Casting-rolling installation, and method for producing a steel strip

Abstract

The invention relates to a casting-rolling installation (10) and to a corresponding method for producing a steel strip (1) which runs through the casting-rolling installation (10) in a conveying direction (F). Such a casting-rolling installation (10) comprises a casting device (12) which is in the form of a two-roller casting device (12) and accordingly has two casting rollers (13) which are each arranged mounted rotatably about axes aligned axially parallel to one another and at the same height, a cast steel strip (1) being produced by means of the two-roller casting device (12). A roll stand (14) for rolling the cast steel strip (1) is mounted downstream of the casting device (12) in the conveying direction (F) of the steel strip. The roll stand (14) here is arranged relative to the casting device (12) in such a manner that a roll nip inlet (15) of the rolling mechanism – as seen in the vertical direction – is located with respect to the position of the axes of the casting rollers (13) at the same height as or above same.

Description

[0001] Casting-rolling plant and method for producing a steel strip

[0002] The invention relates to a casting-rolling plant for producing a steel strip according to the preamble of claim 1 or 2, and to a corresponding method according to the preamble of claim 10.

[0003] According to the prior art, a technology (device and method) for producing cast strip from molten metal is known, for example from WO 2014 / 049150 A1. In this process, a molten metal flows through a casting gap defined by two counter-rotating casting rollers and is formed into the cast strip. When casting molten metals on such devices, also known as "twin-roller casting machines," two axially parallel and internally cooled casting rollers rotate in opposite directions, defining the long sides of a casting gap between them. The casting gap is usually sealed on its narrow sides by plates made of refractory material. Sufficient liquid melt is poured into the casting gap at a time to form a so-called "melt pool" above the casting gap and is maintained there until the casting process is completed.The melt flowing from the melt pool onto the casting rolls solidifies into a shell, which is then conveyed by the respective casting roll into the casting gap. In the casting gap, the shells are then pressed against each other, forming the cast strip from them and the melt trapped between them. The cast strip continuously emerging from the casting gap in this way is drawn off below the casting rolls and fed to the roll gap of a rolling mill at a lower level for further processing.

[0004] Other conventional casting and rolling plants with associated processes for producing steel strip are known, for example, from EP 2162251 B1 or CN 112522575 A. i A conventional casting and rolling plant according to the prior art is shown in simplified form in the side view of Fig. 8, which is a typical production plant for steel strip. The height difference between the casting rolls of the twin roller and the floor of the rolling mill is, for example, 5000 mm.

[0005] Such a conventional plant according to Fig. 8 has the disadvantage that, with regard to the casting plant provided, the position of the axes of its casting rolls - viewed in the vertical direction - is always arranged considerably higher than a roll gap inlet of a rolling mill that is directly connected to the casting plant. As a result, the previous solutions have the disadvantage that, due to the different heights of the casting plant and the rolling mill, the costs for hall construction, foundations and the associated steel structures, e.g. for the erection of the continuous casting plant, represent a comparatively large factor for an investment in a new plant or an expansion of existing steelworks plants. The associated crane systems, lighting, ventilation, entrances and access routes for operating equipment are also adversely affected by the height structure and arrangement of plants.For the operating personnel (maintenance, repair and operation of the system), the use of necessary staircases, the use of decentralized control points and the restricted access routes for the delivery of operating resources due to the given height differences of the systems also represent a continuous hindrance to the work tasks at hand and lead to disadvantageously high operating costs.

[0006] Accordingly, the invention is based on the object of optimizing a casting-rolling plant and an associated method for producing a steel strip, thereby reducing both the required construction and manufacturing costs (CAPEX) of the entire plant and its ongoing operating costs (OPEX) for the production of steel strip. The above-mentioned object is achieved by a casting-rolling plant having the features of claims 1 and 2, respectively, and by a method specified by the features of claim 10. Advantageous developments of the invention are defined in the dependent claims.

