onto roller conveyor 2, the translation furnace 12 returns to... Figure 3AThe position shown is such that section 12c can receive the slab that has been cut to length by the shearer 17 from roller 18, and then unload it onto roller 2, where its head is close to the tail of the preceding intermediate slab that is already moving forward, and its head is undergoing the process of engaging with the tail of the preceding slab from roller 18.

[0038] Through a joining process in which slabs from continuous casting and intermediate slabs from reversible roughing mill 10 are alternately welded, a continuous intermediate slab is created. This intermediate slab is then rolled in a headless mode at significantly higher speeds in roughing mill 4 and then in finishing mill 7, resulting in higher productivity. For example, the intermediate slab can enter roughing mill 4 at approximately 12 m / min and finishing mill 7 at approximately 80 m / min, with a productivity of approximately 6 million tons per year, which is unattainable with a headless unit on a single continuous casting line.

[0039] Please note that in order to achieve this productivity level through this "mixed" loading, the cycle time of the joining unit must be reduced to [a certain value]. Figure 2A-2B The configuration shown achieves approximately half the time. Therefore, a faster welding station is required, preferably using so-called "flash butt welding," where a higher current intensity arc is used to melt the head and tail.

[0040] Furthermore, a sophisticated automated system is required to precisely coordinate the operation of the reversible roughing mill 10, the transverse tunnel furnace 12, the roller conveyors 2 and 18, the casting machine 1, and the joining unit, synchronizing them with the roughing mill 4. In this respect, although the three sections 12a, 12b, and 12c of the transverse tunnel furnace 12 are illustrated as an “integrated” configuration, moving synchronously under the action of a single actuator to perform the same stroke, depending on the layout of the equipment (particularly distance D), these three sections can be independent to perform different strokes and / or different times, thus conforming to the cycle time required for proper equipment management. For example, the third section 12c can move separately from the other two sections, in… Figure 3A Location and Figure 3B The stroke between positions is much shorter because it only needs to make room for segment 12b to align with roller 2.

[0041] Similarly, segment 12c can return to alignment with roll table 18 before segment 12b returns to alignment with reversible roughing mill 10, in order to prepare in advance for receiving slabs cast by casting machine 1. The same applies to the first segment 12a, in... Figure 3A The position shown allows it to be closer to the reversible roughing mill 10, in order to transition to... Figure 3B At the position shown, before aligning segment 12b with roller table 2, travel a shorter distance to align with reversible roughing mill 10.

[0042] The same automated system, through precise thickness control, must also ensure that the thickness of the intermediate billet from the translation furnace 12 is basically the same as the thickness of the slab from the roller table 18, so as to obtain a joint intermediate billet with basically uniform thickness.

[0043] In this third embodiment, the mill loading process can therefore be summarized as follows: a) Multiple purchased slabs are loaded into heating furnace 11 to increase and homogenize their temperature, preferably to a value between 1150°C and 1300°C, while thin slabs are cast from casting machine 1 onto roller conveyor 18 and cut to length by fourth shearing machine 17. b) The heated slab is transferred from the furnace 11 to the reversible roughing mill 10 via the connecting roller table 13, where it is thinned to obtain an intermediate slab with a preferred thickness between 60 and 140 mm, while the thin slab is transferred from the roller table 18 to the inlet roller table 2 via the third section 12c of the tunnel furnace 12, which is aligned with said roller tables 18 and 2. c) Load the intermediate billet into the second section 12b of the translational tunnel furnace 12, and move the second section 12b to a position aligned with the inlet roller table 2, while moving the first section 12a to a position aligned with the reversible roughing mill 10, and moving the third section 12c to a rest position, while transferring the slab from the roller table 2 to the joining unit, where it joins with the previous intermediate billet. d) The intermediate billet is transferred from the second section 12b to the inlet roller table 2, and the next slab heated by the furnace 11 is transferred to the reversible roughing mill 10, where the slab is at least partially or almost completely thinned, while the subsequent slab is cast from the casting machine 1 onto the roller table 18 and cut to length by the shearing machine 17. e) Move the first segment 12a to its rest position, move the second segment 12b to the position aligned with the reversible roughing mill 10, at which point the next slab is located on the connecting roller table 13, and move the third segment 12c to the position aligned with roller tables 18 and 2. f) Complete the thickness reduction of the next slab until an intermediate slab is obtained, and transfer the subsequent thin slab from roller table 18 to inlet roller table 2 through the third section 12c; g) Repeat steps c) - f) in a loop.