[0007] A casting and rolling plant according to the present invention serves to produce a steel strip that passes through the casting and rolling plant in a conveying direction. Such a casting and rolling plant comprises a casting device designed as a two-roll casting device and correspondingly having two casting rolls, each of which is rotatably mounted about axes parallel to one another and aligned at the same height. A cast steel strip is produced by means of the two-roll casting device. A rolling stand arranged downstream of the casting device in the conveying direction is arranged for rolling the cast steel strip.

[0008] According to one embodiment of the invention, in such a casting-rolling plant, it is provided that the rolling stand is arranged relative to the casting device in such a way that a roll gap inlet of the rolling mill - viewed in the vertical direction - is located at the same height as or above the position of the axes of the casting rolls.

[0009] According to an alternative embodiment, such a casting and rolling plant provides that the rolling stand is arranged relative to the casting device such that a roll gap inlet of the rolling stand - viewed in the vertical direction - is located below it with respect to the position of the axes of the casting rolls, and the distance of the roll gap inlet from the position of the axes - viewed in the vertical direction - assumes a distance s that satisfies the following condition: s < (2 x D), where D denotes a diameter of a casting roll. Similarly, the invention also provides a method for producing a steel strip, which can be carried out using a casting and rolling plant as explained above. In any case, this method provides that a steel strip is cast by a casting device in the form of a two-roll casting device and is then moved in a conveying direction to a downstream rolling stand for rolling the cast steel strip.In this case, a loop formed by the cast steel strip between the casting device and the rolling stand is preferably adjusted in a controlled manner to a predetermined contour or position.

[0010] The invention is based on the essential finding that in a casting-rolling plant, the characteristic positioning or arrangement of a rolling stand provided directly after the casting device relative to the position of the axes of its casting rolls achieves that the resulting construction height of such a plant is advantageously reduced.

[0011] The method according to the invention is characterized in that for a loop formed by the cast steel strip between the casting device and the rolling stand, a predetermined contour or position is always achieved or set, in particular by a suitable adjustment or control of a rotational speed of the casting rolls and / or a rolling speed of the rolling stand, in order to thereby achieve both a high operational reliability of the system and a high production quality for the steel strip produced.

[0012] In an advantageous embodiment of the invention, the casting rolls are designed such that the width of the steel strip cast therewith is < 2,200 mm. In other words, a steel strip with a width of up to 2,200 mm can be cast using casting rolls designed in this way.

[0013] In an advantageous development of the invention, the casting rolls are designed such that their diameter is < 1,500 mm. In this context, it should be noted that the two casting rolls, which are part of a two-roll casting device, expediently have the same diameter.

[0014] In an advantageous development of the invention, a loop detection device is provided, by means of which the position of the cast steel strip and of a loop formed thereby, which is located between the casting device and the rolling stand, can be determined. Such a loop detection device comprises at least one contactless distance sensor, which can be designed in the form of a laser and / or a video camera. In any case, by means of such a loop detection device, it is possible, during operation of the casting-whitening system according to the invention or when carrying out the method according to the invention, to suitably detect or recognize the contour of a loop formed by the cast steel strip between the casting device and the rolling stand. As already explained elsewhere, a suitable adjustment orBy controlling a rotational speed of the casting rolls and / or a rolling speed of the rolling stand, a predetermined contour can be realized with respect to this loop.

[0015] In an advantageous development of the invention, a control unit is provided that is signal-connected to the loop detection device. The control unit is programmed in such a way that the rotational speed of the casting rolls and / or the rolling speed of the rolling stand can be controlled in such a way that the loop formed by the cast steel strip assumes a predetermined contour.

[0016] Taking into account the above-mentioned control unit, when carrying out the method according to the invention, it is achieved that, depending on the contour or position of the loop formed by the cast steel strip detected by the loop detection device, a rotational speed of the casting rolls and / or a rolling speed of the rolling stand are set or changed in a controlled manner, so that the resulting loop formed by the cast steel strip assumes a predetermined contour.

[0017] In an advantageous development of the method according to the invention, it can be provided that a rotational speed of the casting rolls about their axes is selected such that the resulting casting speed for the cast steel strip assumes a value between 20-100 m / min.

[0018] Further advantages of the present invention consist of the following aspects or features:

[0019] • Reduction in the construction and manufacturing costs of the systems, in particular by reducing the required hall height.