[0044] Therefore, the equipment described above according to the invention is suitable for producing high-quality strip steel with a thickness of up to 0.6 mm, using either thin slabs of 90-140 mm thickness from a continuous casting machine aligned with the rolling mill, or commercially available slabs of 200-300 mm thickness. Furthermore, the equipment can operate in headless mode (without interruption of slab movement between the continuous casting machine 1 and the rolling mill), in batch mode, and even in the second and third embodiments, in an “artificial” headless mode by individually joining the slabs and / or intermediate billets before they enter the rolling mill.

[0045] Obviously, the embodiments of the device according to the present invention described and illustrated above are merely examples, and various modifications are possible. In particular, other embodiments not illustrated in the drawings are clearly possible combinations of these three embodiments. For example, the translation furnace 12 in the first and second embodiments may also include a third segment 12c, in order to... Figure 1A and Figure 2A In the position, there is no interruption on the casting and rolling line, or in the third embodiment, there may be no joining unit, which would be more compact but would not be able to operate in an "artificial" headless mode.

Claims

1. An apparatus for online continuous, batch, or combined production of hot-rolled steel strip with a thickness as low as 0.6 mm, comprising a device (1), a loading roller conveyor (2), a first shear (3), a rolling mill, a second shear (5), an induction furnace (6), an exit roller conveyor, a third shear (8), and multiple coilers (9); wherein, The device (1) is equipped with a liquid core press and is used for thin slab continuous casting. After the device (1) are the charging roller table (2), the first shear (3), and the rolling mill. The rolling mill is preferably divided into a roughing mill (4) and a finishing mill (7). Between the roughing mill (4) and the finishing mill (7) is a second shear (5) and an induction furnace (6). After the finishing mill (7) is the exit roller table with a cooling device, followed by the third shear (8) and the plurality of coilers (9). The equipment also includes an offline slab charging unit arranged on the same horizontal plane. The offline slab charging unit includes a reversible roughing mill. (10) The reversible roughing mill (10) receives slabs loaded into the heating furnace (11) via a connecting roller table (13). The offline slab loading unit further includes a translational tunnel furnace (12) positioned to accommodate the slabs processed in the reversible roughing mill (10). The translational tunnel furnace (12) is characterized in that it includes at least two parallel sections (12a, 12b), wherein the first section (12a) is movable between a position aligned with the reversible roughing mill (10) and an offline rest position, and the second section (12b) is movable between a position aligned with the reversible roughing mill (10) and a position aligned with the loading roller table (2).

2. The device according to claim 1, characterized in that, It also includes a joining unit between the loading roller conveyor (2) and the first shearing machine (3), the joining unit comprising, in sequence, a trimming shearing machine (14), a welding station (15) and a deburring station (16), and the loading roller conveyor (2) is divided into two sections with independent feed speeds, preferably controlled by two frequency converters.

3. The device according to claim 1 or 2, characterized in that, It also includes a fourth shear (17) between the continuous casting unit (1) and the translational furnace (12), after which is a heat-insulating roller conveyor (18), and the translational tunnel furnace (12) includes a third section (12c) that is movable between an aligned position and an offline rest position located between the heat-insulating roller conveyor (18) and the charging roller conveyor (2).

4. The device according to claims 2 and 3, characterized in that, The welding station (15) employs flash butt welding technology.

5. The device according to any one of claims 2 to 4, characterized in that, The welding station (15) is located on a slide that moves synchronously with the rolling speed of the first mill stand, and welding is performed during the forward stroke of the slide, preferably during the return stroke for a cleaning cycle.