[0020] • Installation of the casting facility and a subsequent rolling mill on a common level, for example in the form of a steelworks corridor or a corresponding work platform, which reduces construction costs and also results in lower operating costs for subsequent use.

[0021] • Reduction in operating costs.

[0022] • If the production of liquid steel for supplying the casting facility in the form of the two-roller casting facility, e.g. via several smaller induction furnaces (preferably with a capacity of 5 - 10 t), the upstream area for the steel production process can also be lowered to a lower height level for the entire hall construction (steelworks, twin roller and rolling mill).

[0023] Embodiments of the invention are described in detail below with reference to a simplified schematic drawing. They show:

[0024] Fig. 1 schematically shows a casting-rolling plant for producing a steel strip according to a first embodiment of the invention, Fig. 2 schematically shows further details of the casting-rolling plant of Fig. 1, namely with regard to an arrangement of the associated casting device and a rolling stand arranged downstream in the conveying direction relative to each other,

[0025] Fig. 3 schematically shows the casting device of the plant of Fig. 1 for the production of a strip-shaped material from molten steel,

[0026] Fig. 4 shows schematically the arrangement of a casting device and a rolling stand arranged downstream in the conveying direction relative to each other for a casting-rolling plant according to a second embodiment of the invention,

[0027] Fig. 5 shows schematically the arrangement of a casting device and a rolling stand arranged downstream in the conveying direction relative to each other for a casting-rolling plant according to a third embodiment of the invention,

[0028] Fig. 6 shows schematically a loop detection device with which a casting-rolling plant according to the invention can be equipped, and

[0029] Fig. 7 schematically shows further details with regard to a possible supply of the casting device of a casting-rolling plant according to the invention with liquid steel.

[0030] Preferred embodiments of an apparatus 10 according to the invention and a corresponding method for producing a steel strip are explained below with reference to Figs. 1-7. Identical features in the drawings are provided with identical reference numerals. It is specifically noted that the drawings are merely simplified and, in particular, are not drawn to scale.

[0031] Fig. 1 shows schematically a side view of a casting-rolling plant 10 according to the invention, with which a steel strip 1 can be produced.

[0032] The casting and rolling plant 10 comprises a casting device 12, which is designed as a two-roll casting device and accordingly has two casting rollers 13. The casting rollers 13 are each rotatably mounted about axes (X1, X2) that are axially parallel to one another and aligned at the same height (see Fig. 3).

[0033] A casting gap G is formed between the casting rolls 13, which can be seen in the end view of the casting rolls 13 in Fig. 3. To provide a liquid steel melt, a ladle 2 and an intermediate container 3 are provided for the system 10 of Fig. 1, wherein liquid steel melt is introduced from above into the casting gap G via an outlet of the intermediate container 3. The liquid steel melt can then flow vertically downwards through this casting gap G to solidify into a cast steel strip 1.

[0034] Furthermore, the casting-rolling plant 10 comprises a rolling stand 14 arranged downstream of the casting device 12 in the conveying direction F for rolling the cast steel strip 1.

[0035] After exiting the casting gap G, the cast steel strip 1 is moved in a conveying direction through the casting and rolling plant 10. This conveying direction is symbolized in Fig. 1 by an arrow and designated "F".

[0036] Transport of the cast steel strip 1 through the rolling stand 14 is ensured by drivers T, which - seen in the conveying direction F - are arranged upstream and downstream of the rolling stand 14.

[0037] Downstream of the rolling stand 14, the casting-rolling plant 10 according to the invention is further equipped with a cooling section 24, at least one shear 26 and a final reel 28 on which the produced steel strip 1 can be wound in a known manner.

[0038] Between the casting device 12 and the rolling stand 14 arranged downstream of it in the conveying direction F, the casting-rolling plant 10 according to the invention has at least one turning roll 16. This turning roll 16 is arranged such that the cast steel strip 1 is deflected in the direction of the rolling stand 14.

[0039] The aforementioned turning roll 16 is important in that the cast steel strip 1, after it has emerged vertically downwards from the casting gap G, initially takes on the shape of a loop 19, which is formed by the cast steel strip 1 between the casting device 12 and the rolling stand 14. This loop 19 is then deflected horizontally in a controlled manner towards the rolling mill 14 by means of the turning roll 16. It is important here that the turning roll 16 is located approximately at the same height as a roll gap inlet of the rolling stand 14, so that with the help of the turning roll 16, a horizontal running of the steel strip 1 into the roll gap inlet of the rolling stand 14 is possible.

[0040] With regard to the casting-rolling plant 10 according to the invention, it should be emphasized that its essential components are formed by the casting device 12 and the downstream rolling stand 14. Of key importance to the present invention—viewed in the vertical direction—is the arrangement of the casting device 12 and the rolling stand 14 relative to one another. This is explained in detail below with reference to Figures 2, 4, and 5.

[0041] Fig. 2 illustrates an arrangement of the casting device 12 and the rolling stand 14 relative to one another, according to a first embodiment of the invention. The casting device 12 and the rolling stand 14 are each attached or set up on a common metallurgical floor H (or a comparable area). The axes X1, X2 of the casting rolls 13 are spaced from the metallurgical floor H by a distance a, with a roll gap inlet 15 of the rolling stand 14 being spaced from the metallurgical floor by a distance b. In the first embodiment according to Fig. 2, the two distances a and b each assume the same value, ie the axes X1, X2 of the two casting rolls 13 on the one hand and the roll gap inlet 15 of the rolling stand 14 are each the same distance orabove the mill floor H, it is achieved that the roll gap inlet 15 of the rolling mill 14 - viewed in the vertical direction - is at the same height with respect to the position of the axes X1, X2 of the casting rolls 13. It is also important here that the turning roll 16, as already explained, is located approximately at the same height as the roll gap inlet 15 of the rolling mill 14. With respect to the axes X1, X2 of the casting rolls 13 and the roll gap of the rolling stand 14, an equal level is thus achieved - viewed in the vertical direction.

[0042] Fig. 4 illustrates an arrangement of the casting device 12 and the rolling stand 14 relative to one another, according to a second embodiment of the invention. Here, the distance a, by which the axes X1, X2 of the casting rolls 13 are spaced from the mill floor H, is selected to be greater than the distance b, by which the roll gap inlet 15 of the rolling stand 14 is spaced from the mill floor H. As a result, the roll gap inlet 15 of the rolling stand 14 is located—viewed in the vertical direction—below the position of the axes X1, X2 of the casting rolls 13. This, in turn, has the consequence that the distance of the roll gap inlet 15 from the position of the axes X1, X2—viewed in the vertical direction—assumes a distance s that satisfies the following condition: s < (2 x D), where D = diameter of a casting roll 13.

[0043] The diameter of a casting roll is illustrated in Fig. 3. In the illustration of the second embodiment according to Fig. 4, the distance s is approximately half the diameter of a casting roll, i.e., s = 0.5 x D. Important for this second embodiment is that the arrangement of the casting device 12 and the rolling stand 14 relative to each other is selected such that the distance s, as explained, does not exceed twice the diameter of a casting roll 13.

[0044] Fig. 5 illustrates an arrangement of the casting device 12 and the rolling stand 14 relative to one another, according to a third embodiment of the invention. Here, the distance a, by which the axes X1, X2 of the casting rolls 13 are spaced from the mill floor H, is selected to be smaller than the distance b, by which the roll gap inlet 15 of the rolling stand 14 is spaced from the mill floor H. As a result, the roll gap inlet 15 of the rolling stand 14 is located—viewed in the vertical direction—above the position of the axes X1, X2 of the casting rolls 13.

[0045] At this point, it is specifically pointed out that in the second and third embodiments in Figs. 4 and 5, both the complete loop 19 of the cast steel strip 1 and the turning roller 16 are not shown to simplify the illustration.