6. The device according to any one of claims 2 to 5, characterized in that, The joining unit can be removed offline and replaced by a roller conveyor.

7. The device according to any one of the preceding claims, characterized in that, At least some of the sections (12a, 12b, 12c) of the translational tunnel furnace (12) perform the same stroke by moving synchronously under the action of a single actuator.

8. A method for loading material into a rolling mill of the equipment according to claim 1, comprising the following steps: a) Load multiple purchased slabs into the heating furnace (11), which is adapted to increase and homogenize the temperature of the slabs, preferably to a value between 1150°C and 1300°C; b) The heated slab is transferred from the heating furnace (11) to the reversible roughing mill (10) via the connecting roller conveyor (13), where the slab is thinned to an intermediate slab with a preferred thickness between 60 and 140 mm. c) The intermediate billet is loaded into the second section (12b) of the translational tunnel furnace (12), and the second section (12b) is moved to a position aligned with the charging roller table (2), while the first section (12a) is moved to a position aligned with the reversible roughing mill (10); d) The intermediate billet is transferred from the second section (12b) to the loading roller table (2), and the next heated slab is transferred from the heating furnace (11) to the reversible roughing mill (10), where the slab is at least partially or almost completely thinned. e) Move the first segment (12a) to its rest position and move the second segment (12b) to a position aligned with the reversible roughing mill (10), at which point the next slab is located on the connecting roller table (13); f) Complete the thickness reduction of the next slab until it becomes an intermediate slab; g) Repeat steps (c)-(f) in a loop.

9. A method for loading a mill for the equipment according to claim 2, comprising, in addition to the steps of claim 8, an additional step d'): transferring the intermediate billet from the loading roller table (2) to the joining unit, joining the intermediate billet with a previous intermediate billet at the joining unit, the step d') occurring after step d), and substantially simultaneously with step e) and possibly also with step f).

10. A method for loading material into a rolling mill of the equipment according to claim 3, comprising the following steps: a) Multiple purchased slabs are loaded into the heating furnace (11), which is suitable for increasing and homogenizing the temperature of the slabs, preferably to a value between 1150°C and 1300°C, while thin slabs are cast from the continuous casting device (1) onto the heat-insulating roller conveyor (18) and cut to length by the fourth shearing machine (17). b) The heated slab is transferred from the heating furnace (11) to the reversible roughing mill (10) via the connecting roller conveyor (13), where the slab is thinned to an intermediate slab with a preferred thickness between 60 and 140 mm. At the same time, the thin slab is transferred from the heat-insulating roller conveyor (18) to the charging roller conveyor (2) via the third section (12c) of the tunnel furnace (12), which is aligned with the roller conveyors (18, 2). c) The intermediate billet is loaded into the second section (12b) of the tunnel furnace (12), and the second section (12b) is moved to a position aligned with the charging roller table (2), while the first section (12a) is moved to a position aligned with the reversible roughing mill (10), the third section (12c) is moved to a rest position, and the slab is transferred from the charging roller table (2) to the joining unit, where the slab is joined with the previous intermediate billet; d) The intermediate billet is transferred from the second section (12b) to the loading roller table (2), and the next heated slab is transferred from the heating furnace (11) to the reversible roughing mill (10), whereby the slab is at least partially or almost completely thinned, while the next slab is cast from the continuous casting device (1) onto the heat-insulating roller table (18) and cut to length by the fourth shearing machine (17); e) Move the first segment (12a) to its rest position, move the second segment (12b) to a position aligned with the reversible roughing mill (10), at which point the next slab is located on the connecting roller table (13), and move the third segment (12c) to a position aligned with the roller table (18, 2); f) Complete the thickness reduction of the next slab until an intermediate slab is obtained, and transfer the subsequent thin slab from the heat-insulating roller conveyor (18) to the loading roller conveyor (2) through the third section (12c). g) Repeat steps (c)-(f) in a loop.

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