[0046] With regard to the above-mentioned first, second, and third embodiments of the casting-rolling plant 10 according to the invention, it is specifically noted at this point that the characteristic arrangement of the casting device 12 and the rolling stand 14 relative to one another results in a reduction in the height difference (cf. Fig. 2) or even a complete elimination (cf. Fig. 2) of this height difference between the axes of rotation of the casting rolls 13 and the roll gap inlet of the downstream rolling stand 14. This advantageously results in a lower overall height for the casting-rolling plant 10 and a smaller vertical distance between the casting device 12 and the rolling stand 14 and a common steelworks floor H. As already explained at the beginning, this can reduce the required hall height and further reduce construction costs for the casting-rolling plant 10.

[0047] In Figs. 6 and 7, further options are shown and explained which can be provided in the same way in the first, second and third embodiments of the casting-rolling plant 10 according to the invention.

[0048] According to the illustration in Fig. 6, a loop detection device 18 is preferably arranged adjacent to an underside of the casting device 12, by means of which a position of the cast steel strip 1 and the loop 19 formed thereby, which is located between the casting device 12 and the rolling stand 14, can be determined. Such a loop detection device 18 comprises at least one contactless distance sensor 20, which can be designed in the form of a laser and / or a video camera.

[0049] In conjunction with the loop detection device 18, the casting-rolling plant 10 according to Fig. 6 is further equipped with a control unit R, which is signal-connected to the loop detection device 18. Accordingly, by means of the control unit R and depending on the contour or position of the loop 19 formed by the cast steel strip 1 detected by the loop detection device 18, it is possible to adjust or change a rotational speed of the casting rolls 13 and / or a rolling speed of the rolling stand 14 in a controlled manner such that the resulting loop 19 formed by the cast steel strip 1 assumes a predetermined contour.

[0050] According to the illustration in Fig. 7, instead of a ladle 1, it is possible that - viewed in the conveying direction F - upstream of the casting device 12 through at least one induction furnace 22. In such an induction furnace 22, starting material 4, for example scrap, is heated and melted. The steel melt 5 thus formed is then suitably fed from above into the casting gap G formed between the two casting rollers 13 of the

[0051] Pouring device 12 is introduced.

[0052] The illustration in Fig. 7 shows two such induction furnaces 22, with which, as explained, a steel melt can be provided or generated for the casting device 12. Alternatively to the illustration in Fig. 7, only one induction furnace 22 can be provided. Regardless of the number of such induction furnaces 22, it should be emphasized for the present invention that this achieves a further advantageous reduction in the overall height of the casting-rolling plant 10 or its height level above a steelworks floor H or the like.

[0053] List of reference symbols

[0054] 1 steel band

[0055] 2 pans

[0056] 3 intermediate containers

[0057] 4 Source material

[0058] 5 steel melt

[0059] 10 Casting and rolling plant

[0060] 12 Pouring device

[0061] 13 Casting roller

[0062] 14 rolling stand

[0063] 15 Roll gap inlet

[0064] 16 turning roll

[0065] 18 Loop detection device

[0066] 19 Loop (formed by a cast steel band 1 )

[0067] 20 contactless distance sensors

[0068] 21 Signal path

[0069] 22 Induction furnace

[0070] 24 cooling section

[0071] 26 scissors

[0072] 28 reels

[0073] D Diameter (of a casting roll 13)

[0074] F Conveying direction

[0075] G casting gap

[0076] H Hut corridor

[0077] R Control unit s Distance or distance - seen in vertical direction - between

[0078] Roll gap inlet 15 and axis (X1, X2) of a casting roll 13

[0079] T Driver

[0080] X1 , X2 axis (of a casting roller 13)

Claims

Patent claims 1. A casting and rolling plant (10) for producing a steel strip (1) which passes through the casting and rolling plant (10) in a conveying direction (F), comprising a casting device (12) which is designed in the form of a two-roll casting device (12) and accordingly has two casting rolls (13) which are each rotatably mounted about axes (X1, X2) aligned parallel to each other and at the same height, wherein a cast steel strip (1) is produced by means of the two-roll casting device (12), and a rolling stand (14) downstream of the casting device (12) in the conveying direction (F) for rolling the cast steel strip (1), characterized in that the rolling stand (14) is arranged relative to the casting device (12) such that a roll gap entry (15) of the rolling mill (14) – viewed in the vertical direction – is aligned with respect to the position of the axes (X1, X2) of the casting rollers (13) is at the same level or above it.

2. Casting and rolling plant (10) for producing a steel strip (1) which passes through the casting and rolling plant (10) in a conveying direction (F), comprising a casting device (12) which is designed in the form of a two-roll casting device (12) and accordingly has two casting rolls (13) which are each rotatably mounted about axes (X1, X2) aligned parallel to each other and at the same height, wherein a cast steel strip (1) is produced by means of the two-roll casting device (12), and a rolling stand (14) downstream of the casting device (12) in the conveying direction (F) for rolling the cast steel strip (1), characterized in that the rolling stand (14) is arranged relative to the casting device (12) such that a roll gap entry (15) of the rolling stand (14) – viewed in the vertical direction – is aligned with respect to the position of the axes (X1, X2). X2) the Casting rollers (13) are located below it and the distance of the roll gap inlet (15) from the position of the axes (X1 , X2) - seen in the vertical direction - assumes a distance s which satisfies the following condition: s < (2 x D), with D = diameter of a casting roller (13).

3. Casting and rolling plant (10) according to claim 1 or 2, characterized in that at least one turning roller (16) is arranged between the casting device (12) and the rolling stand (14) downstream in the conveying direction (F), with which the cast steel strip (1) can be deflected in the direction of the rolling stand (14).

4. Casting and rolling plant (10) according to one of the preceding claims, characterized in that the casting rollers (13) are designed such that the width of the steel strip (1) cast therein is < 2,200 mm.

5. Casting and rolling plant (10) according to one of the preceding claims, characterized in that the diameter of the casting rollers (13) is < 1,500 mm.

6. Casting and rolling plant (10) according to one of the preceding claims, characterized by a loop detection device (18) by means of which a position of the cast steel strip (1) and a loop (19) formed therein, which is located between the casting device (12) and the rolling stand (14), can be determined.

7. Casting and rolling plant (10) according to claim 6, characterized in that the loop detection device (18) has at least one non-contact The distance sensor (20) preferably comprises a laser and / or a video camera. The casting and rolling plant (10) according to claim 6 or 7 is characterized by a control unit (R) that is connected to the loop detection device (18) via a signal, wherein the control unit (R) is programmed such that the rotational speed of the casting rolls (13) and / or the rolling speed of the rolling stand (14) can be controlled such that the loop (19) formed by the cast steel strip (1) assumes a predetermined contour. The casting and rolling plant (10) according to one of the preceding claims is characterized by at least one induction furnace (22), which is preferably arranged above the casting device (12) and serves to feed molten steel into a casting gap (G) formed between the casting rolls (13).A method for producing a steel strip, particularly with a casting-rolling plant (10) according to any one of claims 1 to 9, in which a steel strip (1) is cast by a casting device (12) in the form of a two-roll casting device (12) and subsequently moved in a conveying direction (F) to a downstream rolling stand (14) for rolling the cast steel strip (1), characterized in that a loop (19) formed by the cast steel strip (1) between the casting device (12) and the rolling stand (14) is preferably controlled and adjusted to a predetermined contour or position. A method according to claim 10, characterized in that the loop (19) formed by the cast steel strip (1) is adjusted to a predetermined contour or position. A predetermined contour, a rotational speed of the casting rolls (13) and / or a rolling speed of the rolling stand (14) are changed. A method according to claim 10 or 11, characterized in that a loop detection device (18) detects the contour of the loop (19) formed by the cast steel strip (1). A method according to claim 12, characterized by a control unit (R) that is connected to the loop detection device (18) via a signal, wherein, by means of the control unit (R) and depending on the contour or position of the loop (19) formed by the cast steel strip (1) detected by the loop detection device (18), a rotational speed of the casting rolls (13) and / or a rolling speed of the rolling stand (14) are controlled, set, or changed such that the resulting loop (19) formed by the cast steel strip (1) assumes a predetermined contour.Method according to one of claims 10 to 13, characterized in that the rotational speed of the casting rollers (13) about their axes (X1 , X2) is selected such that the resulting casting speed for the cast steel strip (1 ) assumes a value between 20-100 m / min.

Images